Long Li, Zhi Peng, Xinguo Mao, Jingyi Wang, Chaonan Li, Xiaoping Chang, Ruilian Jing

　　Journal of Experimental Botany, 01 November 2020,  IF：5.908

　　DOI: 10.1093/jxb/eraa500

　　https://doi.org/10.1093/jxb/eraa500

　　Abstract

　　Developing salt-tolerant crop varieties is one of the important approaches to cope with increasing soil salinization worldwide. In this study, a diversity panel of 323 wheat accessions and 150 doubled haploid lines were phenotyped for salt-responsive morphological and physiological traits across two growth stages. The comprehensive salt tolerance of each wheat accession was evaluated based on principal component analysis. A total of 269 associated loci for salt-responsive traits and/or salt tolerance indices were identified by genome-wide association studies using 395,675 single nucleotide polymorphisms, among which 22 overlapping loci were simultaneously identified by biparental quantitative trait loci mapping. Two novel candidate genes TaRN1 and TaRN2 involved in root response to salt stress fell within overlapping loci, and showed different expression patterns and a frameshift mutation (in TaRN2 ) in contrasting salt-tolerant wheat genotypes. Moreover, the decline in salt tolerance of Chinese wheat varieties was observed from genetic and phenotypic data. We demonstrate that a haplotype controlling root responses to salt stress has been diminished by strong selection for grain yield, which highlights that linkage drag constrains the salt tolerance of Chinese wheat. This study will facilitate salt-tolerant wheat breeding in terms of elite germplasm, favorable alleles and selection strategy.