Abstract
Salt tolerance in cotton is highly imperative for improvement in the response to decreasing farmland and soil salinization. However, little is known about the genetic basis underlying salt tolerance in cotton, especially the seedling stage. In this study, we evaluated two salt-tolerance-related traits of a natural population comprising 713 upland cotton (Gossypium hirsutum L.) accessions worldwide at the seedling stage and performed a genome-wide association study (GWAS) to identify marker-trait associations under salt stress using the Illumina Infinium CottonSNP63K array. A total of 23 single nucleotide polymorphisms (SNPs) that represented seven genomic regions on chromosomes A01, A10, D02, D08, D09, D10, and D11 were significantly associated with the two salt-tolerance-related traits, relative survival rate (RSR) and salt tolerance level (STL). Of these, the two SNPs i46598Gh and i47388Gh on D09 were simultaneously associated with the two traits. Based on all loci, we screened 280 possible candidate genes showing different expression levels under salt stress. Most of these genes were involved in transcription factors, transporters and enzymes and were previously reported as being involved in plant salt tolerance, such as NAC, MYB, NXH, WD40, CDPK, LEA, and CIPK. We further validated six putative candidate genes by qRT-PCR and found a differential expression level between salt-tolerant and salt-sensitive varieties. Our findings provide valuable information for enhancing the understanding of complicated mechanisms of salt tolerance in G. hirsutum seedlings and cotton salt tolerance breeding by molecular marker-assisted selection.
Highlights
Soil salinity is a major abiotic stress that threatens crop yield, the ecological environment and agricultural sustainability (Hamwieh et al, 2011; Farooq et al, 2017)
Under salt stress of 0.3% NaCl content, extensive phenotypic variations were observed for relative survival rate (RSR) and salt tolerance level (STL) in 713 upland cotton accessions
The cotton accessions consisting of diverse germplasms worldwide showed large variations in RSR and STL under salt stress
Summary
Soil salinity is a major abiotic stress that threatens crop yield, the ecological environment and agricultural sustainability (Hamwieh et al, 2011; Farooq et al, 2017). The demand for cotton fiber production will increase as the human population grows. To meet this challenge, breeders are working on developing new varieties using conventional and modern breeding methods to enhance cotton yield and tolerance under salt conditions. Salinity affects plants in osmotic and ionic ways. Under long-term salt exposure, plants are affected by the continuing osmotic damage plus the excessive accumulation of Na+ in plant cells. Plants have mechanisms to compartmentalize Na+ in vacuoles and to remove the excess of Na+ from the cytosol to the apoplast (Maathuis and Amtmann, 1999; Munns et al, 2012)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
