Reproductive Meristem (REM) family genes GhREM1 and GhREM5.4 act as potential regulators of temperature stress...

Cotton (Gossypium spp.) is considered a major cash crop in agriculture, food, and textile industries all over the world. The foremost focus of scientists and farmers is to meet global food security needs, but unfortunately, evolving weather conditions have significantly reduced the overall production. Latest genome sequence of Gossypium hirsutum enables us to understand the molecular mechanisms and identify development-related and stress-responsive genes. The Reproductive Meristem (REM) gene family, a subfamily of B3 DNA-binding superfamily of transcription factors, is characterized in model plants including Arabidopsis and Chickpea, but no study reported in G. hirsutum. In current study, 33 members of REM gene family were predicted and confirmed to possess the conserved REM-related domains in G. hirsutum. The phylogenetic analysis revealed that REM family members are divided into six sub-groups consistent with Arabidopsis, further confirming the evolutionary relationship across species. The pattern of introns, exons, and conserved motifs also indicated evolutionary conservation. Gene duplication analysis suggested segmental duplication as a reason for the expansion of REM gene family. RNA-seq and real-time qPCR assisted expression analysis in root, leaf and stem under multiple abiotic stresses (drought, salt, low and high temperature) collectively suggesting GhREM1 and GhREM5.4 as potential regulators under low and high temperature stress which is supported with the presence of temperature responsive cis-elements. Furthermore, GhREM1-OE and GhREM5.4-OE revealed the significant regulation of peroxidase (POD) under both low and high temperature stress indicating the potential involvement in temperature tolerance. Green fluorescent protein GFP revealed that both genes were localized in the nucleus. Our findings elucidate the ground work for co-regulatory relationship of REM genes and antioxidant activity in cotton under temperature stress.