Phylogenetic Analysis And Functional Study Of GRAS Transcription Factor Family In Rlce

The GRAS gene family is an important plant-specific transcription factor.Studies on the GRAS family in Arabidopsis show that this family of genes is widely involved in the regulation of plant signal transduction,gamete formation,meristem growth and response to stress,etc.However,the functions of most members of the rice GRAS gene family have not been reported.This study aimed to systematically study the evolution and function of the GRAS family genes in rice through the evolutionary analysis of the rice GRAS gene family and the use of CRISPR/Cas9 methods for gene knockout.The GRAS family protein has a common GRAS domain.Using this domain as a marker,through systematic phylogenetic analysis,we identified a total of 60 GRAS genes from the rice genome.By introducing the genomic data of 391 different rice ecotypes and 80 Arabidopsis ecotypes,Pi,Ka/Ks,and Fst of GRAS homologous genes in different eco-samples were systematically compared.Then we used the paired T-test to detect whether there was a significant difference in the degree of conservation of the domain and surrounding non-domain sequences,and screened outliers with special selective effects based on intergroup Ka/Ks mapping.The results showed that although the GRAS domain of rice is highly conserved,the function of the GRAS family in rice and Arabidopsis may have been significantly different.Finally,we found six genes that may be highly related to the artificial selection effect of indica and japonica rice or the differentiation between cultivated and wild rice.Based on the polymorphism analysis results,we selected 24 rice GRAS genes,constructed their CRISPR/Cas9 knockout vector,and adopted TP309 and Kasalath as their receptor.Till now,a total of 8 GRAS genes have been successfully transformed,2 of which are improved fatal,and the other 6 genes finally get 57 strains.3 genes only got Kasalath mutant plant,and 1 gene got only TP309 mutant plant.All the mutant strains displayed a visible mutant trait,including height,tillering,breeding,growth period,and etc.We studied the un-reported OsGO18 knockout mutant for the first time.