Genome-Wide Association Mapping of Seedling Biomass and Root Traits Under Different Water Conditions in Wheat

Iza Fatima,Shuonan Duan,Yutian Gao,Xiangru Xu,Wenchao Zhen,Chaojie Xie,Jun Ma,Jingjing Jin

doi:10.3389/fgene.2021.663557

Iza Fatima, Shuonan Duan + Show 6 more

Open Access

https://doi.org/10.3389/fgene.2021.663557

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Abstract

Drought is a major threat to global wheat production. In this study, an association panel containing 200 Chinese wheat germplasms was used for genome-wide association studies (GWASs) of genetic loci associated with eight root and seedling biomass traits under normal water and osmotic stress conditions. The following traits were investigated in wheat seedlings at the four-leaf stage: root length (RL), root number (RN), root fresh weight (RFW), root dry weight (RDW), shoot fresh weight (SFW), shoot dry weight (SDW), total fresh weight (TFW), and total dry weight (TDW). A total of 323 and 286 SNPs were detected under two water environments, respectively. Some of these SNPs were near known loci for root traits. Eleven SNPs on chromosomes 1B, 2B, 4B, and 2D had pleiotropic effects on multiple traits under different water conditions. Further analysis indicated that several genes located inside the 4 Mb LD block on each side of these 11 SNPs were known to be associated with plant growth and development and thus may be candidate genes for these loci. Results from this study increased our understanding of the genetic architecture of root and seedling biomass traits under different water conditions and will facilitate the development of varieties with better drought tolerance.

Highlights

Wheat (Triticum aestivum L.) is a widely cultivated crop in the world that provides the main source of calories and protein in the human diet (Shewry, 2009)
TFWD is positively correlated with SFWD and TDWD with a value range of (0.83) and (0.87) in the drought environment, while RFWN was positively correlated with SDWN (0.81), SFWN (0.87), TDWN (0.86), and TFWN (0.94), respectively (Figure 1)
A total of 164 SNPs were associated with root traits under controlled environment, whereas 152 SNPs were identified under osmotic stress (Supplementary Table 2)

Summary

Introduction

Wheat (Triticum aestivum L.) is a widely cultivated crop in the world that provides the main source of calories and protein in the human diet (Shewry, 2009). In many regions of the world, wheat production suffered significant losses due to drought stress (Trethowan and Pfeiffer, 2000). Drought stress can induce significant morphological and physiological changes in plants, including stomatal closure, reductions in photosynthesis and transpiration, shoot and root growth inhibition, antioxidant production, and changes in hormonal composition (Szegletes et al, 2000; Lawlor and Cornic, 2002; Zhu, 2002). The frequency and severity of drought stress will significantly increase in the future and pose a threat to the food security of the rapidly increasing world population (IPCC, 2014). The root system is vital for plants to obtain water and nutrients from the soil. Every millimeter of water extracted from the soil increased wheat

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