Over-expression of a DUF1644 protein gene, SIDP361, enhances tolerance to salt stress in transgenic rice

Salt stress has adverse effects on the growth and production of rice crops. In this study, we isolated and characterized SIDP361, which encodes a DUF1644 family protein. This gene was expressed in various rice tissues and was induced by high salt (200 mM NaCl), dehydration, and abscisic acid (100 A mu M ABA) treatments. Stable expression of SIDP361-GFP in rice cells suggested that SIDP361 is a cytoplasmic protein. When compared with the untransformed wild-type (WT) control, transgenic plants over-expressing SIDP361 exhibited significantly improved tolerance to salt stress at both the seedling and heading stages. Under salinity conditions, the transgenics also had elevated amounts of free proline. Moreover, transcript levels for genes encoding proline synthetase enzymes were significantly higher in transformants than in the WT. The transgenic lines were also hypersensitive to exogenous ABA. Quantitative real-time PCR analysis showed that transcription of several stressrelated genes was greater in SIDP361-overexpressing plants than in the WT under both normal and salt-stressed conditions. These results demonstrate that SIDP361 has high potential as a tool for genetically improving salt tolerance in rice.