Vera D I, Murray T D
Department of Plant Pathology, Washington State University, Pullman; and Plant Protection Department, National Institute of Agricultural Research, Pichilingue, Los Rios, Ecuador.
Department of Plant Pathology, Washington State University, Pullman.
Plant Dis. 2016 May;100(5):991-995. doi: 10.1094/PDIS-09-15-1056-RE. Epub 2016 Mar 2.
Eyespot is a chronic disease of wheat caused by Oculimacula yallundae and O. acuformis that results in premature ripening of grain, lodging, and reduced grain yield. Discovery of the sexual stage of these Oculimacula spp. in the Pacific Northwest (PNW) of the United States is relatively recent and the role of apothecia in the epidemiology of eyespot is unclear. Our goals were to determine whether and when apothecia of these Oculimacula spp. are found in the PNW, and monitor their ability to survive over summer and over winter. Seventy-three harvested commercial wheat fields in Idaho, Oregon, and Washington were surveyed for apothecia during spring and fall 2012 and spring 2013. Apothecia of both species were found in both spring and fall in 19% of fields. Apothecia survived on straw placed on the soil surface over the summer but not the winter. This is the first report of O. yallundae apothecia in commercial wheat fields in the PNW. Occurrence of apothecia in spring and fall demonstrates that sexual reproduction of both species occurs regularly in the PNW and at a time when ascospores could serve as primary inoculum for infection of winter wheat. Results of this study are consistent with previous population genetic studies that found high genotypic diversity of both eyespot pathogens in winter wheat fields and provides a baseline for understanding the influence of sexual reproduction on population dynamics and genetics of both pathogens.
眼斑病是一种由黄斑柄锈菌和尖孢黄斑柄锈菌引起的小麦慢性病，会导致谷物过早成熟、倒伏并降低谷物产量。这些黄斑柄锈菌属物种的有性阶段在美国太平洋西北部（PNW）的发现相对较新，子囊盘在眼斑病流行病学中的作用尚不清楚。我们的目标是确定这些黄斑柄锈菌属物种的子囊盘是否以及何时在PNW被发现，并监测它们在夏季和冬季的存活能力。2012年春季和秋季以及2013年春季，对爱达荷州、俄勒冈州和华盛顿州的73块已收割的商业小麦田进行了子囊盘调查。在19%的田地中，春季和秋季都发现了这两个物种的子囊盘。子囊盘在夏季放置在土壤表面的秸秆上存活，但在冬季不能存活。这是黄斑柄锈菌子囊盘在PNW商业小麦田中的首次报道。春季和秋季子囊盘的出现表明，这两个物种的有性繁殖在PNW经常发生，且此时子囊孢子可作为冬小麦感染的主要接种体。本研究结果与之前的群体遗传学研究一致，之前的研究发现冬小麦田中两种眼斑病病原体的基因型多样性都很高，并为理解有性繁殖对两种病原体群体动态和遗传学的影响提供了基线。
