Evolutionary Study Of MAM Genes And Analysis Of MAM1.2Gene Promoter Activity In Brassica Rapa

Brassica rapa, a specie of the genus Brassica, is very important in the domestic vegetable marketwith its variety, widely adaptable, high nutritional value. Glucosinolates are a group of secondarymetabolites in Brassica rapa. Glucosinolates and their hydrolytic products play central roles in flavor,plant defense and human health. So it is important to improve the accumulation of glucosinolates inplant. MAM genes are key genes in glucosinolates biosynthesis passway. They are responsible foradding one methylene group to side chain and lead to the diversity of glucosinolates. But there are fewresearches about Brassica rapa MAM genes.In this study, we analyzed the syntenic relationship of MAM genes between Arabidopsis thaliana,Schrenkiella parvula and Brassica rapa, conserved motif, the expression of candidate MAM genes in93materials of Brassica rapa and constructed phylogenetic tree in order to search the evolution of MAMgenes in the B.rapa. We cloned MAM1.2gene promoter in B.rapa (L144) which has higherglucosinolates accumulation and MAM genes expression, then predicted cis-element of the sequence byPlace and Plant care datebase. Four different MAM1.2promoter-GUS fusion vector were constructedand the GUS activity were detected.The conclusions of this research as follows:1. The results showed that the MAM candidate genes were located in three subgenomes of B.rapa. Five genes which are synteny orthologs to A. thaliana mainly originated from wholegenome triplication. The remaining two genes may derive from translocation. There weremany differences in both ends of protein sequences in BrMAM candidate genes, comparedwith AtMAM genes. Expression level of these candidate genes was variable, and threecandidate genes hardly expressed. In the phylogenetic tree, BrMAM candidate genes andAtMAM genes were located in different branches. These results indicated that the B.rapaMAM genes had independent evolution after the divergence of B.rapa and A. thaliana.2. According to the result of GUS activity in transgenic A.thanalia, promoter of1585bp and1042bp can drive GUS genes, while the promoter of585bp and310bp can’t drive GUS genes.This result indicated that the efficient elements should be located in-1042bp~-585bp.3. There are many TATA-box and CAAT-box in the sequence of MAM1.2gene promoter. Thenearest TATA-box from ATG located in-19bp~-24bp. In addition, G-box, CGTCA-motif,TGACG-motif and Skn-1motif are scattered in the sequence. They may function in thetranscription of MAM1.2gene.