Digital expression analysis of the genes associated with salinity resistance after overexpression of a stress-responsive small GTP-binding RabG protein in peanut.

The Rab protein family is the largest family of the small GTP-binding proteins. Among them, the RabG genes are known to be responsive to abiotic stresses, but the molecular mechanisms of the stress responses mediated by RabG genes in plants is poorly understood. To investigate the molecular mechanism of AhRabG gene in peanut, transgenic plants overexpressing the AhRabG gene (S6) with relatively higher salinity resistance than the non-transgenic plants (S7) were obtained. Digital gene expression (DGE) sequencing was performed with the leaves of S6 and S7 plants before and after salinity-stress treatment. The AhRabG gene in peanut was found to be involved in a few pathways such as "photosynthesis", "oxidative phosphorylation", "AMPK signaling pathway", "plant hormone signal transduction", etc. A total of 298 differentially expressed genes (DEGs) were found to be upregulated or downregulated at five sampling time points based on the comparison between S6 and S7 plants. Among them, 132 DEGs were responsive to salinity stress in S6 and/or S7 after salinity-stress treatment. These 132 DEGs included genes encoding various transcription factors and proteins involved in resistance to salinity stress such as MYB, AP2, RING-H2 zinc finger proteins, late embryogenesis abundant (LEA) proteins, dehydration-responsive protein RD22, peroxidases, CBL-interacting protein kinases, calcium-binding proteins, and others. The information from this study will be useful for further studies on elucidating the mechanism of salinity resistance conferred by RabG genein peanut.