AHA1转基因拟南芥的抗铝性生理解析

Aluminum-resistance of AHA1 transgenic Arabidopsis thaliana:Physiological analysis

AHA1基因是植物体内编码质膜H+-ATPase的一个重要基因,参与植物的生长发育与抗逆胁迫反应.本文以AHA1转基因型及其野生型拟南芥为材料,研究了铝胁迫对拟南芥养分吸收、抗氧化胁迫和有机酸分泌的影响.结果表明:Al降低了拟南芥根系对N、K、Ca和Mg的吸收,但增加了根系对P的吸收,且AHA1转基因型拟南芥比野生型积累更多的P和较少的Al.铝胁迫诱导拟南芥抗氧化酶SOD和POD活性增加,转基因型与野生型之间没有明显差异.Al对拟南芥有机酸分泌具有明显的诱导作用,且AHA1转基因型分泌较多的有机酸.质膜H+-ATPase的活性抑制剂钒酸盐对拟南芥有机酸分泌具有明显的抑制作用;而Zn2+、Mg2+可促进Al对拟南芥有机酸分泌的诱导,并部分恢复钒酸盐的抑制效应.说明AHA1基因通过增加拟南芥根系对P的吸收以及有机酸分泌,提高了植物的抗铝性.

As one of the major genes encoding plasma membrane H^＋-ATPase, AHA1 gene plays an important role in regulating plant development and resistance to adverse stress. Taking AHA 1 transgenic and wild type Arabidopsis thaliana as test plants, the nutrient uptake, resistance to oxidative stress, and organic acid secretion of the plants under aluminum （Al） stress were examined. The resuits showed that Al decreased the uptake of nitrogen （ N）, potassium （ K）, calcium （Ca） and magnesium （ Mg）, but increased the phosphorus （P） uptake by A. thaliana roots. AHA1 transgenic plant could accumulate more P and less Al than wild type plant. Al stress induced the increase of plant SOD and POD activities, but no significant difference was observed between AHA1 transgenic and wild type A. thaliana. Al triggered the secretion of organic acids significantly, and AHA1 transgenic plant secreted more organic acids than wild type plant. Vanadate, an inhibitor of plasma membrane H^＋ -ATPase, could inhibit the secretion of organic acids significantly, while Zn^2＋ and Mg^2＋ could promote the Al-induced secretion, and partially improve the inhibitory effects triggered by vanadate. It was suggested that AHA1 transgenic A. thaliana could increase its Al resistance via enhanced P uptake and organic acid secretion.