Genome-Wide Association of Stem Water Soluble Carbohydrates in Bread Wheat.

Yan Dong,Yan Zhang,Jindong Liu,Ruilian Jing,Shuanghe Cao,Awais Rasheed,Yong Zhang,Weie Wen,Zhonghu He,Jun Yan,Hongwei Geng,Xianchun Xia,Yonggui Xiao,Luping Fu,Hikmet Budak

doi:10.1371/journal.pone.0164293

Abstract

Water soluble carbohydrates (WSC) in stems play an important role in buffering grain yield in wheat against biotic and abiotic stresses; however, knowledge of genes controlling WSC is very limited. We conducted a genome-wide association study (GWAS) using a high-density 90K SNP array to better understand the genetic basis underlying WSC, and to explore marker-based breeding approaches. WSC was evaluated in an association panel comprising 166 Chinese bread wheat cultivars planted in four environments. Fifty two marker-trait associations (MTAs) distributed across 23 loci were identified for phenotypic best linear unbiased estimates (BLUEs), and 11 MTAs were identified in two or more environments. Liner regression showed a clear dependence of WSC BLUE scores on numbers of favorable (increasing WSC content) and unfavorable alleles (decreasing WSC), indicating that genotypes with higher numbers of favorable or lower numbers of unfavorable alleles had higher WSC content. In silico analysis of flanking sequences of trait-associated SNPs revealed eight candidate genes related to WSC content grouped into two categories based on the type of encoding proteins, namely, defense response proteins and proteins triggered by environmental stresses. The identified SNPs and candidate genes related to WSC provide opportunities for breeding higher WSC wheat cultivars.

Highlights

Bread wheat (Triticum aestivum L.) is a widely grown cereal crop globally, feeding nearly onehalf of the world population and supplying one-fifth of total food nutrition [1]
The stem samples from each line were chipped into 3–5 mm length pieces and the Water soluble carbohydrates (WSC) content for each sample was determined by near-infrared reflectance spectroscopy (NIRS) following Wang et al [29]
The wheat cultivars used in the present study includes 144 Chinese cultivars and 22 foreign wheats

Summary

Introduction

Bread wheat (Triticum aestivum L.) is a widely grown cereal crop globally, feeding nearly onehalf of the world population and supplying one-fifth of total food nutrition [1]. The most important abiotic factors affecting wheat production hinder increases in grain yield. Water soluble carbohydrates (WSC) stored in stems and leaf sheaths are important in buffering grain yield potential against hostile environments during the grain filling period [6]. Mobilization of WSC during grain filling potentially contributes to 10–20% of final grain weight under normal conditions and up to 30–50% of grain dry matter under drought stress [9,10,11]. The release of representative cultivars in Australia and the United Kingdom were associated with increasing WSC content [15], indicating that high stem WSC was a potentially useful trait for improving grain weight and yield [13,16,17]

Methods

Results

Conclusion