过量表达AtNHXS1新基因显著提高水稻的耐盐性

Overexpression of a shuffled Na^+/H^+ antiporter gene AtNHXS1 improving salt tolerance of rice(Oryza sativa L.)

以转基因和野生型水稻为材料,通过农杆菌介导法将AtNHXS1转到水稻植株中花11号中,分析在盐胁迫下Na+、K+含量的变化,对两者耐盐性进行比较,并对转基因株系进行分子鉴定和转录表达分析。结果表明:PCR初步鉴定得到了20个转基因株系,随机挑选2个PCR阳性株系进行Southern blot鉴定,确定AtNHXS1以单拷贝的形式成功插入到水稻基因组中。耐盐性分析表明,在盐胁迫条件下,转基因水稻植株的生长状况、干质量、鲜质量、Na+含量显著优于或高于野生型水稻植株;此外,300mmol/L NaCl处理下,转基因水稻植株能够正常存活,而野生型水稻5d内几乎全部死亡。将300mmol/L NaCl处理过的植株在无盐胁迫的条件下进行恢复生长试验,转基因植株10d内恢复正常,而野生型则不能。过量表达改组后的AtNHXS1新基因显著提高了水稻的耐盐性。

This study was to overexpress the AtNHXSI,a new vacuolar Na＋/H＋ antiporter gene obtained from AtNHX1 by DNA shuffling and study its effect on the salt tolerance of rice （Oryza sativa L. ）. AtNHXS1 was transformed into Oryza sativa L. ssp. japonica cv. zhonghual 1 by Agrobacterium- mediated method and confirmed by polymerase chain reaction （PCR） and Southern blot. The transcrip- tion level was analyzed by RT-PCR. The contents of Na＋ , K＋ and the ability of salt tolerance were com- pared between transgenic lines and wild-type lines. Twenty T2 transgenic lines habo：：ing AtNHXS1 were obtained,two of which were verified as insertion of single gene by Southern blot. RT-PCR analyses showed that the expression levels of AtNHXS1 mRNA were significantly higher after salt treatment in transgenic lines. After salt stress,it was found that the growth status, dry weight, fresh weight and Na＋ content of transgenic rice plants were significantly higher than those of wild-type plants, however the ac- cumulation of K＋ was slightly low. Transgenic plants were able to survive and recover after exposure to 300 mmol/L NaCl for 5 days,whereas wild-type plants could not. These results demonstrated that over- expression of AtNHXS1 significantly improved the salt tolerance of rice.