抗盐胡杨Na^+/H^+逆向转运蛋白基因PeNhaD1的功能

Function of the Putative Na^+/H^+ Antiporter Gene PeNhaD1 from Salt-resistant Populus euphratica Oliv.

将胡杨Na+/H+逆向转运蛋白基因PeNhaD1,分别转入对盐敏感的缺失质膜和缺失液泡膜Na+/H+逆向转运蛋白基因的酵母突变菌株ANT3和GX1中。结果表明,在pH6.0、Na+浓度为80mmol/L(固体培养基)或400mmol/L(液体培养基)的条件下,转化具有目的基因的酵母ANT3具有更高的耐盐性,而将目的基因转化到突变株GX1时,却不能提高其耐盐性。实验结果说明PeNhaD1可能是通过编码质膜Na+/H+逆向转运蛋白而提高酵母的耐盐性的,推测其在胡杨耐盐机制中的作用可能是提高拒盐性。

Yeast complementation experiments were carried out to define the possible function of PeNhaD1, a Na^＋/H^＋ antiporter gene from Populus euphratica Oliv., a salt resistant tree. PeNhaD1 was introduced to the Saccharomyces cerevisiae mutant strain ANT3 （△enal-4∷HIS3 Anhal∷LEU2）, which lacks the plasma membrane Na^＋/H^＋ antiporter gene ScNHA1 or GX 1 （△nhx 1∷TRP1）, which lacks tonoplast Na^＋/H^＋ antiporter gene ScNHX1 （Figs.1, 2）. Our results showed that PeNhaD1 rescued the normal growth of ANT3 in the presence of high salt （80 mmol/L NaCl on solid medium or 400 mmol/L in liquid medium, pH 6.0） （Figs.3, 5）, but not that of GX1 （Figs.4, 6）, suggesting that PeNhaD1 may play a role in salt tolerance of Populus euphratica by maintaining the capacity for salt exclusion under saline condition.