Genetic dissection of the powdery mildew resistance in wheat breeding line LS5082 using BSR-Seq

Liru Wu,Tong Zhu,Huagang He,Xinyou Cao,Haosheng Li,Hongxing Xu,Mengshu Jia,Lipei Zhang,Jiancheng Song,Ghader Mirzaghaderi,Cheng Liu,Pengtao Ma

doi:10.1016/j.cj.2021.12.008

Abstract

Powdery mildew of wheat is a destructive disease seriously threatening yield and quality worldwide. Comprehensive dissection of new resistance-related loci/genes is necessary to control this disease. LS5082 is a Chinese wheat breeding line with resistance to powdery mildew. Genetic analysis, using the populations of LS5082 and three susceptible parents (Shannong 29, Shimai 22 and Huixianhong), indicated that a single dominant gene, tentatively designated PmLS5082, conferred seedling resistance to different Blumeria graminis f. sp. tritici (Bgt) isolates. Bulked segregant RNA-Seq was carried out to map PmLS5082 and to profile differentially expressed genes associated with PmLS5082. PmLS5082 was mapped to a 0.7 cM genetic interval on chromosome arm 2BL, which was aligned to a 0.7 Mb physical interval of 710.3–711.0 Mb. PmLS5082 differs from the known powdery mildew (Pm) resistance genes on chromosome arm 2BL based on their origin, chromosome positions and/or resistance spectrum, suggesting PmLS5082 is most likely a new Pm gene/allele. Through clusters of orthologous groups and kyoto encyclopedia of genes and genomes analyses, differentially expressed genes (DEGs) associated with PmLS5082 were profiled. Six DEGs in the PmLS5082 interval were confirmed to be associated with PmLS5082 via qPCR analysis, using an additional set of wheat samples and time-course analysis post-inoculation with Bgt isolate E09. Ten closely linked markers, including two kompetitive allele-specific PCR markers, were confirmed to be suitable for marker-assisted selection of PmLS5082 in different genetic backgrounds, thus can be used to detect PmLS5082 and pyramid it with other genes in breeding programs.

Highlights

Common wheat (Triticum aestivum L., 2n=6x=42, AABBDD) is one of the most widely cultivated cereal crops worldwide (Li et al 2019)
We concluded that the resistance to Blumeria graminis f. sp. tritici (Bgt) isolate E09 in LS5082 is controlled by a single dominant gene, tentatively designated as PmLS5082
LS5082 is an elite wheat breeding line which we have maintained in our lab as a powdery mildew resistant germplasm

Summary

Introduction

Common wheat (Triticum aestivum L., 2n=6x=42, AABBDD) is one of the most widely cultivated cereal crops worldwide (Li et al 2019). Infection by the Bgt pathogen can reduce chlorophyll content, affect photosynthesis, and typically decrease wheat yield by 10-15% and up to 62% in severe cases (Singh et al 2016). To control this disease, fungicides have been and currently are used, but long-term use of fungicides has led to resistance due to pathogenic variation within Bgt (Manoharachary et al 2014). More than 100 formally and 30 temporarily designated powdery mildew resistance (Pm) genes/alleles have been identified at 63 loci within common wheat and its diverse relatives (McIntosh et al 2020; He et al 2021)

Methods

Results

Conclusion