甘肃陇南感病小檗在小麦条锈病发生中起提供(初始)菌源作用的直接证据

陇南是中国小麦条锈菌易变区、小麦条锈病的常发流行区和防治的关键地区.明确陇南小麦条锈菌转主寄主小檗在小麦条锈病发生中的作用,对阐释该地区小麦条锈菌新小种产生的来源和指导小麦条锈病的综合防控具有重要意义.本研究从陇南春季自然受锈菌侵染的堆花小檗及其邻近的小麦上分离获得小麦条锈菌菌系,19个来自发病小檗的单夏孢子堆菌系在中...

Evidence of roles of susceptible barberry in providing (primary) inocula to trigger stripe rust infection on wheat in Longnan,Gansu

Longnan, located in southern Gansu, is a virulence variable region (hotspot) for the wheat stripe rust pathogen Puccinia striiformis f. sp. tritici (Pst), a frequent epidemic region for wheat stripe rust, and an important area for management of the disease in China. Determination of the role of barberry (Berberis) as alternate host for Pst in occurrence of wheat stipe rust in Longnan will be beneficial for understanding origin of new races of the pathogen and guiding integrated management of the disease. In the present study, Pst isolates were recovered from naturally rusted barberry (B. aggregata) and wheat plants in field adjacent to the diseased barberry bushes in spring respectively. Nineteen Pst single-uredinium (SU) isolates from the rusted barberry produced 5 virulence patterns (VPs) of VP1-VP5 based on tests on the routine classical differential hosts that are used to differentiating Chinese Pst races, indicating that all of the 19 Pst SU isolates of 5 VPs were new. The 19 Pst SU isolates generated 17 various VPs on a set of combined differentials consisting of near isogenic lines (NILs) and wheat genotypes carrying Yr genes. Twenty nine SU Pst isolates from wheat fields gave rise to 10 VPs of VP1-VP10, identifying that all of them were new races. The 29 SU Pst isolates showed 24 different VPs on the set of the same combined differentials as mentioned the above. Comparisons between the two Pst populations showed that the shared pathotypes VP1-VP5 were shared, and that virulence patterns of some of Pst isolates from the diseased barberry were different from those from wheat fields. Analyses using principal coordinate analysis and clustering of phenotypes based on virulence on the combined differentials indicated the existence of gene flow between both populations from the naturally rusted barberry and wheat fields close to the diseased barberry bushes. Altogether, the results indicated that under natural conditions occurrence of Pst sexual reproduction on wild susceptible Berberis species in Longnan is routine, and that susceptible Berberis species play in a role in providing aeciospores-derived from barberry plants as inocula to cause stripe rust infection on wheat in this area. Therefore, treatment of barberry bushes should be considered in integrated management of wheat stripe rust in Longnan. This strategy will be apt to reduce rates of generating new races of Pst and breakdown of the resistance of wheat cultivars against stripe rust, extending utilization of stripe rust-resistant wheat cultivars and decreasing spread of new races to wheat production areas in eastern China for ensuring safe production of wheat.