Genome-wide Identification Of GDSL Lipase Gene In Cotton And Studies On Salt Tolerance Mechanism Of GbaGELP184D Gene

The cotton is a pioneer crop of saline-alkali resistance,and cotton planting in saline-alkali lands is the main direction of our cotton industry adjustment.Research on the mechanism of salt tolerance of cotton and creation of new materials for salt tolerance of cotton can greatly promote the breeding process of new varieties of salt tolerance of cotton,which is of great significance to promote the sustainable development of agriculture.However,in the study of salt tolerance mechanism of cotton,most of the objects are upland cotton.The basic germplasm of upland cotton is too concentrated,and the genetic basis of salt-tolerant varieties is rather narrow,which is one of the main reasons for the slow progress in the study of salt tolerance mechanism of cotton.Island cotton not only has the advantages of long fiber,high fineness,high strength,but also has the advantages of strong stress resistance.Therefore,it is of great significance to study the salt tolerance mechanism of island cotton and fully explore the excellent genetic resources for salt tolerance breeding of cotton.In this study,two accessioons of sea island cotton with relatively good salt tolerance were selected as materials,and the salt-resistance gene(GDSL lipase gene)was screened by transcriptome and proteomics.Secondly,GDSL lipase gene families were analyzed in 10 cotton species.Finally,the salt tolerance of GbaGELP184 D gene in transgenic Arabidopsis thaliana and cotton was analyzed,and its mechanism was studied by molecular simulation.The main research results are as follows:1.Transcriptome and proteomic analysis indicated that GDSL lipase gene family was involved in the response of island cotton to salt stress.Among the differentially expressed genes between the salt treatment group and the control group in Yuehai 9,25 GDSL lipase genes were differentially expressed,and 23 were up-regulated in the salt treatment group.Meanwhile,one GDSL lipase was differentially expressed in proteomics data.Among the differentially expressed genes between the salt treatment group and the control group in PS-7,36 GDSL lipase genes were differentially expressed,and 27 were up-regulated in the salt treatment group.Meanwhile,two GDSL lipase were differentially expressed in proteomics data.These data indicate that GDSL lipase gene family is involved in the response of island cotton to salt stress and plays an important role in response to salt stress in island cotton.2.Transcriptome and proteomic analysis suggested that members of the GDSL lipase gene family may be induced by salicylic acid in response to salt stress processes.Through GO enrichment analysis,it was found that the several differentially expressed genes were significantly enriched in the biological process-response to salicylic acid(GO: 0009751).Further analysis showed that 102 differentially expressed genes were involved in the biological process between the salt stress treatment group and the control group,among which 8 were GDSL lipase family genes in Yuehai 9.There were 206 differentially expressed genes involved in the biological process between the salt stress group and the control group,among which there were 14 genes of GDSL lipase family in PS-7.Moreover,it has been reported that SA regulates abiotic stress signaling pathways with significantly differentially expressed molecules at transcriptome and proteome levels.GO and KEGG enrichment analysis of 1820 differentially expressed genes in the transcriptome and 57 differentially expressed proteins in the proteome showed that catalytic activities and oxidoreductase activity were enriched in molecular functions.The biological processes related to lipid molecules are enriched in salt stress.Metabolic pathways related to lipid molecules are also enriched in transcriptome and proteome during salt stress.Therefore,based on transcriptome and proteomics data,we hypothesized that members of the GDSL lipase gene family may be induced by salicylic acid in response to salt stress processes.3.Identification of GDSL lipase gene family in cotton indicated that the binding pocket properties were fundamental to functional diversification among members of GDSL lipase family in cotton.A total of1502 GELP genes were identified in 10 cotton species.Segmental duplication and differences in evolutionary rates are the leading causes of the increase in the number and diversity of GELP genes during evolution for ecological adaptation.Structural analysis revealed that the GELP family has high structural diversity.Moreover,molecular simulation studies have demonstrated significant differences in the properties of the binding pockets among cotton GELPs.In the process of adapting to the environment,GELPs not only have segmental duplication but also have different evolutionary rates,resulting in gene diversity.This diversity leads to significant differences in the 3D structure and binding pocket properties and,finally,to functional diversity.4.GbaGELP184 D gene could improve the salt tolerance of plants.GbaGELP184 D gene could not only increase the germination rate of Arabidopsis thaliana seeds under salt stress,enhance the salt tolerance of seedlings and palnts,but also improve the salt tolerance of cotton seedlings,and show the gene dose effect.In addition,GbaGELP184 D gene also affected the plant height of cotton,but had no effect on the number of fruit branches.It was also found that during salt stress,GbaGELP184 D gene was induced by salicylic acid,thereby enhancing the salt tolerance of cotton.Molecular simulation showed that GbaGELP184 D may potentially play roles in stress resistance by hydrolyzing long chain lipid molecules.This study provides a foundation for further revealing the molecular mechanism of GbaGELP184 D gene from sea island cotton in response to salt stress,and contributes gene resources for the breeding salt-tolerant cotton varieties.