敲除AMP1基因可提高干旱响应基因的表达量从而增强拟南芥的抗旱能力

Knockout of AMP1 Gene in Arabidopsis Increaces Stress-responsive Gene Expression Thereby Improving Drought Tolerance

干旱严重影响植物的生长发育及农作物产量,因此研究植物的干旱反应机制显得至关重要.我们发现在拟南芥中一个推测的谷氨酸羧肽酶,AMP1,其缺失突变体amp1的抗旱能力大大增强.基因芯片分析表明,amp1突变体抗旱能力的提高与许多干旱响应基因的高表达息息相关,例如,在amp1突变体中2个干旱诱导表达的转录因子基因,DREB2A和DREB1A的表达量升高;AT1G61340(LEA蛋白)的表达量也升高了很多,它在干旱条件下具有解毒和缓解细胞伤害的作用.而且,在amp1突变体中DREB2A转录因子的2个下游基因RD29A和COR47受干旱诱导的表达量和时间都比野生型中高和早.在突变体中一些参与蛋白代谢、糖代谢和脂代谢的基因上调,一些保护和解毒相关基因表达量也升高,这些都可以给突变体在抗旱反应过程提供一定的保护作用.因此,我们认为AMP1基因在干旱胁迫反应中对干旱响应基因的表达起到一个负调控作用.实验中我们还发现,amp1突变体具有较低的水势与非常发达的根系,这也可能在抗旱反应中起到了一定作用.

Drought greatly impairs the growth and development of plants and crop yields. We found that a putative glutamate carboxypeptidase, AMP1, significantly affected the drought tolerance in Arabidopisis. Microarray analysis revealed that drought tolerance in amp1 mutant plants coincided with an up-regulation of many drought-responsive genes, like DREB2A and DREB1A （ drought-responsive transcription factors ）, AT1G61340 （ LEA protein of detoxification and protection in response to drought）,and RD29A and COR47 （ downstream genes of DREB2A）. The up-regulated GO clusters in amp1 mutant were protein,fat,sugar metabolism and certain detoxificative and protective processes, suggesting a protective influence on essential processes. It suggested that AMP1 gene might play a negative role in responsive to drought stress in plants,as the drought-resisting amp1 mutants exerted lower water potential and more developed root system than wild types.