Transcript analysis of abscisic acid-inducible genes in response to different abiotic disturbances in two indica rice varieties

Abstract

The present study focused upon comprehensive analysis of the expression of stress-responsive genes at different time points in two indica rice varieties, IR-64 (moderately salt-sensitive) and Nonabokra (salt-tolerant), under salinity, dehydration and cold, and exogenous ABA treatment. The massively parallel signature sequencing and publicly-available microarray data indicated the physiological role of the concerned genes in different tissues. Gene expression through semi-quantitative reverse transcriptase-polymerase chain reaction followed by factorial analyses of variance identified that members of the antioxidant genes (OsCAT, OsSOD, OsGR2 and OsAPX8) showed early response and higher expression under different abiotic stresses in IR-64. The TFs and LEA family (TRAB1 and Osem), osmolyte (OsBADH1, OsP5CS) and polyamine (SAMDC) metabolic genes were more up regulated in the salt-tolerant cultivar, whereas the proline (ProDH) and polyamine (DAO and PAO) catabolic genes were significantly up regulated in the salt-sensitive one. The higher accumulation of TRAB1 transcript and protein in the tolerant cultivar during various stresses suggested it as an important component in stress signaling pathway, which participates in mediating cross-talk signaling between diverse metabolic pathways to withstand various forms of abiotic stress. Heat map data further corroborated differential transcript abundance in the two varieties, coinciding with the transcript profiling data. We envisage that the identified genes in this study, linked with tolerance against various abiotic stress factors, are the chief candidates involved in regulating the complexity of multiple stress responses in rice. The finding of the candidate genes in this study would be helpful in generating multiple abiotic stress tolerance in rice.