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

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.

Genome-wide analysis for root and leaf architecture traits associated with drought tolerance at the seedling stage in a highly ecologically diverse wheat population

“…Promising significant SNPs were reported in this study for root traits. Genome-wide association mapping was performed before to reveal the genetic architecture of wheat roots under drought stress in wheat [5] . A major QTL for root architecture located on 6 A in wheat seedlings under drought stress was reported by [59] .…”

“…Root traits at the seedling stage have received little attention. Therefore, root system architecture (RSA) provides very important information on the ability of plants to absorb water and nutrients from the soil [5] . One of the crop defense strategies to combat abiotic stress is a well-developed root system.…”

“…To find seedling-related traits (roots and shoots) QTLs in wheat, several quantitative trait loci (QTL) analyses have been carried out to detect markers associated with drought tolerance at the seedling stage [10] , [11] , [12] . Root parameters including root length and root biomass were significantly influenced by numerous QTL governing plant heights and shoot dry weight, especially at the seedling stage, highlighting the critical functions of the root system in plant growth and development [5] , [12] , [13] , [14] , [15] , [16] .…”

“…drought tolerance) in wheat. GWAS has been widely employed in numerous crops, including wheat, employing genome-wide dense markers for the prediction of candidate genes [1] , [5] , [17] , [18] , [19] . Sequence-based DNA markers, particularly SNP tri [8] , [20] .…”

Deciphering the genetic landscape of seedling drought stress tolerance in wheat (Triticum aestivum L.) through genome-wide association studies

“…For instance, the GWAS was used to identify and clone a transcriptional factor, TaWD40-4B.1 , responsible for increased grain yield under drought stress in wheat ( Tanin et al., 2022 ). In addition, GWAS was used to identify the candidate genes (CGs) responsible for abscisic acid accumulation ( Kalladan et al., 2017 ), proline accumulation ( Verslues et al., 2014 ), root traits ( Fatima et al., 2021 ), and biomass accumulation ( Fatima et al., 2021 ) under drought stress.…”