Pitaya canker disease, caused by Neoscytalidium dimidiatum, is the primary threat to pitaya cultivation, significantly compromising fruit quality and reducing yield. WRKY transcription factors are essential regulators in plant pathogen recognition and defense mechanisms, yet their specific roles in the development of pitaya canker disease remain largely unexplored. In this study, five genes (HmeWRKY33, HmeWRKY51, HmePR1, HmeHsp70, and HmeSERK) associated with pitaya canker disease were identified through RNA-Seq analysis. The expression levels of HmeWRKY33 and HmeWRKY51 were upregulated following N. dimidiatum infection. Transient transformation revealed that these five genes negatively influenced the resistance of Nicotiana benthamiana leaves to canker disease, while promoting the accumulation of reactive oxygen species (ROS) and inducing cell death. Yeast one-hybrid and dual-luciferase reporter assays revealed that HmeWRKY33 directly activated the expression of HmeSERK, while HmeWRKY51 directly inhibited the expression of HmePR1 and HmeHsp70, co-participating in regulating the susceptibility of 'Youcihuanglong' pitaya to canker. These findings provide a theoretical basis for breeding new canker-resistant pitaya varieties through genetic transformation.
{"title":"Transcription factors HmeWRKY33 and HmeWRKY51 regulate the susceptibility of pitaya to canker disease.","authors":"Rongzheng Luo, Rong Zhang, Jiaxuan Chen, Shujun Peng, Irfan Ali Sabir, Zhaoqing Li, Liangfang Wu, Guibing Hu, Kamran Shah, Yonghua Qin","doi":"10.1094/PDIS-08-24-1589-RE","DOIUrl":"https://doi.org/10.1094/PDIS-08-24-1589-RE","url":null,"abstract":"<p><p>Pitaya canker disease, caused by <i>Neoscytalidium dimidiatum</i>, is the primary threat to pitaya cultivation, significantly compromising fruit quality and reducing yield. WRKY transcription factors are essential regulators in plant pathogen recognition and defense mechanisms, yet their specific roles in the development of pitaya canker disease remain largely unexplored. In this study, five genes (<i>HmeWRKY33</i>, <i>HmeWRKY51</i>, <i>HmePR1</i>, <i>HmeHsp70</i>, and <i>HmeSERK</i>) associated with pitaya canker disease were identified through RNA-Seq analysis. The expression levels of <i>HmeWRKY33</i> and <i>HmeWRKY51</i> were upregulated following <i>N. dimidiatum</i> infection. Transient transformation revealed that these five genes negatively influenced the resistance of <i>Nicotiana benthamiana</i> leaves to canker disease, while promoting the accumulation of reactive oxygen species (ROS) and inducing cell death. Yeast one-hybrid and dual-luciferase reporter assays revealed that HmeWRKY33 directly activated the expression of <i>HmeSERK</i>, while HmeWRKY51 directly inhibited the expression of <i>HmePR1</i> and <i>HmeHsp70</i>, co-participating in regulating the susceptibility of 'Youcihuanglong' pitaya to canker. These findings provide a theoretical basis for breeding new canker-resistant pitaya varieties through genetic transformation.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143067290","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}
<p><p>'Lanjingling' [China National Plant Variety Protection (CNPVP) 20200389] is the first new nationally registered cultivar of blue honeysuckle (Lonicera caerulea L.) developed by the Northeast Agricultural University for the fresh-fruit market (Zhu et al. 2022). Between September 2022 and September 2023, a leaf spot disease was observed on approximately 30% of blue honeysuckle Lanjingling plants grown in a 0.02 ha field in the city of Harbin (45.07° N, 128.14° E) in Heilongjiang Province, China. The leaves of the affected plants initially displayed gray-colored spots that gradually expanded into irregular white blotches with dark brown borders affecting the whole leaf. To identify the causal agent, total 10 symptomatic leaves were randomly collected from ten individual plants in representing entire filed. Small (3 to 4 mm) segments of infected tissue from 10 leaves from different plants were surface sterilized using 75% ethanol for 30 s and 5% sodium hypochlorite (NaClO) for 3 min, and then rinsed three times with sterile distilled water, dried in a paper towel, and plated in 9 cm Petri dishes containing potato dextrose agar (PDA). Seven isolates (LD-366 to LD-372) from each piece were isolated on the PDA plate, and all colonies displayed a conidial morphology consistent with Pestaloid taxa. They have undulated margins, white to pale in color, with moderate aerial mycelium on the surface. The conidia were ellipsoid, straight to slightly curved, four septate, and measuring 12.30 to 33.40 × 2.10 to 7.60 μm (n = 50). The apical cell was cylindrical and hyaline, with two to three tubular apical appendages, unbranched, and filiform. To confirm this identification, PCR amplification of two representative strains LD-366 and LD-367 genomic DNA were performed with ITS1/ITS4 (White et al. 1990), TUB2Fd/TUB4Rd (Glass and Donaldson 1995), and EF1-728F/EF1-986R (Carbone and Kohn 1999) primers. Sequences of LD-366 and LD-367 ITS (PP697761, PP697762), TUB (PP700299, PP700300), and TEF (PQ567378, PQ567379) revealed 99.09, 98.78, and 98.78% (547/552 nt, 547/552 nt; 438/440 nt, 438/440 nt; 243/246 nt, 243/246 nt) consistency with Pestalotiopsis disseminata sequences (MT374688, MT374713, and MT374700), respectively. Phylogenetic analysis of the combined sequences were performed using maximum-likelihood (ML) and Bayesian inference (BI) methods (Jiang et al. 2022), isolates LD-366 and LD-367 were located in the same clade with P. disseminata. A pathogenicity test was performed using six healthy, two-year-old blue honeysuckle Lanjingling plants. Three plants were inoculated with either the LD-366 or the LD-367 conidial suspension (1 × 106 spores/ml) or with clean water as an experimental control. All plants were placed in a greenhouse (28℃, 75% relative humidity, 12 h light and dark cycle), and each experiment was replicated three times. Typical leaf spot symptoms were first observed on inoculated leaves after 10 days. Two pathogens, reisolated from infected leave
{"title":"First report of leaf spot disease caused by <i>Pestalotiopsis disseminata</i> on <i>Lonicera caerulea</i> L. in Heilongjiang Province, China.","authors":"Haohao Yan, Yaozu Mi, Zijian Man, Pin Lv, Liangchuan Guo, Junwei Huo, Mingyu Sang, Hailian Zang, Yi Cheng","doi":"10.1094/PDIS-01-25-0066-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-01-25-0066-PDN","url":null,"abstract":"<p><p>'Lanjingling' [China National Plant Variety Protection (CNPVP) 20200389] is the first new nationally registered cultivar of blue honeysuckle (Lonicera caerulea L.) developed by the Northeast Agricultural University for the fresh-fruit market (Zhu et al. 2022). Between September 2022 and September 2023, a leaf spot disease was observed on approximately 30% of blue honeysuckle Lanjingling plants grown in a 0.02 ha field in the city of Harbin (45.07° N, 128.14° E) in Heilongjiang Province, China. The leaves of the affected plants initially displayed gray-colored spots that gradually expanded into irregular white blotches with dark brown borders affecting the whole leaf. To identify the causal agent, total 10 symptomatic leaves were randomly collected from ten individual plants in representing entire filed. Small (3 to 4 mm) segments of infected tissue from 10 leaves from different plants were surface sterilized using 75% ethanol for 30 s and 5% sodium hypochlorite (NaClO) for 3 min, and then rinsed three times with sterile distilled water, dried in a paper towel, and plated in 9 cm Petri dishes containing potato dextrose agar (PDA). Seven isolates (LD-366 to LD-372) from each piece were isolated on the PDA plate, and all colonies displayed a conidial morphology consistent with Pestaloid taxa. They have undulated margins, white to pale in color, with moderate aerial mycelium on the surface. The conidia were ellipsoid, straight to slightly curved, four septate, and measuring 12.30 to 33.40 × 2.10 to 7.60 μm (n = 50). The apical cell was cylindrical and hyaline, with two to three tubular apical appendages, unbranched, and filiform. To confirm this identification, PCR amplification of two representative strains LD-366 and LD-367 genomic DNA were performed with ITS1/ITS4 (White et al. 1990), TUB2Fd/TUB4Rd (Glass and Donaldson 1995), and EF1-728F/EF1-986R (Carbone and Kohn 1999) primers. Sequences of LD-366 and LD-367 ITS (PP697761, PP697762), TUB (PP700299, PP700300), and TEF (PQ567378, PQ567379) revealed 99.09, 98.78, and 98.78% (547/552 nt, 547/552 nt; 438/440 nt, 438/440 nt; 243/246 nt, 243/246 nt) consistency with Pestalotiopsis disseminata sequences (MT374688, MT374713, and MT374700), respectively. Phylogenetic analysis of the combined sequences were performed using maximum-likelihood (ML) and Bayesian inference (BI) methods (Jiang et al. 2022), isolates LD-366 and LD-367 were located in the same clade with P. disseminata. A pathogenicity test was performed using six healthy, two-year-old blue honeysuckle Lanjingling plants. Three plants were inoculated with either the LD-366 or the LD-367 conidial suspension (1 × 106 spores/ml) or with clean water as an experimental control. All plants were placed in a greenhouse (28℃, 75% relative humidity, 12 h light and dark cycle), and each experiment was replicated three times. Typical leaf spot symptoms were first observed on inoculated leaves after 10 days. Two pathogens, reisolated from infected leave","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143067267","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}
Pantoeaananatis is a bacterium commonly found in various agronomic crops and agricultural pests. In this study, we present findings on a genome-reduced strain of P. ananatis, known as Lstr, which was initially isolated from Laodelphax striatellus (small brown rice planthopper [SBPH]). We identified Lstr as a plant pathogen causing disease in rice using Koch's postulates. The pathogenicity of Lstr on rice is comparable to that of Xanthomonas oryzae pv. oryzae, the main causative agent of rice bacterial blight. Through a series of experiments involving live insects, molecular investigations, and microscopy, we find that Lstr can accumulate within SBPH. Subsequently, Lstr can be transmitted from SBPH to rice plants, resulting in leaf blight, and can also be transmitted to other SBPH individuals. Collectively, our results suggest that SBPH serves as a vector for P. ananatis Lstr in rice plants. P. ananatis may encounter susceptible insect populations and become endemic through horizontal transmission from these insects. This could also be valuable for predicting future occurrences of bacterial leaf blight in rice and other crops caused by P. ananatis.
{"title":"Horizontal Transmission of the Rice Bacterial Pathogen <i>Pantoea ananatis</i> Among Plants by Rice Planthoppers.","authors":"Zi-Hao He, Ying-Xia Wang, Zhi Jin, Yue-Di Niu, Cong-Feng Song, Xiao-Yue Hong, Xiao-Li Bing","doi":"10.1094/PDIS-09-24-1908-SR","DOIUrl":"10.1094/PDIS-09-24-1908-SR","url":null,"abstract":"<p><p><i>Pantoea</i> <i>ananatis</i> is a bacterium commonly found in various agronomic crops and agricultural pests. In this study, we present findings on a genome-reduced strain of <i>P. ananatis</i>, known as Lstr, which was initially isolated from <i>Laodelphax striatellus</i> (small brown rice planthopper [SBPH]). We identified Lstr as a plant pathogen causing disease in rice using Koch's postulates. The pathogenicity of Lstr on rice is comparable to that of <i>Xanthomonas oryzae</i> pv<i>. oryzae</i>, the main causative agent of rice bacterial blight. Through a series of experiments involving live insects, molecular investigations, and microscopy, we find that Lstr can accumulate within SBPH. Subsequently, Lstr can be transmitted from SBPH to rice plants, resulting in leaf blight, and can also be transmitted to other SBPH individuals. Collectively, our results suggest that SBPH serves as a vector for <i>P. ananatis</i> Lstr in rice plants. <i>P. ananatis</i> may encounter susceptible insect populations and become endemic through horizontal transmission from these insects. This could also be valuable for predicting future occurrences of bacterial leaf blight in rice and other crops caused by <i>P. ananatis</i>.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS09241908SR"},"PeriodicalIF":4.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142351985","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}
<p><p>Ashwagandha (Withania somnifera), enriched in alkaloids, steroidal lactones and saponins, is a valuable herb in Indian Ayurvedic medicine. During December 2023, Va-1 (Vallabh Ashwagandha-1) plants at ICAR -Central Tobacco Research Institute, Vedasandur, Tamil Nadu (10.53717ºN, 77.9507°E) were noticed with anthracnose-like disease symptoms, characterized by irregular necrotic lesions on stem, leaves and pods. Infected plants dried entirely in the advanced stage and had pin-head-shaped fruiting bodies. In the assessment of 185 plants, 42 were symptomatic, while five were dried, and the disease severity varied between 17 to 22%. Pathogen was isolated from infected leaf and stem tissues (3 to 5 mm2) using a potato dextrose agar (PDA) medium amended with streptomycin sulphate (20 mg/l). Infected tissues were surface sterilized using 1% sodium hypochlorite, and the PDA plates were incubated at 27°C for three days. The pathogen was purified, and two cultures, AVCT01 and AVCT02, were used for the downstream characterization. Colonies on the PDA medium were initially pale white and later turned to dark grey, with an average growth of 42.6 mm (diameter) on the 7th day after inoculation (DAI). Conidia were smooth, hyaline, aseptate and curved, with a tapering end and truncate base. The conidial dimensions (n=30) were 22.8 ± 1.32 × 3.4 ± 0.29 µm (20.6 to 25.8 × 2.9 to 4.2). Acervuli were scattered, containing dark brown conidiomata with septate, pointed setae and measured 119 ± 16.6 × 4.2 ± 0.5 µm (81 to 148 × 3.1 to 5.3) in dimension. Morphological and cultural characteristics were identical to Colletotrichum truncatum described by Damm et al. (2009). Further, the molecular characterization was executed with primers targeting ITS (ITS1/ITS4) and three housekeeping genes; act (ACT-512F/ACT-783R), tub2 (Bt2a/Bt2b) and gapdh (GDF1/GDFR1) (Kim et al. 2020). The amplified products were sequenced bidirectionally and in BLASTn analysis, sequences revealed 100% identity with C. truncatum [(NCBI GenBank OM327672 (ITS), OR147336 (act), MG214130 (tub2) and MK675260 (gapdh)]. In the maximum likelihood phylogeny of concatenated alignments, these cultures clustered with CBS119189. All sequences were deposited in NCBI GenBank (ITS: PP919605 and PP919606; act: PP921525 and PP921526; tub2: PP921527 and PP921528; gapdh: PP921529 and PP921530). Pathogenicity was done by spraying conidial suspension of AVCT01 (1 × 106/ml) on leaves of three plants (two months old). Non-injury technique of Gupta et al. (2020) was conducted for stem inoculation. The inoculated and control plants (sprayed with sterile distilled water) were maintained separately at 25°C with 90% relative humidity. Necrotic lesions were observed on leaves and stems of inoculated plants on 8th DAI confirming Koch's postulates and the pathogen re-isolation was also done. Disease severity was assessed using the scale of Yang and Hartman, 2015. Previously, leaf spots caused by C. gloeosporioides and C. dematium w
{"title":"First report of <i>Colletotrichum truncatum</i> causing anthracnose of ashwagandha (<i>Withania somnifera</i>) in India.","authors":"Boopathi Natesan, Gopinath Palanichamy, Manivel Ponnuchamy, Saraswathi Thiruvenkatasamy, Iruthayasamy Johnson, Sambasivam Periyannan, Muthusamy Karthikeyan","doi":"10.1094/PDIS-09-24-1898-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-1898-PDN","url":null,"abstract":"<p><p>Ashwagandha (Withania somnifera), enriched in alkaloids, steroidal lactones and saponins, is a valuable herb in Indian Ayurvedic medicine. During December 2023, Va-1 (Vallabh Ashwagandha-1) plants at ICAR -Central Tobacco Research Institute, Vedasandur, Tamil Nadu (10.53717ºN, 77.9507°E) were noticed with anthracnose-like disease symptoms, characterized by irregular necrotic lesions on stem, leaves and pods. Infected plants dried entirely in the advanced stage and had pin-head-shaped fruiting bodies. In the assessment of 185 plants, 42 were symptomatic, while five were dried, and the disease severity varied between 17 to 22%. Pathogen was isolated from infected leaf and stem tissues (3 to 5 mm2) using a potato dextrose agar (PDA) medium amended with streptomycin sulphate (20 mg/l). Infected tissues were surface sterilized using 1% sodium hypochlorite, and the PDA plates were incubated at 27°C for three days. The pathogen was purified, and two cultures, AVCT01 and AVCT02, were used for the downstream characterization. Colonies on the PDA medium were initially pale white and later turned to dark grey, with an average growth of 42.6 mm (diameter) on the 7th day after inoculation (DAI). Conidia were smooth, hyaline, aseptate and curved, with a tapering end and truncate base. The conidial dimensions (n=30) were 22.8 ± 1.32 × 3.4 ± 0.29 µm (20.6 to 25.8 × 2.9 to 4.2). Acervuli were scattered, containing dark brown conidiomata with septate, pointed setae and measured 119 ± 16.6 × 4.2 ± 0.5 µm (81 to 148 × 3.1 to 5.3) in dimension. Morphological and cultural characteristics were identical to Colletotrichum truncatum described by Damm et al. (2009). Further, the molecular characterization was executed with primers targeting ITS (ITS1/ITS4) and three housekeeping genes; act (ACT-512F/ACT-783R), tub2 (Bt2a/Bt2b) and gapdh (GDF1/GDFR1) (Kim et al. 2020). The amplified products were sequenced bidirectionally and in BLASTn analysis, sequences revealed 100% identity with C. truncatum [(NCBI GenBank OM327672 (ITS), OR147336 (act), MG214130 (tub2) and MK675260 (gapdh)]. In the maximum likelihood phylogeny of concatenated alignments, these cultures clustered with CBS119189. All sequences were deposited in NCBI GenBank (ITS: PP919605 and PP919606; act: PP921525 and PP921526; tub2: PP921527 and PP921528; gapdh: PP921529 and PP921530). Pathogenicity was done by spraying conidial suspension of AVCT01 (1 × 106/ml) on leaves of three plants (two months old). Non-injury technique of Gupta et al. (2020) was conducted for stem inoculation. The inoculated and control plants (sprayed with sterile distilled water) were maintained separately at 25°C with 90% relative humidity. Necrotic lesions were observed on leaves and stems of inoculated plants on 8th DAI confirming Koch's postulates and the pathogen re-isolation was also done. Disease severity was assessed using the scale of Yang and Hartman, 2015. Previously, leaf spots caused by C. gloeosporioides and C. dematium w","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143067243","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 : 2025-01-30DOI: 10.1094/PDIS-10-24-2271-PDN
Mehran Khan, Muhammad Dilshad Hussain, Keyi Hu, Ali Kamran, Liting Luo, Sanwei Yang, Xin Xie
<p><p>Passion fruit (Passiflora edulis) is a commercially important crop known for its nutritional value, high antioxidant content, and use in beverages and desserts. Gulupa baciliform virus A (GBVA), tentatively named Badnavirus in the family Caulimoviridae, is a cryptic circular double-stranded DNA (dsDNA, ≈6,951 bps) virus recently reported in Colombia with asymptomatic infection of passion fruit (Sepúlveda et al. 2022). In July 2024, viral-like symptoms, including vein clearing, mottling, leaf distortion, and yellowing, were observed on passion fruit leaves in Pingtang, Guizhou, China (Supplementary figure S1), with a 30% incidence rate, and 30 samples were collected. Total RNA was extracted from these samples using TRIzol reagent (Invitrogen, CA, USA). The intact RNA from the two pools (each consisting of 14 samples) was subjected to library construction using TruseqTM Small RNA sample prep Kit (Illumina) followed by Hiseq sequencing (Hiseq2000 Truseq SBS Kit v3-HS, Illumina platform) to complete the sRNA sequencing. Approximately 12,923,899 and 10,877,466 raw while 10,135,256 and 4,184,706 clean reads were obtained for the samples in pool A and pool B, respectively. Next, the de novo assembly was carried out using metaSPAdes (Nurk et al., 2017) which resulted in 4,770 virus related trimmed contigs with the maximum length of 883 bp. BLASTn searches of sequence contigs against the NCBI viral genome database confirmed the presence of telosma mosaic virus (TEMV, Hanoi isolate, accession No. NC_009742, >96.0% nucleotide identity), East Asian passiflora virus (EAPV, Taiwan isolate, accession No. KP114137, >97.5% nucleotide identity), and papaya leaf curl Guangdong virus (PaLCuGdV, Fujian isolate, accession No. FJ495184, >98.0% nucleotide identity). Interestingly, more than 70 sequence contigs revealed >98.7% nucleotide identity with the GBVA Colombia isolate (accession No. MW393828). Whereas, the overall similarity of newly identified GBVA Guizhou isolate was calculated to be more than 99% with corresponding sequences in NCBI database. Moreover, out of 4,770 trimmed contigs, the mapping of 241 contigs to the reference genome sequence (accession No. MW393828) using Geneious R9 further confirmed the presence of GBVA. To validate the Hiseq sequencing results, total RNA was extracted from the same samples used for high throughput sequence (HTS) analysis, and reverse-transcription polymerase chain reaction (RT-PCR) was performed using specific primers (GBVA-P2-F1: 5´-ATGAATTGGAAATCAACYGTAG-3´/GBVA-P2-R1: 5´-TTCTTCTCGAGGCGTCTCTT-3´) targeting the p2 protein region of the reference genome (accession No. MW393828) (Sepúlveda et al. 2022). Amplicon of expected size of 408bp was subjected to Sanger sequencing, and the resulted sequence (GBVA, Guizhou isolate) was submitted to GenBank (accession No. PQ240853). Multiple sequence alignment was executed based on the p2 protein sequence of GBVA in MEGA X with the ClustalW program. Subsequently, the phylogenetic
{"title":"First report of Gulupa baciliform virus A associated with passion fruit in China.","authors":"Mehran Khan, Muhammad Dilshad Hussain, Keyi Hu, Ali Kamran, Liting Luo, Sanwei Yang, Xin Xie","doi":"10.1094/PDIS-10-24-2271-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2271-PDN","url":null,"abstract":"<p><p>Passion fruit (Passiflora edulis) is a commercially important crop known for its nutritional value, high antioxidant content, and use in beverages and desserts. Gulupa baciliform virus A (GBVA), tentatively named Badnavirus in the family Caulimoviridae, is a cryptic circular double-stranded DNA (dsDNA, ≈6,951 bps) virus recently reported in Colombia with asymptomatic infection of passion fruit (Sepúlveda et al. 2022). In July 2024, viral-like symptoms, including vein clearing, mottling, leaf distortion, and yellowing, were observed on passion fruit leaves in Pingtang, Guizhou, China (Supplementary figure S1), with a 30% incidence rate, and 30 samples were collected. Total RNA was extracted from these samples using TRIzol reagent (Invitrogen, CA, USA). The intact RNA from the two pools (each consisting of 14 samples) was subjected to library construction using TruseqTM Small RNA sample prep Kit (Illumina) followed by Hiseq sequencing (Hiseq2000 Truseq SBS Kit v3-HS, Illumina platform) to complete the sRNA sequencing. Approximately 12,923,899 and 10,877,466 raw while 10,135,256 and 4,184,706 clean reads were obtained for the samples in pool A and pool B, respectively. Next, the de novo assembly was carried out using metaSPAdes (Nurk et al., 2017) which resulted in 4,770 virus related trimmed contigs with the maximum length of 883 bp. BLASTn searches of sequence contigs against the NCBI viral genome database confirmed the presence of telosma mosaic virus (TEMV, Hanoi isolate, accession No. NC_009742, >96.0% nucleotide identity), East Asian passiflora virus (EAPV, Taiwan isolate, accession No. KP114137, >97.5% nucleotide identity), and papaya leaf curl Guangdong virus (PaLCuGdV, Fujian isolate, accession No. FJ495184, >98.0% nucleotide identity). Interestingly, more than 70 sequence contigs revealed >98.7% nucleotide identity with the GBVA Colombia isolate (accession No. MW393828). Whereas, the overall similarity of newly identified GBVA Guizhou isolate was calculated to be more than 99% with corresponding sequences in NCBI database. Moreover, out of 4,770 trimmed contigs, the mapping of 241 contigs to the reference genome sequence (accession No. MW393828) using Geneious R9 further confirmed the presence of GBVA. To validate the Hiseq sequencing results, total RNA was extracted from the same samples used for high throughput sequence (HTS) analysis, and reverse-transcription polymerase chain reaction (RT-PCR) was performed using specific primers (GBVA-P2-F1: 5´-ATGAATTGGAAATCAACYGTAG-3´/GBVA-P2-R1: 5´-TTCTTCTCGAGGCGTCTCTT-3´) targeting the p2 protein region of the reference genome (accession No. MW393828) (Sepúlveda et al. 2022). Amplicon of expected size of 408bp was subjected to Sanger sequencing, and the resulted sequence (GBVA, Guizhou isolate) was submitted to GenBank (accession No. PQ240853). Multiple sequence alignment was executed based on the p2 protein sequence of GBVA in MEGA X with the ClustalW program. Subsequently, the phylogenetic","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143067201","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}
<p><p>The roots of Salvia yunnanensis, an herbaceous perennial widely distributed in Southwest China, is often used as a substitute for S. miltiorrhiza, a highly valued plant in traditional Chinese medicine (Wu et al. 2014). In June 2023, wilted plants of S. yunnanensis were observed in Wenshan City (23.20°N, 104.01°E), China. The average disease incidence was 40% to 65% and the total area affected by the disease was approximately 50 ha. The infected plants displayed wilted leaves, black necrotic lesions on roots, and eventually plant death. Fungal colonies with similar morphology were consistently isolated from the symptomatic roots. Eighteen monosporic isolates were individually cultured on potato dextrose agar (PDA) in separate petri dishes at 25 ± 1°C in darkness. After 7 days, the mycelia within the colonies exhibited a cottony texture and the colors ranged from white to pink or purple, while their reverse sides were white to purple. After 20 days incubation on carnation leaf agar (CLA) medium, spore characteristics of the isolates were evaluated (Zheng et al. 2024). On CLA medium, macroconidia had 2 to 5 septa, usually 3 septa, measuring 21.7 to 39.8 × 4.0 to 6.5 μm (n = 100). Microconidia were falciform, slightly curved or straight, measuring 6.8 to 15.4 × 2.5 to 5.4 μm (n = 100), with 0 to 1 septa. Chlamydospores were globose to subglobose, intercalary or terminal, with an average diameter of 8.9 μm (n = 100). Morphologically, the isolates were identified as Fusarium oxysporum (Lombard et al. 2019; Zheng et al. 2024). To confirm the identification, the translation elongation factor 1-α (EF1α) region was amplified with the primers EF-1/EF-2 (O'Donnell et al. 1998) and the RNA polymerase second largest subunit region (RPB2) was amplified with the primers fRPB2-6f/fRPB2-7cr (Eddouzi et al. 2013). The EF1α (GenBank accession no. PP805676) and RPB2 (PQ383276) sequences of isolate DS10-1 were compared with all sequences in the FUSARIUM ID database (O'Donnell et al. 2022) using polyphasic identification. The highest similarity (100%) was with F. oxysporum isolates, including the ex-epitype of Fusarium cugennagense isolate InaCC F984 (100% similarity). To further assess the phylogenetic relationships, a phylogenetic tree was constructed based on the Neighbor-Joining method in MEGA-X (Kumar et al. 2018). The tree confirmed that the isolate DS10-1 was closely related to F. oxysporum. Pathogenicity tests of the 18 isolates were conducted on five healthy one-year-old S. yunnanensis plants per isolate. Inoculum (1 ml of 106 conidia/ml) of each strain was brushed onto the roots of individual plants with a paintbrush. As controls, five plants were inoculated with sterile water. All plants were potted in plastic containers (diameter = 25 cm, five plants per pot) filled with a sterilized substrate mixture of sand and vermiculite (1:1, v/v), and maintained in the greenhouse at 20 to 26°C with 80% relative humidity. After 45 days, symptoms similar to those
{"title":"First Report of <i>Fusarium oxysporum</i> Causing Root Rot on <i>Salvia yunnanensis</i> in China.","authors":"Ying-Shu Pan, Shang-Ge Huang, Zhengpan Xiang, Zhong-Shun Mao, Yue-Juan Long, Hui Fang, Jinlong Cai, Yong Wang, Zhong-Jian Chen","doi":"10.1094/PDIS-11-24-2353-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2353-PDN","url":null,"abstract":"<p><p>The roots of Salvia yunnanensis, an herbaceous perennial widely distributed in Southwest China, is often used as a substitute for S. miltiorrhiza, a highly valued plant in traditional Chinese medicine (Wu et al. 2014). In June 2023, wilted plants of S. yunnanensis were observed in Wenshan City (23.20°N, 104.01°E), China. The average disease incidence was 40% to 65% and the total area affected by the disease was approximately 50 ha. The infected plants displayed wilted leaves, black necrotic lesions on roots, and eventually plant death. Fungal colonies with similar morphology were consistently isolated from the symptomatic roots. Eighteen monosporic isolates were individually cultured on potato dextrose agar (PDA) in separate petri dishes at 25 ± 1°C in darkness. After 7 days, the mycelia within the colonies exhibited a cottony texture and the colors ranged from white to pink or purple, while their reverse sides were white to purple. After 20 days incubation on carnation leaf agar (CLA) medium, spore characteristics of the isolates were evaluated (Zheng et al. 2024). On CLA medium, macroconidia had 2 to 5 septa, usually 3 septa, measuring 21.7 to 39.8 × 4.0 to 6.5 μm (n = 100). Microconidia were falciform, slightly curved or straight, measuring 6.8 to 15.4 × 2.5 to 5.4 μm (n = 100), with 0 to 1 septa. Chlamydospores were globose to subglobose, intercalary or terminal, with an average diameter of 8.9 μm (n = 100). Morphologically, the isolates were identified as Fusarium oxysporum (Lombard et al. 2019; Zheng et al. 2024). To confirm the identification, the translation elongation factor 1-α (EF1α) region was amplified with the primers EF-1/EF-2 (O'Donnell et al. 1998) and the RNA polymerase second largest subunit region (RPB2) was amplified with the primers fRPB2-6f/fRPB2-7cr (Eddouzi et al. 2013). The EF1α (GenBank accession no. PP805676) and RPB2 (PQ383276) sequences of isolate DS10-1 were compared with all sequences in the FUSARIUM ID database (O'Donnell et al. 2022) using polyphasic identification. The highest similarity (100%) was with F. oxysporum isolates, including the ex-epitype of Fusarium cugennagense isolate InaCC F984 (100% similarity). To further assess the phylogenetic relationships, a phylogenetic tree was constructed based on the Neighbor-Joining method in MEGA-X (Kumar et al. 2018). The tree confirmed that the isolate DS10-1 was closely related to F. oxysporum. Pathogenicity tests of the 18 isolates were conducted on five healthy one-year-old S. yunnanensis plants per isolate. Inoculum (1 ml of 106 conidia/ml) of each strain was brushed onto the roots of individual plants with a paintbrush. As controls, five plants were inoculated with sterile water. All plants were potted in plastic containers (diameter = 25 cm, five plants per pot) filled with a sterilized substrate mixture of sand and vermiculite (1:1, v/v), and maintained in the greenhouse at 20 to 26°C with 80% relative humidity. After 45 days, symptoms similar to those ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143067245","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}
<p><p>Manglietia decidua is an extremely endangered species, known for its limited population and a narrow distribution range restricted to China (Yu 1994). In October 2021, a leaf disease affecting the foliage of 3-year-old M. decidua was observed at the nursery garden of the Yichun Forestry Institute of Jiangxi Province (27°55'52.7"N, 114°17'36.4"E), with approximately 60% disease incidence. Initially, small reddish-brown specks with round or oval-shaped spots appeared. These spots gradually expanded, resulting in large irregular lesions with grayish-white centers. Furthermore, the affected areas exhibited desiccation and curling, with lesion diameters exceeding two cm. Fifteen diseased leaves were collected to isolate the pathogen using the method described by Zhang et al. (2021). Out of 40 fungal isolates obtained, 28 exhibited consistent culture characteristics and were identified as Pestalotiopsis sp.. We chose HML2-1 as the representative for morphological research. Colonies on Potato Dextrose Agar (PDA) reached a diameter of 80 mm after seven days at 25°C, displaying a pale honey-colored appearance with fluffy aerial mycelia arranged in a concentric-pattern, while the back of the colony appeared orange. Conidia were fusoid and ellipsoidappearing straight to slightly curved, composed of five cells, with four septa at which were slightly constricted, and measured 17.5-22.5 × 5-7.5 µm. The 3 median cells exhibited a brown color; the apical cells were conical and colorless, featuring 2-3 branches at the top as flagella; the basal cells were conical, transparent, and smooth. For further identification, three isolates were selected for the amplification and sequencing of three loci: the internal transcribed spacer (ITS), the partial translation elongation factor1-alpha (TEF1) and beta-tubulin (TUB2). The sequences were deposited in GenBank (ITS: OR415306-OR415308; TEF1: OR420799, PP278043, PP278044; TUB2: OR420798, PP278045, PP278046). All three DNA sequences of HML2-1 had a high identity to P. lushanensis (the ex-type isolate LC4344) with the accession numbers KX895005 (100%), KX895223 (100%) and KX895337 (99.34%), respectively. The multi-locus phylogenetic tree employing W-IQ-TREE (Trifinopoulos et al. 2016), revealed that the studied three isolates clustered in P. lushanensis clade with strong support. Based on morphological and molecular evidence, the isolate HML2-1 was identified as P. lushanensis, despite the fact that conidia sizes are smaller than those of type strain (Liu et al. 2017). To verify pathogenicity, a 20 µL conidial suspension (5×105 conidia/mL) of isolate HML2-1 was added to each leaf from an 8-year-old tree in the field, with 10 leaves punctured and 10 leaves left intact. Control including wounded or unwounded leaves were treated with sterile water in another tree. The treated leaves were wrapped in plastic bags to maintain moisture. After three to seven days, field-inoculated leaves exhibited typical reddish-brown lesions
{"title":"First report of <i>Pestalotiopsis lushanensis</i> causing leaf spot of <i>Manglietia decidua</i> (Magnoliaceae) in China.","authors":"Huanhuan Liu, Chongli Sun, Baixun Zhou, Dong Li, Qingni Song, Jun Liu, Fenggang Luan, Sheng-Li Zhang","doi":"10.1094/PDIS-04-24-0841-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-04-24-0841-PDN","url":null,"abstract":"<p><p>Manglietia decidua is an extremely endangered species, known for its limited population and a narrow distribution range restricted to China (Yu 1994). In October 2021, a leaf disease affecting the foliage of 3-year-old M. decidua was observed at the nursery garden of the Yichun Forestry Institute of Jiangxi Province (27°55'52.7\"N, 114°17'36.4\"E), with approximately 60% disease incidence. Initially, small reddish-brown specks with round or oval-shaped spots appeared. These spots gradually expanded, resulting in large irregular lesions with grayish-white centers. Furthermore, the affected areas exhibited desiccation and curling, with lesion diameters exceeding two cm. Fifteen diseased leaves were collected to isolate the pathogen using the method described by Zhang et al. (2021). Out of 40 fungal isolates obtained, 28 exhibited consistent culture characteristics and were identified as Pestalotiopsis sp.. We chose HML2-1 as the representative for morphological research. Colonies on Potato Dextrose Agar (PDA) reached a diameter of 80 mm after seven days at 25°C, displaying a pale honey-colored appearance with fluffy aerial mycelia arranged in a concentric-pattern, while the back of the colony appeared orange. Conidia were fusoid and ellipsoidappearing straight to slightly curved, composed of five cells, with four septa at which were slightly constricted, and measured 17.5-22.5 × 5-7.5 µm. The 3 median cells exhibited a brown color; the apical cells were conical and colorless, featuring 2-3 branches at the top as flagella; the basal cells were conical, transparent, and smooth. For further identification, three isolates were selected for the amplification and sequencing of three loci: the internal transcribed spacer (ITS), the partial translation elongation factor1-alpha (TEF1) and beta-tubulin (TUB2). The sequences were deposited in GenBank (ITS: OR415306-OR415308; TEF1: OR420799, PP278043, PP278044; TUB2: OR420798, PP278045, PP278046). All three DNA sequences of HML2-1 had a high identity to P. lushanensis (the ex-type isolate LC4344) with the accession numbers KX895005 (100%), KX895223 (100%) and KX895337 (99.34%), respectively. The multi-locus phylogenetic tree employing W-IQ-TREE (Trifinopoulos et al. 2016), revealed that the studied three isolates clustered in P. lushanensis clade with strong support. Based on morphological and molecular evidence, the isolate HML2-1 was identified as P. lushanensis, despite the fact that conidia sizes are smaller than those of type strain (Liu et al. 2017). To verify pathogenicity, a 20 µL conidial suspension (5×105 conidia/mL) of isolate HML2-1 was added to each leaf from an 8-year-old tree in the field, with 10 leaves punctured and 10 leaves left intact. Control including wounded or unwounded leaves were treated with sterile water in another tree. The treated leaves were wrapped in plastic bags to maintain moisture. After three to seven days, field-inoculated leaves exhibited typical reddish-brown lesions","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143067192","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 : 2025-01-28DOI: 10.1094/PDIS-11-24-2349-PDN
Pan Xie, Shuaishuai Sha, Hongyue Li, Hanhan Zhai
<p><p>Fig (Ficus carica L.) holds economic significance in Atushi, Xinjiang, but as fig cultivation expands, disease prevalence has risen. In July 2024, approximately 22% of harvested fig (cv. Xinjiang Zaohuang) from 20 commercial orchards (covering 40 hectares) in Atushi (39°39'37.65" N, 76°14'3.62" E) showed varying degrees of fruit rot symptoms. The initial symptoms were characterized by the appearance of small, brown lesions on the fruit surface. These lesions rapidly progressed into water-soaked spots, which expanded quickly. As the disease advanced, the affected areas became covered with dense, white, fluffy mycelia, accompanied by prominent black sporulation. In later stages, the infected tissues softened further, ultimately resulting in the complete decay of the fruit. Twenty diseased fig were collected from the sampling site. Tissue samples (5×5×5 mm) were cut at the diseased-healthy junction, surface-sterilized in 0.5% NaClO for 1 minute, rinsed twice in sterile distilled water, air-dried, and transferred aseptically onto potato dextrose agar (PDA), and incubated at 25°C for 5 days with a 12-hour photoperiod. Fifteen isolates were obtained from the infected tissues, with two representative isolates (WH 12 and WH 23) selected for further study due to morphological similarity. The fungal colonies initially appeared as white mycelium, later turning olive green to grayish-black. Colony growth was rapid (32 mm/day). Arthrospores were colorless to light brown, short columnar, aseptate, with a truncated base, 0 to 1 septate, averaging 11.9±2.3×3.6±0.8 μm (n = 50), and sometimes formed arthric chains. Chlamydospores were dark brown, round or oval, 0 to 1 septate, averaging 7.26±1.7×5.05±1.0 μm (n = 50). Genomic DNA was extracted from the two isolates. The internal transcribed spacer (ITS), translation elongation factor 1-alpha (TEF1-α), and beta-tubulin (TUB2) genes were amplified using primers ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone & Kohn. 1999), and BT2a/BT2b (Glass & Donaldson. 1995), respectively, and sequences were deposited in GenBank (ITS: PQ555020, PQ555021; TUB2: PQ557519, PQ557521; TEF1-α: PQ557520, PQ557522). BLAST analysis revealed 99-100% similarity to Neoscytalidium dimidiatum Arp2-D (ITS: MK813852; TUB2: MK816354; TEF1-α: MK816355). Phylogenetic analysis using IQ-Tree and MrBayes3.2.7 based on concatenated ITS-TEF1-TUB sequences showed WH 12 and WH 23 clustering with N. dimidiatum Arp2-D (99% bootstrap). Morphological and molecular data identified the isolates as N. dimidiatum (Penz.) Crous & Slippers (Crous et al. 2006). Pathogenicity tests were conducted on 20 healthy fig (cv. Xinjiang Zaohuang) by inoculating each fruit with 10 µl of a WH 12 conidial suspension (1 × 10⁶ conidia/ml) using sterile needles. The Control were treated with 10 µl of sterile distilled water. All fruits were placed in sterile plastic containers and incubated at 25 ± 1°C, 90% relative humidity, and a 12-hour light cycle. This experime
{"title":"First Report of <i>Neoscytalidium dimidiatum</i> Causing Fruit Rot on Fig in China.","authors":"Pan Xie, Shuaishuai Sha, Hongyue Li, Hanhan Zhai","doi":"10.1094/PDIS-11-24-2349-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2349-PDN","url":null,"abstract":"<p><p>Fig (Ficus carica L.) holds economic significance in Atushi, Xinjiang, but as fig cultivation expands, disease prevalence has risen. In July 2024, approximately 22% of harvested fig (cv. Xinjiang Zaohuang) from 20 commercial orchards (covering 40 hectares) in Atushi (39°39'37.65\" N, 76°14'3.62\" E) showed varying degrees of fruit rot symptoms. The initial symptoms were characterized by the appearance of small, brown lesions on the fruit surface. These lesions rapidly progressed into water-soaked spots, which expanded quickly. As the disease advanced, the affected areas became covered with dense, white, fluffy mycelia, accompanied by prominent black sporulation. In later stages, the infected tissues softened further, ultimately resulting in the complete decay of the fruit. Twenty diseased fig were collected from the sampling site. Tissue samples (5×5×5 mm) were cut at the diseased-healthy junction, surface-sterilized in 0.5% NaClO for 1 minute, rinsed twice in sterile distilled water, air-dried, and transferred aseptically onto potato dextrose agar (PDA), and incubated at 25°C for 5 days with a 12-hour photoperiod. Fifteen isolates were obtained from the infected tissues, with two representative isolates (WH 12 and WH 23) selected for further study due to morphological similarity. The fungal colonies initially appeared as white mycelium, later turning olive green to grayish-black. Colony growth was rapid (32 mm/day). Arthrospores were colorless to light brown, short columnar, aseptate, with a truncated base, 0 to 1 septate, averaging 11.9±2.3×3.6±0.8 μm (n = 50), and sometimes formed arthric chains. Chlamydospores were dark brown, round or oval, 0 to 1 septate, averaging 7.26±1.7×5.05±1.0 μm (n = 50). Genomic DNA was extracted from the two isolates. The internal transcribed spacer (ITS), translation elongation factor 1-alpha (TEF1-α), and beta-tubulin (TUB2) genes were amplified using primers ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone & Kohn. 1999), and BT2a/BT2b (Glass & Donaldson. 1995), respectively, and sequences were deposited in GenBank (ITS: PQ555020, PQ555021; TUB2: PQ557519, PQ557521; TEF1-α: PQ557520, PQ557522). BLAST analysis revealed 99-100% similarity to Neoscytalidium dimidiatum Arp2-D (ITS: MK813852; TUB2: MK816354; TEF1-α: MK816355). Phylogenetic analysis using IQ-Tree and MrBayes3.2.7 based on concatenated ITS-TEF1-TUB sequences showed WH 12 and WH 23 clustering with N. dimidiatum Arp2-D (99% bootstrap). Morphological and molecular data identified the isolates as N. dimidiatum (Penz.) Crous & Slippers (Crous et al. 2006). Pathogenicity tests were conducted on 20 healthy fig (cv. Xinjiang Zaohuang) by inoculating each fruit with 10 µl of a WH 12 conidial suspension (1 × 10⁶ conidia/ml) using sterile needles. The Control were treated with 10 µl of sterile distilled water. All fruits were placed in sterile plastic containers and incubated at 25 ± 1°C, 90% relative humidity, and a 12-hour light cycle. This experime","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143060160","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 : 2025-01-28DOI: 10.1094/PDIS-09-24-2014-PDN
Sheng Jun Xu, Zhuo Qiong Jing, Zhi Jie Guo
<p><p>Astragalus mongholicus is a perennial Chinese medicinal herb in the family Leguminosae widely cultivated in China. In September 2023, A. mongholicus plants in a field in Weiyuan County, Gansu Province, showed symptoms of circular or irregular brown, sunken and necrotic lesions, multiple lesions coalesced, and brown longitudinal cracks in the roots. An investigation was performed in a 1998 m2 field with a root rot incidence of 10%, and the severity ranged from 5 to 60% of root surface area. Five rotted root samples were collected. Fragments of symptomatic roots were surface sterilized with 75% ethanol for 10 s, 2% sodium hypochlorite for 2 min, washed three times with sterilized distilled water, and then blotted dry on sterile filter paper. Fragments were placed on potato dextrose agar (PDA) medium and incubated at 25 ± 1°C in darkness for 5 days and five isolates were purified by transferring single hyphal tips to new PDA plates. Isolates WY23AM01 and WY23AM05, two of five isolates with similar morphology, were randomly selected for morphological and molecular identification and pathogenicity tests. Colonies of the fungus were white initially, then turned light brown to brown, raised, and with entire or undulate edges. Sclerotia were brown and produced on PDA after 20 days of incubation at 25 ± 1°C in the dark. Genomic DNA from each of the two isolates was extracted, and the internal transcribed spacer (ITS) region was amplified and sequenced with the primer pair ITS5/ITS4 (White et al. 1990). The sequences of isolates WY23AM01 and WY23AM05 were deposited in GenBank (PQ362092 and PQ362093). Phylogenetic analyses were performed by the maximum likelihood method with ITS sequences for anastomosis groups (AG) of Rhizoctonia solani using MEGA 10.0. The phylogenetic tree grouped the two isolates within the R. solani AG-5 clade with high bootstrap support (99%). PCR analysis was performed with 21 primers specifically designed to detect individual anastomosis groups or anastomosis subgroups of R. solani (Carling et al., 2002; Misawa and Kurose, 2019; Misawa et al., 2020; Okubara et al., 2008). Among the 21 specific primer pairs, only AG-5 specific primer amplified the fungal DNA, indicating that the two isolates belonged to the R. solani AG-5. For pathogenicity tests, two isolates were grown individually on sterile wheat kernels at 25 ± 1°C for 10 days. Certified pathogen-free seedling stage roots were grown in the plastic pot filled with the commercially available sterilized horticultural soil and inoculated by burying twenty infested wheat kernels in the soil adjacent to the roots. Control plants were inoculated with sterile wheat kernels using the same procedure. Each pot had three roots, and each treatment had 12 pots as replicates. All plants were placed in a greenhouse with 60% relative humidity and a 12h/12h light/dark photoperiod at 15 to 30°C. Sixty days after inoculation, typical root rot symptoms developed on all inoculated plants, simil
{"title":"Occurrence of <i>Rhizoctonia solani</i> AG-5 Causing Root Rot on <i>Astragalus mongholicus</i> in Northwestern China.","authors":"Sheng Jun Xu, Zhuo Qiong Jing, Zhi Jie Guo","doi":"10.1094/PDIS-09-24-2014-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-2014-PDN","url":null,"abstract":"<p><p>Astragalus mongholicus is a perennial Chinese medicinal herb in the family Leguminosae widely cultivated in China. In September 2023, A. mongholicus plants in a field in Weiyuan County, Gansu Province, showed symptoms of circular or irregular brown, sunken and necrotic lesions, multiple lesions coalesced, and brown longitudinal cracks in the roots. An investigation was performed in a 1998 m2 field with a root rot incidence of 10%, and the severity ranged from 5 to 60% of root surface area. Five rotted root samples were collected. Fragments of symptomatic roots were surface sterilized with 75% ethanol for 10 s, 2% sodium hypochlorite for 2 min, washed three times with sterilized distilled water, and then blotted dry on sterile filter paper. Fragments were placed on potato dextrose agar (PDA) medium and incubated at 25 ± 1°C in darkness for 5 days and five isolates were purified by transferring single hyphal tips to new PDA plates. Isolates WY23AM01 and WY23AM05, two of five isolates with similar morphology, were randomly selected for morphological and molecular identification and pathogenicity tests. Colonies of the fungus were white initially, then turned light brown to brown, raised, and with entire or undulate edges. Sclerotia were brown and produced on PDA after 20 days of incubation at 25 ± 1°C in the dark. Genomic DNA from each of the two isolates was extracted, and the internal transcribed spacer (ITS) region was amplified and sequenced with the primer pair ITS5/ITS4 (White et al. 1990). The sequences of isolates WY23AM01 and WY23AM05 were deposited in GenBank (PQ362092 and PQ362093). Phylogenetic analyses were performed by the maximum likelihood method with ITS sequences for anastomosis groups (AG) of Rhizoctonia solani using MEGA 10.0. The phylogenetic tree grouped the two isolates within the R. solani AG-5 clade with high bootstrap support (99%). PCR analysis was performed with 21 primers specifically designed to detect individual anastomosis groups or anastomosis subgroups of R. solani (Carling et al., 2002; Misawa and Kurose, 2019; Misawa et al., 2020; Okubara et al., 2008). Among the 21 specific primer pairs, only AG-5 specific primer amplified the fungal DNA, indicating that the two isolates belonged to the R. solani AG-5. For pathogenicity tests, two isolates were grown individually on sterile wheat kernels at 25 ± 1°C for 10 days. Certified pathogen-free seedling stage roots were grown in the plastic pot filled with the commercially available sterilized horticultural soil and inoculated by burying twenty infested wheat kernels in the soil adjacent to the roots. Control plants were inoculated with sterile wheat kernels using the same procedure. Each pot had three roots, and each treatment had 12 pots as replicates. All plants were placed in a greenhouse with 60% relative humidity and a 12h/12h light/dark photoperiod at 15 to 30°C. Sixty days after inoculation, typical root rot symptoms developed on all inoculated plants, simil","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143060261","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}
<p><p>Katsumada galangal seed (<i>Alpinia hainanensis</i> K. Schum) is an important member of the Zingiberaceae family, with both medicinal value and culinary applications (Park et al. 2020). In May 2023, a stem disease of <i>Al. hainanensis</i> was detected in a 100-acre plantation located in Danzhou City, Hainan Province in China, with an average incidence of 15% to 20%. The disease primarily targeted the basal stems, with the pathogen spreading by mycelia in the soil around the rhizome, and reaching neighboring plants. The infection caused the stem base to undergo necrosis, turning the tissue brown to black, and leading to a loosely attached epidermis. As the disease advanced, the necrosis progressed upward along the stem, resulting in curling of the leaves. A large number of white mycelia, as well as white immature sclerotia and brown mature sclerotia, were also observed on the surfaces of the leaves, stems and soil. The diameter of the mature sclerotia ranged from 0.7 to 1.6 mm (aver. ± SD = 1.2 ± 0.3 mm, <i>n</i> = 50). To identify the pathogen, eleven tissue samples were collected from symptomatic stems. The sclerotia on the surface of the tissue were sterilized with 75% (V/V) ethanol for 30 s, followed by three rinses with sterile water, and finally incubated on potato dextrose agar (PDA) at 28°C in darkness. Eleven isolates were obtained and subcultured at 28°C in darkness. After 48 hours, the colonies of these isolates had an average daily radial growth of 39.5 ± 0.4 mm (<i>n</i> = 11) and were white, featuring entire margins and abundant aerial mycelia. By the seventh day, spherical or oval white sclerotia began to form on the surface of their colonies. These sclerotia eventually turned brown, with a diameter ranging from 0.6 to 1.5 mm (aver. ± SD = 1.3 ± 0.3 mm, <i>n</i> = 50). The morphological characteristics of these isolates were similar to those of <i>Agroathelia rolfsii</i> (Sacc.) Redhead & Mullineux (basionym: <i>Sclerotium rolfsii</i> Sacc.; Amylocorticiaceae) (Redhead and Mullineux 2023). DNA of a representative isolate DZAS-01 was extracted for amplification of its internal transcribed spacer (ITS) rDNA region, the translation elongation factor 1-alpha (<i>TEF1</i>) gene and the large subunit (LSU) region using the primers ITS1/ITS4, EF1-983F/EF1-2218R and LROR/LR5, respectively (Moncalvo et al. 2000, Rehner and Buckley 2005, White et al. 1990). The three sequences have been deposited in GenBank (accession nos. PP659527 for ITS, 607 bp; PP976301 for <i>TEF1</i>, 1,040 bp; PP968104 for LSU, 876 bp). The BLASTn results showed that the similarity of the three sequences with the known sequences PP908473 (ITS), OL416131 (<i>TEF1</i>) and KY446370 (LSU) of <i>Ag. rolfsii</i> was 100%, 99.81% and 100%, respectively. Pathogenicity tests were conducted on ten potted, 6-week-old healthy <i>Al. hainanensis</i> plants. The stem bases of ten plants were wounded with sterile needles and divided into two groups with five plants in each gr
{"title":"First Report of <i>Agroathelia rolfsii</i> Causing Southern Blight on <i>Alpinia hainanensis</i> in China.","authors":"Chao Zhang, Yaru Guo, Peixin Luo, Changping Xie, Li Zheng, Daipeng Chen","doi":"10.1094/PDIS-07-24-1453-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1453-PDN","url":null,"abstract":"<p><p>Katsumada galangal seed (<i>Alpinia hainanensis</i> K. Schum) is an important member of the Zingiberaceae family, with both medicinal value and culinary applications (Park et al. 2020). In May 2023, a stem disease of <i>Al. hainanensis</i> was detected in a 100-acre plantation located in Danzhou City, Hainan Province in China, with an average incidence of 15% to 20%. The disease primarily targeted the basal stems, with the pathogen spreading by mycelia in the soil around the rhizome, and reaching neighboring plants. The infection caused the stem base to undergo necrosis, turning the tissue brown to black, and leading to a loosely attached epidermis. As the disease advanced, the necrosis progressed upward along the stem, resulting in curling of the leaves. A large number of white mycelia, as well as white immature sclerotia and brown mature sclerotia, were also observed on the surfaces of the leaves, stems and soil. The diameter of the mature sclerotia ranged from 0.7 to 1.6 mm (aver. ± SD = 1.2 ± 0.3 mm, <i>n</i> = 50). To identify the pathogen, eleven tissue samples were collected from symptomatic stems. The sclerotia on the surface of the tissue were sterilized with 75% (V/V) ethanol for 30 s, followed by three rinses with sterile water, and finally incubated on potato dextrose agar (PDA) at 28°C in darkness. Eleven isolates were obtained and subcultured at 28°C in darkness. After 48 hours, the colonies of these isolates had an average daily radial growth of 39.5 ± 0.4 mm (<i>n</i> = 11) and were white, featuring entire margins and abundant aerial mycelia. By the seventh day, spherical or oval white sclerotia began to form on the surface of their colonies. These sclerotia eventually turned brown, with a diameter ranging from 0.6 to 1.5 mm (aver. ± SD = 1.3 ± 0.3 mm, <i>n</i> = 50). The morphological characteristics of these isolates were similar to those of <i>Agroathelia rolfsii</i> (Sacc.) Redhead & Mullineux (basionym: <i>Sclerotium rolfsii</i> Sacc.; Amylocorticiaceae) (Redhead and Mullineux 2023). DNA of a representative isolate DZAS-01 was extracted for amplification of its internal transcribed spacer (ITS) rDNA region, the translation elongation factor 1-alpha (<i>TEF1</i>) gene and the large subunit (LSU) region using the primers ITS1/ITS4, EF1-983F/EF1-2218R and LROR/LR5, respectively (Moncalvo et al. 2000, Rehner and Buckley 2005, White et al. 1990). The three sequences have been deposited in GenBank (accession nos. PP659527 for ITS, 607 bp; PP976301 for <i>TEF1</i>, 1,040 bp; PP968104 for LSU, 876 bp). The BLASTn results showed that the similarity of the three sequences with the known sequences PP908473 (ITS), OL416131 (<i>TEF1</i>) and KY446370 (LSU) of <i>Ag. rolfsii</i> was 100%, 99.81% and 100%, respectively. Pathogenicity tests were conducted on ten potted, 6-week-old healthy <i>Al. hainanensis</i> plants. The stem bases of ten plants were wounded with sterile needles and divided into two groups with five plants in each gr","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143060151","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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