The Study On The StBAG3 Cloning And Possibile Function On The Resistance Establishment To Potato Late Blight

The BAG(Bcl-2 associated athanogene)family is a multifunctional group of protein which has been found in yeasts,plants and animals.BAG genes perform diverse functions ranging from apotosis to tumorigenesis.Some research data indicated that BAG was also involved in plant defense responses and environmental stress.In this study,we cloned StBAG3 gene from potato through alignmnet in genebank,and constructed expression and silencing vector.Using transient expression method,we analysed the possibile effect of StBAG3 in the establishment of potato resistance to P.infestans.Oue results listed as follows:1.According to the conserved domain sequence in Arabidopsis tha liana,we have designed primer to clone potato endogenous St BA G3 gen e.The full length of StBAG3 is 2704 bp,the open reading frame is 1026bp,encoding 341 amino acids.The secondary protein structure showe d that the StBAG3 is insist of 89a-helixs,35 sheets,and 217 coils.Th e sequence analysis indicated that the StBAG3 protein contain 2 conserv ed domains,which are BAG domain and UBQ domain.StBAG3 protein i s a hydrophlic and unstable protein,which has no transmembrance helice s and signal peptides.2.The expression profile of StABG3 suggested that the St BAG 3 ex pression level was different in diverse potato cultivars and different tiss ues.The expresson level of StABG3 in Jizhangshul2 was highest and in Shepody was lowest.The expression level of StBAG3 was highest in st ems,followed by young leaves,roots and old leves.3.After infected with P.infestans,the expression level of StBAG3 increased in both Jizhangshul2 and Shepody varieties.The highest expression level occurred at 48hpi and decreased at 72hpi.4.We obtained overexpression vector pCAMBIA-1302-GFP-BAG and Silencing vector pRV-BAG.5.The transient expression mediated by Agobacterium showed that the lesion expanding speed on leaves transient expressed with StBAG3 is much slower than that of leaves transient expresed with H2O2 and pCAMBIA1302-GFP empty vector,indicating that StBAG3 maybe involved in the establishment of potato resistance to P.infestans.