Cloning And Stress Expression Analysis Of Metabolism Related Genes Of Cd Resistance Formation In Chinese Cabbage (Brassica Rapa Subsp. Chinensis)

Cadmium(Cd),'top-five of poisons', is a threat to food security and human health.Farmland in many places were greatly polluted by Cd, which mainly spread over plowing layer and could be easily absorbed by plants,consequently, human health and other biological survival could be directly affected via food chain.As staple subsidiary foodstuff, vegetables were greatly polluted by industrial pollution, and because production bases of which were mainly located at industrial suburbs, concentration of Cd exceed the national standard significantly.For this reason, it was signality to basical and applied research on soil Cd contamination controlling and vegetables Cd content reducing.In this study, 12 Chinese cabbages (Brassica rapa subsp. Chinensis) of different genotypes were employed, aimed to screening out Chinese cabbages of various genotypes resistant(R), middle resistant (MR), sensitive(S) to Cd, by water culturing method under heavy mental stress and correlative determination index.And take it as test materials to clone key gene related to biochemical metabolism pathway of plant heavy metal resistant formation. With Real Time PCR, transcriptional level of genes, at different locations of Chinese cabbages of R, MR, S genotypes before and after heavy mental stress were figured out. Main results of this study were as follows:⑴Screening on Chinese cabbages of different Cd resistance genotypes. According to content indexes of Cd and reducing GSH expression in 12 Chinese cabbages after Cd stress, HR genotype K, MR genotype H, G and S genotype C, E were screened out.⑵Cloning of key genes related to biochemical metabolism pathway of Cd resistance formation of Chinese cabbage.In this study, overall length of 5 key enzyme genes and a conventional gene segment related to Cd resistance formation PCs, MTs metabolic pathways were amplified. Which were"OASA4"(1271bp,login No:GQ996586),"OASA6"(1231bp,login No:GQ996587),"γ-GCS"(1536bp,login No:GQ996585),"GSHS"(1437bp,login No:GQ9965874),"Mta"(545bp,login No:GQ9965878)respectively, and conventional segment OASA6-2(935bp), number of coding amino acids were 322,322,511, 478 , 80 and 208 respectively. Homology of which were over 90% with Brassica juncea, Brassica napus, Brassica napobrassica.⑶Construction of eukaryotic expression vector.Eukaryon expression vector PBI121 containing OASA4,γ-GCS, GSHS complete coding region alignments and 35S promoter was triumphantly structured.⑷Analysis on transcriptional level of gene OASA4,γ-GCS, GSHS, Mta. Results about Cd stress showed that: ①After Cd stress, generally, transcriptional level of gene OASA4 in Chinese cabbage was brought down, however, in root of genotype HR, it was increased.②After Cd stress, transcriptional level of gene r-GCS in Chinese cabbage of genotype S was decreased, it was remain unchanged in genotype MR, however, transcriptional level of which in root of genotype HR was increased.③After Cd stress, transcriptional level of gene GSHS in shoot of all genotype and in root of genotype Swere declined, but in roots of genotype MR, genotype HR, transcriptional levels of which were increased.④After Cd stress, transcriptional level of gene MTa in shoot of genotype HR was greatly multiplied, but in root of genotype HR and in whole of genotype MR and genotype S, it was decreased.