拟南芥AMP1负调控植物对高盐胁迫的反应

Arabidopsis AMP1 Negatively Modulates Plant Responses to Salt Stress

高盐胁迫严重影响植物的生长发育及农作物产量,因此鉴定盐胁迫响应相关基因至关重要。拟南芥的AMP1编码一个推测的谷氨酸羧肽酶,参与植物的生长发育、光形态建成与种子休眠。研究证明了AMP1的一个新功能,它的缺失提高了缺失突变体amp1的抗高盐胁迫的能力,研究证明amp1突变体的强抗高盐胁迫表型一方面是由于在高盐胁迫下amp1突变体比野生型中积累了更多的甜菜碱和脯氨酸降低了突变体细胞的水势,另一方面高盐胁迫条件下amp1突变体中高盐胁迫响应的下游基因RD29A,以及AHA3的表达量也高于野生型,后者可促进Na+的外排;高盐条件能够对植物造成氧化胁迫,研究发现AMP1的缺失还上调了抗氧化相关基因ZAT10/12的表达量,进而降低了在高盐胁迫条件下amp1突变体内过氧化物的积累水平,减轻对细胞的损伤和生长的抑制,这些都提高了amp1突变体的抗高盐胁迫的能力。以上结果证明在拟南芥中AMP1负调控植物对高盐胁迫的反应过程。

Salt stress severely affects the growth and development of plants and crop yield, therefore it is crucial to identify the related genes responding to salt stress in plants. Altered Meristem Program （AMP1） of Arabidopsis, encoding a putative glutamate carboxypeptidase, is involved in plant growth, photomorphogenesis and seed dormancy. In this study, we revealed new function of AMP1, i.e., its deficiency increased t the capacity of salt resistance in deletion mutant amp1. The study convinced that phenotype of solid salt resistance resulted from 2 aspects： firstly the accumulating more betaine and proline in mutant than in wild one led to the decrease of cell potential in the mutants, and secondly t the expression of downstream gene RD29A and AHA3 in the mutants was higher than that in wild ones and the latter promoted the exocytosis of Na~. The salt stress also triggered the oxidation stress in the plants; the study discovered that the deletion of AMP1 up-regulated the expression of antioxidant gene ZATIO/12, consequently lowered the accumulated level of peroxide in ampl mutants, and thereby diminished the damages to cells and the prohibition of growth. All of them jointly enhanced the capacity of salt resistance in amp1 mutants. Our resuhs proved that Arabidopsis AMP1 negatively regulated plant responses to salt stress.