分离自甘肃小麦与转主寄主小檗的小麦条锈菌新菌系ZS-G毒性分析与分子检测

Virulence analysis and molecular detection of new isolate ZS-G virulent to Zhongsi of the wheat stripe rust pathogen in Gansu province.Abstract: Wheat stripe rust is the most serious disease in wheat production areas. The continuous emergence and development of new virulent races are fundamental approach for frequently leading to loss of resistance of wheat varieties and causing subsequent disease pandemics. Longnan in Gansu Province is considered as hot spot (variable region) for the rust fungus in China. Therefore it is very important to monitor emergence of new races of the rust pathogen in advance and make prediction for epidemic trend of new races in this area. This will aid to breeding of resistance wheat to stripe rust and sustainable management of the disease. Zhongsi is an important resistant germplasm resource and possess durable resistance for a long time in China, which is immune to current predominant race CYR34 and each of previous races. New races, ZS-G, virulent to Zhongsi have been detected from wheat and barberry as alternate host for the wheat stripe rust pathogen since 2015, presenting strong virulence and virulence to wheat Guinong 22, but distinct from CYR34 in virulence patterns. The objectives of this study will to study pathogenicity, composition of virulence genes of new isolates of the wheat stripe rust pathogen, to monitor dynamics of development and decline trend, and determine parasitic fitness of the rust fungus. The results will reveal pathogenic characteristics, trend of development, and influence to wheat resistance genes. Molecular detection system will be established based on the specific SCAR marker technology, which will provide a scientific basis for determining potential status and role of the new races, and timely guiding breeding of wheat resistant to stripe rust in advance and sustainable control of the disease..Keyword: Wheat stripe rust; Virulence variation; New race; Zhongsi; Molecular detection; Berberis

小麦条锈病是小麦生产上最重要的病害，条锈菌新毒性小种的不断产生及发展是造成历次品种抗锈性“丧失”并导致病害流行的主要原因。甘肃陇南是我国条锈菌易变区，对该区域新小种的毒性变异监测及流行趋势超前预测，是抗锈育种及病害持续控制的重要基础环节。小麦条锈菌转主寄主小檗的发现证明有性生殖是毒性变异的主要途径。中四是国内抗性保持最长并对CYR34及以前各小种均表现免疫的重要抗源材料，近年来连续从小麦和小檗上监测到对中四有毒性的致病菌，其中ZS-G是一成株致病力强、对贵农22有联合毒性、且有别于CYR34的新菌系。本项目拟通过对其致病特性研究、毒性基因组成分析、消长动态监测及致病性、寄生适合度测定及有性菌系分析等系统研究，探明其毒性特点和下一步发展趋势及对小麦抗病基因的影响；建立基于特异性SCAR标记的分子检测体系。从而为明确新菌系在条锈病流行中的地位和作用、及时指导抗锈育种及条锈病持续控制提供科学依据

小麦条锈病是小麦生产上最重要的病害之一，利用抗病品种是防治该病最经济有效的措施。新毒性菌系不断产生并成为优势小种是造成历次大面积推广种植品种抗锈性“丧失”并导致病害大流行的根本原因。对新菌系的系统监测及流行趋势进行科学评价，将会超前指导抗锈育种、指导品种布局及锈病持续治理意义重大。项目经4年研究，得到如下结论：.（1）消长趋势分析。2017-2022年对2359份小麦条锈菌无性标样监测结果发现：ZS类群出现频率由2017年10.50%上升到2018年13.85%和2019年的22.78%，2020年和2021年降为7.56%和0.22%，2022年上升到7.37%，成为居贵农、HY之后的第三位致病类群。其中ZS-1是主要致病类型，出现频率在0.4%-7.34%之间。对861份有性菌系监测发现：ZS菌系年度间消长频率分别为18.75%、12.50%、8.02%、6.36%、2.79%、22.66%；其中ZS-1、ZS-18是两个主要类型，出现频率在0.53%-8.37%之间。.（2）致病特性研究及毒性组成分析。通过对145份无性、有性单孢及分离纯化菌系进行研究结果发现：ZS菌系致病稳定性较贵农菌系差，其中ZS-1、ZS-18、ZS-52是主要代表类型，他们中含有CYR34、CYR32、CYR33号所不具备的Yrzhong4毒性基因。其中ZS-1是当前毒性最强的新菌系。.（3）致病性测定：2017-2021年对2048份小麦生产品种（系）及抗源材料进行致病性测定结果发现：ZS无性菌系致病性呈逐年提高趋势，各年度分别为17.80%、20.46%、21.77%、36.52% 、55.63%。ZS有性菌系致病力更强，其中2021年达60.19%。ZS菌系对小麦安全生产威胁大。.（4）寄生适合度测定：对76份甘肃重要生产品种进行苗期、成株期相对寄生适合度测定结果发现，ZS无性菌系与有性菌系0.2487、0.3530和0.1840、0.3627。与CYR32、CYR34相比较，致病性更高、繁殖扩展能力更强。.（5）品种抗病性及布局分析：自2017年以来的多年系统调查结果发现，由于新菌系ZS的出现，使得原来抗病的诸多生产品种如兰天19号、天选63号等在田间丧失抗锈性，品种布局将面临再一次大的变化。抗锈目标在聚焦CYR34的同时，要兼顾ZS和CYR32。.这些工作的开展，为持续控制小