Arabidopsis Thaliana Recombinant SERKs And Setaria Italica BAK1 Involved In The Regulation Of Brassinosteroid Signaling And Cell Death Pathway

The SERKs,a group of receptor like protein kinases in plants,are widely involved in plant growth,development and immune response.The function of SERKs family genes is partially redundant and specific.As a co-receptor,SERK3/BAK1 is involved in the regulation of multiple signaling pathways.In the first part of my dissertation,the extracellular domain-transmembrane domain of arabidopsis BAK1 and the intracellular kinase domain of SERK1,SERK2,SERK4 and SERK5 were cloned.The extracellular domain-transmembrane domain of BAK1 and the intracellular kinase domain of four SERKs were combined to form the complete recombinant SERKs(CS3ET-CS1 IN,CS3ET-CS2 IN,CS3ET-CS4 IN,CS3ET-CS5IN)genes,and then overexpressed the recombinant SERKs into the brassinolide receptor mutant bri1-5.The second part of the dissertation explored the function of BAK1 in millet of BR signaling and cell death pathway.The millet SiBAK1 gene was cloned and overexpressed into arabidopsis mutant bri1-5 and the cell death mutant bak1-3/bkk1-1,to analyzed functions of recombinant SERKs and SiBAK1 genes.The subcellular localization,the phenotypes of seedlings and adult plants were observed.On the other hand,the length data of roots and hypocotyls of recombinant SERKs and SiBAK1 treated with various concentrations BL were collected,to explored the differentiation of SERKs intracellulor domain in BR signal transduction.To investigating whether recombinant SERKs and SiBAK1 is involved in the BR signaling pathway and the cell death regulatory pathway by bioinformatics,the SiBAK1 and recombinant SERKs protein sequence,tissue localization expression,seedling and adult plant phenotype,root length and hypocotyl,sensibility to BL,BR synthesis genes CPD and DWF4 expression,and the result of trypan blue staining had been analyzed.The main results are as follows:1.The recombinant SERKs were transiently transformed into the leaves of Nicotiana benthamiana.The fluorescence was observed in the plasma membrane by laser confocal microscopy.The subcellular localization of recombinant SERKs is not changed and localized on the plasma membrane.2.Overexpression of CS3ET-CS1 IN increased plant height,leaf elongation,hypocotyl and root length of bri1-5,and its sensibility to exogenous BL is partially restored by overexpressed recombinant SERKs excepted CS3ET-CS5 IN.3.SiBAK1 is located on the cytoplasmic membrane,and the promoter of SiBAK1 candrive its expression in the vascular bundles,roots and stems of the euphylla and cotyledons in arabidopsis.This results indicated that the expression pattern of SiBAK1 is similar to the AtBAK1.4.Overexpression of SiBAK1 partially restored the phenotype of bri1-5,and inhibited the BL-insensitive of bri1-5.It indicated that SiBAK1 is involved in the arabidopsis BR signaling pathway.5.Overexpression of SiBAK1 in the bak1-3/bkk1-1 significantly inhibited the cell death phenotype under 22°C,which suggested that SiBAK1 is involved in the regulation of cell death signal in arabidopsis.