Bioinformatics Analysis Of Wheat GRF Gene Family And Functional Identification Of TaGRF1 And TaGRF2

Wheat(Triticum aestivum L.)is the third largest food crop in China.Its output accounts for about 17% of the global total output.Its quality and output are closely related to the national food security.Cultivated wheat is a heterologous six fold body,with a large genome,complex genetic background,and difficult gene identification.The identification of wheat key functional genes at the whole genome level will lay a foundation for the development of gene markers and the application of gene editing.Growth-regulating factor(GRF)is involved in the development of many plant tissues and organs,involving plant height,grain,nutrient utilization and other key agronomic characters.Therefore,the study of GRF gene family in wheat has important theoretical value for the function mining and Breeding Application of wheat genes.At present,there are reports on the identification and functional research of GRF gene family in Arabidopsis,rice,corn,stipe and other plants,but the identification and research of GRF gene in wheat has not been carried out.With the results of wheat genome sequencing published in 2018,55 Ta GRF genes have been identified from wheat genome by using multiple biological informatics analysis methods,the relationship between the sequence characteristics of these Ta GRF genes and species evolution was analyzed.The expression of Ta GRF gene in different tissues and its response to exogenous GA were studied.Ta GRF1 and Ta GRF2 were silenced by VIGS system to study their biological functions.The main results are as follows:1)Fifty five Ta GRF genes were identified from wheat genome by bioinformatics method,among which 33 genes had three partial homologous genes,and all Ta GRF genes had mir396 target sites,which might be regulated by mir396.According to phylogenetic analysis,Ta GRF can be divided into three categories: the first category contains WRC and QLQ domains,and the second and third categories only contain WRC domains.According to phylogenetic analysis with other species,Ta GRF 13-15,which only contains WRC domain,originated earlier in evolution.The analysis of chromosome collinearity shows that most of Ta GRF genes are homologous fragment repeats,and the collinear gene pairs between 4A and 7A / D or 5B / D are related to chromosome translocation.Most of the Ta GRF genes are under the pressure of purification and selection,and their functions are conservative;the Ta GRF 2-7 genes are under the pressure of neutral selection.2)According to the expression data of Ta GRF in different organs of wheat at different development stages in the expression profile database,Ta GRF was divided into three categories: the first one had higher expression in seedlings,young ears and reproductive organs,the second one had the highest expression in pistil,and the third one had no significant change in expression in various tissues,indicating that most of Ta GRF genes were mainly in growing organs and reproductive organs Expressed in organs.It was found that the response of different Ta GRF to GA was different,some genes did not respond to GA,such as Ta GRF 3,4,6,7;some gene expression was induced by GA,such as Ta GRF 1,8,10,12,13,18;some gene expression was inhibited by GA,such as Ta GRF 15,9,11,16.3)Ta GRF1 and Ta GRF2 were silenced by bmsv-vigs system to study the functions of these two genes.The results showed that after Ta GRF2 silencing,the growth of new leaves of wheat seedlings was accelerated;after Ta GRF1 silencing,the growth period of wheat was delayed,the development of young spike was abnormal,and the elongation of peduncle was inhibited;the related genes VRN1 of wheat growth period were up-regulated and VRN2 was down regulated.This study showed that Ta GRF2 and the growth and development of wheat leaves were inhibited,Ta GRF1 is involved in the regulation of young spike development and growth period through VRN1 or VRN2.