Overexpression of Arabidopsis XERICO gene confers enhanced drought and salt stress tolerance in rice (Oryza Sativa L.)

Drought and salinity are two major limiting factors in rice (Oryza. sativa L.) productivity worldwide. XERICO, encoding a RING-H2 zinc finger protein, substantially enhanced drought tolerance by increasing ABA biosynthesis in Arabidopsis. Here, we report the isolation of the full-length cDNA of XERICO from Arabidopsis and its heterologous expression in rice (O. sativa L.). Homozygous transgenic plants overexpressing XERICO (OE-XERICO) exhibited hypersensitivity to stress stimuli (salt, osmotic stress and exogenous ABA) during seed germination and early seedling growth. When subjected to dehydration and salinity stress, 4-week-old transgenic seedlings showed a considerable increase in tolerance to these stimuli compared with that of the wild type (WT) seedlings. Detached leaves from the transgenic rice lines showed lower transpirational water loss than WT. The OE-XERICO lines exhibited a significant increase in endogenous ABA contents, and expression levels of Four ABA biosynthesis or ABA-response genes, OsNCED, OsABA3, OsABI5, OsLEA3-1, under drought and salt stress condition. These results suggest that the overexpression of XERICO in rice plants confers improved drought and salt tolerance probably through enhanced ABA level and ABA-mediated stress response.