Genome-wide association study revealed that the TaGW8 gene was associated with kernel size in Chinese bread wheat

Xuefang Yan,Yan Ren,Zhongdong Dong,Feng Chen,Dangqun Cui,Lei Zhao

doi:10.1038/s41598-019-38570-2

Xuefang Yan, Yan Ren + Show 4 more

Open Access

https://doi.org/10.1038/s41598-019-38570-2

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Journal: Scientific Reports	Publication Date: Feb 25, 2019
Citations: 65	License type: open-access

Affiliation: Henan Agricultural University

Abstract

Using Wheat 90 K SNP assay, kernel-related traits of Chinese bread wheat were used to perform association mapping in 14 environments by GWAS. Results indicated that 996 and 953 of 4417 and 3172 significant SNPs for kernel length and thousand-kernel weight were located on the chromosome 7B. Haplotype analysis of these SNPs on 7B generated the block containing the predicted TaGW8-B1 gene. TaGW8-B1 gene was further cloned by sequencing in bread wheat and a 276-bp InDel was found in the first intron. TaGW8-B1 without and with the 276-bp InDel were designated as TaGW8-B1a and TaGW8-B1b, respectively. Analysis of agronomic traits indicated that cultivars with TaGW8-B1a possessed significantly wider kernel width, significantly more kernel number per spike, longer kernel length, higher thousand-kernel weight and more spikelet number per spike than cultivars with TaGW8-B1b. Furthermore, cultivars with TaGW8-B1a possessed significantly higher yield than cultivars with TaGW8-B1b. Therefore, TaGW8-B1a was considered as a potentially superior allele. Meanwhile, TaGW8-B1a possessed a significantly higher expression level than TaGW8-B1b in mature seeds by qRT-PCR. It possibly suggested that the high expression of TaGW8-B1 was positively associated with kernel size in bread wheat. Distribution of TaGW8-B1 allele indicated that TaGW8-B1a has been positively selected in Chinese wheat.

Highlights

Bread wheat (Triticum aestivum L.) is one of the most important crops in the world
The aim of this study is to provide valuable information for improvement of wheat yield in Chinese bread wheat breeding program
After excluding poor quality data, 44,791 polymorphism SNPs was used for GWAS and results showed that a total of 4417, 3172 and 650 SNPs were identified to be significantly associated with kernel length, thousand kernel weight (TKW) and kernel width, respectively, and they distributed on all chromosomes

Summary

Introduction

Bread wheat (Triticum aestivum L.) is one of the most important crops in the world. With the increasing population, continuous improvement of yield potential is the long-term goal of wheat breeding[1]. Hexaploid wheat has a lager genome size (≈17.9 Gb) when compared with rice (≈400 Mb) and maize (≈3 Gb), which limited cloning of related genes to some extent. QTLs associated with kernel size have been identified on all of the wheat chromosomes[16]. It has been reported that TaGS5 genes on the short arm of chromosome 3A and 3D were significantly associated with kernel width, TKW, plant height, spike length and pedicle length[21,22,23]. GWAS for agronomic traits in hexaploid and texaploid wheats indicated that some SNPs on 7A and 7B were significantly associated with kernel length in multiple environments[40,41]. We further analyzed association of TaGW8-B1 alleles with agronomic traits as well as yield in multiple environments. The aim of this study is to provide valuable information for improvement of wheat yield in Chinese bread wheat breeding program

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