Pub Date : 2024-11-07DOI: 10.1094/PDIS-01-24-0075-RE
Tarciso A Ferreira Junior, Larissa C Ferreira, Vitor A S Moura, Katia V Xavier
Fusarium wilt, caused by Fusarium oxysporum f. sp. apii (Foa), is a vascular disease affecting celery. This soilborne pathogen is classified into four distinct pathogenic races: 1, 2, 3, and 4. Notably, race 4 emerges as the most virulent, representing the latest evolutionary development of this pathogen, which was first reported in 2013 in California. In 2022, celery plants in South Florida exhibited typical Fusarium wilt symptoms, with the disease reaching a 100% incidence and causing yield losses ranging from 20 to 100%. Given the significance of celery as a vegetable crop and the severity of this outbreak, the primary objective of this study was to identify and characterize the causal agent of Fusarium wilt in South Florida. The second goal aimed to test the pathogenicity and virulence of the Fusarium isolates from Florida on celery and parsley plants. Using race-specific primers and dual-loci phylogenetic analyses, the isolates surveyed in this study were identified as Foa race 4. Pathogenicity assays in the greenhouse showed that the Foa race 4 isolate from celery induced disease not only on the two celery cultivars (Duda 30 and Duda 71) but also on two commonly cultivated parsley varieties (curly and Italian). Our study also revealed that the Foa race 4 significantly (P < 0.05) affected plant health attributes in all cultivars, including plant height, total plant weight, and root weight. Interestingly, the pathogen exhibited higher (P < 0.0001) virulence on parsley than celery based on vascular discoloration. These findings strongly indicate the urgency of comprehending and managing Fusarium wilt on celery and related crops. Furthermore, the ability of Foa race 4 to affect different plant species highlights a potential threat to agricultural production, emphasizing the need for proactive measures to mitigate the impact of this virulent pathogen.
{"title":"<i>Fusarium oxysporum</i> f. sp. <i>apii</i> Race 4 Threatening Celery Production in South Florida.","authors":"Tarciso A Ferreira Junior, Larissa C Ferreira, Vitor A S Moura, Katia V Xavier","doi":"10.1094/PDIS-01-24-0075-RE","DOIUrl":"10.1094/PDIS-01-24-0075-RE","url":null,"abstract":"<p><p>Fusarium wilt, caused by <i>Fusarium oxysporum</i> f. sp. <i>apii</i> (<i>Foa</i>), is a vascular disease affecting celery. This soilborne pathogen is classified into four distinct pathogenic races: 1, 2, 3, and 4. Notably, race 4 emerges as the most virulent, representing the latest evolutionary development of this pathogen, which was first reported in 2013 in California. In 2022, celery plants in South Florida exhibited typical Fusarium wilt symptoms, with the disease reaching a 100% incidence and causing yield losses ranging from 20 to 100%. Given the significance of celery as a vegetable crop and the severity of this outbreak, the primary objective of this study was to identify and characterize the causal agent of Fusarium wilt in South Florida. The second goal aimed to test the pathogenicity and virulence of the <i>Fusarium</i> isolates from Florida on celery and parsley plants. Using race-specific primers and dual-loci phylogenetic analyses, the isolates surveyed in this study were identified as <i>Foa</i> race 4. Pathogenicity assays in the greenhouse showed that the <i>Foa</i> race 4 isolate from celery induced disease not only on the two celery cultivars (Duda 30 and Duda 71) but also on two commonly cultivated parsley varieties (curly and Italian). Our study also revealed that the <i>Foa</i> race 4 significantly (<i>P</i> < 0.05) affected plant health attributes in all cultivars, including plant height, total plant weight, and root weight. Interestingly, the pathogen exhibited higher (<i>P</i> < 0.0001) virulence on parsley than celery based on vascular discoloration. These findings strongly indicate the urgency of comprehending and managing Fusarium wilt on celery and related crops. Furthermore, the ability of <i>Foa</i> race 4 to affect different plant species highlights a potential threat to agricultural production, emphasizing the need for proactive measures to mitigate the impact of this virulent pathogen.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS01240075RE"},"PeriodicalIF":4.4,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141634210","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 : 2024-11-06DOI: 10.1094/PDIS-08-24-1691-SC
Eva Garcia, Fabiana Soares, Cristiana Oliveira Rodrigues, João Trovão, Joël F Pothier, Alexandra Camelo, Christophe Espirito Santo, Dian Dragnev, Eli Petrova, Joana Costa, Svetoslav Ganchev Bobev
Sunflower is a short-season crop of the Asteraceae family and the Helianthus genus and is the fourth most important oilseed crop in the world. During a field campaign, unusual symptoms (necrosis and longitudinal cracking of the petiole) were observed in a sunflower crop grown in the region of Kavarna (Dobrich district, Bulgaria) and strains of the genus Xanthomonas were isolated. Results based on phylogenetic and phylogenomic analyses showed that they clustered with Xanthomonas euroxanthea CPBF 424T species, a pathogenic strain isolated from walnut buds in Portugal and responsible for causing walnut bacterial blight (WBB). The sunflower strain showed five out of eight X. euroxanthea-specific markers (XEA4-XEA8), a pattern also observed in some strains isolated from Solanum lycopersicum, Phaseolus vulgaris and rainwater sources, reinforcing the emergence of a recent lineage-driven by evolutionary adaptations to new plant hosts. This is the first report of X. euroxanthea in sunflower crops in Bulgaria, which represents a potential threat to production and its distribution should be monitored.
{"title":"Expansion of the Host Range of <i>Xanthomonas euroxanthea</i>: First Occurrence in Sunflower in Bulgaria.","authors":"Eva Garcia, Fabiana Soares, Cristiana Oliveira Rodrigues, João Trovão, Joël F Pothier, Alexandra Camelo, Christophe Espirito Santo, Dian Dragnev, Eli Petrova, Joana Costa, Svetoslav Ganchev Bobev","doi":"10.1094/PDIS-08-24-1691-SC","DOIUrl":"https://doi.org/10.1094/PDIS-08-24-1691-SC","url":null,"abstract":"<p><p>Sunflower is a short-season crop of the Asteraceae family and the Helianthus genus and is the fourth most important oilseed crop in the world. During a field campaign, unusual symptoms (necrosis and longitudinal cracking of the petiole) were observed in a sunflower crop grown in the region of Kavarna (Dobrich district, Bulgaria) and strains of the genus Xanthomonas were isolated. Results based on phylogenetic and phylogenomic analyses showed that they clustered with Xanthomonas euroxanthea CPBF 424T species, a pathogenic strain isolated from walnut buds in Portugal and responsible for causing walnut bacterial blight (WBB). The sunflower strain showed five out of eight X. euroxanthea-specific markers (XEA4-XEA8), a pattern also observed in some strains isolated from Solanum lycopersicum, Phaseolus vulgaris and rainwater sources, reinforcing the emergence of a recent lineage-driven by evolutionary adaptations to new plant hosts. This is the first report of X. euroxanthea in sunflower crops in Bulgaria, which represents a potential threat to production and its distribution should be monitored.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142591199","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 : 2024-11-06DOI: 10.1094/PDIS-05-24-1040-SC
Morgan Bragg, Oluwakemisola Olofintila, Zachary Albert Noel
Seedling disease management recommendations rely on comprehensive identification of the pathogens. A recent manuscript isolated oomycetes from diseased cotton (Gossypium hirsutum L.) roots to identify the species associated. However, culture-dependent surveys may miss species because of the microbiological medium and work required to isolate and maintain all cultured organisms. Alternatively, culture-independent methods using PCR amplification and high-throughput sequencing can identify species' presence and relative abundance, including obligate pathogens and rare members of communities. We used culture-independent sequencing from the same cotton soils in the culture-based survey to determine the oomycete species in oomycete-containing soils. The results of the two methods were generally similar regarding the species identified. Similarly to the culture-based method, Globisporangium irregular accounted for 24% of the relative abundance and was encountered in all fields sequenced. In contrast, we identified three operational taxonomic units matching Globisporangium ultimum, but accounted for less than 0.06% of total relative abundance, potentially explaining why it was not isolated from cotton roots in the original survey. Phytophthora nicotianae was identified in soils but not at the concentrations recorded in the culture-based study. The results of this study, combined with the results of the culture-based survey, demonstrate the most comprehensive identification of oomycetes associated with cotton in the cotton belt and the oomycetes related to seedling disease. The combined results will be essential for future research into the specific pathogen species mentioned and stimulate similar research in other states.
{"title":"Diversity of Oomycetes From Alabama Cotton Soils Using Culture-Independent Methods.","authors":"Morgan Bragg, Oluwakemisola Olofintila, Zachary Albert Noel","doi":"10.1094/PDIS-05-24-1040-SC","DOIUrl":"https://doi.org/10.1094/PDIS-05-24-1040-SC","url":null,"abstract":"<p><p>Seedling disease management recommendations rely on comprehensive identification of the pathogens. A recent manuscript isolated oomycetes from diseased cotton (<i>Gossypium hirsutum</i> L.) roots to identify the species associated. However, culture-dependent surveys may miss species because of the microbiological medium and work required to isolate and maintain all cultured organisms. Alternatively, culture-independent methods using PCR amplification and high-throughput sequencing can identify species' presence and relative abundance, including obligate pathogens and rare members of communities. We used culture-independent sequencing from the same cotton soils in the culture-based survey to determine the oomycete species in oomycete-containing soils. The results of the two methods were generally similar regarding the species identified. Similarly to the culture-based method, <i>Globisporangium irregular</i> accounted for 24% of the relative abundance and was encountered in all fields sequenced. In contrast, we identified three operational taxonomic units matching <i>Globisporangium ultimum</i>, but accounted for less than 0.06% of total relative abundance, potentially explaining why it was not isolated from cotton roots in the original survey. <i>Phytophthora nicotianae</i> was identified in soils but not at the concentrations recorded in the culture-based study. The results of this study, combined with the results of the culture-based survey, demonstrate the most comprehensive identification of oomycetes associated with cotton in the cotton belt and the oomycetes related to seedling disease. The combined results will be essential for future research into the specific pathogen species mentioned and stimulate similar research in other states.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142591185","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 : 2024-11-06DOI: 10.1094/PDIS-06-24-1312-PDN
Huafeng Liu, Tingfu Zhang, Yingqing Luo, Guoqin Wen, Na Li
<p><p>Symphyotrichum subulatum (Michx.) G. L. Nesom (syn. Aster subulatus), an annual herb in the Asteraceae family, is native to North America. Nowadays, it has become an invasive weed in several provinces of China, including Jiangsu, Zhejiang, and Sichuan (Li and Xie, 2002). Despite being invasive, this species holds significance in Chinese medicine, where it is used for the external treatment of eczema and swollen sore poison (Hu, 2020). In June 2023, symptoms of powdery mildew were observed in S. subulatum populations in Deyang and Nanchong, Sichuan Province, China. About 32.73% among 55 surveyed S. subulatum plants showed signs of infection. Symptoms initially appeared as small, scattered white powdery patches on the leaves, which enlarged and coalesced over time. Subsequently, hyphal growth forming extensive conidia covered up to 90% of the leaf area on both surfaces (Fig. S1A, B), and the infected leaves withered and fell off (Fig. S1A). A specimen was archived at China West Normal University (SsPM-ZL). Conidiophores were cylindrical and erect, 66.4 to 183.2 µm (avg. 108.2±40.8 μm) in length (n=30) (Fig. S1C). Conidia, produced singly, were ellipsoid-ovoid to nearly cylindrical, measuring 29.5 to 36.7 μm in length (avg. 32.9±2.6 μm) and 16.0 to 19.9 μm in width (avg. 17.4±1.3 μm), lacking distinct fibrosin bodies (n=30) (Fig. S1D). Under a scanning electron microscope, turgid conidia displayed reticulate wrinkles on the surface, with gentle contractions or bulges at both poles (Fig. S1E, F). Based on these characteristics, the powdery mildew fungus was consistent with the genus Golovinomyces (Bradshaw et al. 2022a). To confirm the identity of the causal fungus of specimen (SsPM-ZL), the calmodulin (CAM), RNA polymerase II subunit (RPB2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glutamine synthetase (GS), and the internal transcribed spacer (ITS) were amplified using PMCAMF/R, PMRPB2F/R, PMGAPDH1/3R, PMGSF/R, and PM5/ITS4 primers (Bradshaw et al. 2022b), and deposited in GenBank (CAM: OR761878; RPB2: OR761881; GAPDH: OR761879; GS: OR761880; ITS: OR758452). BLAST analysis showed 99 to 100% identity with the sequences of Golovinomyces ambrosiae (FH00941234) for CAM (ON101658, 99.65%), RPB2 (ON119165, 100%), GS (ON075690, 99.78%), and ITS (ON073876, 99.47%). Phylogenetic analysis was performed in MEGAX with maximum likelihood method (Kumar et al. 2016) and clustered SsPM-ZL into the G. ambrosiae clade with a 100% bootstrap support value based on the concatenated sequences of CAM, RPB2, GAPDH, GS and ITS (Fig. S2). Combining morphological and phylogenetic analyses, SsPM-ZL was identified as Golovinomyces ambrosiae. To evaluate pathogenicity, leaves of 3 healthy potted S. subulatum plants (3 leaves per plant) were inoculated by gently pressing them with diseased leaves, while 3 non-contact plants were used as control. Plants in two groups were incubated in separate greenhouses maintained at 27±1°C, with a photoperiod of 14 hours and a r
Symphyotrichum subulatum (Michx.) G. L. Nesom (syn. Aster subulatus) 是菊科一年生草本植物，原产于北美洲。如今，它已成为中国江苏、浙江和四川等几个省份的入侵杂草（李和谢，2002）。尽管具有入侵性，但该物种在中药中仍有重要地位，可用于外敷治疗湿疹和肿毒（Hu，2020）。2023 年 6 月，在中国四川省德阳市和南充市的 S. subulatum 种群中观察到白粉病症状。在调查的 55 株 S. subulatum 植物中，约 32.73% 出现了感染迹象。症状最初表现为叶片上散落的白色粉状小斑点，随着时间的推移，斑点逐渐扩大和凝聚。随后，形成大量分生孢子的菌丝生长覆盖了叶片两面 90% 的面积（图 S1A、B），受感染的叶片枯萎并脱落（图 S1A）。一份标本保存在西华师范大学（SsPM-ZL）。分生孢子梗呈圆柱状直立，长 66.4 至 183.2 微米（平均 108.2±40.8 微米）（n=30）（图 S1C）。单生的分生孢子呈椭圆状卵球形至近圆柱形，长 29.5 至 36.7 微米（平均 32.9±2.6 微米），宽 16.0 至 19.9 微米（平均 17.4±1.3 微米），缺乏明显的纤维素体（n=30）（图 S1D）。在扫描电子显微镜下，膨大的分生孢子表面呈现网状皱纹，两极有平缓的收缩或隆起（图 S1E、F）。根据这些特征，白粉病真菌与 Golovinomyces 属一致（Bradshaw 等人，2022a）。为确认标本（SsPM-ZL）的病原真菌身份，钙调蛋白（CAM）、RNA 聚合酶 II 亚基（RPB2）、甘油醛-3-磷酸脱氢酶（GAPDH）使用 PMCAMF/R、PMRPB2F/R、PMGAPDH1/3R、PMGSF/R 和 PM5/ITS4 引物（Bradshaw et al.2022b），并存入 GenBank（CAM：OR761878；RPB2：OR761881；GAPDH：OR761879；GS：OR761880；ITS：OR758452）。BLAST 分析表明，CAM（ON101658，99.65%）、RPB2（ON119165，100%）、GS（ON075690，99.78%）和 ITS（ON073876，99.47%）与 Golovinomyces ambrosiae（FH00941234）的序列具有 99 至 100%的一致性。利用最大似然法（Kumar 等，2016 年）在 MEGAX 中进行了系统发育分析，并根据 CAM、RPB2、GAPDH、GS 和 ITS 的连接序列将 SsPM-ZL 聚类到 G. ambrosiae 支系中，自举支持值为 100%（图 S2）。结合形态学和系统发生学分析，SsPM-ZL 被确定为伏洛温霉菌。为了评估致病性，将 3 株健康的盆栽 S. subulatum（每株 3 片叶）的叶片与病叶轻轻按压后接种，同时用 3 株未接触的植株作为对照。两组植物分别放在温度为 27±1°C、光周期为 14 小时、相对湿度为 80% 的温室中培养。7 天后，接种植株出现白粉病症状（图 S1H、J），而对照植株仍无症状（图 S1G、I）。人工诱导的白粉病的形态特征与自然感染植株一致。在中国，有报道称由 G. ambrosiae 引起的白粉病影响到 Helianthus tuberosus（Huang 等人，2017 年）和 Bidens pilosa（Mukhtar 等人，2022 年）。据我们所知，这是中国首次报道由 G. ambrosiae 在 S. subulatum 上引起的白粉病。我们的发现将为今后白粉病的诊断和潜在防治策略的开发提供基础知识。
{"title":"First Report of Powdery Mildew Caused by <i>Golovinomyces ambrosiae</i> on <i>Symphyotrichum subulatum</i> in China.","authors":"Huafeng Liu, Tingfu Zhang, Yingqing Luo, Guoqin Wen, Na Li","doi":"10.1094/PDIS-06-24-1312-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1312-PDN","url":null,"abstract":"<p><p>Symphyotrichum subulatum (Michx.) G. L. Nesom (syn. Aster subulatus), an annual herb in the Asteraceae family, is native to North America. Nowadays, it has become an invasive weed in several provinces of China, including Jiangsu, Zhejiang, and Sichuan (Li and Xie, 2002). Despite being invasive, this species holds significance in Chinese medicine, where it is used for the external treatment of eczema and swollen sore poison (Hu, 2020). In June 2023, symptoms of powdery mildew were observed in S. subulatum populations in Deyang and Nanchong, Sichuan Province, China. About 32.73% among 55 surveyed S. subulatum plants showed signs of infection. Symptoms initially appeared as small, scattered white powdery patches on the leaves, which enlarged and coalesced over time. Subsequently, hyphal growth forming extensive conidia covered up to 90% of the leaf area on both surfaces (Fig. S1A, B), and the infected leaves withered and fell off (Fig. S1A). A specimen was archived at China West Normal University (SsPM-ZL). Conidiophores were cylindrical and erect, 66.4 to 183.2 µm (avg. 108.2±40.8 μm) in length (n=30) (Fig. S1C). Conidia, produced singly, were ellipsoid-ovoid to nearly cylindrical, measuring 29.5 to 36.7 μm in length (avg. 32.9±2.6 μm) and 16.0 to 19.9 μm in width (avg. 17.4±1.3 μm), lacking distinct fibrosin bodies (n=30) (Fig. S1D). Under a scanning electron microscope, turgid conidia displayed reticulate wrinkles on the surface, with gentle contractions or bulges at both poles (Fig. S1E, F). Based on these characteristics, the powdery mildew fungus was consistent with the genus Golovinomyces (Bradshaw et al. 2022a). To confirm the identity of the causal fungus of specimen (SsPM-ZL), the calmodulin (CAM), RNA polymerase II subunit (RPB2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glutamine synthetase (GS), and the internal transcribed spacer (ITS) were amplified using PMCAMF/R, PMRPB2F/R, PMGAPDH1/3R, PMGSF/R, and PM5/ITS4 primers (Bradshaw et al. 2022b), and deposited in GenBank (CAM: OR761878; RPB2: OR761881; GAPDH: OR761879; GS: OR761880; ITS: OR758452). BLAST analysis showed 99 to 100% identity with the sequences of Golovinomyces ambrosiae (FH00941234) for CAM (ON101658, 99.65%), RPB2 (ON119165, 100%), GS (ON075690, 99.78%), and ITS (ON073876, 99.47%). Phylogenetic analysis was performed in MEGAX with maximum likelihood method (Kumar et al. 2016) and clustered SsPM-ZL into the G. ambrosiae clade with a 100% bootstrap support value based on the concatenated sequences of CAM, RPB2, GAPDH, GS and ITS (Fig. S2). Combining morphological and phylogenetic analyses, SsPM-ZL was identified as Golovinomyces ambrosiae. To evaluate pathogenicity, leaves of 3 healthy potted S. subulatum plants (3 leaves per plant) were inoculated by gently pressing them with diseased leaves, while 3 non-contact plants were used as control. Plants in two groups were incubated in separate greenhouses maintained at 27±1°C, with a photoperiod of 14 hours and a r","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142591243","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 : 2024-11-06DOI: 10.1094/PDIS-02-24-0321-PDN
Zixuan Zhao, Qiao Wang, Yanxia Shi, Xuewen Xie, A Li Chai, Baoju Li, Lei Li
<p><p>Lettuce (Lactuca sativa) is a leafy vegetable that belongs to the family Asteraceae. This cool-season crop grows well during Spring and Fall in China (Qi et al., 2021). In October 2023, a leaf disease with dark brown to black lesions was observed on lettuce (var. iceberg) in Yongning Town, Yanqing District, Beijing, China (40°53'N, 116°16'E). The disease incidence ranged from 10 to 40% in the surveyed greenhouse and field. Translucent and water-soaked brown spots were observed on the margins of leaf, then coalesced into large necrotic lesions surrounded by a chlorotic halo. Infected sections were soaked with 75% ethyl alcohol for 7 second, rinsed with sterile water for 15 second twice, and cut into pieces in the sterile water. The sample extracts were streaked on Nutrient agar medium. After incubation for 48 hours, 12 colonies were obtained and all the colonies were Gram-negative and aerobic with yellow, round-shape, smooth and glistening appearance. Four isolates SCZX1-SCZX4 with typical characteristics were selected for further identification tests. Pathogenicity test of SCZX1-SCZX4 was performed on the three-week-old lettuce (var. butterhead) by spraying with the bacterial suspension (108 CFU·ml-1). Inoculated lettuce were incubated at 26℃ and 70% relative humidity in the growth chamber. Another set of lettuce plants were mock inoculated with sterile distilled water. Three trials were carried out per isolate, and each treatment included fifteen lettuce plants. Symptoms appeared within 7-10 days after inoculation and are identical to those naturally infected lettuces. Negative control plants had no symptoms. The 16S rRNA region and two housekeeping genes (gyrB and atpD) of each isolate were amplified with universal primers F27/R1492 (Monciardini et al., 2006) and specific primers (Roach et al., 2018), respectively. According to BLAST analysis of each isolate (Genbank accession number PP027925, PP140779, PP140781 to PP140783, PP137422 to PP137428), BLAST searches of the obtained sequences revealed 100.0% of 16S rRNA region(1400/1400 nucleotides), 100.0% of gyrB(774/774 nucleotides), and 100.0% of atpD(768/768 nucleotides) identity and query coverage to Xhv CFBP 498 (Genbank accession number LR828257.1). Phylogenetic analysis revealed that SCZX1-SCZX4 clustered with the neopathotype strain Xhv LMG 938PT, which was isolated from a diseased L. sativa in Zimbabwe (Timilsina, S et al., 2015). Physiological and biochemical tests of SCZX1-SCZX4 were conducted by the BIOLOG GENIII microplate system (Biolog, Hayward, CA, USA), and the test results are consistent with the Xhv LMG 938PT (Morinière, L et al., 2020) and L1-L7 (Pernezny, K et al., 1995). Strains were re-isolated from re-inoculated lettuce, then re-identified as Xhv by the same method, fulfilling Koch's postulates. Bacterial leaf spot (BLS) is a worldwide-spread lettuce disease caused by numerous bacterial pathogens, including Xhv (Dia, N.C et al., 2022), Pseudomonas cichorii (Patel, N e
{"title":"First Report of <i>Xanthomonas hortorum</i> pv. <i>vitians</i> as the Causal Agent of Bacterial Leaf Spot on Lettuce in China.","authors":"Zixuan Zhao, Qiao Wang, Yanxia Shi, Xuewen Xie, A Li Chai, Baoju Li, Lei Li","doi":"10.1094/PDIS-02-24-0321-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-02-24-0321-PDN","url":null,"abstract":"<p><p>Lettuce (Lactuca sativa) is a leafy vegetable that belongs to the family Asteraceae. This cool-season crop grows well during Spring and Fall in China (Qi et al., 2021). In October 2023, a leaf disease with dark brown to black lesions was observed on lettuce (var. iceberg) in Yongning Town, Yanqing District, Beijing, China (40°53'N, 116°16'E). The disease incidence ranged from 10 to 40% in the surveyed greenhouse and field. Translucent and water-soaked brown spots were observed on the margins of leaf, then coalesced into large necrotic lesions surrounded by a chlorotic halo. Infected sections were soaked with 75% ethyl alcohol for 7 second, rinsed with sterile water for 15 second twice, and cut into pieces in the sterile water. The sample extracts were streaked on Nutrient agar medium. After incubation for 48 hours, 12 colonies were obtained and all the colonies were Gram-negative and aerobic with yellow, round-shape, smooth and glistening appearance. Four isolates SCZX1-SCZX4 with typical characteristics were selected for further identification tests. Pathogenicity test of SCZX1-SCZX4 was performed on the three-week-old lettuce (var. butterhead) by spraying with the bacterial suspension (108 CFU·ml-1). Inoculated lettuce were incubated at 26℃ and 70% relative humidity in the growth chamber. Another set of lettuce plants were mock inoculated with sterile distilled water. Three trials were carried out per isolate, and each treatment included fifteen lettuce plants. Symptoms appeared within 7-10 days after inoculation and are identical to those naturally infected lettuces. Negative control plants had no symptoms. The 16S rRNA region and two housekeeping genes (gyrB and atpD) of each isolate were amplified with universal primers F27/R1492 (Monciardini et al., 2006) and specific primers (Roach et al., 2018), respectively. According to BLAST analysis of each isolate (Genbank accession number PP027925, PP140779, PP140781 to PP140783, PP137422 to PP137428), BLAST searches of the obtained sequences revealed 100.0% of 16S rRNA region(1400/1400 nucleotides), 100.0% of gyrB(774/774 nucleotides), and 100.0% of atpD(768/768 nucleotides) identity and query coverage to Xhv CFBP 498 (Genbank accession number LR828257.1). Phylogenetic analysis revealed that SCZX1-SCZX4 clustered with the neopathotype strain Xhv LMG 938PT, which was isolated from a diseased L. sativa in Zimbabwe (Timilsina, S et al., 2015). Physiological and biochemical tests of SCZX1-SCZX4 were conducted by the BIOLOG GENIII microplate system (Biolog, Hayward, CA, USA), and the test results are consistent with the Xhv LMG 938PT (Morinière, L et al., 2020) and L1-L7 (Pernezny, K et al., 1995). Strains were re-isolated from re-inoculated lettuce, then re-identified as Xhv by the same method, fulfilling Koch's postulates. Bacterial leaf spot (BLS) is a worldwide-spread lettuce disease caused by numerous bacterial pathogens, including Xhv (Dia, N.C et al., 2022), Pseudomonas cichorii (Patel, N e","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142591233","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 : 2024-11-06DOI: 10.1094/PDIS-09-24-1841-PDN
Fayu Li, Bin Shan, Xiaoxiao Zhang, Wei Zhao, Lingling Pan, Chaorong Wu, Shanshan Yang
<p><p>Luffa cylindrica (L.), an annual climbing herb of the Cucurbitaceae family, has a long planting history in China and is deeply loved by people due to its nutritional and medicinal value (Partap S, Kumar A et al., 2012). April 2023, symptoms such as plant dwarfism, decreased yield and serious root-knots appeared on L. cylindrica sampled from a commercial production base in Beihai, Guangxi, China (GPS 21°55'79″ N;109°49'61″ E). The investigated area of L. cylindrica was about 1.3 ha, the incidence of root-knot nematode disease was almost 90%. The roots of 20 L. cylindrica were dug up and many root-knots and egg masses were found. Nematodes in samples at different stages were collected by shallow dish method, and morphological identification was caried out. Males were worm-like, annulated, with the anterior part slightly conical. Females were globular to pyriform. The perineal pattern was oval, with the dorsal arch being moderately high to tall. The tail of the second-stage juvenile (J2) was very slender with a sharp tip. The transparent tail end was clearly visible. Morphological measurements of females (n = 20): body length = 677.2 ± 34.4 μm, body width = 512.8 ± 45.4 μm, stylet = 13.7 ± 0.5 μm, dorsal pharyngeal gland orifice to stylet base (DGO) = 5.7 ± 0.8 μm. The measurements of J2s (n = 20): body length = 412.5 ± 19.4 μm, body wide = 16.2 ± 1.3 μm, stylet lengths = 12.6 ± 0.92 μm, DGO length = 3.1 ± 0.3 μm. Average tail length = 45.44 ± 4.1μm. The observed typical characteristics of M. enterolobii were consistent with those previously described by Yang & Eisenback (1983) and EPPO (2016). J2s hatched by single egg mass were used for DNA extraction and identification of molecular biology. Me-F/Me-R (AACTTTTGTGAAAGTGCCGCTG/TCAGTTCAGGCAGGATCAACC), the specific primers of M. enterolobii, was used to validate this pathogen (Long et al., 2006). Consistent with that described before, the target amplification product was about 236 bp, and no product was obtained from the negative control, M. incognita and M. javanica (Chen et al., 2023). Using V5367/26S (TTGATTACGTCCCTGCCCTTT/TTTCACTCGCCGTTACTAAGG), the rDNA ITS region was obtained and sequenced (Vrain et al., 1992). The target product was 765 bp (GenBank accession no. PQ205316), which was 100% homologous to those M. enterolobii ITS sequence available in the GenBank (KX823372, KJ146863). Koch's postulates were used to verify the pathogenicity of M. enterolobii on L. cylindrica, twelve 2-week-old L. cylindrica were planted in sterilized soil and inoculated with M. enterolobii J2s at a rate of 3,000 individuals per plant. The plants were grown at 26°C in a greenhouse, with non-inoculated controls set up. After 8 weeks, the roots of the non-inoculated plants (n = 12) showed no root-knot and grew well, while all inoculated plants developed root-knots and exhibited stunted growth. The average reproduction factor of the inoculated plants was 19.5, and the average root-knot rating was 7.2 (on a scale o
{"title":"First Report of Root-knot Nematode, <i>Meloidogyne enterolobii</i>, on <i>Luffa cylindrica</i> (L.) in Guangxi, China.","authors":"Fayu Li, Bin Shan, Xiaoxiao Zhang, Wei Zhao, Lingling Pan, Chaorong Wu, Shanshan Yang","doi":"10.1094/PDIS-09-24-1841-PDN","DOIUrl":"10.1094/PDIS-09-24-1841-PDN","url":null,"abstract":"<p><p>Luffa cylindrica (L.), an annual climbing herb of the Cucurbitaceae family, has a long planting history in China and is deeply loved by people due to its nutritional and medicinal value (Partap S, Kumar A et al., 2012). April 2023, symptoms such as plant dwarfism, decreased yield and serious root-knots appeared on L. cylindrica sampled from a commercial production base in Beihai, Guangxi, China (GPS 21°55'79″ N;109°49'61″ E). The investigated area of L. cylindrica was about 1.3 ha, the incidence of root-knot nematode disease was almost 90%. The roots of 20 L. cylindrica were dug up and many root-knots and egg masses were found. Nematodes in samples at different stages were collected by shallow dish method, and morphological identification was caried out. Males were worm-like, annulated, with the anterior part slightly conical. Females were globular to pyriform. The perineal pattern was oval, with the dorsal arch being moderately high to tall. The tail of the second-stage juvenile (J2) was very slender with a sharp tip. The transparent tail end was clearly visible. Morphological measurements of females (n = 20): body length = 677.2 ± 34.4 μm, body width = 512.8 ± 45.4 μm, stylet = 13.7 ± 0.5 μm, dorsal pharyngeal gland orifice to stylet base (DGO) = 5.7 ± 0.8 μm. The measurements of J2s (n = 20): body length = 412.5 ± 19.4 μm, body wide = 16.2 ± 1.3 μm, stylet lengths = 12.6 ± 0.92 μm, DGO length = 3.1 ± 0.3 μm. Average tail length = 45.44 ± 4.1μm. The observed typical characteristics of M. enterolobii were consistent with those previously described by Yang & Eisenback (1983) and EPPO (2016). J2s hatched by single egg mass were used for DNA extraction and identification of molecular biology. Me-F/Me-R (AACTTTTGTGAAAGTGCCGCTG/TCAGTTCAGGCAGGATCAACC), the specific primers of M. enterolobii, was used to validate this pathogen (Long et al., 2006). Consistent with that described before, the target amplification product was about 236 bp, and no product was obtained from the negative control, M. incognita and M. javanica (Chen et al., 2023). Using V5367/26S (TTGATTACGTCCCTGCCCTTT/TTTCACTCGCCGTTACTAAGG), the rDNA ITS region was obtained and sequenced (Vrain et al., 1992). The target product was 765 bp (GenBank accession no. PQ205316), which was 100% homologous to those M. enterolobii ITS sequence available in the GenBank (KX823372, KJ146863). Koch's postulates were used to verify the pathogenicity of M. enterolobii on L. cylindrica, twelve 2-week-old L. cylindrica were planted in sterilized soil and inoculated with M. enterolobii J2s at a rate of 3,000 individuals per plant. The plants were grown at 26°C in a greenhouse, with non-inoculated controls set up. After 8 weeks, the roots of the non-inoculated plants (n = 12) showed no root-knot and grew well, while all inoculated plants developed root-knots and exhibited stunted growth. The average reproduction factor of the inoculated plants was 19.5, and the average root-knot rating was 7.2 (on a scale o","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142591249","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 : 2024-11-06DOI: 10.1094/PDIS-12-23-2575-RE
Jinfa Zhao, Song Zhang, Jiajun Wang, Binghai Lou, Yan Zhou
Citrus chlorotic dwarf disease (CCDD) seriously affects the citrus industry. Citrus chlorotic dwarf-associated virus (CCDaV) is speculated to be the causal agent of CCDD. However, this speculation has not been confirmed by fulfilling Koch's postulates. In this study, an infectious clone comprising a 1.6-fold tandem CCDaV genome in the binary vector pBinPLUS was constructed and agro-inoculated into 'Eureka' lemon (Citrus limon) seedlings through vacuum infiltration. At 60 days postinoculation, 25% of the 'Eureka' lemon seedlings developed symptoms of crinkling and curling that were the same as those associated with the wild-type virus. Western blotting and graft transmission assays confirmed that the infectious clone systemically infected 'Eureka' lemon seedlings. In addition, CCDaV can establish infection on three more Citrus species and one hybrid, although at different infection rates. These findings support that CCDaV is the primary causal agent of CCDD. The infectious CCDaV clone will allow further studies on the functions of viral proteins and molecular interactions of CCDaV with its hosts.
{"title":"Construction of an Infectious Clone of Citrus Chlorotic Dwarf-Associated Virus and Confirmation of Its Pathogenicity.","authors":"Jinfa Zhao, Song Zhang, Jiajun Wang, Binghai Lou, Yan Zhou","doi":"10.1094/PDIS-12-23-2575-RE","DOIUrl":"10.1094/PDIS-12-23-2575-RE","url":null,"abstract":"<p><p>Citrus chlorotic dwarf disease (CCDD) seriously affects the citrus industry. Citrus chlorotic dwarf-associated virus (CCDaV) is speculated to be the causal agent of CCDD. However, this speculation has not been confirmed by fulfilling Koch's postulates. In this study, an infectious clone comprising a 1.6-fold tandem CCDaV genome in the binary vector pBinPLUS was constructed and agro-inoculated into 'Eureka' lemon (<i>Citrus limon</i>) seedlings through vacuum infiltration. At 60 days postinoculation, 25% of the 'Eureka' lemon seedlings developed symptoms of crinkling and curling that were the same as those associated with the wild-type virus. Western blotting and graft transmission assays confirmed that the infectious clone systemically infected 'Eureka' lemon seedlings. In addition, CCDaV can establish infection on three more <i>Citrus</i> species and one hybrid, although at different infection rates. These findings support that CCDaV is the primary causal agent of CCDD. The infectious CCDaV clone will allow further studies on the functions of viral proteins and molecular interactions of CCDaV with its hosts.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS12232575RE"},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141634211","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 : 2024-11-06DOI: 10.1094/PDIS-01-24-0180-PDN
Junhui Li, Shiyang Qin, Yanxia Shi, Xuewen Xie, A Li Chai, Yuanhong Wang, Baoju Li, Lei Li
<p><p>The purple stem mustards (Brassica rapa subsp. chinensis var. purpuraria) (Govaerts R, 2003) are widely cultivated along Yangtze River Valley in China, which is famous for its flavorful and nutritious edible stalks (Wang et al., 2022). In February 2023, a disease of soft rot was observed in multiple purple stem mustards planting fields in Wuhan city, Hubei province, China (30.41°N, 114.22°E). Disease incidence rates were almost 20 to 30% in the planting area (5 ha in size), causing severe economic loss. Infected plants displayed water-soaked symptoms at the base of the petioles, emitting a foul soft rot odor. The severely infected petioles, stems and roots exhibit pus symptoms leading to plant death. To identify the causal agent, small pieces of soft rot symptomatic tissue were cut from the margin of necrotic lesions and surface disinfected with 75% (v/v) ethanol for 30 seconds, followed by three successive rinses with sterile distilled water. The exudates from the clipped tissues were serially diluted and then incubated onto nutrient agar (NA) plates to obtain purified strains at 28°C for 48 hours (Koike et al., 2002). After incubation, 15 strains were obtained and the colonies of all strains were Gram-negative, aerobic, small, round, convex, whitish to dull white, and had smooth slimy edges. Three single bacterial strains CT020801 - CT020803, which were individually isolated from three different diseased samples, were selected as representative strains for further study. Biochemical tests using the BIOLOG GENIII microplate system (Biolog, Hayward, CA, USA) revealed that these strains were positive for methyl red, pectin, dextrin, D-Cellobiose, β-galactosidase, citrate, and maltose, but negative for indole, arginine dihydrolase, urease, ornithine decarboxylase, and gelatinase tests. The 16S ribosomal RNA gene and the three housekeeping genes, atpD, rpoB, and recN were amplified using genomic DNA of Lelliottia amnigena NCTC12124T as the template, with specially designed primers. All amplified fragments were sequenced and deposited in GenBank with accession numbers OQ954706-OQ954707, OQ954713, and OQ953873-OQ953881. BLAST alignments of the 16S rRNA, atpD, rpoB and recN sequences revealed that the sequences of Strain CT020801-03 exhibited the highest identity (100%, ≥97.97%, ≥98.85% and ≥94.52%, respectively) with L. amnigena （Figure S2）. Phylogenetic tree analysis based on multilocus sequence joint 16S rRNA - atpD - rpoB - recN revealed that CT020801 - CT020803 and L. amnigena clustered together in the same clade (Carrie et al., 2013). These results were consistent with those reported for Lelliottia amnigena (Osei et al., 2022). To confirm pathogenicity, healthy base petioles of three-week-old purple stem mustards seedlings were stab inoculated with 20 μL bacterial suspensions (approximately 108 CFU/mL) and then incubated at 28°C and 80% relative humidity in a growth chamber. A sterile liquid NB medium served as the negative control. The tes
{"title":"First Report of <i>Lelliottia amnigena</i> Causing Soft Rot on Purple Stem Mustards in China.","authors":"Junhui Li, Shiyang Qin, Yanxia Shi, Xuewen Xie, A Li Chai, Yuanhong Wang, Baoju Li, Lei Li","doi":"10.1094/PDIS-01-24-0180-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-01-24-0180-PDN","url":null,"abstract":"<p><p>The purple stem mustards (Brassica rapa subsp. chinensis var. purpuraria) (Govaerts R, 2003) are widely cultivated along Yangtze River Valley in China, which is famous for its flavorful and nutritious edible stalks (Wang et al., 2022). In February 2023, a disease of soft rot was observed in multiple purple stem mustards planting fields in Wuhan city, Hubei province, China (30.41°N, 114.22°E). Disease incidence rates were almost 20 to 30% in the planting area (5 ha in size), causing severe economic loss. Infected plants displayed water-soaked symptoms at the base of the petioles, emitting a foul soft rot odor. The severely infected petioles, stems and roots exhibit pus symptoms leading to plant death. To identify the causal agent, small pieces of soft rot symptomatic tissue were cut from the margin of necrotic lesions and surface disinfected with 75% (v/v) ethanol for 30 seconds, followed by three successive rinses with sterile distilled water. The exudates from the clipped tissues were serially diluted and then incubated onto nutrient agar (NA) plates to obtain purified strains at 28°C for 48 hours (Koike et al., 2002). After incubation, 15 strains were obtained and the colonies of all strains were Gram-negative, aerobic, small, round, convex, whitish to dull white, and had smooth slimy edges. Three single bacterial strains CT020801 - CT020803, which were individually isolated from three different diseased samples, were selected as representative strains for further study. Biochemical tests using the BIOLOG GENIII microplate system (Biolog, Hayward, CA, USA) revealed that these strains were positive for methyl red, pectin, dextrin, D-Cellobiose, β-galactosidase, citrate, and maltose, but negative for indole, arginine dihydrolase, urease, ornithine decarboxylase, and gelatinase tests. The 16S ribosomal RNA gene and the three housekeeping genes, atpD, rpoB, and recN were amplified using genomic DNA of Lelliottia amnigena NCTC12124T as the template, with specially designed primers. All amplified fragments were sequenced and deposited in GenBank with accession numbers OQ954706-OQ954707, OQ954713, and OQ953873-OQ953881. BLAST alignments of the 16S rRNA, atpD, rpoB and recN sequences revealed that the sequences of Strain CT020801-03 exhibited the highest identity (100%, ≥97.97%, ≥98.85% and ≥94.52%, respectively) with L. amnigena （Figure S2）. Phylogenetic tree analysis based on multilocus sequence joint 16S rRNA - atpD - rpoB - recN revealed that CT020801 - CT020803 and L. amnigena clustered together in the same clade (Carrie et al., 2013). These results were consistent with those reported for Lelliottia amnigena (Osei et al., 2022). To confirm pathogenicity, healthy base petioles of three-week-old purple stem mustards seedlings were stab inoculated with 20 μL bacterial suspensions (approximately 108 CFU/mL) and then incubated at 28°C and 80% relative humidity in a growth chamber. A sterile liquid NB medium served as the negative control. The tes","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142591166","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 : 2024-11-06DOI: 10.1094/PDIS-09-24-1884-PDN
Yi Wen, YanHong Qin, Suxia Gao, Yuxia Liu, Wenping Qi, Shaojian Li, Chuantao Lu, Fei Wang
<p><p>Epimedium [Epimedium sagittatum (Sieb. et Zucc.) Maxim., E. brevicornu Maxim., E. pubescens Maxim., E. koreanum Nakai] plants are perennial herbs and the dry leaves were used in traditional Chinese medicine with different medicinal effects (Chinese Pharmacopoeia, 2020 edition). In early August 2022 (the high temperature was 33 ℃ and the low temperature was 25 ℃ on average with above 70% relative humidity), large necrotized leaf spots were initially observed in one-year and two-year old E. sagittatum plants in Dengzhou (32°35'26.84" N, 112°11'8.37" E), Henan province, China. White mycelia, yellow and brown sclerotia were observed along the petioles and colonized to the back of leaves and also on soil-petioles interface around the diseased Epimedium plants. White mycelia spread rapidly from the disease plants as a center to neighboring plants and the infected plants eventually wilted. The disease incidence was 16.0% and 28.0% in the surveyed cultivation fields in Dengzhou (Henan) and Danjiangkou (Hubei), respectively, which resulted in above 20% of yield loss. The symptomatic tissues (petioles, n≥10) were cut into 0.5 cm sections with autoclaved scissors and surface sterilized with 75% ethanol for 30 s, followed by 3 min in 1% NaClO, rinsed three times with distilled sterile water, plated on autoclaved filter paper to remove excess moisture in a biological laminar hood, transferred onto potato dextrose agar (PDA) plates and incubated at 28℃ in incubator in the dark for 3-5 days. Twelve fungal isolates with white radial colony morphology were obtained and purified by hyphal-tip method. The isolates formed radial colonies showing abundant aerial mycelia with a growth rate of 19.25 to 22.25 mm/day (mean = 21.67 ± 0.77 mm; n = 36) and white abundant sclerotia were observed after 5-7 days post inoculation at 28℃. The hyphae of the isolates were hyaline, branched with clamp connections at septa. The isolates formed dark brown sclerotia on PDA plate post 10-14 days incubation. The diameter of mature brown sclerotia ranged from 1.31 to 3.07 mm (mean = 1.91 ± 0.39 mm; n = 40) and 13 to 45 sclerotia (mean = 28; n = 24) were observed on each Petri dish. The isolates were tentatively identified as Agroathelia rolfsii based on morphological characteristics (Yi Y., et al. 2024) and isolate YYHBJ1 was selected as representative isolate for molecular identification and pathogenicity test. The genomic DNA was extracted using CTAB method. For molecular identification, ITS region, translation elongation factor-1alpha (TEF-1α) and nuclear large-subunit ribosomal DNA (nLSU-rDNA) were amplified (White et al. 1990, Wendland and Kothe, 1997). The sequences 684-bp ITS (OR428367), 534-bp TEF1α (OR485567), and 965-bp nLSU-rDNA (OR426612) of isolate YYHBJ1 were deposited in GenBank. Sequence analysis revealed that ITS, TEF1α and nLSU-rDNA sequences of YYHBJ001 showed 100%, 99.63%, and 100% identity to ITS (MN380242 and JF819727), EF1α (MN262527) and nLSU-rDNA (MT225781
{"title":"First Report of Southern Blight of <i>Epimedium sagittatum</i> Caused by <i>Agroathelia rolfsii</i> in Henan, China.","authors":"Yi Wen, YanHong Qin, Suxia Gao, Yuxia Liu, Wenping Qi, Shaojian Li, Chuantao Lu, Fei Wang","doi":"10.1094/PDIS-09-24-1884-PDN","DOIUrl":"10.1094/PDIS-09-24-1884-PDN","url":null,"abstract":"<p><p>Epimedium [Epimedium sagittatum (Sieb. et Zucc.) Maxim., E. brevicornu Maxim., E. pubescens Maxim., E. koreanum Nakai] plants are perennial herbs and the dry leaves were used in traditional Chinese medicine with different medicinal effects (Chinese Pharmacopoeia, 2020 edition). In early August 2022 (the high temperature was 33 ℃ and the low temperature was 25 ℃ on average with above 70% relative humidity), large necrotized leaf spots were initially observed in one-year and two-year old E. sagittatum plants in Dengzhou (32°35'26.84\" N, 112°11'8.37\" E), Henan province, China. White mycelia, yellow and brown sclerotia were observed along the petioles and colonized to the back of leaves and also on soil-petioles interface around the diseased Epimedium plants. White mycelia spread rapidly from the disease plants as a center to neighboring plants and the infected plants eventually wilted. The disease incidence was 16.0% and 28.0% in the surveyed cultivation fields in Dengzhou (Henan) and Danjiangkou (Hubei), respectively, which resulted in above 20% of yield loss. The symptomatic tissues (petioles, n≥10) were cut into 0.5 cm sections with autoclaved scissors and surface sterilized with 75% ethanol for 30 s, followed by 3 min in 1% NaClO, rinsed three times with distilled sterile water, plated on autoclaved filter paper to remove excess moisture in a biological laminar hood, transferred onto potato dextrose agar (PDA) plates and incubated at 28℃ in incubator in the dark for 3-5 days. Twelve fungal isolates with white radial colony morphology were obtained and purified by hyphal-tip method. The isolates formed radial colonies showing abundant aerial mycelia with a growth rate of 19.25 to 22.25 mm/day (mean = 21.67 ± 0.77 mm; n = 36) and white abundant sclerotia were observed after 5-7 days post inoculation at 28℃. The hyphae of the isolates were hyaline, branched with clamp connections at septa. The isolates formed dark brown sclerotia on PDA plate post 10-14 days incubation. The diameter of mature brown sclerotia ranged from 1.31 to 3.07 mm (mean = 1.91 ± 0.39 mm; n = 40) and 13 to 45 sclerotia (mean = 28; n = 24) were observed on each Petri dish. The isolates were tentatively identified as Agroathelia rolfsii based on morphological characteristics (Yi Y., et al. 2024) and isolate YYHBJ1 was selected as representative isolate for molecular identification and pathogenicity test. The genomic DNA was extracted using CTAB method. For molecular identification, ITS region, translation elongation factor-1alpha (TEF-1α) and nuclear large-subunit ribosomal DNA (nLSU-rDNA) were amplified (White et al. 1990, Wendland and Kothe, 1997). The sequences 684-bp ITS (OR428367), 534-bp TEF1α (OR485567), and 965-bp nLSU-rDNA (OR426612) of isolate YYHBJ1 were deposited in GenBank. Sequence analysis revealed that ITS, TEF1α and nLSU-rDNA sequences of YYHBJ001 showed 100%, 99.63%, and 100% identity to ITS (MN380242 and JF819727), EF1α (MN262527) and nLSU-rDNA (MT225781 ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142591256","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 : 2024-11-06DOI: 10.1094/PDIS-07-24-1396-RE
Fiona Harrigian, Nicholas LeBlanc, Renee L Eriksen, Elizabeth A Bush, Lina Rodriguez Salamanca, Catalina Salgado-Salazar
Calonectria spp. can cause destructive diseases on forestry crops, legumes like soybean and peanut, and ornamentals. Species of Calonectria affecting ornamental plants are not well characterized or understood, though they have been widely documented as an issue in the ornamental industry. This research focused on the molecular identification, pathogenicity validation, and genome analysis of a Calonectria sp. isolate recovered from ornamental blue false indigo (Baptisia australis) plants showing disease symptoms of crown and root rot in a commercial nursery in Virginia. The fungus on B. australis was identified as C. fujianensis (Nectriaceae, Hypocreales), a member of the C. colhuonii species complex using multilocus sequencing. Pathogenicity tests were fulfilled by inoculating C. fujianensis conidia on B. australis seedlings, confirming a causal relationship between this pathogen and the disease symptoms observed. A 62.7 Mb high-quality hybrid genome assembly generated using Illumina and Nanopore data was obtained, contained in 16 contigs, four of which were complete chromosomes. A total of 750 effectors were found in the genome, similar to cutinase and pectinase virulence factors described from other Calonectria species' genomes. Characterization of this novel disease of B. australis advances our understanding of Calonectria as an important but poorly studied group of plant pathogens.
Calonectria 属可对林业作物、豆类（如大豆和花生）和观赏植物造成破坏性病害。影响观赏植物的 Calonectria 物种还没有被很好地描述或了解，尽管它们已被广泛记录为观赏植物行业的一个问题。这项研究的重点是对从弗吉尼亚州一家商业苗圃中出现冠腐病和根腐病症状的观赏蓝花楹（Baptisia australis）植物中分离出的 Calonectria sp.进行分子鉴定、致病性验证和基因组分析。通过多焦点测序，B. australis 上的真菌被鉴定为 C. fujianensis（花蜜科，Hypocreales），是 C. colhuonii 物种群的成员。通过将 C. fujianensis 分生孢子接种到 B. australis 的幼苗上进行致病性试验，证实了该病原体与所观察到的病害症状之间的因果关系。利用 Illumina 和 Nanopore 数据生成了 62.7 Mb 的高质量杂交基因组，包含 16 个等位基因，其中 4 个是完整的染色体。基因组中共发现了 750 个效应因子，与其他 Calonectria 物种基因组中描述的角质酶和果胶酶毒力因子相似。对这种新病害的特征描述，加深了我们对 Calonectria 这类重要但研究较少的植物病原体的了解。
{"title":"Uncovering the fungus responsible for stem and root rot of false indigo: pathogen identification, new disease description, and genome analyses.","authors":"Fiona Harrigian, Nicholas LeBlanc, Renee L Eriksen, Elizabeth A Bush, Lina Rodriguez Salamanca, Catalina Salgado-Salazar","doi":"10.1094/PDIS-07-24-1396-RE","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1396-RE","url":null,"abstract":"<p><p>Calonectria spp. can cause destructive diseases on forestry crops, legumes like soybean and peanut, and ornamentals. Species of Calonectria affecting ornamental plants are not well characterized or understood, though they have been widely documented as an issue in the ornamental industry. This research focused on the molecular identification, pathogenicity validation, and genome analysis of a Calonectria sp. isolate recovered from ornamental blue false indigo (Baptisia australis) plants showing disease symptoms of crown and root rot in a commercial nursery in Virginia. The fungus on B. australis was identified as C. fujianensis (Nectriaceae, Hypocreales), a member of the C. colhuonii species complex using multilocus sequencing. Pathogenicity tests were fulfilled by inoculating C. fujianensis conidia on B. australis seedlings, confirming a causal relationship between this pathogen and the disease symptoms observed. A 62.7 Mb high-quality hybrid genome assembly generated using Illumina and Nanopore data was obtained, contained in 16 contigs, four of which were complete chromosomes. A total of 750 effectors were found in the genome, similar to cutinase and pectinase virulence factors described from other Calonectria species' genomes. Characterization of this novel disease of B. australis advances our understanding of Calonectria as an important but poorly studied group of plant pathogens.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142591270","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号