Molecular Cloning And Analysis Of Dif Ferential Expression Genes Of Sesame Inducted By Ralstonia Solanacearum

Sesame,riched of protein and some natural antioxidants,is one of the world's most important high quality oil crops and whose products with significant application values.Sesame bacterial wilt is an important disease which has affected the yield and quality of sesame in South China.Bacterial wilt is a bacterial disease and caused by Ralstonia solanacearum,which has a wide host range and can infect more than 50 families and 200 species of plants,especially the economic crops,such as potatoes,tomatoes,eggplant,pepper,banana,peanut,ginger etc.Ralstonia solanacearum has multiply ways to infect plants,and can be spread through the soil,irrigation,plant seed,etc.Plant bacterial wilt,whoes pathogenic strains spread all over the world,is widely distributed in tropical,subtropical and temperate regions.So Ralstonia solanacearum has become the second largest plant pathogenic bacteria.At present,domestic and foreign research about bacterial wilt mostly concentrated in economic crops such as potato,tomato,and other model plants like Arabidopsis,tobacco.And there was few studies on sesame.In this study,we have used 40 random primers to analyze the differentially expr essed gene of sesame before and after the induction by Ralstonia solanacearum.And we found two genes were significantly down-regulated by Ralstonia solanacearum.The expression of the gene was further verified by quantitative and semi quantitative PCR.Cloning and sequencing results showed that one gene named SiAQP is the homo logous gene of aquaporin,and was located in cell membrane,predicted to be a tetra mer with 5 transmembrane domains.The main function of aquaporins is to transport water or other small molecules,and there were lots of studies have shown that aq uaporins in plant play a positive role in response to abiotic stress.The low expressi on of SiAQP may be one of the reason of sesame that induction by Ralstonia sola nacearum to became wilt.Another gene,encods a proline rich protein and is named SiPRP,is divided into three domains:signal peptide domain,N terminal proline rich-domain and C terminal domain.Blast analysis revealed that the protein has low hom ology with other plant PRPs,suggesting that SiPRP is a new member in PRP family.Avaible evidence show that most plant PRPs localize at plant cell walls,however,SiPRP was shown to locate at cell membrances,with a little secreted outside the cell.SiPRP which is found in this study may play pivotal roles in Ralstonia solanacearum-sesame interactions.