Fine mapping of powdery mildew resistance gene MlWE74 derived from wild emmer wheat (Triticum turgidum ssp. dicoccoides) in an NBS-LRR gene cluster.

Qiuhong Wu,Panpan Zhang,Lingli Dong,Hua Hsi Wu ,Deyun Zhang,Jianfeng Zhu ,Qifei Wang,Beibei Li,Haixin Wu ,Yongxing Chen,Wenli Hu,Kèyù Zhü ,Wenling Li,Rongge Wang,Ping Lü ,Miaomiao Li,Hongjie Li,Chengguo Yuan,Lü Dong ,Yong Li ,Jingzhong Xie,Guanghao Guo,Huaizhi Zhang,Lei Guo

doi:10.1007/s00122-021-04027-2

Abstract

Powdery mildew resistance gene MlWE74, originated from wild emmer wheat accession G-748-M, was mapped in an NBS-LRR gene cluster of chromosome 2BS. Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a globally devastating disease. Wild emmer wheat (Triticum turgidum var. dicoccoides) is a valuable genetic resource for improving disease resistance in common wheat. A powdery mildew resistance gene was transferred to hexaploid wheat line WE74 from wild emmer accession G-748-M. Genetic analysis revealed that the powdery mildew resistance in WE74 is controlled by a single dominant gene, herein temporarily designated MlWE74. Bulked segregant analysis (BSA) and molecular mapping delimited MlWE74 to the terminal region of chromosome 2BS flanking by markers WGGBD412 and WGGBH346 within a genetic interval of 0.25cM and corresponding to 799.9kb genomic region in the Zavitan reference sequence. Sequence annotation revealed two phosphoglycerate mutase-like genes, an alpha/beta-hydrolases gene, and five NBS-LRR disease resistance genes that could serve as candidates for map-based cloning of MlWE74. The geographical location analysis indicated that MlWE74 is mainly distributed in Rosh Pinna and Amirim regions, in the northern part of Israel, where environmental conditions are favorable to the occurrence of powdery mildew. Moreover, the co-segregated marker WGGBD425 is helpful in marker-assisted transfer of MlWE74 into elite cultivars.

Highlights

Powdery mildew, caused by the fungal pathogen Blumeria graminis f. sp. tritici (Bgt), is one of the devastating diseases of wheat (Triticum aestivum L.) in areas with temperate climates.Breeding for resistance is the most economical and effective strategy to control powdery mildew.Up to now, more than a hundred powdery mildew resistance genes/alleles have been documented, and some of them have played important roles in stabilizing wheat yield, such as Pm21 (He et al.2018; Pm46/Yr46/Lr67/Sr55 (Moore er al. 2015)
In response to the newly evolved Bgt virulent isolates, it is necessary to continuous search for new powdery mildew resistance genes
WE74, XZ and F1, F2, and F2:3 progenies from the WE74 × XZ cross were challenged by Bgt isolate E09 at the two-leaf stage

Summary

Introduction

Powdery mildew, caused by the fungal pathogen Blumeria graminis f. sp. tritici (Bgt), is one of the devastating diseases of wheat (Triticum aestivum L.) in areas with temperate climates.Breeding for resistance is the most economical and effective strategy to control powdery mildew.Up to now, more than a hundred powdery mildew resistance genes/alleles have been documented, and some of them have played important roles in stabilizing wheat yield, such as Pm21 (He et al.2018; Pm46/Yr46/Lr67/Sr55 (Moore er al. 2015). Powdery mildew, caused by the fungal pathogen Blumeria graminis f. Tritici (Bgt), is one of the devastating diseases of wheat (Triticum aestivum L.) in areas with temperate climates. Breeding for resistance is the most economical and effective strategy to control powdery mildew. More than a hundred powdery mildew resistance genes/alleles have been documented, and some of them have played important roles in stabilizing wheat yield, such as Pm21 The emergence of new virulent pathotypes of Bgt reduces the resistance conferred by resistance (R) genes (Singh et al 2016). In response to the newly evolved Bgt virulent isolates, it is necessary to continuous search for new powdery mildew resistance genes

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Conclusion