Function And Molecular Mechanism Of Heat Shock Transcription Factor HsfB1 And HsfB2b In Abiotic Stress

The challenges of abiotic stresses surround plants’ whole life from the natural environment.Among them,heat stress is one of the main abiotic stresses restricting plant growth and development.For its sessile growth,plants can only evolve a series of stress response mechanisms to respond to high temperature.Heat shock transcription factors(Hsfs)are critical regulatory factors that regulate the heat shock proteins(HSPs)expression in response to heat stress.Hsfs are divided into A,B and C three classes.Most research focuses on the A family members meanwhile little about B and C.It has been reported that At Hsf B1 is directly or indirectly regulated by At Hsf A1 and At Hsf A2 in Arabidopsis thaliana;It is unclear about the definite function and molecular regulation mechanism that At Hsf B1 and At Hsf B2 b negative regulated heat shock.We clarify the function heat shock transcription factor At Hsf B1 response to heat shock by using hsf B1 mutants and overexpressed materials of Arabidopsis thaliana.The interacting proteins will be identifiy through Yeast one-to-one rotation verification and LCA(Luciferase complementation assay)which screened by the Yeast two-hybrid system.We will find At Hsf B1 interacting proteins and identifiy their function under heat stress.Then,explore the function of At Hsf B1 and At Hsf B2 b in salt,drought and ABA stress.Finally,identify and analyze the homologous genes of At Hsf B1 and At Hsf B2 b in wheat.This study is expected to provide theoretical support direction for the wheat HSFs regulation mechanisms.The main results are as follows:(1)We observed that the survival rate of hsf B1,hsf B2 b and hsf B1/hsf B2 b has higher survival rate at high temperature though identifying high temperature phenotype of arabidopsis wild-type Col-0,mutant material hsf B1,hsf B2 b,hsf B1/hsf B2 b and overexpres-sed material Hsf B1-GFP(self promoter).The results showed that At Hsf B1 and At Hsf B2 b both negatively regulated the growth and development of Arabidopsis thaliana under high temperature.(2)As the reason for going a layer deeper research about the biological function of At Hsf B1 we initiated arabidopsis overexpressed material Hsf B1-Flag-m Cherry(35S promoter).Though observing the growth and development of Col-0,Hsf B1-Flagm Cherry,Hsf B1-GFP(self-promoter),we found that the overexpressed Hsf B1-flagMcherry had shorter roots than the wild type at seedling stage;more stunted and some plants died in the early stage of bolting;shorter and had few flowers and fruits and even some plants abortion on reproduction.These results suggest that At Hsf B1 inhibited the growth and development of Arabidopsis thaliana under normal conditions.(3)There are 19 At Hsf B1 interacting proteins and 23 At Hsf B2 b interacting proteins were preliminarily screened by yeast two-hybrid system.We use yeast mating and coswitching for one-to-one verification.Finally,found At Hsf B1 and At Hsf B2 b interacted with RPL11(AT3G53430).(4)We identified the mutant material rpl11 for going a layer deeper research about the biological function of RPL11.Then,though identifying high temperature phenotype of arabidopsis wild-type Col-0,overexpression material(Hsf B1-GFP and Hsf B1-Flagm Cherry,Hsf B2b-GFP),the mutant material(hsf B1,hsf B2 b,hsf B1/hsf B2 b,rpl11),we clearly observed Col-0,Hsf B1-GFP,Hsf B1-Flag-m Cherry,Hsf B2b-GFP barely survived at higher temperatures,the survival rate of hsf B1,hsf B2 b,hsf B1/hsf B2 b,rpl11 was higher.These results indicate that At RPL11 with At Hsf B1,At Hsf B2 b collaborative involvement response to heat shock reaction on Arabidopsis thaliana.(5)We identified the phenotype of arabidopsis wild-type Col-0,overexpression material(Hsf B1-GFP,Hsf B1-Flag-m Cherry,Hsf B2b-GFP)and the mutant material(hsf B1,hsf B2 b,hsf B1/hsf B2 b,rpl11)under other abiotic stresses(salt,drought)and ABA.The results show that At Hsf B1 negative response to ABA,salt stree and At Hsf B2 b plays a negative regulatory role in drought stress response in Arabidopsis thaliana.(6)In this study,we analyse system evolution,gene structure,protein structure,chro-mosome location,of the whole genome of heat shock transcription factor family genes in wheat.We identified respectively of the At Hsf B1 and At Hsf B2 b homologous genes Traes CS5A02G237900 and Traes CS5A02G314700 in wheat.And the wheat heat shock transcription factors could be involved in drought and ABA stress response though the results of the promoter cis-acting element prediction.The overexpressed transgenic vectors of these two genes were constructed,in order to create transgenic wheat overexpre-ssed materials.