Cloning And Function Analysis Of LTPs Gene Family In Tibetan Hulless Barley (Qingke)

Plant lipid transfer proteins(LTPs)were a group of small,basic proteins that have been reported to be involved in regulation of multiple growth and development stages of plants,and participation in cutin formation,lipid transfer,stress response,etc.In this study,a genome-wide analysis of the LTPs gene family in barley was carried out.Then 16 LTPs family genes were cloned from Tibetan hulless barley ‘Dulihuang'by PCR method and the bioinformatics analysis of this 16 LTPs family gene sequences was also carried out.The expression pattern of the LTPs family gene was studied.Simultaneously,In order to further explore the role of HtLTP gene in the stress resistance of Tibetan hulless barley,four HtLTP gene expression vectors were constructed,and then transformArabidopsis thaliana,which provided support for further study of HtLTP function.The main findings are as follows:1.The LTP gene family in barley was analyzed by genome-wide analysis.A total of 40 LTP genes were identified,which can be divided into 4 types(1,2,D and G).Prediction and analysis of physicochemical properties,sequence structure,phylogeny,gene structure,proteins structure,chromosomal location,collinearity within species,upstream cis elements,and expression patterns of 40 barley LTPs were carried out.It was found that Hv LTP genes are consistent with LTP characteristics and the pattern of expression exhibits tissue specificity.In addition,the expression pattern of HvLTP gene in response to abiotic stress indicates that the HvLTP gene was associated with stress resistance.2.16 LTPs family genes were cloned from Tibetan hulless barley.Based on gene sturcture,the lipid transporter was named HtLTP1-10 and the lipid transport-like protein was named HtLTPlike1-6.The physicochemical properties,signal peptide,transmembrane region,protein II structure,tertiary structure and phylogenetic of the LTPs family gene proteins were predicted.3.The expression pattern of this family gene was studied in Tibetan hulless barley.The LTPs gene showed tissue expression differences in roots,stems,leaves,seeds and flowers.Under cold,drought and salt stress,the relative expression levels of 8,4 and 6 HtLTP genes were significantly up-regulated in leaves,respectively.It indicated that the HtLTP genes were consistent with LTP characteristics.Moreover,the expression pattern of HtLTP gene in response to abiotic stress indicates that HtLTP gene is involved in stress resistance.4.In order to further explore the role of HtLTP gene in the stress resistance of Tibetan hulless barley,four overexpression vectors of LTPs were constructed.The HtLTP1 transgenic Arabidopsis thaliana was transform by floral-dip method and positively screened.It was found that the leaves of Arabidopsis transgenic plants became smaller and flower development was advanced.Over-expression of HtLTP1 in transgenic materials under drought stress enhanced the stability of cell membrane and enhanced the activity of SOD,POD and CAT.