Association Analysis of Drought Tolerance and Associated Traits in Upland Cotton at the Seedling Stage

Abstract

(1) Background: Upland cotton (Gossypium hirsutum L.) is the most important natural fiber worldwide, and it is extensively planted and plentifully used in the textile industry. Major cotton planting regions are frequently affected by abiotic stress, especially drought stress. Drought resistance is a complex, quantitative trait. A genome-wide association study (GWAS) constitutes an efficient method for dissecting the genetic architecture of complex traits. In this study, the drought resistance of a population of 316 upland cotton accessions was studied via GWAS. (2) Methods: GWAS methodology was employed to identify relationships between molecular markers or candidate genes and phenotypes of interest. (3) Results: A total of 8, 3, and 6 SNPs were associated with the euphylla wilting score (EWS), cotyledon wilting score (CWS), and leaf temperature (LT), respectively, based on a general linear model and a factored spectrally transformed linear mixed model. For these traits, 7 QTLs were found, of which 2 each were located on chromosomes A05, A11, and D03, and of which 1 was located on chromosome A01. Importantly, in the candidate regions WRKY70, GhCIPK6, SnRK2.6, and NET1A, which are involved in the response to abscisic acid (ABA), the mitogen-activated protein kinase (MAPK) signaling pathway and the calcium transduction pathway were identified in upland cotton at the seedling stage under drought stress according to annotation information and linkage disequilibrium (LD) block analysis. Moreover, RNA sequencing analysis showed that WRKY70, GhCIPK6, SnRK2.6, and NET1A were induced by drought stress, and the expression of these genes was significantly different between normal and drought stress conditions. (4) Conclusions: The present study should provide some genomic resources for drought resistance in upland cotton. Moreover, the germplasm of the different phenotypes, the detected SNPs and, the potential candidate genes will be helpful for molecular marker-assisted breeding studies about increased drought resistance in upland cotton.

Genome-wide association analysis reveals quantitative trait loci and candidate genes involved in yield components under multiple field environments in cotton (Gossypium hirsutum)

“…In Arabidopsis , NET1A is anchored at the plasma membrane and predominates at cell junctions, the plasmodesmata [ 31 ]. Besides, NET1A was also found to be involved in response to abscisic acid (ABA), the mitogen-activated protein kinase (MAPK) signaling pathway, and the calcium transduction pathway in upland cotton [ 32 ]. The two NET genes identified in this study might play an important role during fiber development.…”

Rice OsHSFA3 Gene Improves Drought Tolerance by Modulating Polyamine Biosynthesis Depending on Abscisic Acid and ROS Levels

“…We observed significant increases in the root length under mannitol treatment in transgenic Arabidopsis plants overexpressing OsHSFA3 as compared to WT (Figure 3), suggesting that OsHSFA3 may positively regulate drought tolerance. ABA is an important phytohormone that acts as a signaling molecule to activate the expression of various TFs under abiotic stress [47][48][49]. We observed a significant decrease in root length under ABA treatment in OsHSFA3-overexpressing plants as compared to WT, suggesting that OsHSFA3 is hypersensitive to ABA and ABA may regulate the expression of OsHSFA3 (Figure 3).…”

GWAS Mediated Elucidation of Heterosis for Metric Traits in Cotton (Gossypium hirsutum L.) Across Multiple Environments

“…Both Gh_D02G1201 and Gh_A10G1233 encode FAR-RED elongated proteins which are involved in light responses and FE development ( Ju et al, 2019 ) along with the positive regulation of chlorophyll biosynthesis ( Tang et al, 2012 ; Miao et al, 2017 ). Gh_A11G1858 , which displayed an association with the hQTN related to FL, encodes a serine-threonine kinase SAPK1 protein that may play a role in the signal transduction of a hyperosmotic response markedly influencing the fiber development process ( Kobayashi et al, 2004 ; Magwanga et al, 2018 ; Li et al, 2019 ). FU was identified with hQTNs associated with Gh_A01G0481 and Gh_A11G0475 ; the former encodes a cytochrome P450 protein which may have a role in the maturation or aging of tissues ( Ju et al, 2019 ), while the latter encodes the Ras-related protein RAB11A, it detected previously in fiber development and elongation ( Qin et al, 2017 ).…”