Drought stress threatens yield in cotton, the most important crop in the
textile industry. Thus, developing cotton lines with tolerance to drought is
important in cotton breeding. Quantitative trait loci (QTLs) have been
developed using traditional molecular markers (SSRs, RFLPs), but only a few
of these QTLs have been verified in terms of their functions.
Scientist Wangzhen Guo and colleagues from Nanjing Agricultural University
use single nucleotide polymorphisms (SNPs), the most abundant variation in
the DNA of many organisms, to find markers associated with drought. They use
the CottonSNP63K SNP array to screen 719 cotton accessions and performed
genome-wide association study (GWAS). By combining the GWAS results with
RNA-seq and qRT-PCR data, they find four major genes that are potentially
important to drought stress. These genes include RD2 (response to
desiccation 2 protein), HAT22 (homeobox-leucine zipper protein), PIP2
(plasma membrane intrinsic protein 2), and PP2C (protein phosphatase 2C).