Over-Expression of a Rice Tau Class Glutathione S-Transferase Gene Improves Tolerance to Salinity and Oxidative Stresses in Arabidopsis

Abstract

Glutathione S-transferases (GSTs) are multifunctional proteins encoded by large gene family in plants, which play important role in cellular detoxification of several endobiotic and xenobiotic compounds. Previously, we suggested the diverse roles of rice GST gene family members in plant development and various stress responses based on their differential expression. In this study, we report the functional characterization of a rice tau class GST gene, OsGSTU4. OsGSTU4 fusion protein was found to be localized in nucleus and cytoplasm. The over-expression of OsGSTU4 in E. coli resulted in better growth and higher GST activity under various stress conditions. Further, we raised over-expression transgenic Arabidopsis plants to reveal its in planta function. These transgenic lines showed reduced sensitivity towards plant hormones, auxin and abscisic acid. Various analyses revealed improved tolerance in transgenic Arabidopsis plants towards salinity and oxidative stresses, which may be attributed to the lower accumulation of reactive oxygen species and enhanced GST activity. In addition, microarray analysis revealed up-regulation of several genes involved in stress responses and cellular detoxification processes in the transgenic plants as compared to wild-type. These results suggest that OsGSTU4 can be used as a good candidate for the generation of stress-tolerant crop plants.

Overexpression of Artemisia annua sterol C-4 methyl oxidase gene, AaSMO1, enhances total sterols and improves tolerance to dehydration stress in tobacco

“…4b). Similar behavior of transgenic plants expressing transgenes have also been observed and reported earlier (Vivek et al 2013;Sharma et al 2014). Higher chlorophyll retention in transgenic plants indicated lesser damage in the chloroplast and thylakoid structure that may occur due to dehydration.…”

Emerging Roles of Auxin in Abiotic Stress Responses

“…Likewise, GST gene family was analyzed through genome-wide analysis and 31 GST genes were found to be responsive to auxin and cytokinin and many of them showed differential expression under abiotic stress conditions ). The role of GST genes in mediating crosstalk between auxin and abiotic stress responses has also been reported (Smith et al 2003 ;Sharma et al 2014 ). In another study, the transcriptome analysis of AZF1 and AZF2 overexpression transgenic lines showed downregulation of many auxin-responsive genes during osmotic stress and ABA treatments (Kodaira et al 2011 ).…”

“…The overexpression of an auxin-responsive GST gene, OsGSTU4 , enhanced tolerance to salinity and oxidative stresses in transgenic Arabidopsis plants (Sharma et al 2014 ). In another genome-wide analysis of glutaredoxin (GRX) gene family, among the 48 members, at least 11 GRX genes exhibited differential expression pattern under different hormone treatments.…”

Elucidation of Abiotic Stress Signaling in Plants

“…Likewise, GST gene family was analyzed through genome-wide analysis and 31 GST genes were found to be responsive to auxin and cytokinin and many of them showed differential expression under abiotic stress conditions ). The role of GST genes in mediating crosstalk between auxin and abiotic stress responses has also been reported Sharma et al 2014 ). In another study, the transcriptome analysis of AZF1 and AZF2 overexpression transgenic lines showed downregulation of many auxin-responsive genes during osmotic stress and ABA treatments (Kodaira et al 2011 ).…”