Functional Analysis Of G Protein β Subunit Gene TaGB1-B In Wheat

Wheat(Triticum aestivum L.)is one of the main grain crops in our country.The production of wheat is vital to our food security.However,wheat is often affected by abiotic stress during its growth and development,which will not only negatively affect its yield,but also cause changes in its metabolism and physiological mechanism,thus affecting its quality.G protein is a sensor involved in a variety of important biological pathways.It plays an important role in plant response to abiotic stress by participating in a variety of signal pathways and different signal transduction levels.It has been reported that there are 3 Ga genes,3 Gβgenes and 12 Gγ genes in the hexaploid wheat genome,but the role of Gβ subunit in wheat has not been explored.Based on previous studies in our laboratory,we conducted functional verification of wheat G protein β subunit gene TaGB1-B,and preliminary screening and analysis of interacting proteins of TaGB1-B,which laid a foundation for further research on the mechanism of action of TaGB1-B.The main research results of this paper are as follows:1.The analysis results of TaGB1 expression characteristics showed that TaGB1 had high homology on chromosome A,B and D,and the expression levels of TaGB1 gene were similar under different stress conditions,but the expression levels of TaGB1-B under different stress treatments were significantly different.The biogenic analysis of TaGB1-B showed that TaGB1-B had no transmembrane region and belonged to nuclear protein.2.The analysis results of TaGB1-B expression characteristics showed that under stress and hormone treatment,the expression of TaGB1-B generally showed a trend of first increasing and then decreasing.The expression of TaGB1-B in roots and leaves was upregulated by drought treatment and the expression of TaGB1-B was the highest after 6h of stress,about 3.5 times.Under salt stress,the expression level of TaGB1-B showed little difference in roots,stems and leaves.The expression level showed an upward trend,reached the peak at 12h,and slowly recovered to the initial level 24h later.3.Functional identification of TaGB1-B indicated that overexpression of TaGB1-B gene could enhance drought and salt tolerance in Arabidopsis and wheat.(1)Under drought and salt stress,the germination rate,root length,fresh weight,survival rate and proline content of Arabidopsis thaliana with overexpression TaGB1-B gene and the restoring lines of corresponding mutants were higher than those of the wild type and corresponding mutants(agb1-2),and the malondialdehyde content was lower than that of the wild type and agb1-2.These results suggested that overexpression of TaGB1-B gene could enhance tolerance of Arabidopsis to drought and salt.(2)Overexpression of TaGB1-B significantly increased root length,number of lateral roots,survival rate,proline content and superoxide dismutase(SOD)activity of transgenic wheat lines,while significantly decreased malondialdehyde content.These results indicated that overexpression of Ta GB1-B gene improved drought and salt tolerance of wheat at seedling stage.4.Seven interacting proteins were obtained by yeast two-hybridization,one of which was NPL4-Like protein involved in nuclear transport.The above research results on the functional analysis of TaGB1-B further clarified the drought and salt tolerance functions of TaGB1-B,and provided evidence for the involvement of TaGB1-B in the response of wheat to drought and salt stress,and provided new genetic resources for the creation of new drought and salt tolerant wheat germplasm.