Rodriguez-Herrera Kensy D, Vargas Alejandra, Amie Jonathan, Price Paul P, Salgado Leonardo D, Doyle Vinson P, Richards Jonathan K, Moseley David, Rojas Alejandro, Thomas-Sharma Sara
Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803.
Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853.
Phytopathology. 2024 May;114(5):1039-1049. doi: 10.1094/PHYTO-10-23-0390-KC. Epub 2024 May 25.
Aerial blight, caused by the fungus anastomosis group (AG) 1-IA, is an economically important soybean disease in the mid-Southern United States. Management has relied on fungicide applications during the season, but there is an increasing prevalence of resistance to commonly used strobilurin fungicides and an urgent need to identify soybean varieties resistant to aerial blight. Because the patchy distribution of the pathogen complicates field variety screening, the present study aimed to develop a greenhouse screening protocol to identify soybean varieties resistant to aerial blight. For this, 88 pathogen isolates were collected from commercial fields and research farms across five Louisiana parishes, and 77% were confirmed to be AG1-IA. Three polymorphic codominant microsatellite markers were used to explore the genetic diversity of 43 AG1-IA isolates, which showed high genetic diversity, with 35 haplotypes in total and only two haplotypes common to two other locations. Six genetically diverse isolates were chosen and characterized for their virulence and fungicide sensitivity. The isolate AC2 was identified as the most virulent and was resistant to both active ingredients, azoxystrobin and pyraclostrobin, tested. The six isolates were used in greenhouse variety screening trials using a millet inoculation protocol. Of the 31 varieties screened, only Armor 48-D25 was classified as moderately resistant, and plant height to the first node influenced final disease severity. The study provides short-term solutions for growers to choose less susceptible varieties for planting and lays the foundation to characterize host resistance against this important soybean pathogen.
由真菌融合群（AG）1-IA引起的空中枯萎病是美国中南部一种具有经济重要性的大豆病害。病害管理一直依赖于在生长季节施用杀菌剂，但对常用的甲氧基丙烯酸酯类杀菌剂的抗性日益普遍，因此迫切需要鉴定抗空中枯萎病的大豆品种。由于病原菌的斑块状分布使田间品种筛选变得复杂，本研究旨在制定一种温室筛选方案，以鉴定抗空中枯萎病的大豆品种。为此，从路易斯安那州五个教区的商业田地和研究农场收集了88个病原菌分离株，其中77%被确认为AG1-IA。使用三个多态性共显性微卫星标记来探究43个AG1-IA分离株的遗传多样性，结果显示其具有高度的遗传多样性，共有35个单倍型，且只有两个单倍型与其他两个地点相同。选择了六个遗传多样性不同的分离株，并对其毒力和杀菌剂敏感性进行了表征。分离株AC2被鉴定为毒力最强，且对所测试的两种活性成分嘧菌酯和吡唑醚菌酯均具有抗性。这六个分离株被用于采用小米接种方案的温室品种筛选试验。在筛选的31个品种中，只有Armor 48-D25被归类为中度抗性，且第一节的株高影响最终病害严重程度。该研究为种植者提供了短期解决方案，以便他们选择较不易感的品种进行种植，并为表征宿主对这种重要大豆病原菌的抗性奠定了基础。
