Pub Date : 2024-10-30DOI: 10.1094/PDIS-07-24-1367-RE
Liza M DeGenring, Kari Peter, Anissa M Poleatewich
Chitosan is a natural product that has potential use in agriculture for managing diseases. Chitosan has been shown to effectively suppress storage rots when applied postharvest. Application of chitosan pre- and postharvest has potential to manage both latent and postharvest rots but these effects are not well studied. Furthermore, to determine the most effective strategy for using chitosan to manage apple diseases, research on application rates, chitosan molecular weight, phytotoxicity potential, and formulation is needed. The objectives of this study were to (1) identify non-phytotoxic concentrations of chitosan on apple fruit; (2) evaluate commercial chitosan products for reduction of postharvest disease severity on inoculated fruit; (3) evaluate the effect of pre-harvest chitosan applications on suppression of latent infections, postharvest rots, and fruit quality; and (4) evaluate the effect of pre-harvest plus postharvest chitosan applications on suppression of Penicillium expansum and Colletotrichum fioriniae on inoculated fruit. Under lab conditions, chitosan products applied at higher rates were more effective at reducing disease but tended to cause phytotoxicity. This phytotoxic effect was remediated when the product's pH was adjusted to ~5. Tidal Grow products applied at 1.0% (v/v) chitosan reduced lesion size caused by P. expansum and C. fioriniae on inoculated apples up to 86% compared to a water treatment. Pre-harvest applications of chitosan and Serenade ASO reduced bitter rot up to 85% on immature fruit in a research orchard. The results from this research suggest that Tidal Grow adjusted to pH ~5 can reduce postharvest diseases of apple fruit.
{"title":"Postharvest chitosan sprays reduce bitter rot and blue mold on apple fruit.","authors":"Liza M DeGenring, Kari Peter, Anissa M Poleatewich","doi":"10.1094/PDIS-07-24-1367-RE","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1367-RE","url":null,"abstract":"<p><p>Chitosan is a natural product that has potential use in agriculture for managing diseases. Chitosan has been shown to effectively suppress storage rots when applied postharvest. Application of chitosan pre- and postharvest has potential to manage both latent and postharvest rots but these effects are not well studied. Furthermore, to determine the most effective strategy for using chitosan to manage apple diseases, research on application rates, chitosan molecular weight, phytotoxicity potential, and formulation is needed. The objectives of this study were to (1) identify non-phytotoxic concentrations of chitosan on apple fruit; (2) evaluate commercial chitosan products for reduction of postharvest disease severity on inoculated fruit; (3) evaluate the effect of pre-harvest chitosan applications on suppression of latent infections, postharvest rots, and fruit quality; and (4) evaluate the effect of pre-harvest plus postharvest chitosan applications on suppression of <i>Penicillium expansum</i> and <i>Colletotrichum fioriniae</i> on inoculated fruit. Under lab conditions, chitosan products applied at higher rates were more effective at reducing disease but tended to cause phytotoxicity. This phytotoxic effect was remediated when the product's pH was adjusted to ~5. Tidal Grow products applied at 1.0% (v/v) chitosan reduced lesion size caused by <i>P. expansum</i> and <i>C. fioriniae</i> on inoculated apples up to 86% compared to a water treatment. Pre-harvest applications of chitosan and Serenade ASO reduced bitter rot up to 85% on immature fruit in a research orchard. The results from this research suggest that Tidal Grow adjusted to pH ~5 can reduce postharvest diseases of apple fruit.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546759","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 : 2024-10-30DOI: 10.1094/PDIS-11-23-2418-RE
Galvin Alonzo, Juliana Silveira Baggio, Natalia A Peres
Florida's strawberry industry has been facing an emerging threat after several outbreaks of an aggressive Neopestalotiopsis sp. affecting fruit, leaf, and crown caused severe yield losses. Our studies found Neopestalotiopsis sp. can survive from one production season to the next on crop debris in soil, which led us to evaluate the effect of fumigants on resident inoculum in strawberry crowns and soil. Different rates of 1,3-dichloropropene, chloropicrin, and metam potassium were applied to pasteurized soil inside glass jars containing infected strawberry crowns. Soil samples were taken after broadcast and bed fumigation treatments with a combination of 1,3-dichloropropene/chloropicrin at ratios of 63:35 were applied at four commercial fields. Crowns and soil samples were processed and plated on a semi-selective medium for Neopestalotiopsis spp. and colony-forming units (CFU) were counted 5 days after plating. CFU counts in crowns treated with 1,3-dichloropropene, chloropicrin, and metam potassium decreased significantly as rates increased and were described by exponential decay models. CFUs were not recovered in most of the soil samples from fumigated strawberry beds after broadcast or bed fumigation. However, CFUs were found in non-fumigated row middles between fumigated beds which can serve as a source of inoculum to start new epidemics. Chloropicrin, 1,3-dichloropropene, and metam potassium were effective on reducing Neopestalotiopsis spp. inoculum in strawberry crowns and soil, providing new evidence on the fungicidal activity of 1,3-dichloropropene. Broadcast fumigation with 1,3-dichloropropene/chloropicrin at ratios of 63:35 could potentially be used to reduce inoculum of Neopestalotiopsis sp. in severely infested fields.
{"title":"Effect of fumigants on inoculum of <i>Neopestalotiopsis</i> spp. in strawberry crowns and soil.","authors":"Galvin Alonzo, Juliana Silveira Baggio, Natalia A Peres","doi":"10.1094/PDIS-11-23-2418-RE","DOIUrl":"https://doi.org/10.1094/PDIS-11-23-2418-RE","url":null,"abstract":"<p><p>Florida's strawberry industry has been facing an emerging threat after several outbreaks of an aggressive <i>Neopestalotiopsis</i> sp. affecting fruit, leaf, and crown caused severe yield losses. Our studies found <i>Neopestalotiopsis</i> sp. can survive from one production season to the next on crop debris in soil, which led us to evaluate the effect of fumigants on resident inoculum in strawberry crowns and soil. Different rates of 1,3-dichloropropene, chloropicrin, and metam potassium were applied to pasteurized soil inside glass jars containing infected strawberry crowns. Soil samples were taken after broadcast and bed fumigation treatments with a combination of 1,3-dichloropropene/chloropicrin at ratios of 63:35 were applied at four commercial fields. Crowns and soil samples were processed and plated on a semi-selective medium for <i>Neopestalotiopsis</i> spp. and colony-forming units (CFU) were counted 5 days after plating. CFU counts in crowns treated with 1,3-dichloropropene, chloropicrin, and metam potassium decreased significantly as rates increased and were described by exponential decay models. CFUs were not recovered in most of the soil samples from fumigated strawberry beds after broadcast or bed fumigation. However, CFUs were found in non-fumigated row middles between fumigated beds which can serve as a source of inoculum to start new epidemics. Chloropicrin, 1,3-dichloropropene, and metam potassium were effective on reducing Neopestalotiopsis spp. inoculum in strawberry crowns and soil, providing new evidence on the fungicidal activity of 1,3-dichloropropene. Broadcast fumigation with 1,3-dichloropropene/chloropicrin at ratios of 63:35 could potentially be used to reduce inoculum of <i>Neopestalotiopsis</i> sp. in severely infested fields.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546751","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 : 2024-10-30DOI: 10.1094/PDIS-05-24-0990-RE
Agnes Szabo-Hever, Katherine Running, Sudeshi Seneviratne, Gurminder Singh, Zengcui Zhang, Amanda Peters Haugrud, Marco Maccaferri, Roberto Tuberosa, Steven S Xu, Timothy L Friesen, Justin D Faris
Septoria nodorum blotch is an important disease of both durum and hard red spring wheat (HRSW) worldwide. The disease is caused by the necrotrophic fungal pathogen Parastagonospora nodorum when compatible gene-for-gene interactions occur between pathogen-produced necrotrophic effectors (NEs) and corresponding host sensitivity genes. To date, nine sensitivity gene-NE interactions have been identified, but there is little information available regarding their overall frequency in durum and HRSW. Here, we infiltrated a global HRSW panel (HRSWP) and the Global Durum Panel (GDP) with P. nodorum NEs SnToxA, SnTox1, SnTox267, SnTox3, and SnTox5. Frequencies of sensitivity to SnTox1 and SnTox5 were higher in durum compared to HRSW and vice versa for SnTox267 and SnTox3. Strong associations for the known sensitivity loci Tsn1, Snn1, Snn2, Snn3, Snn5, and Snn7 along with potentially novel sensitivity loci on chromosome arms 7DS and 3BL associated with SnToxA and SnTox267, respectively, were identified in the HRSWP. In the GDP, Snn1, Snn3, and Snn5 were identified along with novel loci associated with sensitivity to SnTox267 on chromosome arms 2AS, 2AL, and 6AS and with SnTox5 sensitivity on 2BS and 7BL. These results reveal additional NE sensitivity loci beyond those previously described demonstrating a higher level of genetic complexity of the wheat-P. nodorum system than previously thought. Knowledge regarding the prevalence and genomic locations of SNB susceptibility genes in HRSW and durum will prove useful for developing efficient breeding strategies and improving varieties for SNB resistance.
{"title":"Evaluation of durum and hard red spring wheat panels for sensitivity to necrotrophic effectors produced by <i>Parastagonospora nodorum</i>.","authors":"Agnes Szabo-Hever, Katherine Running, Sudeshi Seneviratne, Gurminder Singh, Zengcui Zhang, Amanda Peters Haugrud, Marco Maccaferri, Roberto Tuberosa, Steven S Xu, Timothy L Friesen, Justin D Faris","doi":"10.1094/PDIS-05-24-0990-RE","DOIUrl":"https://doi.org/10.1094/PDIS-05-24-0990-RE","url":null,"abstract":"<p><p>Septoria nodorum blotch is an important disease of both durum and hard red spring wheat (HRSW) worldwide. The disease is caused by the necrotrophic fungal pathogen Parastagonospora nodorum when compatible gene-for-gene interactions occur between pathogen-produced necrotrophic effectors (NEs) and corresponding host sensitivity genes. To date, nine sensitivity gene-NE interactions have been identified, but there is little information available regarding their overall frequency in durum and HRSW. Here, we infiltrated a global HRSW panel (HRSWP) and the Global Durum Panel (GDP) with P. nodorum NEs SnToxA, SnTox1, SnTox267, SnTox3, and SnTox5. Frequencies of sensitivity to SnTox1 and SnTox5 were higher in durum compared to HRSW and vice versa for SnTox267 and SnTox3. Strong associations for the known sensitivity loci Tsn1, Snn1, Snn2, Snn3, Snn5, and Snn7 along with potentially novel sensitivity loci on chromosome arms 7DS and 3BL associated with SnToxA and SnTox267, respectively, were identified in the HRSWP. In the GDP, Snn1, Snn3, and Snn5 were identified along with novel loci associated with sensitivity to SnTox267 on chromosome arms 2AS, 2AL, and 6AS and with SnTox5 sensitivity on 2BS and 7BL. These results reveal additional NE sensitivity loci beyond those previously described demonstrating a higher level of genetic complexity of the wheat-P. nodorum system than previously thought. Knowledge regarding the prevalence and genomic locations of SNB susceptibility genes in HRSW and durum will prove useful for developing efficient breeding strategies and improving varieties for SNB resistance.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546752","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 : 2024-10-30DOI: 10.1094/PDIS-06-24-1302-PDN
Jiaxing Ji, Lu Zhang, He Zhou, Maocun Wang, Zhenhua Jia, Tianliang Zhang, Zhiqiang Wang, Yue Wang, Qinghua Gao
<p><p>Honeysuckle (<i>Lonicera japonica</i> Thunb, LJ) is a common medicinal and edible plant (He et al. 2022). It has been utilized in various industries such as biomedicine, animal husbandry, and food production (Li et al. 2014; Su et al. 2020). In June 2023, a significant leaf lesion was observed on approximately 20% of honeysuckle "Juhua No.1" leaves in a 3.33-ha field at the base of Julu County, Hebei province, China. Almost all leaves were infected. Leaf spot disease occurred in the field honeysuckle throughout the flowering period, especially after picking. The disease mainly infected the leaves of honeysuckle, forming irregular spots on the edge of the leaf surface with black-brown edges, the midrib and lateral veins were affected (Figure S1A). In advanced stages, the entire leaf would become necrotic. For pathogen isolation, small pieces (4×4 mm) of the infected tissue from diseased leaves were surface sterilized with 75% ethanol and 5% sodium hypochlorite, rinsed with the sterile water, incubated on PDA. Finally, six isolated pathogens were obtained. Hyphae were white. The mycelium was multicellular, had diaphragm. Conidiophores protruded from the stroma, started as spherical structures and gradually developed into radial, black-brown formations. Spore acrosome was subglobose, bilayered pedicels covering acrosome, 40-60 µm in diameter, yellowish brown (Figures S1B, S1C). Based on morphological and cultural characteristics, the leaf spot disease fungus was tentatively identified as <i>Aspergillus</i> spp. (Wei 1979). To test the pathogenicity of pathogen, leaves of three healthy potted honeysuckle "Juhua No.1" plants were inoculated by sprayed with conidial suspensions (10<sup>6</sup> spores/ml) (Figure S1D). Negative controls were established by inoculating leaf with sterile distilled water. All plants were incubated in a greenhouse at 28 ± 2℃. The experiment was replicated three times. After 10 days, typical leaf spot symptoms were observed on inoculated leaves, whereas no symptoms were found on the control groups. The re-isolated fungus from the inoculated leaves displayed the same morphological traits (Figures S1E-S1H), again identified as <i>Aspergillus</i> spp., confirming Koch's postulates, designated as H2. To confirm the pathogen's identity, genomic DNA was extracted from the pathogenicity isolate H2. The 18S rDNA and the ITS genes were amplified and sequenced using primer pairs S1/S2 (Zhang et al. 2018) and ITS1/ITS4 (Zhang et al. 2023), respectively. Results of BLAST searches showed that the 18s rDNA and ITS sequences of H2 were highly homologous (>99%) with <i>Aspergillus niger</i>. The close genetic relationship indicated that H2 belonged to the genus <i>Aspergillus</i> (Figure S2a). We further sequenced the whole genome of H2. The sequence data were available in the NCBI GenBank (Accession number: PRJNA1117256). We also analyzed the ANI (Yoon et al. 2017) and digital DNA-DNA blotting (dDDH) (Figures S2b, S2c). The ANI value
{"title":"First Report of Leaf Spot on <i>Lonicera japonica</i> Caused by <i>Aspergillus niger</i> in China.","authors":"Jiaxing Ji, Lu Zhang, He Zhou, Maocun Wang, Zhenhua Jia, Tianliang Zhang, Zhiqiang Wang, Yue Wang, Qinghua Gao","doi":"10.1094/PDIS-06-24-1302-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1302-PDN","url":null,"abstract":"<p><p>Honeysuckle (<i>Lonicera japonica</i> Thunb, LJ) is a common medicinal and edible plant (He et al. 2022). It has been utilized in various industries such as biomedicine, animal husbandry, and food production (Li et al. 2014; Su et al. 2020). In June 2023, a significant leaf lesion was observed on approximately 20% of honeysuckle \"Juhua No.1\" leaves in a 3.33-ha field at the base of Julu County, Hebei province, China. Almost all leaves were infected. Leaf spot disease occurred in the field honeysuckle throughout the flowering period, especially after picking. The disease mainly infected the leaves of honeysuckle, forming irregular spots on the edge of the leaf surface with black-brown edges, the midrib and lateral veins were affected (Figure S1A). In advanced stages, the entire leaf would become necrotic. For pathogen isolation, small pieces (4×4 mm) of the infected tissue from diseased leaves were surface sterilized with 75% ethanol and 5% sodium hypochlorite, rinsed with the sterile water, incubated on PDA. Finally, six isolated pathogens were obtained. Hyphae were white. The mycelium was multicellular, had diaphragm. Conidiophores protruded from the stroma, started as spherical structures and gradually developed into radial, black-brown formations. Spore acrosome was subglobose, bilayered pedicels covering acrosome, 40-60 µm in diameter, yellowish brown (Figures S1B, S1C). Based on morphological and cultural characteristics, the leaf spot disease fungus was tentatively identified as <i>Aspergillus</i> spp. (Wei 1979). To test the pathogenicity of pathogen, leaves of three healthy potted honeysuckle \"Juhua No.1\" plants were inoculated by sprayed with conidial suspensions (10<sup>6</sup> spores/ml) (Figure S1D). Negative controls were established by inoculating leaf with sterile distilled water. All plants were incubated in a greenhouse at 28 ± 2℃. The experiment was replicated three times. After 10 days, typical leaf spot symptoms were observed on inoculated leaves, whereas no symptoms were found on the control groups. The re-isolated fungus from the inoculated leaves displayed the same morphological traits (Figures S1E-S1H), again identified as <i>Aspergillus</i> spp., confirming Koch's postulates, designated as H2. To confirm the pathogen's identity, genomic DNA was extracted from the pathogenicity isolate H2. The 18S rDNA and the ITS genes were amplified and sequenced using primer pairs S1/S2 (Zhang et al. 2018) and ITS1/ITS4 (Zhang et al. 2023), respectively. Results of BLAST searches showed that the 18s rDNA and ITS sequences of H2 were highly homologous (>99%) with <i>Aspergillus niger</i>. The close genetic relationship indicated that H2 belonged to the genus <i>Aspergillus</i> (Figure S2a). We further sequenced the whole genome of H2. The sequence data were available in the NCBI GenBank (Accession number: PRJNA1117256). We also analyzed the ANI (Yoon et al. 2017) and digital DNA-DNA blotting (dDDH) (Figures S2b, S2c). The ANI value","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546757","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 : 2024-10-30DOI: 10.1094/PDIS-07-24-1424-SC
Carlton Collins, Jonathan E Oliver, Apurba Barman, Gabriel Munoz, Alejandra M Jimenez Madrid
The Asian citrus psyllid (ACP) is the vector of Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus greening or Huanglongbing (HLB), one of the most devastating citrus diseases worldwide. The citrus industry in Georgia (U.S.A.) is in the process of a rapid expansion, and based on experiences with HLB in Florida, there is great concern about the potential impacts of HLB on this emerging industry. Prior to 2023, ACP had been identified in residential citrus trees in isolated Georgia counties but little to no testing of psyllids for CLas had occurred. However, in 2023, one individual psyllid collected from Chatham County was confirmed positive for CLas by PCR and sequencing. Furthermore, during 2023, ACP adults and nymphs were identified for the first time in a Georgia commercial citrus grove. The finding of ACP in a commercial planting represents a significant risk for CLas dissemination, and thereby has the potential to stall the rapid expansion of Georgia's citrus industry. In the coming years, surveillance and testing of ACP from commercial groves will be essential for the early detection and management of HLB and its vector to reduce HLB spread within Georgia's commercial groves.
{"title":"Confirmation of <i>Candidatus</i> Liberibacter asiaticus in Asian Citrus Psyllids and Detection of Asian Citrus Psyllids in Commercial Citrus in Georgia (U.S.A.).","authors":"Carlton Collins, Jonathan E Oliver, Apurba Barman, Gabriel Munoz, Alejandra M Jimenez Madrid","doi":"10.1094/PDIS-07-24-1424-SC","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1424-SC","url":null,"abstract":"<p><p>The Asian citrus psyllid (ACP) is the vector of Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus greening or Huanglongbing (HLB), one of the most devastating citrus diseases worldwide. The citrus industry in Georgia (U.S.A.) is in the process of a rapid expansion, and based on experiences with HLB in Florida, there is great concern about the potential impacts of HLB on this emerging industry. Prior to 2023, ACP had been identified in residential citrus trees in isolated Georgia counties but little to no testing of psyllids for CLas had occurred. However, in 2023, one individual psyllid collected from Chatham County was confirmed positive for CLas by PCR and sequencing. Furthermore, during 2023, ACP adults and nymphs were identified for the first time in a Georgia commercial citrus grove. The finding of ACP in a commercial planting represents a significant risk for CLas dissemination, and thereby has the potential to stall the rapid expansion of Georgia's citrus industry. In the coming years, surveillance and testing of ACP from commercial groves will be essential for the early detection and management of HLB and its vector to reduce HLB spread within Georgia's commercial groves.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546749","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 : 2024-10-30DOI: 10.1094/PDIS-08-24-1769-PDN
Shaoli Yang, Shiying Fu, Lilin Zhou, Pan Wang, Shuangmei Li, Jing Zhang, Jing Kuang, Xiang Cai
<p><p><i>Trapa natans</i> L., or water chestnut, is a currently globally distributed aquatic plant. The Yangtze River basin in China, a site origin of water chestnut (Fan et al., 2022), has extensive cultivation as a vegetable. In June 2021, a survey at the National Aquatic Vegetable Resource Garden in Wuhan, Hubei, China, revealed browning and wilting of water chestnut plants, with abundant white mycelia and brown to black sclerotia on leaves, indicative of southern blight (<i>Sclerotium rolfsii</i>). Field disease incidence a 1 ha area reached 70%, reducing fruit yield by 50%. About 10% of diseased plants showed blackening and rot from petioles to leaves. White sclerotial primordia and small brown to black sclerotia formed on the plant surfaces. By late August, symptoms exceeded 60%. To identify the pathogen, isolations were made from 243 sclerotial samples using 75% alcohol to disinfect, rinsed three times with water, and then incubated on potato dextrose agar (PDA) at 25℃. A total of 129 isolates were obtained, most of which exhibited characteristics of <i>S. rolfsii</i>. However, 21 isolates had sclerotia significantly smaller than those of <i>S. rolfsii</i> (1 to 1.5 mm in diameter). These isolates, cultured on PDA, produced abundant fluffy white aerial hyphae, 3 to 6 μm wide. Optimal mycelium growth was between 25 °C to 30 °C, with an average daily rate of 10 mm. White to light brown sclerotia appeared after 5 days and turned black within 10 to 14 days, averaging 0.34 mm in diameter (n=50). Some isolates produced a light brown pigment. These traits matched the description of <i>S. hydrophilum</i> (Bashyal et al. 2021). Isolates 221 and 238 were selected for molecular identification, with genomic DNA extracted from mycelia using the CTAB method. PCR amplification was conducted using ITS1/ITS4 and NS1/NS6 primers to target the internal transcribed spacer (ITS) and the small subunit ribosomal RNA gene (ssrRNA). Sequence analysis showed that the ITS sequence of isolate 221 (GenBank Acc. No. OR512512) had 99.84% sequence identity with <i>S. hydrophilum</i> Msh6 (GenBank Acc. No. FJ595946), and isolate 238 (GenBank Acc. No. PP035993) had 99.72% identity with <i>S. hydrophilum</i> Whcc-4 (GenBank Acc. No. PP035994). The ssrRNA sequences of both isolates (GenBank Acc. No. PP237261) had 99.69% identity with <i>S. hydrophilum</i> strain Hbq001 (GenBank Acc. No. KY995575), confirming their identification as <i>S. hydrophilum</i>. To assess pathogenicity, 16 water chestnut plants (cultivar Jia-yu Ling) at the rosette stage were placed individually in 32 cm diameter, 10 cm deep containers with fresh water. Eight plants were inoculated with 50 mature sclerotia from PDA cultures of isolates 221 and 238, and incubated at 25 °C for 14 days, with four plants per isolate. The remaining eight plants served as controls. Containers were covered to maintain 100% relative humidity at 25 °C to 32 °C for 3 days. This procedure was repeated twice. After 7 days, inoc
{"title":"First report of leaf blight of water chestnut (<i>Trapa natans</i> L.) caused by <i>Sclerotium hydrophilum</i> in central China.","authors":"Shaoli Yang, Shiying Fu, Lilin Zhou, Pan Wang, Shuangmei Li, Jing Zhang, Jing Kuang, Xiang Cai","doi":"10.1094/PDIS-08-24-1769-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-08-24-1769-PDN","url":null,"abstract":"<p><p><i>Trapa natans</i> L., or water chestnut, is a currently globally distributed aquatic plant. The Yangtze River basin in China, a site origin of water chestnut (Fan et al., 2022), has extensive cultivation as a vegetable. In June 2021, a survey at the National Aquatic Vegetable Resource Garden in Wuhan, Hubei, China, revealed browning and wilting of water chestnut plants, with abundant white mycelia and brown to black sclerotia on leaves, indicative of southern blight (<i>Sclerotium rolfsii</i>). Field disease incidence a 1 ha area reached 70%, reducing fruit yield by 50%. About 10% of diseased plants showed blackening and rot from petioles to leaves. White sclerotial primordia and small brown to black sclerotia formed on the plant surfaces. By late August, symptoms exceeded 60%. To identify the pathogen, isolations were made from 243 sclerotial samples using 75% alcohol to disinfect, rinsed three times with water, and then incubated on potato dextrose agar (PDA) at 25℃. A total of 129 isolates were obtained, most of which exhibited characteristics of <i>S. rolfsii</i>. However, 21 isolates had sclerotia significantly smaller than those of <i>S. rolfsii</i> (1 to 1.5 mm in diameter). These isolates, cultured on PDA, produced abundant fluffy white aerial hyphae, 3 to 6 μm wide. Optimal mycelium growth was between 25 °C to 30 °C, with an average daily rate of 10 mm. White to light brown sclerotia appeared after 5 days and turned black within 10 to 14 days, averaging 0.34 mm in diameter (n=50). Some isolates produced a light brown pigment. These traits matched the description of <i>S. hydrophilum</i> (Bashyal et al. 2021). Isolates 221 and 238 were selected for molecular identification, with genomic DNA extracted from mycelia using the CTAB method. PCR amplification was conducted using ITS1/ITS4 and NS1/NS6 primers to target the internal transcribed spacer (ITS) and the small subunit ribosomal RNA gene (ssrRNA). Sequence analysis showed that the ITS sequence of isolate 221 (GenBank Acc. No. OR512512) had 99.84% sequence identity with <i>S. hydrophilum</i> Msh6 (GenBank Acc. No. FJ595946), and isolate 238 (GenBank Acc. No. PP035993) had 99.72% identity with <i>S. hydrophilum</i> Whcc-4 (GenBank Acc. No. PP035994). The ssrRNA sequences of both isolates (GenBank Acc. No. PP237261) had 99.69% identity with <i>S. hydrophilum</i> strain Hbq001 (GenBank Acc. No. KY995575), confirming their identification as <i>S. hydrophilum</i>. To assess pathogenicity, 16 water chestnut plants (cultivar Jia-yu Ling) at the rosette stage were placed individually in 32 cm diameter, 10 cm deep containers with fresh water. Eight plants were inoculated with 50 mature sclerotia from PDA cultures of isolates 221 and 238, and incubated at 25 °C for 14 days, with four plants per isolate. The remaining eight plants served as controls. Containers were covered to maintain 100% relative humidity at 25 °C to 32 °C for 3 days. This procedure was repeated twice. After 7 days, inoc","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546754","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 : 2024-10-30DOI: 10.1094/PDIS-06-23-1210-SR
Davide Greco, Erika Sabella, Giambattista Carluccio, Mariarosaria DePascali, Eliana Nutricati, Luigi De Bellis, Andrea Luvisi
In the olive-growing areas of Apulia (southern Italy) where Xylella fastidiosa has caused enormous damage, there is a need to identify alternative crops. These could include pistachio (Pistacia vera L.), but it is critical to define the impact of the bacterium on this crop and what are the main phytosanitary threats for this species in the areas where the bacterium is now endemic. Therefore, we started evaluating infections caused by X. fastidiosa, the fungus Neofusicoccum mediterraneum, and other pathogens on four pistachio cultivars ('Kerman', 'Aegina', 'Lost Hills', and 'Napoletana') grown in areas where X. fastidiosa has been present for a long time. X. fastidiosa was detected only in one orchard (incidence: 18% 'Napoletana' and 55% 'Kerman') out of six surveyed orchards, with low bacterium concentration (1.67 to 5.98 × 103 CFU ml-1) and no symptoms. N. mediterraneum was retrieved in three orchards just on the cultivar Kerman but with high incidence (up to 30%) and infection level quantified as molecular severity (6.82 to 7.43); no other pathogens were detected. The N. mediterraneum representative isolates characterized in this study showed similarity with Spanish and Portuguese isolates. A confocal microscope analysis for this host-pathogen association suggested no differences in plant response to fungal aggression between the cultivars Kerman and Aegina, but just lack of latent inoculum in 'Aegina' plants, pointing to a possible nursery origin of the infection. Waiting for additional targeted experiments to clearly define host response of pistachio cultivars to Xylella spp., this study also points at N. mediterraneum as a potential threat to this tree crop new for the area.
{"title":"Could Pistachio (<i>Pistacia vera</i>) Be a Suitable Alternative Crop for Olive-Growing Mediterranean Areas Affected by <i>Xylella fastidiosa</i> subsp. <i>pauca</i> ST53?","authors":"Davide Greco, Erika Sabella, Giambattista Carluccio, Mariarosaria DePascali, Eliana Nutricati, Luigi De Bellis, Andrea Luvisi","doi":"10.1094/PDIS-06-23-1210-SR","DOIUrl":"https://doi.org/10.1094/PDIS-06-23-1210-SR","url":null,"abstract":"<p><p>In the olive-growing areas of Apulia (southern Italy) where <i>Xylella fastidiosa</i> has caused enormous damage, there is a need to identify alternative crops. These could include pistachio (<i>Pistacia vera</i> L.), but it is critical to define the impact of the bacterium on this crop and what are the main phytosanitary threats for this species in the areas where the bacterium is now endemic. Therefore, we started evaluating infections caused by <i>X. fastidiosa</i>, the fungus <i>Neofusicoccum mediterraneum</i>, and other pathogens on four pistachio cultivars ('Kerman', 'Aegina', 'Lost Hills', and 'Napoletana') grown in areas where <i>X. fastidiosa</i> has been present for a long time. <i>X. fastidiosa</i> was detected only in one orchard (incidence: 18% 'Napoletana' and 55% 'Kerman') out of six surveyed orchards, with low bacterium concentration (1.67 to 5.98 × 10<sup>3</sup> CFU ml<sup>-1</sup>) and no symptoms. <i>N. mediterraneum</i> was retrieved in three orchards just on the cultivar Kerman but with high incidence (up to 30%) and infection level quantified as molecular severity (6.82 to 7.43); no other pathogens were detected. The <i>N. mediterraneum</i> representative isolates characterized in this study showed similarity with Spanish and Portuguese isolates. A confocal microscope analysis for this host-pathogen association suggested no differences in plant response to fungal aggression between the cultivars Kerman and Aegina, but just lack of latent inoculum in 'Aegina' plants, pointing to a possible nursery origin of the infection. Waiting for additional targeted experiments to clearly define host response of pistachio cultivars to <i>Xylella</i> spp., this study also points at <i>N. mediterraneum</i> as a potential threat to this tree crop new for the area.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546750","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 : 2024-10-30DOI: 10.1094/PDIS-04-24-0839-PDN
Pengfei Li, Ronghua Sun, Lei Gao, Xiaogai Hou, Jian-Qiang Xu, Qingquan Luo
<p><p><i>Gleditsia sinensis</i> Lam (Lamarck et al., 1788) is an endemic species widely distributed in China. In Sep. 2022, leaf spot symptoms were observed on <i>G. sinensis</i> in Xuhui district (31◦9'16''N, 121◦26'36''E), Shanghai, China, with an incidence rate of 55% in the examination of 9 trees. The leaves showed typical symptoms of anthracnose with irregular gray-brown spots and sunken areas. For isolation, 5 × 5 mm sections were cut from the lesion edge of 20 infected leaves collected from 2 trees. The surface of the sections was sterilized by immersion in 75% ethanol for 30 s, followed by 5% NaClO for 1 min, rinsed three times with sterile water, and dried on sterile filter paper. These sections were placed on PDA plates incubated at 25°C in darkness. Eighteen isolates with similar colony morphology were obtained and purified by single spore culturing. Two isolates (YKY2301, 2302) from separate trees were further tested. On the 6<sup>th</sup> day, the colonies had a diameter of 7.6 to 8.4 cm and appeared white to gray-white with aerial hyphae. The colony's central part exhibited an orange hue due to the conidia accumulation, while the undersides displayed an orange-yellow color. The hyphae were hyaline and smooth, with septa and branches, and the conidia were cylindrical with blunt to slightly rounded ends, measuring 13.1 to 18.8 (average 15.9) μm× 4.0 to 6.6 (average 5.4) μm (n=184). From conidia germinated on glass slides, the appressoria measured 5.5 to 6.3 μm ×4.9 to 5.1 μm (n=50) and were nearly spherical or elliptical in shape. These characteristics matched those of the <i>Colletotrichum gloeosporioides</i> species complex (Cannon et al., 2012; Weir et al., 2012). For molecular identification, the genomic DNA was extracted using a modified CTAB method (Luo et al., 2012). Gene fragments including ITS (PP125667, PP125668), <i>GAPDH</i> (PP153428, PP153429), <i>ACT</i> (PP153424, PP153425), <i>TUB2</i>(PP153917, PP190256), and <i>ApMAT</i> (PP153426, PP153427) were obtained by PCR using universal primers (Huang et al., 2022) and sequenced. The sequences exhibited 98.19% to 99.82% identity with the corresponding gene of the type strain <i>C. gloeosporioides</i> IMI356878 (JX010152, JX010056, JX009531, JX010445, JQ807843) in NCBI BLAST. A multilocus Maximum likelihood phylogenetic tree was constructed based on concatenated the five genes by PhyloSuite. It showed that YKY2301, 2302 were on the same branch with <i>C. gloeosporioides</i>. Based on these results, the isolates were identified as <i>C. gloeosporioides</i>. Pathogenicity tests were conducted by mycelial and conidia inoculation. 5 mm mycelial or blank agar plugs were inoculated onto the leaves of 2 healthy trees in a garden (25 to 30 °C), with and without wounds made by toothpick pricking (n≥3 per group). All mycelial inoculated leaves showed leaf spots on the 6<sup>th</sup> day. Three healthy 2-year-old seedlings were inoculated with either conidia (10<sup>8</sup> conidia/ml)
{"title":"First report of leaf spot on <i>Gleditsia sinensis</i> caused by <i>Colletotrichum gloeosporioides</i> in China.","authors":"Pengfei Li, Ronghua Sun, Lei Gao, Xiaogai Hou, Jian-Qiang Xu, Qingquan Luo","doi":"10.1094/PDIS-04-24-0839-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-04-24-0839-PDN","url":null,"abstract":"<p><p><i>Gleditsia sinensis</i> Lam (Lamarck et al., 1788) is an endemic species widely distributed in China. In Sep. 2022, leaf spot symptoms were observed on <i>G. sinensis</i> in Xuhui district (31◦9'16''N, 121◦26'36''E), Shanghai, China, with an incidence rate of 55% in the examination of 9 trees. The leaves showed typical symptoms of anthracnose with irregular gray-brown spots and sunken areas. For isolation, 5 × 5 mm sections were cut from the lesion edge of 20 infected leaves collected from 2 trees. The surface of the sections was sterilized by immersion in 75% ethanol for 30 s, followed by 5% NaClO for 1 min, rinsed three times with sterile water, and dried on sterile filter paper. These sections were placed on PDA plates incubated at 25°C in darkness. Eighteen isolates with similar colony morphology were obtained and purified by single spore culturing. Two isolates (YKY2301, 2302) from separate trees were further tested. On the 6<sup>th</sup> day, the colonies had a diameter of 7.6 to 8.4 cm and appeared white to gray-white with aerial hyphae. The colony's central part exhibited an orange hue due to the conidia accumulation, while the undersides displayed an orange-yellow color. The hyphae were hyaline and smooth, with septa and branches, and the conidia were cylindrical with blunt to slightly rounded ends, measuring 13.1 to 18.8 (average 15.9) μm× 4.0 to 6.6 (average 5.4) μm (n=184). From conidia germinated on glass slides, the appressoria measured 5.5 to 6.3 μm ×4.9 to 5.1 μm (n=50) and were nearly spherical or elliptical in shape. These characteristics matched those of the <i>Colletotrichum gloeosporioides</i> species complex (Cannon et al., 2012; Weir et al., 2012). For molecular identification, the genomic DNA was extracted using a modified CTAB method (Luo et al., 2012). Gene fragments including ITS (PP125667, PP125668), <i>GAPDH</i> (PP153428, PP153429), <i>ACT</i> (PP153424, PP153425), <i>TUB2</i>(PP153917, PP190256), and <i>ApMAT</i> (PP153426, PP153427) were obtained by PCR using universal primers (Huang et al., 2022) and sequenced. The sequences exhibited 98.19% to 99.82% identity with the corresponding gene of the type strain <i>C. gloeosporioides</i> IMI356878 (JX010152, JX010056, JX009531, JX010445, JQ807843) in NCBI BLAST. A multilocus Maximum likelihood phylogenetic tree was constructed based on concatenated the five genes by PhyloSuite. It showed that YKY2301, 2302 were on the same branch with <i>C. gloeosporioides</i>. Based on these results, the isolates were identified as <i>C. gloeosporioides</i>. Pathogenicity tests were conducted by mycelial and conidia inoculation. 5 mm mycelial or blank agar plugs were inoculated onto the leaves of 2 healthy trees in a garden (25 to 30 °C), with and without wounds made by toothpick pricking (n≥3 per group). All mycelial inoculated leaves showed leaf spots on the 6<sup>th</sup> day. Three healthy 2-year-old seedlings were inoculated with either conidia (10<sup>8</sup> conidia/ml) ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546756","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>Aphelenchoides oryzae Yokoo caused a large reduction in rice yields in Japan (1948). It was later synonymised with A. besseyi by Allen (1952), but Subbotin et al. (2021) considered it a valid species. In the main foxtail millet (Setaria italica (L.) P. Beauv.) production area of western Jilin Province, China, many plants were stunted, with thin spikes and open, smooth, shiny glumes. Severely affected spikes were noticeably shorter, fluffy at the top, and erect. In August 2023, 10 foxtail millet samples were collected and nematodes were isolated from 9 of them. A population from Songyuan City, Jilin Province (E:123.64, N:44.86) was studied. The average number of nematodes isolated per gram of ear was 510.7 ± 15.17. Female body slender, lip region rounded, lateral fields with 4 or 6 incisures, vulva located at 71.6% of the body length, post vulvar uterine sac (PUS) 3.7 times anal body width long but less than quarter distance from vulva to anus (VA), tail conical with 3 or 4 terminal spikes. The body length (L), maximum body width (W) and tail length of the female (mean, n=25) were 648 μm, 15.9 μm and 36.7 μm, respectively. PUS length / (VA)% = 23.5, L/W = 41.1, L/ tail length = 17.8. Male body tail curves like a sickle, lacks bursa and shows three pairs of copulatory papillae. Spicules typical of the genus except that the proximal end lacks a dorsal process and has only a moderately developed rostrum. Male measured (mean, n = 25): L = 525.8 μm, W = 14.8 μm, tail length = 34.0 ± 0.7 μm, spicule length = 16.4 μm; L/W = 35.6; L/tail length = 15.6 μm. Amplification of the D2-D3 expansion segments of the 28S ribosomal RNA and the cytochrome oxidase subunit I (COI) gene of mitochondrial DNA (mtDNA) with primers the forward D2A (5'-ACAAGTACCGTGAGGGAAAGTTG-3') and the reverse D3B (5'-TCGGAAGGAACCAGCTACTA-3') (Subbotin et al. 2006), and forward COI-F1 (5'-CCTACTATGATTGGTGGTTTTGGTAATTG-3') and the reverse COI-R2 (5'-GTAGCAGCAGTAAAATAAGCACG-3') (Kanzaki and Futai 2002). PCR conditions were as described by Ye et al. (2007). The sequences of 28S D2-D3 region (726 bp, PP573753- PP573761) of rDNA were 100% identical to A. oryzae (KY123700, KY123694) and COI region (698-700 bp, PP733171-PP733179), were 98.88% identical to A. oryzae (GU367867). Bayesian inference was used to construct phylogenetic tree of 28S D2-D3 region and COI gene, which showed that the Jilin populations clustered together with A. oryzae, which was a sister branch of A. besseyi. Pathogenicity was established via the infection of foxtail millet (cv. Jiyou 2). The germinated foxtail millet seeds were planted in pots containing 350 ml of sterile soil mixture. On the 15th day, every 10 seedlings were inoculated with 100 A. oryzae at the leaf sheet wounds and 3 plants were noninoculated as control. Three independent replicates were performed on different dates. Forty days post-inoculation, an average of 88.3 ± 2.26 A. oryzae were extracted from each nematode-inoculated plant, and the plants w
{"title":"First Record of <i>Aphelenchoides oryzae</i> on Foxtail Millet (<i>Setaria italica</i> (L.) P. Beauv.) in Jilin Province of China.","authors":"Feng Zhu, Chengli Tian, Baihui Zhou, Ming Gao, Yiwu Fang, Jichun Wang, Jianfeng Gu, Weilong Zhang","doi":"10.1094/PDIS-07-24-1528-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1528-PDN","url":null,"abstract":"<p><p>Aphelenchoides oryzae Yokoo caused a large reduction in rice yields in Japan (1948). It was later synonymised with A. besseyi by Allen (1952), but Subbotin et al. (2021) considered it a valid species. In the main foxtail millet (Setaria italica (L.) P. Beauv.) production area of western Jilin Province, China, many plants were stunted, with thin spikes and open, smooth, shiny glumes. Severely affected spikes were noticeably shorter, fluffy at the top, and erect. In August 2023, 10 foxtail millet samples were collected and nematodes were isolated from 9 of them. A population from Songyuan City, Jilin Province (E:123.64, N:44.86) was studied. The average number of nematodes isolated per gram of ear was 510.7 ± 15.17. Female body slender, lip region rounded, lateral fields with 4 or 6 incisures, vulva located at 71.6% of the body length, post vulvar uterine sac (PUS) 3.7 times anal body width long but less than quarter distance from vulva to anus (VA), tail conical with 3 or 4 terminal spikes. The body length (L), maximum body width (W) and tail length of the female (mean, n=25) were 648 μm, 15.9 μm and 36.7 μm, respectively. PUS length / (VA)% = 23.5, L/W = 41.1, L/ tail length = 17.8. Male body tail curves like a sickle, lacks bursa and shows three pairs of copulatory papillae. Spicules typical of the genus except that the proximal end lacks a dorsal process and has only a moderately developed rostrum. Male measured (mean, n = 25): L = 525.8 μm, W = 14.8 μm, tail length = 34.0 ± 0.7 μm, spicule length = 16.4 μm; L/W = 35.6; L/tail length = 15.6 μm. Amplification of the D2-D3 expansion segments of the 28S ribosomal RNA and the cytochrome oxidase subunit I (COI) gene of mitochondrial DNA (mtDNA) with primers the forward D2A (5'-ACAAGTACCGTGAGGGAAAGTTG-3') and the reverse D3B (5'-TCGGAAGGAACCAGCTACTA-3') (Subbotin et al. 2006), and forward COI-F1 (5'-CCTACTATGATTGGTGGTTTTGGTAATTG-3') and the reverse COI-R2 (5'-GTAGCAGCAGTAAAATAAGCACG-3') (Kanzaki and Futai 2002). PCR conditions were as described by Ye et al. (2007). The sequences of 28S D2-D3 region (726 bp, PP573753- PP573761) of rDNA were 100% identical to A. oryzae (KY123700, KY123694) and COI region (698-700 bp, PP733171-PP733179), were 98.88% identical to A. oryzae (GU367867). Bayesian inference was used to construct phylogenetic tree of 28S D2-D3 region and COI gene, which showed that the Jilin populations clustered together with A. oryzae, which was a sister branch of A. besseyi. Pathogenicity was established via the infection of foxtail millet (cv. Jiyou 2). The germinated foxtail millet seeds were planted in pots containing 350 ml of sterile soil mixture. On the 15th day, every 10 seedlings were inoculated with 100 A. oryzae at the leaf sheet wounds and 3 plants were noninoculated as control. Three independent replicates were performed on different dates. Forty days post-inoculation, an average of 88.3 ± 2.26 A. oryzae were extracted from each nematode-inoculated plant, and the plants w","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142546753","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 : 2024-10-29DOI: 10.1094/PDIS-03-24-0552-FE
Michael S McLaughlin, Sanna Abbasi, Pervaiz A Abbasi, Shawkat Ali
Bitter rot and Glomerella leaf spot (GLS) are two distinct diseases of apple fruit and foliage caused by members of the ascomycete fungal genus Colletotrichum. Although GLS is restricted to subtropical and, in some areas, to temperate climates, bitter rot is responsible for significant yield loss worldwide, particularly during the postharvest period. Initially thought to be caused by just two species of Colletotrichum, C. acutatum, and C. gloeosporioides, advances in molecular biology and sequencing techniques enabled the identification of 25 different species capable of causing bitter rot and/or GLS of apple belonging to the C. gloeosporioides species complex (CGSC), C. acutatum species complex (CASC), and C. boninense species complex (CBSC). Three species (C. gloeosporioides, C. fructicola, and C. chrysophilum) of CGSC cause both bitter rot and GLS, 18 species (6 of CGSC and 12 of CASC) only cause bitter rot, and 4 species (C. aenigma and C. asianum of CGSC, C. limetticola of CASC, and C. karsti of CBSC) only cause GLS. These species were found to differ in their geographical distribution, environmental and host tissue preference, pathogenicity, and fungicide sensitivities. In this review, we summarize the distribution, life cycle, and pathogenicity mechanisms of all currently known Colletotrichum species responsible for bitter rot and GLS of apple. Furthermore, we describe known apple defense mechanisms and management strategies for the control of these economically significant pathogens and identify gaps in our present understanding for future research.
苦腐病和褐斑病（GLS）是苹果果实和叶片的两种不同病害，由子囊菌属 Colletotrichum 真菌引起。GLS 局限于亚热带气候，在某些地区还局限于温带气候，而苦腐病则在全球范围内造成严重的产量损失，尤其是在采收后时期。最初，人们认为苹果的苦腐病和/或 GLS 只由 C. acutatum 和 C. gloeosporioides 这两种 Colletotrichum 菌引起，但随着分子生物学和测序技术的进步，人们发现了 25 种能引起苹果苦腐病和/或 GLS 的不同菌种，它们分别属于 C. gloeosporioides 菌种复合体（CGSC）、C. acutatum 菌种复合体（CASC）和 C. boninense 菌种复合体（CBSC）。CGSC 中的 3 个种（C. gloeosporioides、C. fructicola 和 C. chrysophilum）同时引起苦腐病和 GLS，18 个种（CGSC 中的 6 个种和 CASC 中的 12 个种）只引起苦腐病，4 个种（CGSC 中的 C. aenigma 和 C. asianum、CASC 中的 C. limetticola 和 CBSC 中的 C. karstii）只引起 GLS。这些物种在地理分布、环境和寄主组织偏好、致病性和杀真菌剂敏感性方面存在差异。在本综述中，我们总结了目前已知的所有导致苹果苦腐病和 GLS 的 Colletotrichum 种类的分布、生命周期和致病机制。此外，我们还介绍了已知的苹果防御机制和控制这些具有重要经济意义的病原菌的管理策略，并指出了我们目前在这方面的认识差距，供今后研究参考。
{"title":"Apple Bitter Rot and Glomerella Leaf Spot: A Comprehensive Review of Causal Species and Their Biology, Fungicide Sensitivities, and Management Strategies.","authors":"Michael S McLaughlin, Sanna Abbasi, Pervaiz A Abbasi, Shawkat Ali","doi":"10.1094/PDIS-03-24-0552-FE","DOIUrl":"10.1094/PDIS-03-24-0552-FE","url":null,"abstract":"<p><p>Bitter rot and Glomerella leaf spot (GLS) are two distinct diseases of apple fruit and foliage caused by members of the ascomycete fungal genus <i>Colletotrichum</i>. Although GLS is restricted to subtropical and, in some areas, to temperate climates, bitter rot is responsible for significant yield loss worldwide, particularly during the postharvest period. Initially thought to be caused by just two species of <i>Colletotrichum</i>, <i>C</i>. <i>acutatum</i>, and <i>C</i>. <i>gloeosporioides</i>, advances in molecular biology and sequencing techniques enabled the identification of 25 different species capable of causing bitter rot and/or GLS of apple belonging to the <i>C</i>. <i>gloeosporioides</i> species complex (CGSC), <i>C</i>. <i>acutatum</i> species complex (CASC), and <i>C</i>. <i>boninense</i> species complex (CBSC). Three species (<i>C</i>. <i>gloeosporioides</i>, <i>C</i>. <i>fructicola</i>, and <i>C</i>. <i>chrysophilum</i>) of CGSC cause both bitter rot and GLS, 18 species (6 of CGSC and 12 of CASC) only cause bitter rot, and 4 species (<i>C</i>. <i>aenigma</i> and <i>C</i>. <i>asianum</i> of CGSC, <i>C</i>. <i>limetticola</i> of CASC, and <i>C</i>. <i>karsti</i> of CBSC) only cause GLS. These species were found to differ in their geographical distribution, environmental and host tissue preference, pathogenicity, and fungicide sensitivities. In this review, we summarize the distribution, life cycle, and pathogenicity mechanisms of all currently known <i>Colletotrichum</i> species responsible for bitter rot and GLS of apple. Furthermore, we describe known apple defense mechanisms and management strategies for the control of these economically significant pathogens and identify gaps in our present understanding for future research.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141071687","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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