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 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 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 ZAT10/12, consequently lowered the accumulated level of peroxide in amp1 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 results proved that Arabidopsis AMP1 negatively regulated plant responses to salt stress.
