Identification Of CRK Gene Family And The Functional Characterization Of ZmCRK27

CRK is one of the largest RLK families in plants.Current functional studies on CRK family genes have been reported in Arabidopsis,but their biological roles in maize are unknown yet.Maize is one of the most important crops in China,whose production is highly affected by abiotic stress,such as high temperature,drought,salt and alkali.Therefore,there is of great significance to analyze whether ZmCRKs participate in maize stress response networks and growth.This study used bioinformatic approaches in analysis and identified 34 ZmCRK genes.Further,we deeply studied the function of ZmCRK27 in abiotic stress responses,growth and development.The main results are as follows:1.Thirty-four ZmCRK genes were identified by using the Hidden Markov Model.2.Phylogenetic analysis revealed that Maize,Rice,Arabidopsis CRK genes can be classified into 4 groups.The genetic distance between maize CRKs and rice CRKs is closer than the distance between maize CRKs and Arabidopsis CRKs.3.Chromosome mapping and collinear analysis showed that most Maize CRK genes derived from tandem repeats.4.Expression profile analysis found that 18 genes in Maize CRK family members were high expression genes,which were expressed in internodes,young ears,developing endosperm,leaves and roots.The expression of several CRK genes was changed significantly in response to various abiotic stresses.5.Analysis to the promoter of ZmCRK27,which has e QTLs associated with its expression,showed that there is a TE insertion in the promoter region.Statistical analysis indicated that the insertion affected agronomic traits and ZmCRK27 expression in maize.6.We constructed ZmCRK27 over-expression lines in Arabidopsis and found that ZmCRK27 over-expression Arabidopsis seed showed an sensitive phenotype based on germination rate with ABA treatment,while they showed a insensitive phenotype during salt treatment.These results indicated that ZmCRK27 is involved in plant response to ABA and salt stress.Our study provides a theoretical basis for the functional study of the CRK family in maize and other plants,and a basis for the study of the mechanism of ZmCRK27 in stress response.