Pub Date : 2024-11-20DOI: 10.1094/PDIS-08-24-1787-RE
Yan Du, Jun Yang, Zhongqiang Qi, Junjie Yu, Rongsheng Zhang, Mina Yu, Huijuan Cao, Tianqiao Song, Xiayan Pan, Shuchen Wang, Qin Xiong, Yongfeng Liu
Rice blast, caused by Pyricularia oryzae, is one of the most destructive fungal diseases in rice, severely impacting rice production worldwide every year. Rapid, accurate and visual detection of P. oryzae is essential for more effective prevention and control. In this study, we developed a recombinase polymerase amplification-lateral flow dipstick (RPA-LFD) assay to detect P. oryzae. Species-specific RPA primer pairs and probe were designed based on target gene MGG_15975. The optimized reaction temperature and time were set at 37 °C and 25 min, respectively. Specificity analysis showed that the assay could specifically detect P. oryzae isolates from rice, whereas other fungal species or Pyricularia species from grasses were not detected. Additionally, this assay demonstrated highly sensitivity, capable of detecting as low as 10-2 ng/µL of P. oryzae genomic DNA, which was found to be 100 times more sensitive than conventional PCR. Furthermore, using this assay, P. oryzae was effectively detected in diseased leaves in rice fields, and could also be identified at an early stage of infection before obvious lesions appeared in artificially inoculated rice seedlings. Therefore, the RPA-LFD assay developed in our study for the detection of P. oryzae is rapid, highly sensitive and efficient, which has the potential application for early diagnosis of P. oryzae infection in rice fields.
由稻瘟病菌（Pyricularia oryzae）引起的稻瘟病是水稻中最具破坏性的真菌病害之一，每年都会严重影响世界各地的水稻产量。要想更有效地防控稻瘟病，就必须对稻瘟病菌进行快速、准确和直观的检测。在这项研究中，我们开发了一种重组酶聚合酶扩增-侧流浸量尺（RPA-LFD）检测方法来检测 P. oryzae。根据目标基因 MGG_15975 设计了物种特异性 RPA 引物对和探针。优化的反应温度和时间分别设定为 37 °C 和 25 分钟。特异性分析表明，该检测方法可特异性检测水稻中分离出的 P. oryzae，而检测不到其他真菌或禾本科植物中分离出的 Pyricularia。此外，该检测方法灵敏度高，能检测到低至 10-2 ng/µL 的 P. oryzae 基因组 DNA，灵敏度是传统 PCR 的 100 倍。此外，利用该检测方法，还能有效地在稻田的病叶中检测到 P. oryzae，并能在人工接种的水稻秧苗出现明显病变之前的早期感染阶段识别出 P. oryzae。因此，本研究开发的 RPA-LFD 检测方法具有快速、高灵敏度和高效率的特点，可用于水稻田 P. oryzae 感染的早期诊断。
{"title":"Rapid and visual detection of <i>Pyricularia oryzae</i> using coupled recombinase polymerase amplification-lateral flow dipstick assay.","authors":"Yan Du, Jun Yang, Zhongqiang Qi, Junjie Yu, Rongsheng Zhang, Mina Yu, Huijuan Cao, Tianqiao Song, Xiayan Pan, Shuchen Wang, Qin Xiong, Yongfeng Liu","doi":"10.1094/PDIS-08-24-1787-RE","DOIUrl":"https://doi.org/10.1094/PDIS-08-24-1787-RE","url":null,"abstract":"<p><p>Rice blast, caused by Pyricularia oryzae, is one of the most destructive fungal diseases in rice, severely impacting rice production worldwide every year. Rapid, accurate and visual detection of P. oryzae is essential for more effective prevention and control. In this study, we developed a recombinase polymerase amplification-lateral flow dipstick (RPA-LFD) assay to detect P. oryzae. Species-specific RPA primer pairs and probe were designed based on target gene MGG_15975. The optimized reaction temperature and time were set at 37 °C and 25 min, respectively. Specificity analysis showed that the assay could specifically detect P. oryzae isolates from rice, whereas other fungal species or Pyricularia species from grasses were not detected. Additionally, this assay demonstrated highly sensitivity, capable of detecting as low as 10-2 ng/µL of P. oryzae genomic DNA, which was found to be 100 times more sensitive than conventional PCR. Furthermore, using this assay, P. oryzae was effectively detected in diseased leaves in rice fields, and could also be identified at an early stage of infection before obvious lesions appeared in artificially inoculated rice seedlings. Therefore, the RPA-LFD assay developed in our study for the detection of P. oryzae is rapid, highly sensitive and efficient, which has the potential application for early diagnosis of P. oryzae infection in rice fields.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MicroRNAs (miRNAs) have been confirmed to play important roles in plant defense response. However, the key maize miRNAs involved in the defense response against Bipolaris maydis are very limited. In this study, a novel member of the miR169 family in response to B. maydis, named zma-miR169s, was discovered and investigated. The expression levels of pre-miR169s and zma-miR169s were significantly repressed during B. maydis infection. The CRISPR/Cas9-induced zma-miR169s mutant exhibited more resistance against B. maydis, whereas overexpression of zma-miR169s enhanced susceptibility, supporting that zma-miR169s might play a negative role in maize resistance. Moreover, RNA-seq and Gene Ontology analysis showed that differentially expressed genes were highly enriched in the oxidation-reduction process and plant hormone pathway. Hence, reactive oxygen species (ROS) and plant hormone levels were further investigated. ROS detection confirmed that the zma-miR169s mutant accumulated more ROS, while less ROS was detected in transgenic maize OE-miR169s. Furthermore, more remarkable changes in PR-1 expression levels and salicylic acid (SA) contents were detected in the zma-miR169s mutant compared with wild-type and transgenic maize during B. maydis infection. Additionally, nuclear transcription factors (NF-YA1 and NF-YA13) were identified as targets regulated by zma-miR169s through the agrobacterium-mediated transient expression method. Overexpression of ZmNF-YA13 enhanced Arabidopsis resistance to Pseudomonas syringae pv. tomato DC3000. Taken together, our results suggest that zma-miR169s negatively regulates maize defense responses by influencing ROS accumulation and the SA-dependent signaling pathway.
微RNA（miRNA）已被证实在植物防御反应中发挥重要作用。然而，参与玉米对 Bipolaris maydis 的防御反应的关键 miRNA 非常有限。在这项研究中，发现并研究了miR169家族中对B. maydis有响应的一个新成员，命名为zma-miR169s。在 B. maydis 感染期间，pre-miR169s 和 zma-miR169s 的表达水平被显著抑制。CRISPR/Cas9诱导的zma-miR169s突变体对B. maydis表现出更强的抗性，而过表达zma-miR169s则会增强易感性，这证明zma-miR169s可能在玉米抗性中起负作用。此外，RNA-seq 和 GO 分析表明，差异表达基因高度富集于氧化还原过程和植物激素途径。因此，对活性氧（ROS）和植物激素水平进行了进一步研究。ROS 检测证实，zma-miR169s 突变体积累了更多的 ROS，而在转基因玉米 OE-miR169s 中检测到的 ROS 较少。此外，与野生型玉米和转基因玉米相比，zma-miR169s 突变体的 PR-1 表达水平和水杨酸（SA）含量在 B. maydis 感染期间发生了更显著的变化。此外，通过农杆菌介导的瞬时表达方法，发现核转录因子（NF-YA1 和 NF-YA13）是受 zma-miR169s 调控的靶标。ZmNF-YA13的过表达增强了拟南芥对西红柿假单胞菌DC3000的抗性。综上所述，我们的研究结果表明，zma-miR169s 通过影响 ROS 积累和 SA 依赖性信号通路来负向调节玉米的防御反应。
{"title":"A Novel Member of miR169 Family Negatively Regulates Maize Resistance Against <i>Bipolaris maydis</i>.","authors":"Shanshan Xie, Han Li, Jiale Lu, Jing Li, Zheng Song, Haiyang Jiang","doi":"10.1094/PDIS-02-24-0398-RE","DOIUrl":"10.1094/PDIS-02-24-0398-RE","url":null,"abstract":"<p><p>MicroRNAs (miRNAs) have been confirmed to play important roles in plant defense response. However, the key maize miRNAs involved in the defense response against <i>Bipolaris maydis</i> are very limited. In this study, a novel member of the miR169 family in response to <i>B. maydis</i>, named zma-miR169s, was discovered and investigated. The expression levels of pre-miR169s and zma-miR169s were significantly repressed during <i>B. maydis</i> infection. The CRISPR/Cas9-induced zma-miR169s mutant exhibited more resistance against <i>B</i>. <i>maydis</i>, whereas overexpression of zma-miR169s enhanced susceptibility, supporting that zma-miR169s might play a negative role in maize resistance. Moreover, RNA-seq and Gene Ontology analysis showed that differentially expressed genes were highly enriched in the oxidation-reduction process and plant hormone pathway. Hence, reactive oxygen species (ROS) and plant hormone levels were further investigated. ROS detection confirmed that the zma-miR169s mutant accumulated more ROS, while less ROS was detected in transgenic maize OE-miR169s. Furthermore, more remarkable changes in <i>PR-1</i> expression levels and salicylic acid (SA) contents were detected in the zma-miR169s mutant compared with wild-type and transgenic maize during <i>B. maydis</i> infection. Additionally, nuclear transcription factors (<i>NF-YA1</i> and <i>NF-YA13</i>) were identified as targets regulated by zma-miR169s through the agrobacterium-mediated transient expression method. Overexpression of <i>ZmNF-YA13</i> enhanced <i>Arabidopsis</i> resistance to <i>Pseudomonas syringae</i> pv. <i>tomato</i> DC3000. Taken together, our results suggest that zma-miR169s negatively regulates maize defense responses by influencing ROS accumulation and the SA-dependent signaling pathway.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS02240398RE"},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141564061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1094/PDIS-07-24-1564-PDN
Jin Li, Mingyue Wu, Jixing Xia, Youjun Zhang, Wen Xie
<p><p>Vigna unguiculata (L.) Walp. (cowpea) is an important economic vegetable in Sanya, Hainan Province, China. But it is easily infected by various viral diseases, especially cowpea mild mottle virus (CPMMV), bean common mosaic virus (BCMV) and cowpea polevirus 2 (CPPV2), causing symptoms such as yellowing, dwarfism and mosaic of leaves, affecting photosynthesis of cowpea. Weeds are perfect intermediate hosts for crop viruses. In the cowpea fields of Sanya, there are a large number of weeds growing nearby, including Sesbania cannabina (Retz.) Poir. and Physalis angulata (L.). S. cannabina, a species of legume, has high nutritional value as the one of the most admired green-manuring plants widely used in crop field for gaining yield and decreasing the quantity of chemical fertilizer (Tiwari et al. 2004). P. angulata, commonly known as husk tomato, is an annual Solanaceaea vegetable crop grown for its fruits (Ramakrishna Pillai et al. 2022). In July 2022, S. cannabina and P. angulata surrounding one hectare of cowpea fields of Sanya with chlorotic and asymptomatic (Figure S1) were collected, and then their total RNAs were individually extracted by the TRIzol Reagent (Life, USA), and two cDNA libraries (one including the RNA samples of S. cannabina, another including the RNA sample of P. angulata) were subsequently constructed using VAHTS Universal V8 RNA-seq Library Prep Kit (Vazyme, China). High-throughput sequencing was performed on a DNBSEQ-T7 platform (BGI, China) with the 150 bp paired-end method. A total of 40,134,299 and 149,473,308 clean reads were de novo assembled by SPAdes 3.15.5 to generate contigs, followed by BLAST-x/n search in viral genomes in GenBank. From the RNA-seq library of S. cannabina, we identified one contig (6255 nt) that exhibited 96.45% nucleotide identity to the CPMMV isolate CPMMV-JS (MT366555), covering 6033 bp out of 6255 bp (6033/6255) of the contig. Additionally, we found seven contigs (ranging in length from 1870 nt to 8336 nt) in the RNA-seq library of P. angulata that showed 78.92% to 84.15% nucleotide identity to the CPMMV isolate Brunt (OK558693), with specific alignment lengths varying from 669/795 to 4244/5337. CPMMV was verified by reverse transcription - polymerase chain reaction (RT-PCR) detection using specific primer (F: 5'-CTGGCCAAGTGGTTTGTTTT-3', R: 5'- AACCGGGTTTACAATCCACA -3') (Wei et al. 2020). PCR products were extracted from an agarose gel, cloned into the pMD19-T Vector (Takara, China), and transformed into Escherichia coli DH5α cells (Sangon Biotech, Shanghai). Two clones for each PCR product were sequenced by Sanger sequencing. The amplified 1865 bp fragments of S. cannabina (PP790744) and P. angulata (PP790743) had 98.07% identity (1727 bp out to 1761 bp) and 97.92% sequence identity (1739 bp out to 1776 bp) to CPMMV-JS (MT366555). Afterwards, we collected S. cannabina and P. angulata with similar symptoms around two cowpea fields (each field covers an area of about one hectare) in three d
豇豆（Vigna unguiculata (L.) Walp.）是中国海南省三亚市的一种重要经济蔬菜。但它很容易感染各种病毒病，尤其是豇豆轻度斑驳病毒（CPMMV）、豆类普通花叶病毒（BCMV）和豇豆细小病毒 2（CPPV2），导致叶片黄化、矮化和马赛克等症状，影响豇豆的光合作用。杂草是作物病毒的理想中间宿主。三亚的豇豆田附近生长着大量杂草，包括 Sesbania cannabina (Retz.) Poir.和 Physalis angulata (L.)。S. cannabina 是豆科植物的一种，具有很高的营养价值，是最受推崇的绿肥植物之一，被广泛用于农田，以提高产量和减少化肥用量（Tiwari 等人，2004 年）。P. angulata，俗称壳番茄，是一年生茄科蔬菜作物，因其果实而被种植（Ramakrishna Pillai 等人，2022 年）。2022年7月，采集了三亚一公顷豇豆田周围的S. cannabina和P. angulata（图S1），分别用TRIzol试剂（美国Life公司）提取它们的总RNA，然后用VAHTS Universal V8 RNA-seq文库制备试剂盒（中国Vazyme公司）构建了两个cDNA文库（一个包括S. cannabina的RNA样本，另一个包括P. angulata的RNA样本）。高通量测序在 DNBSEQ-T7 平台（BGI，中国）上以 150 bp 成对端方法进行。用SPAdes 3.15.5对40,134,299和149,473,308条纯净读数进行从头组装，生成等位基因，然后用BLAST-x/n检索GenBank中的病毒基因组。从 S. cannabina 的 RNA-seq 文库中，我们发现一个等位基因（6255 nt）与 CPMMV 分离物 CPMMV-JS (MT366555)有 96.45% 的核苷酸相同性，覆盖了等位基因 6255 bp 中的 6033 bp（6033/6255）。此外，我们还在 P. angulata 的 RNA-seq 文库中发现了 7 个等位基因（长度从 1870 nt 到 8336 nt 不等），它们与 CPMMV 分离物 Brunt (OK558693) 的核苷酸同一性为 78.92% 到 84.15%，比对长度从 669/795 到 4244/5337 不等。使用特异引物（F：5'-CTGGCCAAGTGGTTTGTT-3'，R：5'-AACCGGTTTACAATCCACA -3'）通过反转录聚合酶链反应（RT-PCR）检测 CPMMV（Wei 等，2020 年）。从琼脂糖凝胶中提取 PCR 产物，克隆到 pMD19-T 载体（Takara，中国）中，然后转化到大肠杆菌 DH5α 细胞（上海生工生物技术有限公司）中。对每个 PCR 产物的两个克隆进行 Sanger 测序。扩增出的 cannabina S. （PP790744）和 angulata P. （PP790743）的 1865 bp 片段与 CPMMV-JS （MT366555）的序列同一性分别为 98.07%（1727 bp 至 1761 bp）和 97.92%（1739 bp 至 1776 bp）。随后，我们在三亚市崖州、天涯、海棠三个区的两块豇豆田（每块田面积约一公顷）周围采集了症状相似的S. cannabina和P. angulata，并进行了CPMMV检测。我们发现在所有六个样本中都检测到了 CPMMV。CPMMV 包括 Carlavirus 属和 Betaflexiviridae 科，于 20 世纪 70 年代首次在加纳的豇豆上发现。从那时起，它就被证明具有非常广泛的地理分布和广泛的自然宿主范围。CPMMV 主要感染豆科植物，也能感染茄科、夜交藤科、绣线菊科、菊科和杓兰科植物的寄主（Celli 等，2016 年；Lamas 等，2017 年；Zanardo 和 Carvalho，2017 年）。据我们所知，这是 CPMMV 自然感染 S. cannabina 和 P. angulata 的首次报道，它们可能代表了该地区该病毒的其他储库。同时，调查 S. cannabina 和 P. angulata 中的 CPMMV 对于制定综合战略以防止其传播给豇豆等具有重要经济价值的植物至关重要。
{"title":"First report of natural infection by cowpea mild mottle virus on <i>Sesbania cannabina</i> and <i>Physalis angulata</i> in China.","authors":"Jin Li, Mingyue Wu, Jixing Xia, Youjun Zhang, Wen Xie","doi":"10.1094/PDIS-07-24-1564-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1564-PDN","url":null,"abstract":"<p><p>Vigna unguiculata (L.) Walp. (cowpea) is an important economic vegetable in Sanya, Hainan Province, China. But it is easily infected by various viral diseases, especially cowpea mild mottle virus (CPMMV), bean common mosaic virus (BCMV) and cowpea polevirus 2 (CPPV2), causing symptoms such as yellowing, dwarfism and mosaic of leaves, affecting photosynthesis of cowpea. Weeds are perfect intermediate hosts for crop viruses. In the cowpea fields of Sanya, there are a large number of weeds growing nearby, including Sesbania cannabina (Retz.) Poir. and Physalis angulata (L.). S. cannabina, a species of legume, has high nutritional value as the one of the most admired green-manuring plants widely used in crop field for gaining yield and decreasing the quantity of chemical fertilizer (Tiwari et al. 2004). P. angulata, commonly known as husk tomato, is an annual Solanaceaea vegetable crop grown for its fruits (Ramakrishna Pillai et al. 2022). In July 2022, S. cannabina and P. angulata surrounding one hectare of cowpea fields of Sanya with chlorotic and asymptomatic (Figure S1) were collected, and then their total RNAs were individually extracted by the TRIzol Reagent (Life, USA), and two cDNA libraries (one including the RNA samples of S. cannabina, another including the RNA sample of P. angulata) were subsequently constructed using VAHTS Universal V8 RNA-seq Library Prep Kit (Vazyme, China). High-throughput sequencing was performed on a DNBSEQ-T7 platform (BGI, China) with the 150 bp paired-end method. A total of 40,134,299 and 149,473,308 clean reads were de novo assembled by SPAdes 3.15.5 to generate contigs, followed by BLAST-x/n search in viral genomes in GenBank. From the RNA-seq library of S. cannabina, we identified one contig (6255 nt) that exhibited 96.45% nucleotide identity to the CPMMV isolate CPMMV-JS (MT366555), covering 6033 bp out of 6255 bp (6033/6255) of the contig. Additionally, we found seven contigs (ranging in length from 1870 nt to 8336 nt) in the RNA-seq library of P. angulata that showed 78.92% to 84.15% nucleotide identity to the CPMMV isolate Brunt (OK558693), with specific alignment lengths varying from 669/795 to 4244/5337. CPMMV was verified by reverse transcription - polymerase chain reaction (RT-PCR) detection using specific primer (F: 5'-CTGGCCAAGTGGTTTGTTTT-3', R: 5'- AACCGGGTTTACAATCCACA -3') (Wei et al. 2020). PCR products were extracted from an agarose gel, cloned into the pMD19-T Vector (Takara, China), and transformed into Escherichia coli DH5α cells (Sangon Biotech, Shanghai). Two clones for each PCR product were sequenced by Sanger sequencing. The amplified 1865 bp fragments of S. cannabina (PP790744) and P. angulata (PP790743) had 98.07% identity (1727 bp out to 1761 bp) and 97.92% sequence identity (1739 bp out to 1776 bp) to CPMMV-JS (MT366555). Afterwards, we collected S. cannabina and P. angulata with similar symptoms around two cowpea fields (each field covers an area of about one hectare) in three d","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1094/PDIS-07-24-1385-PDN
Min-Hye Jeong, Jiwon Park, Eu Ddeum Choi, Sook-Young Park
<p><p>Hydragea (Hydrangea macrophylla) is a garden plant commonly used in parks and landscapes globally. In late May 2023, brown necrotic spots surrounded by chlorotic halos were observed on the leaves of H. macrophylla (cv. Renate Steiniger) at the Suncheonman National Garden in Suncheon (34°55'45.6" N 127°30'26.5" E), South Korea. The affected area covered approximately 20 m2, with the disease incidence ranging from 2% to 5%. Concentric rings with light brown centers measuring 0.5 to 6 cm were observed on the upper sides of the leaves. To isolate the pathogens, each infected leaf from three different plants was cut into 5 × 5 mm pieces, surface-sterilized with 70% ethanol for 1 min, and rinsed three times with sterile distilled water. The samples were cultured on 1.5% water agar amended with 100 μg/mL of streptomycin in the dark at 25 °C. Single-spore isolation from the grown hyphae was performed on the obtained isolates (SYP-1229 to 1231). The fungal colony on potato dextrose agar was olivaceous gray with floccose aerial mycelia, and black pycnidia developed on the medium after 14 days. The conidia observed were hyaline, cylindrical to ellipsoidal-oblong, and aseptate, measuring 4.9 to 9.1 μm × 1.9 to 4.2 μm (avg. 6.3 × 2.7 μm, n = 100) (length × width). The isolates were identified as Boeremia sp. based on their morphological characteristics (Boerema, 1976; Boerema, 2004). For molecular identification, the internal transcribed spacer (GenBank accession nos.: OR682193-OR682195), actin (OR689851- OR689853), β-tubulin (OR689854- OR689856) and translation elongation factor-1 alpha (OR689857- OR689859) sequences from the isolates SYP-1229 to 1231 exhibited 100% (558/558 bp), 100% (263/263), 100% (314/314), and 100% (316/316) similarity, respectively, with Boeremia exigua (EU167567, EU880846, OP611549, and KY484684, respectively) in GenBank BLAST search. Phylogenetics based on concatenated ITS, ACT, TUB2, and TEF sequences, using the maximum likelihood method of MEGA X (Kumar et al., 2018), showed that sequences of SYP-1229 to 1231 were clustered in the same clade as B. exigua. For pathogenicity tests conducted in pots, 10 mL conidial suspension (1 × 106 conidia/mL) derived from isolate SYP-1229, which had been cultured on PDA for 14 days, was sprayed onto two leaves of each of three independent healthy 1-year-old hydrangeas (cv. Renate Steiniger). The leaves of the control plants were inoculated with sterile distilled water, which was also applied to two leaves of each of the three independent healthy plants. The inoculated plants were placed in clear plastic boxes to maintain high humidity and incubated at 25 °C under 18 h of light. Brown spot lesions were observed on the inoculated two leaves seven days after inoculation, whereas the control were asymptomatic. Similar pathogenicity results were obtained for all three independent biological replicates. The fungus isolated from the lesion was identified as B. exigua through morphological character
{"title":"First Report of Leaf Spot on <i>Hydrangea macrophylla</i> Caused by <i>Boeremia exigua</i> in Korea.","authors":"Min-Hye Jeong, Jiwon Park, Eu Ddeum Choi, Sook-Young Park","doi":"10.1094/PDIS-07-24-1385-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1385-PDN","url":null,"abstract":"<p><p>Hydragea (Hydrangea macrophylla) is a garden plant commonly used in parks and landscapes globally. In late May 2023, brown necrotic spots surrounded by chlorotic halos were observed on the leaves of H. macrophylla (cv. Renate Steiniger) at the Suncheonman National Garden in Suncheon (34°55'45.6\" N 127°30'26.5\" E), South Korea. The affected area covered approximately 20 m2, with the disease incidence ranging from 2% to 5%. Concentric rings with light brown centers measuring 0.5 to 6 cm were observed on the upper sides of the leaves. To isolate the pathogens, each infected leaf from three different plants was cut into 5 × 5 mm pieces, surface-sterilized with 70% ethanol for 1 min, and rinsed three times with sterile distilled water. The samples were cultured on 1.5% water agar amended with 100 μg/mL of streptomycin in the dark at 25 °C. Single-spore isolation from the grown hyphae was performed on the obtained isolates (SYP-1229 to 1231). The fungal colony on potato dextrose agar was olivaceous gray with floccose aerial mycelia, and black pycnidia developed on the medium after 14 days. The conidia observed were hyaline, cylindrical to ellipsoidal-oblong, and aseptate, measuring 4.9 to 9.1 μm × 1.9 to 4.2 μm (avg. 6.3 × 2.7 μm, n = 100) (length × width). The isolates were identified as Boeremia sp. based on their morphological characteristics (Boerema, 1976; Boerema, 2004). For molecular identification, the internal transcribed spacer (GenBank accession nos.: OR682193-OR682195), actin (OR689851- OR689853), β-tubulin (OR689854- OR689856) and translation elongation factor-1 alpha (OR689857- OR689859) sequences from the isolates SYP-1229 to 1231 exhibited 100% (558/558 bp), 100% (263/263), 100% (314/314), and 100% (316/316) similarity, respectively, with Boeremia exigua (EU167567, EU880846, OP611549, and KY484684, respectively) in GenBank BLAST search. Phylogenetics based on concatenated ITS, ACT, TUB2, and TEF sequences, using the maximum likelihood method of MEGA X (Kumar et al., 2018), showed that sequences of SYP-1229 to 1231 were clustered in the same clade as B. exigua. For pathogenicity tests conducted in pots, 10 mL conidial suspension (1 × 106 conidia/mL) derived from isolate SYP-1229, which had been cultured on PDA for 14 days, was sprayed onto two leaves of each of three independent healthy 1-year-old hydrangeas (cv. Renate Steiniger). The leaves of the control plants were inoculated with sterile distilled water, which was also applied to two leaves of each of the three independent healthy plants. The inoculated plants were placed in clear plastic boxes to maintain high humidity and incubated at 25 °C under 18 h of light. Brown spot lesions were observed on the inoculated two leaves seven days after inoculation, whereas the control were asymptomatic. Similar pathogenicity results were obtained for all three independent biological replicates. The fungus isolated from the lesion was identified as B. exigua through morphological character","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1094/PDIS-08-24-1668-RE
Roshan Paudel, Landon Balkwill, Koon-Hui Wang
Reniform nematode (Rotylenchulus reniformis) is a damaging and difficult-to-manage pest on many agricultural crops. Sorghum and sorghum-sudangrass hybrids (SSgH) have shown potential in managing plant-parasitic nematodes by releasing toxic hydrogen cyanide gas through the hydrolysis of dhurrin, a cyanogenic glucoside found in leaf epidermal cells. The objectives of this study were to evaluate the effect of different SSgH varieties and their age on the suppression of R. reniformis and to quantify their dhurrin contents. Shoot biomass of seven SSgH varieties was harvested at 1, 2, and 3 months of growth and used as a soil amendment in two greenhouse cowpea bioassay trials. Dhurrin concentration was analyzed using high-performance liquid chromatography (HPLC) from 2-month-old tissues. The results indicated that energy sorghum 'NX-D-61' and SSgH 'Latte' exhibited the highest dhurrin concentrations (P ≤ 0.05) and suppressed R. reniformis development in cowpea roots (P ≤ 0.05). In Trial I, 2-month-old amendments showed the greatest suppression, while in Trial II, 1-month-old amendments were more suppressive (P ≤ 0.05). Potential effect of environmental stress on dhurrin concentration in SSgH tissue was discussed. Nonetheless, dhurrin concentrations were negatively related to the number of R. reniformis infecting cowpea roots (r2 =0.69; P = 0.02). These findings suggest that high dhurrin SSgH varieties can be integrated into reniform nematode management plans as a cover crop and terminated no more than 2 months after planting.
肾形线虫（Rotylenchulus reniformis）是一种对许多农作物具有破坏性且难以治理的害虫。高粱和高粱-苏丹草杂交种（SSgH）通过水解叶片表皮细胞中的氰基葡糖苷（dhurrin）释放出有毒的氰化氢气体，显示出治理植物寄生线虫的潜力。本研究的目的是评估不同 SSgH 品种及其年龄对抑制 R. reniformis 的影响，并量化它们的 dhurrin 含量。七个 SSgH 品种的嫩枝生物量分别在生长 1、2 和 3 个月时收获，并在两个温室豇豆生物测定试验中用作土壤改良剂。采用高效液相色谱法（HPLC）分析了生长 2 个月的高粱组织中 Dhurrin 的浓度。结果表明，能量高粱 "NX-D-61 "和 SSgH "Latte "表现出最高的 Dhurrin 浓度（P ≤ 0.05），并能抑制豇豆根部 R. reniformis 的生长（P ≤ 0.05）。在试验 I 中，使用 2 个月的改良剂的抑制作用最强，而在试验 II 中，使用 1 个月的改良剂的抑制作用更强（P ≤ 0.05）。讨论了环境胁迫对 SSgH 组织中 dhurrin 浓度的潜在影响。然而，dhurrin 浓度与感染豇豆根部的 R. reniformis 数量呈负相关（r2 =0.69; P = 0.02）。这些研究结果表明，高白藜芦醇 SSgH 品种可作为覆盖作物纳入肾形线虫管理计划，并在种植后 2 个月内终止。
{"title":"Allelopathic effects of sorghum/sorghum-sudangrass hybrids against <i>Rotylenchulus reniformis</i>.","authors":"Roshan Paudel, Landon Balkwill, Koon-Hui Wang","doi":"10.1094/PDIS-08-24-1668-RE","DOIUrl":"https://doi.org/10.1094/PDIS-08-24-1668-RE","url":null,"abstract":"<p><p>Reniform nematode (Rotylenchulus reniformis) is a damaging and difficult-to-manage pest on many agricultural crops. Sorghum and sorghum-sudangrass hybrids (SSgH) have shown potential in managing plant-parasitic nematodes by releasing toxic hydrogen cyanide gas through the hydrolysis of dhurrin, a cyanogenic glucoside found in leaf epidermal cells. The objectives of this study were to evaluate the effect of different SSgH varieties and their age on the suppression of R. reniformis and to quantify their dhurrin contents. Shoot biomass of seven SSgH varieties was harvested at 1, 2, and 3 months of growth and used as a soil amendment in two greenhouse cowpea bioassay trials. Dhurrin concentration was analyzed using high-performance liquid chromatography (HPLC) from 2-month-old tissues. The results indicated that energy sorghum 'NX-D-61' and SSgH 'Latte' exhibited the highest dhurrin concentrations (P ≤ 0.05) and suppressed R. reniformis development in cowpea roots (P ≤ 0.05). In Trial I, 2-month-old amendments showed the greatest suppression, while in Trial II, 1-month-old amendments were more suppressive (P ≤ 0.05). Potential effect of environmental stress on dhurrin concentration in SSgH tissue was discussed. Nonetheless, dhurrin concentrations were negatively related to the number of R. reniformis infecting cowpea roots (r2 =0.69; P = 0.02). These findings suggest that high dhurrin SSgH varieties can be integrated into reniform nematode management plans as a cover crop and terminated no more than 2 months after planting.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142682531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1094/PDIS-09-23-1794-PDN
John Samuel Bennett, Breyn Evans, Caitlin Barnes, Tamara D Collum
<p><p>In November 2022, a European pear (Pyrus communis L.) 'Shenandoah' presenting brown discoloration and softening of the tissue over 75% of the fruit surface was found in cold storage at the USDA Appalachian Fruit Research Station in Kearneysville, West Virginia. Two of the 24 'Shenandoah' pears displayed the disease symptoms described. Following surface sanitation with 70% ethanol, tissue was taken at the margin of the lesion area, transferred to potato dextrose agar (PDA), and incubated at 25°C under continuous light. The isolate was hyphal-tip purified and propagated on PDA at 25°C. A growth assay using 7 mm plugs on PDA showed average daily growth of 14.5 mm over 7 days. Colonies appeared cream to light tan darkening with age. Elliptical, guttiferous, and aseptate α-conidia with mean dimensions of 8.74 µm (± 0.13 µm) by 3.7 µm (± 0.05 µm), n = 60, were observed on oatmeal agar after 25 days. β-conidia were filiform with mean dimensions of 24.4 µm (± 0.42 µm) by 1.34 µm (± 0.03 µm), n = 60. Fungal DNA was extracted using a CTAB protocol from one isolate (WV22SR1P5), and five genomic loci were amplified: internal transcribed spacer (ITS), translation elongation factor-1 alpha (TEF1), beta-tubulin (TUB), histone H3 (HIS), and calmodulin (CAL) (Udayanga et al. 2014) (GenBank accession nos. OR504473, OR504505, OR504506, PP213454, and PP213453 respectively). Additionally, part of the MAT1-1-1 gene was amplified (GenBank PP806137), but the MAT1-2-1 gene could not be detected (Santos et al. 2010). Based on a maximum-likelihood phylogenetic tree of concatenated genes (ITS-TEF1-TUB-HIS-CAL) from published isolates (Dissanayake et al. 2024; Gomes et al. 2013; Gomzhina et al. 2021; Moodispaw et al. 2023; Udayanga et al. 2015), WV22SR1P5 was most closely related to a Diaporthe sp. in the D. arctii species complex, Section Sojae, reported to cause disease on cucumber that has not yet been given a Latin binomial (Moodispaw et al. 2023). The WV22SR1P5 isolate was deposited in the USDA-ARS Culture Collection (NRRL# 64834). Organic European pears 'Bartlett' were surface sanitized with 70% ethanol and dried in a laminar flow hood. Fruits were wounded with a cork borer (4 mm diameter x 4 mm depth) and inoculated with a 4-mm mycelial plug of 7- to 10-day-old culture of WV22SR1P5 grown on PDA. Inoculated fruit were placed in fruit trays in plastic bins and stored at 25°C for 7 days in the dark. As a control, fruits were wounded and sterile PDA plugs were placed in wounds under the same conditions. Five fruits were used per treatment group, and the entire test was repeated for a total of two replications. Lesion development was observed within 72 hours and expanded to an average of 44 mm by day 7. Lesions were not observed on control fruit. Lesion appearance on inoculated pears matched the decay symptoms on the original pear selected from cold storage. Fungal isolates obtained from inoculated pears were morphologically and molecularly identified as the same Dia
{"title":"First Report of <i>Diaporthe</i> sp. from the <i>D. arctii</i> Species Complex Causing Postharvest Decay of European Pear in West Virginia, United States.","authors":"John Samuel Bennett, Breyn Evans, Caitlin Barnes, Tamara D Collum","doi":"10.1094/PDIS-09-23-1794-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-09-23-1794-PDN","url":null,"abstract":"<p><p>In November 2022, a European pear (Pyrus communis L.) 'Shenandoah' presenting brown discoloration and softening of the tissue over 75% of the fruit surface was found in cold storage at the USDA Appalachian Fruit Research Station in Kearneysville, West Virginia. Two of the 24 'Shenandoah' pears displayed the disease symptoms described. Following surface sanitation with 70% ethanol, tissue was taken at the margin of the lesion area, transferred to potato dextrose agar (PDA), and incubated at 25°C under continuous light. The isolate was hyphal-tip purified and propagated on PDA at 25°C. A growth assay using 7 mm plugs on PDA showed average daily growth of 14.5 mm over 7 days. Colonies appeared cream to light tan darkening with age. Elliptical, guttiferous, and aseptate α-conidia with mean dimensions of 8.74 µm (± 0.13 µm) by 3.7 µm (± 0.05 µm), n = 60, were observed on oatmeal agar after 25 days. β-conidia were filiform with mean dimensions of 24.4 µm (± 0.42 µm) by 1.34 µm (± 0.03 µm), n = 60. Fungal DNA was extracted using a CTAB protocol from one isolate (WV22SR1P5), and five genomic loci were amplified: internal transcribed spacer (ITS), translation elongation factor-1 alpha (TEF1), beta-tubulin (TUB), histone H3 (HIS), and calmodulin (CAL) (Udayanga et al. 2014) (GenBank accession nos. OR504473, OR504505, OR504506, PP213454, and PP213453 respectively). Additionally, part of the MAT1-1-1 gene was amplified (GenBank PP806137), but the MAT1-2-1 gene could not be detected (Santos et al. 2010). Based on a maximum-likelihood phylogenetic tree of concatenated genes (ITS-TEF1-TUB-HIS-CAL) from published isolates (Dissanayake et al. 2024; Gomes et al. 2013; Gomzhina et al. 2021; Moodispaw et al. 2023; Udayanga et al. 2015), WV22SR1P5 was most closely related to a Diaporthe sp. in the D. arctii species complex, Section Sojae, reported to cause disease on cucumber that has not yet been given a Latin binomial (Moodispaw et al. 2023). The WV22SR1P5 isolate was deposited in the USDA-ARS Culture Collection (NRRL# 64834). Organic European pears 'Bartlett' were surface sanitized with 70% ethanol and dried in a laminar flow hood. Fruits were wounded with a cork borer (4 mm diameter x 4 mm depth) and inoculated with a 4-mm mycelial plug of 7- to 10-day-old culture of WV22SR1P5 grown on PDA. Inoculated fruit were placed in fruit trays in plastic bins and stored at 25°C for 7 days in the dark. As a control, fruits were wounded and sterile PDA plugs were placed in wounds under the same conditions. Five fruits were used per treatment group, and the entire test was repeated for a total of two replications. Lesion development was observed within 72 hours and expanded to an average of 44 mm by day 7. Lesions were not observed on control fruit. Lesion appearance on inoculated pears matched the decay symptoms on the original pear selected from cold storage. Fungal isolates obtained from inoculated pears were morphologically and molecularly identified as the same Dia","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142682533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1094/PDIS-07-24-1393-PDN
Aida Rubí Cruz-Luna, Alfonso Vásquez-López, Delia Soto-Castro, Karla Yeriana Leyva-Madrigal, Guadalupe Arlene Mora-Romero, Carlos Granados-Echegoyen
<p><p><i>Agave potatorum</i> Zucc., also known as "agave tobalá", is an endemic species in the Mexican states of Oaxaca and Puebla and is one of the most important wild species for producing the Mexican alcoholic distillate called mezcal. In September 2021, symptoms of dry stem rot and subsequent death of plants were observed, in a commercial field of 10 acres located in the municipality of Villa Sola de Vega, Oaxaca, Mexico. The disease incidence was 45%. Twenty symptomatic agave stem plants were sampled to isolate the pathogen. Pieces (5 × 5 mm) of the symptomatic tissues from diseased plants were surface disinfested with 1% NaOCl (60 s) and 70% ethanol (1 min), rinsed with sterile water (2 × 60 s), placed on potato dextrose agar (PDA Bioxon®, Mexico), and incubated at 25°C for 6 days with natural light. Next, we prepared single-spore derived cultures on PDA and carnation leaf-piece agar (CLA). <i>Fusarium</i>-like colonies were consistently isolated on potato dextrose agar (PDA) and 14 monoconidial isolates were obtained. On PDA, aerial mycelium was white to beige with diffuse pink pigment in the center of the culture and colonies were appressed with a regular shape after 7 days of incubation at 25℃. Macroconidia (n=100) were falcate, almost straight, 1 to 4-septate, 18.5 to 47.9 × 3.9-5.7 μm. Microconidia (n=100) were ellipsoidal to subcylindrical, slightly curved, hyaline, 8 to 16 × 3.5 to 4.5 μm, 0 to 1-septate, and grouped in false heads. Chlamydospores were globose to subglobose, terminal or intercalary in hyphae, and were solitary or in chains. Morphological features were consistent with the description of <i>Neocosmospora</i> spp. (Crous et al. 2021; Sandoval-Denis et al. 2019). Three isolates were selected for multilocus phylogenetic analysis and pathogenicity tests. Isolates were deposited as IPN-AP1, IPN-AP2, and IPN-AP3 in the Culture Collection of Phytopathogenic Fungi of Plant Pathology Laboratory of the CIIDIR-Oaxaca of the Instituto Politécnico Nacional. For molecular identification, genomic DNA was extracted, and partial sequences of translation elongation factor 1-alpha (<i>EF1-α</i>) and the second largest subunit of RNA polymerase II (<i>rpb2</i>) genes were amplified and sequenced with the primer sets EF1-728F/EF1-986R (Carbone and Kohn 1999) and RBP2-5F/RPB2-7R (Liu et al. 1999), respectively. A phylogenetic tree using concatenated <i>EF1-α</i> and <i>rpb2</i> sequences was constructed for <i>Neocosmospora</i> spp. based on Maximum Likelihood. The phylogenetic analysis suggested that the three isolates belong to a new species, closely related to <i>N. noneumartii</i>, as they formed a sister clade with this species. The sequences were deposited in GenBank with accession nos. OP902594 to OP902596 for <i>EF1-α</i>, and OP902591 to OP902593 for <i>rpb2</i>. A pathogenicity test for each isolate was performed by inoculating five healthy <i>A. potatorum</i> plants (1-year-old) grown in pots. Conidia were cultured on PDA for 7 d
{"title":"First Report of <i>Neocosmospora</i> sp., Causing Stem Rot on <i>Agave potatorum</i> Zucc., in Mexico.","authors":"Aida Rubí Cruz-Luna, Alfonso Vásquez-López, Delia Soto-Castro, Karla Yeriana Leyva-Madrigal, Guadalupe Arlene Mora-Romero, Carlos Granados-Echegoyen","doi":"10.1094/PDIS-07-24-1393-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1393-PDN","url":null,"abstract":"<p><p><i>Agave potatorum</i> Zucc., also known as \"agave tobalá\", is an endemic species in the Mexican states of Oaxaca and Puebla and is one of the most important wild species for producing the Mexican alcoholic distillate called mezcal. In September 2021, symptoms of dry stem rot and subsequent death of plants were observed, in a commercial field of 10 acres located in the municipality of Villa Sola de Vega, Oaxaca, Mexico. The disease incidence was 45%. Twenty symptomatic agave stem plants were sampled to isolate the pathogen. Pieces (5 × 5 mm) of the symptomatic tissues from diseased plants were surface disinfested with 1% NaOCl (60 s) and 70% ethanol (1 min), rinsed with sterile water (2 × 60 s), placed on potato dextrose agar (PDA Bioxon®, Mexico), and incubated at 25°C for 6 days with natural light. Next, we prepared single-spore derived cultures on PDA and carnation leaf-piece agar (CLA). <i>Fusarium</i>-like colonies were consistently isolated on potato dextrose agar (PDA) and 14 monoconidial isolates were obtained. On PDA, aerial mycelium was white to beige with diffuse pink pigment in the center of the culture and colonies were appressed with a regular shape after 7 days of incubation at 25℃. Macroconidia (n=100) were falcate, almost straight, 1 to 4-septate, 18.5 to 47.9 × 3.9-5.7 μm. Microconidia (n=100) were ellipsoidal to subcylindrical, slightly curved, hyaline, 8 to 16 × 3.5 to 4.5 μm, 0 to 1-septate, and grouped in false heads. Chlamydospores were globose to subglobose, terminal or intercalary in hyphae, and were solitary or in chains. Morphological features were consistent with the description of <i>Neocosmospora</i> spp. (Crous et al. 2021; Sandoval-Denis et al. 2019). Three isolates were selected for multilocus phylogenetic analysis and pathogenicity tests. Isolates were deposited as IPN-AP1, IPN-AP2, and IPN-AP3 in the Culture Collection of Phytopathogenic Fungi of Plant Pathology Laboratory of the CIIDIR-Oaxaca of the Instituto Politécnico Nacional. For molecular identification, genomic DNA was extracted, and partial sequences of translation elongation factor 1-alpha (<i>EF1-α</i>) and the second largest subunit of RNA polymerase II (<i>rpb2</i>) genes were amplified and sequenced with the primer sets EF1-728F/EF1-986R (Carbone and Kohn 1999) and RBP2-5F/RPB2-7R (Liu et al. 1999), respectively. A phylogenetic tree using concatenated <i>EF1-α</i> and <i>rpb2</i> sequences was constructed for <i>Neocosmospora</i> spp. based on Maximum Likelihood. The phylogenetic analysis suggested that the three isolates belong to a new species, closely related to <i>N. noneumartii</i>, as they formed a sister clade with this species. The sequences were deposited in GenBank with accession nos. OP902594 to OP902596 for <i>EF1-α</i>, and OP902591 to OP902593 for <i>rpb2</i>. A pathogenicity test for each isolate was performed by inoculating five healthy <i>A. potatorum</i> plants (1-year-old) grown in pots. Conidia were cultured on PDA for 7 d","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142682534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1094/PDIS-06-24-1321-PDN
Abolfazl Hajihassani, Banani Mondal, Ganpati B Jagdale
<p><p>Soil and root samples were collected from two plots (5.5 x 6 m) cultivated with bamboo Phyllostachys reticulata (syn. P. bambusoides) at the USDA Southeastern Fruit and Tree Nut Research Station in Byron, Georgia, USA, in November 2021, December 2022, and December 2023. Each soil sample consisted of five randomly collected subsamples, which were analyzed for the presence of plant-parasitic nematodes as part of regular monitoring. No aboveground symptoms were seen in the field plots, but roots showed discoloration and stunted growth (Fig. 1A). An average population density of 160, 36, and 188 second-stage juveniles (J2) of cyst nematodes (Heterodera spp.) per 100 cm3 of soil was detected in 2021, 2022, and 2023, respectively. To confirm the cyst nematode parasitism, three healthy P. reticulata plants were transplanted into 10 cm diameter pots filled with nematode-infested soil and grown in a greenhouse at 25-28°C. After three months, young cysts containing eggs protruding from the bamboo roots were seen, confirming nematode parasitism (Fig. 1B and C). Morphological and molecular analyses were conducted to identify the nematode species. The J2 body shape was cylindrical with three incisures in lateral field and well-developed rounded stylet knobs. Measurements of J2 (n = 10) included the length (range = 406.0-518.1 μm, mean = 458.2 ± 16.1 μm) and width (16.0-17.2 μm, 16.6 ± 0.5 μm) of body, labial region height (3.0-3.6 μm, 3.2 ± 0.2 μm), stylet (17.2-18.9 μm, 18.02 ± 0.6 μm), tail (61.1-65.9 μm, 63.1 ± 5.8 μm), body width at anus (9.7-12.4 μm, 10.8 ± 0.3 μm), and hyaline tail terminus (35.4-53.0 μm, 44.0 ± 3.8 μm). The cysts (n = 5) were relatively lemon-shaped, light to dark brown in color with projected neck and vulval cone that lacked fenestration, bullae, and underbridge. Morphometrics were body length including neck (420.5-745.0 μm, 550.4 ± 72 μm), body width (345.0-544.1 μm, 430.1 ± 59 μm), and L/W ratio (1.0-1.4 μm, 1.1 ± 0.1 μm). The morphometric of vulval cone included fenestral length (48 to 69 µm, 60.2 ± 4.0 µm), fenestral width (43 to 51 µm, 48.9 ± 4.0 µm) and vulval slit (47 to 58 µm, 49.1 ± 2.6 µm). Morphology and morphometric measurements of the cysts and J2 (Fig. 2A-C) were comparable to previous reports of Korean cyst nematode, H. koreana from other Asian countries (Mundo-Ocampo et al., 2008; Wang et al., 2012; Tanha Maafi and Taheri, 2015; Sekimoto et al., 2017). For molecular diagnosis, DNA was extracted from single cysts (n= 3) using DNeasy Blood and Tissue Kit, and 28S rRNA and partial cytochrome oxidase I (COI) gene fragments were amplified using D2A/D3B and Het-coxiF/Het-coxiR primer sets, respectively according to Subbotin et al. (2015) and Hajihassani et al. (2018). PCR products were then purified by a DNA Clean & Concentrator kit (Zymo Research, CA, USA) and sequenced at Genewiz (South Plainfield, NJ, USA). The resulting sequences were deposited into the GenBank database and subjected to BLASTn searches. Sequence an
{"title":"First Report of the cyst nematode <i>Heterodera koreana</i> parasitizing bamboo (<i>Phyllostachys reticulata</i>) in Georgia, USA.","authors":"Abolfazl Hajihassani, Banani Mondal, Ganpati B Jagdale","doi":"10.1094/PDIS-06-24-1321-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1321-PDN","url":null,"abstract":"<p><p>Soil and root samples were collected from two plots (5.5 x 6 m) cultivated with bamboo Phyllostachys reticulata (syn. P. bambusoides) at the USDA Southeastern Fruit and Tree Nut Research Station in Byron, Georgia, USA, in November 2021, December 2022, and December 2023. Each soil sample consisted of five randomly collected subsamples, which were analyzed for the presence of plant-parasitic nematodes as part of regular monitoring. No aboveground symptoms were seen in the field plots, but roots showed discoloration and stunted growth (Fig. 1A). An average population density of 160, 36, and 188 second-stage juveniles (J2) of cyst nematodes (Heterodera spp.) per 100 cm3 of soil was detected in 2021, 2022, and 2023, respectively. To confirm the cyst nematode parasitism, three healthy P. reticulata plants were transplanted into 10 cm diameter pots filled with nematode-infested soil and grown in a greenhouse at 25-28°C. After three months, young cysts containing eggs protruding from the bamboo roots were seen, confirming nematode parasitism (Fig. 1B and C). Morphological and molecular analyses were conducted to identify the nematode species. The J2 body shape was cylindrical with three incisures in lateral field and well-developed rounded stylet knobs. Measurements of J2 (n = 10) included the length (range = 406.0-518.1 μm, mean = 458.2 ± 16.1 μm) and width (16.0-17.2 μm, 16.6 ± 0.5 μm) of body, labial region height (3.0-3.6 μm, 3.2 ± 0.2 μm), stylet (17.2-18.9 μm, 18.02 ± 0.6 μm), tail (61.1-65.9 μm, 63.1 ± 5.8 μm), body width at anus (9.7-12.4 μm, 10.8 ± 0.3 μm), and hyaline tail terminus (35.4-53.0 μm, 44.0 ± 3.8 μm). The cysts (n = 5) were relatively lemon-shaped, light to dark brown in color with projected neck and vulval cone that lacked fenestration, bullae, and underbridge. Morphometrics were body length including neck (420.5-745.0 μm, 550.4 ± 72 μm), body width (345.0-544.1 μm, 430.1 ± 59 μm), and L/W ratio (1.0-1.4 μm, 1.1 ± 0.1 μm). The morphometric of vulval cone included fenestral length (48 to 69 µm, 60.2 ± 4.0 µm), fenestral width (43 to 51 µm, 48.9 ± 4.0 µm) and vulval slit (47 to 58 µm, 49.1 ± 2.6 µm). Morphology and morphometric measurements of the cysts and J2 (Fig. 2A-C) were comparable to previous reports of Korean cyst nematode, H. koreana from other Asian countries (Mundo-Ocampo et al., 2008; Wang et al., 2012; Tanha Maafi and Taheri, 2015; Sekimoto et al., 2017). For molecular diagnosis, DNA was extracted from single cysts (n= 3) using DNeasy Blood and Tissue Kit, and 28S rRNA and partial cytochrome oxidase I (COI) gene fragments were amplified using D2A/D3B and Het-coxiF/Het-coxiR primer sets, respectively according to Subbotin et al. (2015) and Hajihassani et al. (2018). PCR products were then purified by a DNA Clean & Concentrator kit (Zymo Research, CA, USA) and sequenced at Genewiz (South Plainfield, NJ, USA). The resulting sequences were deposited into the GenBank database and subjected to BLASTn searches. Sequence an","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1094/PDIS-07-24-1498-RE
Adrián Valdez-Tenezaca, Bernardo Antonio Latorre, Gonzalo A Díaz
Studies on susceptibility of the age of the pruning wound and effect of pruning time on infection by Botryosphaeriaceae in apple trees is scarce. This work aimed to determine the susceptibility of different ages of pruning wound (1, 15, 30 or 45 days after pruning) and the effect of pruning time during early (June) and late pruning (August) in apples cvs. Fuji and Gala on the infection of Diplodia mutila, D. seriata, Neofusicoccum arbuti and Lasiodiplodia theobromae. Additionally, seasonal conidial release of Botryosphaeriaceae spp. was monitored using Vaseline-coated glass slides in two orchard cv. Fuji and Gala during two consecutive growing seasons (2020-2021) in Maule region, Central Chile. The analysis of the variance of each pruning wound age showed significant interaction between the factors, Botryosphaeria isolate × apple cultivar (P= 0.0001). The isolates of N. arbuti and D. seriata were significantly more aggressive than the other isolates of Botryosphaeria, with mean values of 45.2 mm (one day of age) to 7.9 mm (45 days of age) and 31.0 mm (one day of age) to 6.6 mm (45 days of age), respectively. Independently of the Botryosphaeriaceae species, the pruning wound susceptibility considerably decreased as the age of the pruning wound increased, where fresh pruning wounds (1 and 15 days) are more susceptible than older pruning wounds (30 and 45 days). Our results indicated significant (P < 0.0001) interaction between Botryosphaeria isolates and pruning time for both cultivars. Necrotic lesions varied among the Botryosphaeriaceae species, where lesion length was significantly greater in the isolates of N. arbuti, D. mutila, and D. seriata inoculated in early pruning than inoculations conducted in late pruning. This study demonstrated a strong relationship between conidial release and rainfall, where 70.3% and 86.3% of the total conidia of Botryosphaeriaceae spp. were released during rainfall periods between June and August (winter). This work suggests that a delay in pruning times may be justified to reduce the risk of Botryosphaeria canker and dieback in apple trees in Maule region, Chile, considering rain-free days.
{"title":"Susceptibility of pruning wounds of apple trees to <i>Diplodia mutila, D. seriata, Lasiodiplodia theobromae</i> and <i>Neofusicoccum arbuti</i> infections and conidia release of Botryosphaeriaceae spp. in the Maule Region, Chile.","authors":"Adrián Valdez-Tenezaca, Bernardo Antonio Latorre, Gonzalo A Díaz","doi":"10.1094/PDIS-07-24-1498-RE","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1498-RE","url":null,"abstract":"<p><p>Studies on susceptibility of the age of the pruning wound and effect of pruning time on infection by Botryosphaeriaceae in apple trees is scarce. This work aimed to determine the susceptibility of different ages of pruning wound (1, 15, 30 or 45 days after pruning) and the effect of pruning time during early (June) and late pruning (August) in apples cvs. Fuji and Gala on the infection of Diplodia mutila, D. seriata, Neofusicoccum arbuti and Lasiodiplodia theobromae. Additionally, seasonal conidial release of Botryosphaeriaceae spp. was monitored using Vaseline-coated glass slides in two orchard cv. Fuji and Gala during two consecutive growing seasons (2020-2021) in Maule region, Central Chile. The analysis of the variance of each pruning wound age showed significant interaction between the factors, Botryosphaeria isolate × apple cultivar (P= 0.0001). The isolates of N. arbuti and D. seriata were significantly more aggressive than the other isolates of Botryosphaeria, with mean values of 45.2 mm (one day of age) to 7.9 mm (45 days of age) and 31.0 mm (one day of age) to 6.6 mm (45 days of age), respectively. Independently of the Botryosphaeriaceae species, the pruning wound susceptibility considerably decreased as the age of the pruning wound increased, where fresh pruning wounds (1 and 15 days) are more susceptible than older pruning wounds (30 and 45 days). Our results indicated significant (P < 0.0001) interaction between Botryosphaeria isolates and pruning time for both cultivars. Necrotic lesions varied among the Botryosphaeriaceae species, where lesion length was significantly greater in the isolates of N. arbuti, D. mutila, and D. seriata inoculated in early pruning than inoculations conducted in late pruning. This study demonstrated a strong relationship between conidial release and rainfall, where 70.3% and 86.3% of the total conidia of Botryosphaeriaceae spp. were released during rainfall periods between June and August (winter). This work suggests that a delay in pruning times may be justified to reduce the risk of Botryosphaeria canker and dieback in apple trees in Maule region, Chile, considering rain-free days.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142682149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1094/PDIS-07-24-1369-PDN
Michael McKee, John Dobbs, Ned Tisserat, James T Blodgett, Kelly Burns, Jane E Stewart
<p><p>Diplodia shoot blight and canker disease (DSB), caused by the fungal pathogen Diplodia sapinea (Fr.) Fuckel (syn=Sphaeropsis sapinea (Fr.) Dyko & Sutton), is found on 2-3 needled pines including ponderosa pine (Pinus ponderosa) and other conifers (Blodgett and Stanosz 1999). Typical symptoms of DSB are short, necrotic needles, necrosis of current-years growth that can progress into older growth, resinous branch and bole cankers, dieback, dead tops and branches, infected cones, and sapwood staining (Blumenstein et al., 2021, Caballol et al., 2022) The latent pathogen is known to persist asymptomatically within the tree allowing it to accumulate unnoticed in healthy trees. (Terhonen et al., 2021). While D. sapinea is a major issue in natural pine stands, outbreaks can occur in nurseries and seed orchards due to monocultures and other stress-inducing factors (Aragonés et al., 2021). Diplodia sapinea outbreaks have been reported in North America, Africa, and several European countries (Blumenstein et al., 2021). Since D. sapinea has never been reported in Colorado, studies were conducted to confirm the presence, pathogenicity, and potential movement of DSB from Wyoming into Colorado. In 2018, DSB symptoms were observed in ponderosa pine stands during aerial surveys in Wyoming, and were confirmed in ground surveys in 2019 (Blodgett et al., 2021). Isolates from host trees were confirmed as Diplodia sapinea using species specific PCR (Blodgett et al., 2021). In 2021, a group of approximately 90-year old ponderosa pines exhibiting DSB symptoms were observed in the northeastern foothills of Colorado. Two D. sapinea isolates were collected from branches off two symptomatic trees. Xylem and phloem tissue samples were cut from the disease margin and placed on 1/2 strength potato dextrose agar (PDA) (Hardy Diagnostics; Santa Maria, CA). Another isolate was collected from the same tree in 2023 from a symptomatic branch. Branches were surface sterilized in 10% sodium hypochlorite for 2 min, placed in sterile water for 1 min, and then placed in humid chambers. Pycnidia were observed after a week. Diplodia sapinea spores were identified morphologically and after 1 day, a single spore was transferred to ½ PDA agar (for each of the three isolates). The three isolates were confirmed as D. sapinea using colony PCR to amplify the internal transcribed spacer (ITS) and translation elongation factor 1 alpha (tef1-α). The master mix for ITS amplification contained 1 µl of the forward and reverse primers ITS1/ITS4 diluted to 10 ng/µl (White et al. 1990), 12.5 µl of GoTaq Green 1x (Promega), and 8.5 µl of MH2O. DNA was diluted to 10 ng/µl and 20 ng were used for a total reaction volume of 25 µl. The cycling parameters followed those described by White et al (1990). The reaction mixture was similar to the tef1-α amplification, however, the forward and reverse primers EF-688F and EF-1251R were used and PCR cycling parameters were completed methods by Carbone and Kohn (1
{"title":"First Report of Diplodia Shoot Blight and Canker Disease Caused by <i>Diplodia sapinea</i> on Ponderosa Pine in Colorado, USA.","authors":"Michael McKee, John Dobbs, Ned Tisserat, James T Blodgett, Kelly Burns, Jane E Stewart","doi":"10.1094/PDIS-07-24-1369-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1369-PDN","url":null,"abstract":"<p><p>Diplodia shoot blight and canker disease (DSB), caused by the fungal pathogen Diplodia sapinea (Fr.) Fuckel (syn=Sphaeropsis sapinea (Fr.) Dyko & Sutton), is found on 2-3 needled pines including ponderosa pine (Pinus ponderosa) and other conifers (Blodgett and Stanosz 1999). Typical symptoms of DSB are short, necrotic needles, necrosis of current-years growth that can progress into older growth, resinous branch and bole cankers, dieback, dead tops and branches, infected cones, and sapwood staining (Blumenstein et al., 2021, Caballol et al., 2022) The latent pathogen is known to persist asymptomatically within the tree allowing it to accumulate unnoticed in healthy trees. (Terhonen et al., 2021). While D. sapinea is a major issue in natural pine stands, outbreaks can occur in nurseries and seed orchards due to monocultures and other stress-inducing factors (Aragonés et al., 2021). Diplodia sapinea outbreaks have been reported in North America, Africa, and several European countries (Blumenstein et al., 2021). Since D. sapinea has never been reported in Colorado, studies were conducted to confirm the presence, pathogenicity, and potential movement of DSB from Wyoming into Colorado. In 2018, DSB symptoms were observed in ponderosa pine stands during aerial surveys in Wyoming, and were confirmed in ground surveys in 2019 (Blodgett et al., 2021). Isolates from host trees were confirmed as Diplodia sapinea using species specific PCR (Blodgett et al., 2021). In 2021, a group of approximately 90-year old ponderosa pines exhibiting DSB symptoms were observed in the northeastern foothills of Colorado. Two D. sapinea isolates were collected from branches off two symptomatic trees. Xylem and phloem tissue samples were cut from the disease margin and placed on 1/2 strength potato dextrose agar (PDA) (Hardy Diagnostics; Santa Maria, CA). Another isolate was collected from the same tree in 2023 from a symptomatic branch. Branches were surface sterilized in 10% sodium hypochlorite for 2 min, placed in sterile water for 1 min, and then placed in humid chambers. Pycnidia were observed after a week. Diplodia sapinea spores were identified morphologically and after 1 day, a single spore was transferred to ½ PDA agar (for each of the three isolates). The three isolates were confirmed as D. sapinea using colony PCR to amplify the internal transcribed spacer (ITS) and translation elongation factor 1 alpha (tef1-α). The master mix for ITS amplification contained 1 µl of the forward and reverse primers ITS1/ITS4 diluted to 10 ng/µl (White et al. 1990), 12.5 µl of GoTaq Green 1x (Promega), and 8.5 µl of MH2O. DNA was diluted to 10 ng/µl and 20 ng were used for a total reaction volume of 25 µl. The cycling parameters followed those described by White et al (1990). The reaction mixture was similar to the tef1-α amplification, however, the forward and reverse primers EF-688F and EF-1251R were used and PCR cycling parameters were completed methods by Carbone and Kohn (1","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142682536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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