Identification Of GPAT Family Genes In Barley And Their Function Analysis Under Abiotic Stress

Barley is the fourth largest crop after wheat,rice and corn.Hulless barley is mainly planted by residents in the Qinghai Tibet Plateau.However,in the process of planting,due to the unique plateau environment of the Qinghai Tibet Plateau,it is often affected by abiotic stress,which has become the main factor affecting the growth of barley and highland barley.Especially due to low temperature,drought and high salt,the yield is reduced and the growth is slow.Therefore,mining stress resistance genes is of great significance to the study of stress resistance of barley and highland barley.Glycerol-3-phosphate acyltransferase has been reported in Arabidopsis thaliana,Oryza sativa,Gossypium,Zea mays and Brassica napus.It plays an important role in plant growth and development and resistance to abiotic stress by regulating the biosynthesis of glycerol lipids.In this study,gene family identification,abiotic stress expression analysis,subcellular localization and physiological index determination of mutants were carried out for GPAT genes in barley and Qingke.The main contents and results of this study are as follows:1.In this study,22 and 21 GPAT gene family members were identified in barley and Qingke respectively.According to their distribution on barley and Qingke chromosomes,HvGPAT1-HvGPAT22 and Ht GPAT1-Ht GPAT21 were named respectively.Through phylogenetic,conserved motif and gene structure analysis,it was found that HvGPATs and Ht GPATs proteins can be divided into group I,Group Ⅱ,and group Ⅲ,and Group Ⅲ can be divided into Ⅲa,Ⅲb and Ⅲc;Cis-acting element analysis found that both barley and hulless barley GPAT genes have many cis-acting elements related to plant stress and hormone regulation.Among them,the representative ones related to plant stress resistant environment are low temperature inducing element(LTR)and drought inducing response element(MBS);Abscisic acid response element(ABRE)is the representative cis acting element related to the regulation of plant hormones,and it is also the one with the largest number in barley and hulless barley GPAT genes.It is speculated that barley and hulless barley GPAT genes are likely to alleviate stress through ABA pathway.2.Tissue expression analysis of 22 genes in barley showed that 22 HVGPATs genes had different expression patterns in different tissues,and 22 barley genes were not expressed in INF1;These 22 barley GPAT genes can be divided into two categories: non-expression and relatively high expression level.According to the classification,11 GPAT genes of barley and qingke were selected for abiotic stress expression analysis.It was found that the expression of HvGPAT5,HvGPAT8,HvGPAT14,HvGPAT17 and HvGPAT18 in leaves increased significantly under low temperature,drought and salt stress;Under cold stress,the expression level of Ht GPAT14 in roots was significantly up-regulated,while under drought stress,the expression level of Ht GPAT14 in leaves was significantly up-regulated.Under salt stress,the expression level of Ht GPAT18 in leaves and Ht GPAT4 in roots were significantly up-regulated.3.HvGPAT14 is located in mitochondria and HvGPAT18 is located in endoplasmic reticulum,while HvGPAT14 has high homology with At GPAT4/6/8,and HvGPAT18 is similar to At GPAT9.The localization of the two proteins is consistent with the classification and website prediction results.4.The phenotypic and physiological indexes of gpat6 mutant(salk-056554)and ats1 mutant(salk-069657c)were determined.It was found that,the phenotypic and physiological indexes of mutants and wild-type Arabidopsis were not significantly different under normal conditions,but the stress resistance of GPAT gene deletion mutants was weaker than that of wild-type under abiotic stress.