Wan Anmin, Chen Xianming
Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430.
United States Department of Agriculture-Agricultural Research Service, Wheat Genetics, Quality, Physiology, and Disease Research Unit and Department of Plant Pathology, Washington State University, Pullman.
Plant Dis. 2014 Nov;98(11):1534-1542. doi: 10.1094/PDIS-01-14-0071-RE.
Puccinia striiformis f. sp. tritici causes stripe rust (yellow rust) of wheat and is highly variable in virulence toward wheat with race-specific resistance. During 2010, wheat stripe rust was the most widespread in the recorded history of the United States, resulting in large-scale application of fungicides and substantial yield loss. A new differential set with 18 yellow rust (Yr) single-gene lines was established and used to differentiate races of P. striiformis f. sp. tritici, which were named as race PSTv in distinction from the PST races identified in the past. An octal system was used to describe the virulence and avirulence patterns of the PSTv races. From 348 viable P. striiformis f. sp. tritici isolates recovered from a total of 381 wheat and grass stripe rust samples collected in 24 states, 41 races, named PSTv-1 to PSTv-41, were identified using the new set of 18 Yr single-gene differentials, and their equivalent PST race names were determined on the previous set of 20 wheat cultivar differentials. The frequencies and distributions of the races and their virulences were determined. The five most predominant races were PSTv-37 (34.5%), PSTv-11 (17.5%), PSTv-14 (7.2%), PSTv-36 (5.2%), and PSTv-34 (4.9%). PSTv-37 was distributed throughout the country while PSTv-11 and PSTv-14 were almost restricted to states west of the Rocky Mountains. The races had virulence to 0 to 13 of the 18 Yr genes. Frequencies of virulences toward resistance genes Yr6, Yr7, Yr8, Yr9, Yr17, Yr27, Yr43, Yr44, YrTr1, and YrExp2 were high (67.0 to 93.7%); those to Yr1 (32.8%) and YrTye (31.3%) were moderate; and those to Yr10, Yr24, Yr32, and YrSP were low (3.4 to 5.7%). All of the isolates were avirulent to Yr5 and Yr15.
条形柄锈菌小麦专化型引起小麦条锈病（黄锈病），对具有小种专化抗性的小麦，其毒力变化很大。2010年期间，小麦条锈病在美国有记录的历史中最为广泛，导致杀菌剂的大规模应用和产量的大幅损失。建立了一个包含18个黄锈病（Yr）单基因系的新鉴别寄主集，并用于区分条形柄锈菌小麦专化型的小种，这些小种被命名为PSTv小种，以区别于过去鉴定的PST小种。采用八进制系统描述PSTv小种的毒力和无毒力模式。从在24个州采集的总共381个小麦和禾本科条锈病样本中分离得到348个可存活的条形柄锈菌小麦专化型分离物，使用新的18个Yr单基因鉴别寄主鉴定出41个小种，命名为PSTv-1至PSTv-41，并根据先前的20个小麦品种鉴别寄主确定了它们对应的PST小种名称。确定了这些小种的频率、分布及其毒力。五个最主要的小种是PSTv-37（34.5%）、PSTv-11（17.5%）、PSTv-14（7.2%）、PSTv-36（5.2%）和PSTv-34（4.9%）。PSTv-37分布在全国各地，而PSTv-11和PSTv-14几乎局限于落基山脉以西的各州。这些小种对18个Yr基因中的0至13个具有毒力。对抗性基因Yr6、Yr7、Yr8、Yr9、Yr17、Yr27、Yr43、Yr44、YrTr1和YrExp2的毒力频率较高（67.0%至93.7%）；对Yr1（32.8%）和YrTye（31.3%）的毒力频率中等；对Yr10、Yr24、Yr32和YrSP的毒力频率较低（3.4%至5.7%）。所有分离物对Yr5和Yr15均无毒力。
