Identification Of CDPK Gene Family And Functional Studies Of GhCDPK60 In Gossypium Hirsutum L.

Cotton is the source of the important fiber and oil crop in world wilde.It’s also an important part of China’s national economy.As the main cotton producing area in our country,the outstanding problems of drought and salinization in Xinjiang seriously affect the yield and quality of cotton and restrict the development of China’s cotton industry.Calcium-dependent protein kinases（CDPKs）are Ca²⁺sensors/protein kinase effector proteins that regulate kinase activity and play an important role in biological and abiotic stress responses.In this study,bioinformatics was used to identify CDPK gene families in upland cotton.Combined with homology annotation,gene expression level analysis and preliminary screening based on laboratory research,a cotton stress-resistant gene GhCDPK60 was obtained.Further cloning of this gene and preliminary function exploration were conducted.The main research results are as follows:Based on the bioinformatics analysis method,the Arabidopsis CDPK family gene was used as the reference sequence to search the upland cotton genome,and finally 80 upland cotton CDPK gene family members were identified,which were distributed on 26 chromosomes of upland cotton（41 in the At subfamily and 39 in the Dt subfamily）.They were named GhCDPK1-GhCDPK80 according to their chromosomal location.GhCDPK60 was cloned from the standard line‘TM-1’of Upland cotton.The results of subcellular localization showed that this gene functions in the cell membrane.Real-time quantitative PCR results showed that GhCDPK60 was preferentially expressed in roots,anthers and fibers.The promoter analysis showed that GhCDPK60 contained ABA and Me JA responsive hormone.After further hormonal treatment,we found that the gene responded to ABA,Me JA,IAA,GA,SA and salt stress induction.We overexpressed GhCDPK60 in Arabidopsis thaliana and simulated drought and salt treatment.By observing the phenotypic changes and physiological indicators between transgenic lines and wild type,we confirmed that GhCDPK60 can improve the tolerance of transgenic Arabidopsis thaliana to drought and salt stress.Overexpression of the gene in rice showed that it changed the rice plant type.Using virus-induced VIGS gene silencing technique,GhCDPK60 expression level was inhibited in six upland cotton varieties.After drought and salt stress treatment,the results showed that the silencing of this gene reduced the drought and salt tolerance of cotton.In conclusion,we identified a member of the calcium-dependent protein kinase family in upland cotton and cloned a gene that responds to a variety abiotic stress induction.The function of this gene under stress was preliminarily investigated by over-expression and gene silencing techniques,which provided theoretical basis for breeding resistant cotton varieties.