病原侵染早期小麦抗白粉病性状的构成因素剖析和QTL定位分析

Dissection and QTL Mapping of Component Traits of Resistance to Wheat Powdery Mildew at Early Infection Stage

以国际小麦作图组织提供的W7984×Opata85重组近交群体为材料,将白粉病抗性分解为互作早期不同时间点的乳突指数、乳突级别、吸器指数和二级菌丝指数等成分性状,在成分性状鉴定和统计的基础上,进行遗传分析和相关QTL定位。白粉菌侵染早期乳突指数和吸器指数随时间的变化趋势均受主效单基因的调控。数量性状分析共找到34个与抗白粉病相关的QTL(21个主效QTL),分布于小麦1B、1D、2B、3A、3B、3D、4A、4B、4D、5B、6A、6B、6D、7B和7D染色体上。位于7B染色体上的QTL(QPmPI16.tn-7B)对乳突形成的影响极为显著,贡献率达48.7%,促进乳突形成的等位变异来自Opata85。不同成分性状存在共定位的QTL。成分性状的特异QTL提供了更多有关抗白粉病遗传机制的信息。

Powdery mildew caused by Blumeria graminis f.sp.tritici（Bgt） is one of the major fungal diseases of wheat,and the use of resistant cultivars is the most effective disease control approach.Here,the International Triticeae Mapping Initiative（ITMI） W7984 × Opata85 wheat recombinant inbred population was used for powdery mildew resistance genetic study.Resistance complex trait was dissected into component traits as papilla index（PI）,papilla scale（PC）,haustorium index（HI） and secondary hypha index（SI） of several successive timepoint at early stage of Bgt infection.The change trends of PI and HI with time were both controlled by single main effect genes.With quantitative trait analysis,34 resistance-related QTLs including 21 main effect QTLs were found and distributed in wheat 1B,1D,2B,3A,3B,3D,4A,4B,4D,5B,6A,6B,6D,7B,and 7D chromosomes.QTL QPmPI16.tn-7B,which regulated the formation of papilla,had the largest effect,singly accounting for 48.69% of the phenotypic variance.Locus of QPmPI16.tn-7B promoting papilla formation was derived from the parent Opata85.Colocalized QTLs were found among different component traits.Component trait-specific QTLs may provide more information about the genetic mechanism of wheat powdery mildew resistance.