DDRT-PCR-based Differential Gene Expression Analysis Of Amaranthus Hypochondriacus Under Cadmium Stress

Amaranthus hypochondriacus are used as grain, feed, fertilizer dishes for both high quality and efficient multi-purpose crops, and also a useful development value biological source of potassium.Industrial activities on earth make heavy metal pollution on soil, which has become a popular global concern environmental issues, and cadmium (Cd) is listed as one of eight heavy metals that China priority pollution control. Phytoremediation is one of the cost-effective method of remediation heavy metal contaminated soil. The Amaranthus hypochondriacus which can enrichment and tolerance of Cd become focus of attention of use this technology for Cd pollution prevention and control. In this study, It’s the first time the mature differential display PCR technique is applied on analysis of differentially expressed genes of Amaranthus hypochondriacus under the Cd stress. The intent of this experiment is to find the differentially expressed gene fragment as a basis for the study of the mechanism that Amaranthus hypochondriacus enrichment and tolerance Cd, and to make some contribution on the the Cd pollution prevention and control. The following experimental results obtained by experiment:1. The RNA extracting efficiency of Amaranthus hypochondriacus samples protectd by reagent are better than fresh specimen, and leaves, roots, fruit are better than stems.2. The optimization of PCR system of DDRT-PCR through uniform design showed that the opitimization conditions of Mix system PCR is:cDNA 1μL, annealing temperature 40.8℃, 35 cycles. And the opitimization conditions of enzyme system PCR is:cDNA 1.5μL, dNTP 2μL, Mg2+1μL, Taq enzyme 2μL, annealing temperature 45℃,45 cycles.3. We definite the primer combinations required for the research through primer selection: five primers for leaf material(RP18, RP19, RP20, RP23, RP24) combine with API, AP2, AP3; and seven primers for roots and fruit material(RP8, RP14, RP18, RP19, RP20, RP23, RP24) combine with API, AP2, AP3. Control and treated Amaranthus hypochondriacus root, fruit, leaf material used for the experiment. Electrophoresis showed that the gene expression of Amaranthus hypochondriacus under cadmium stress has three changes contrast with contraposition materials:up expression, down expression and constant expression. Sequence analysis showed that DNA polymerase III gene expression was up-regulated expression, while the SSA gene, hypothetical protein MTR gene and beta-glucosidase gene was down-regulated in Amaranthus hypochondriacus under Cadmium Stress. Presumably due to its metabolic damage of Amaranthus hypochondriacus under cadmium stress, and DNA polymerase III expression levels rise to active mechanism of molecular replication, reparation the damage caused by stress. And SSA protein expression decreased lead to aging, at the same time reduce the expression of ACC synthase and ACC oxidase, direct and effective inhibition the biosynthesis of ethylene, delaying maturation, and protect plant from reduction in biological activity and recession caused by the cadmium stress. Hypothetical protein MTR expression decreased and regulation cell metabolism by folic acid. Beta-glucosidase enzyme decreased expression, and affects the expression level of the ABA, thereby regulating the metabolic level of plant.