Excavation Salt Tolerance Related Genes And Genome-wide Identification Of OSCA Gene Family In Cotton

With the deterioration of global environment,drought and soil salinization are becoming more and more serious.As one of the main textile materials,cotton plays an important role in the national economy and people’s lives.Under salt and drought stress,the growth,yield and quality of cotton will be seriously affected.Wild upland cotton lines have strong ability to resist unfavorable natural conditions and many good traits lacking in cultivated varieties.They have important application value in improving cotton quality and resistance,and are important genetic resources for cotton breeding.In this study,salt-tolerant materials were used for transcriptome sequencing,and candidate genes（OSCA）related to salt-alkali stress were obtained.The whole genome identification and functional verification of OSCA gene family were carried out by means of bioinformatics.The main content are as follows:1.Transcriptome sequencing of wild upland cotton lines MAR85,LAT40 and CRI12 was carried out after salt treatment,and 64,737 expressed genes were obtained.GO and KEGG enrichment analysis were carried out for 22,359 differentially expressed genes.The results showed that signal transduction was involved in the salt stress response of leaf SS3 and SS12 stages;Carbohydrate metabolism and redox process were involved in leaf SS48 stage;The differentially expressed gene segments in the three stages of root treatment were significantly enriched in the redox process.Generally speaking,signal transduction and redox processes play a key role in different tissues of Upland Cotton under salt stress.In addition,co-expression network analysis showed that GhSOS3,GhCBL10,Gh A05G1480 and other genes were involved in salt stress response.2.Hyperosmdality-gate calcium-permeable channels（OSCA）participate in perceiving the changes of extracellular osmotic potential,which induces the increase of Ca²⁺concentration and regulates osmotic potential.In order to understand the characteristics and functions of OSCA gene in cotton,the whole genome analysis of OSCA gene family in cotton was carried out in this study.35,21 and 22OSCA gene members were identified in G.hirsutum,G.arboreum and G.raimondii genomes,and they were divided into four groups according to their genetic structure and phylogenetic relationship.The analysis of gene and protein structure showed that all 35 GhOSCA family genes contained conserved RSN1₇TM（PF02714）domain.Cis-acting element analysis showed that OSCA gene members may play a key role in response to heat,low temperature,drought and salt stress.RNA-seq and qRT-PCR analysis showed that GhOSCA gene was expressed in different tissues with tissue specificity,which indicated that members of GhOSCA family played a specific role in regulating osmotic pressure in different tissues.Interestingly,GhOSCA1.1 is most similar to AtOSCA1,and its expression is significantly up-regulated under salt and drought stress,suggesting that GhOSCA1.1 may be a key gene involved in salt and drought stress response.3.The potential function of GhOSCA1.1 was analyzed by viral induced gene silencing（VIGS）.Under drought and salt stress,silent plants showed severe wilting compared with CK and empty load plants.Compared with empty load plants,GhOSCA1.1 gene silenced plants had lower SOD activity and PRO content,higher MDA content and lower salt and drought tolerance,which proved that this gene is a key gene involved in drought and salt tolerance response.