Functional Analysis Of Heat Shock Transcription Factor TaHSFB4-2B Under Abiotic Stress In Wheat

Wheat(Triticum aestivum)is a staple crop worldwide.High and stable yield is the most important breeding goal of wheat,but it is often subjected to abiotic stress such as high temperature,high salt and drought.The heat shock transcription factor(HSF)family is one of the hot research families in plants under various abiotic stresses,and its role in plant stress has been widely reported.Plant HSFB4 has been confirmed to be involved in plant growth and development in Arabidopsis,and previous studies in the laboratory found that At HSFB4 is involved in drought stress response.In order to explore the role of wheat hsfb4 gene under abiotic stress,the homologous gene of TaHSFB4 was cloned from wheat variety Chinese spring and temporarily named TaHSFB4-2B.The gene structure,protein domain and phylogenetic relationship of TaHSFB4-2B were analyzed by bioinformatics methods,and transgenic Arabidopsis plants were obtained by constructing plant transformation vectors of TaHSFB4-2B.The function of TaHSFB4-2B gene under abiotic stress was studied by q RT-PCR,subcellular localization,yeast two-hybridization and so on.The main results are as follows:There were six highly similar amino acid sequences of TaHSFB4 in wheat,among which TaHSFB4-2B and At HSFB4 had the highest homology.Bioinformatics analysis showed that TaHSFB4-2B was located on the second chromosome of wheat B subgenome,and its CDS sequence was 963 bp,encoding 320 amino acids,containing an HSF-DNA binding domain,with a predicted molecular weight of 35.29 k Da and an isoelectric point of 7.20.To further understand the evolutionary relationship of TaHSFB4-2B,three Monocotyledons and five Dicotyledons were selected to construct an HSFB4 evolutionary tree.Among them,TaHSFB4-2B with HSFB4 of Monocotyledons rice and maize were clustered in the same group,indicating the different evolutionary processes of HSFB4 members in Monocotyledons and Dicotyledons.Subcellular localization test and tissue expression pattern analysis of TaHSFB4-2B showed that TaHSFB4-2B was located in the nucleus,and the expression of TaHSFB4-2B was detected in young roots,young stems,young leaves,mature roots,mature stems,mature leaves,young spik and young seed tissues of wheat.The expression level of TaHSFB4-2B was the highest in mature roots and the lowest in mature leaves.Studies on the function of TaHSFB4-2B under abiotic stress showed that TaHSFB4-2B responded to high temperature,low temperature,high salt and drought stress,a nd the transcription level of TaHSFB4-2B was up-regulated in young leaves and roots of wheat(Except in leaves under mocked drought stress,which showed a decreased transcription of TaHSFB4-2B).Transgenic Arabidopsis plant TaHSFB4-2BOE was constructed and treated with high salt and drought stress.Statistical results showed that the germination rate of TaHSFB4-2B-OE was significantly reduced,the growth was inhibited,and the root length was also significantly shortened,indicating that TaHSFB4-2B reduced the salt resistance and drought tolerance of Arabidopsis.The abiotic stress-related genes in TaHSFB4-2B-OE plants were detected.The analysis results showed that the expression levels of abiotic stress-related HSP in TaHSFB4-2BOE plants were significantly increased under high salt stress.Under drought stress,only the expression of At HSP17.6B was significantly increased,while the other HSP detected had no significant change.The expression levels of CAT2(key genes in oxidative stress signaling pathway)and SOS1(key genes in calcium ion signaling pathway under salt stress)were significantly decreased regardless of high salt stress or drought stress,suggesting that the presence of TaHSFB4-2B affected the expression of abiotic stress-related genes in Arabidopsis plants.In addition,several interacting proteins belonging to the thioren family,MPN family and γ-gliadin family were preliminarily screened by yeast two-hybrid sieve bank test.In this study,we elucidated the gene structure,protein domain and phylogenetic information of TAHSFB4-2B.The expression of TAHSFB4-2B in wheat and its expression pattern under abiotic stress were investigated.In transgenic lines,ta HSFB4-2B was found to negatively regulate salt and drought tolerance of Arabidopsis thaliana and affect the expression of abiotic stress-related genes.Yeast two-hybrid sieve bank test also laid a foundation for further study on the function of TAHSFB4-2B.