Functional Analysis Of MAPK Genes Related To Abiotic Stress In Gossypium Hirsutum L.

Cotton plant as a major source of oil,protein as well natural fiber crop,is grown all over the world.Drastic environmental stresses have been a major threat to the sustainable production of cotton crops leading to a great economic loss.Stress-related transcription factors and genes,including ROS scavenging,Abscisic acid,and mitogen-activated protein kinases(MAPK)signaling genes,are caused by abiotic stress to activate numerous stress-related mechanisms to induce tolerance in plants.Through phosphorylation of downstream signal pathway,mitogen-activated protein kinase(MAPK)plays a crucial effect in the recognition of environmental stress.We identified a total of 74 MAPK genes in cotton in this study,with41 in G.hirsutum,19 G.raimondii,and 14 G.arboretum respectively.The MAPK genes proteins were studied further to determine their physicochemical characteristics and other properties.The physiochemical properties of these genes revealed that they can be tested as abiotic tolerance genes.To investigate MAPK gene family functioning in cotton response and resistance to drought and salt stress,a systematic analysis of cotton MAPK gene was conducted.The evolutionary relationship of cotton MAPKs was conducted by constructing a phylogenetic tree using MEGA 7.0 by multiple sequence alignment of 41 GHMAPK,14 Ga MPK protein sequences,19 Gr MPK protein sequences,and 18 Arabidopsis MAPK protein sequences.Based on phylogenetic analysis,the cotton MAPK family can be dived into A,B,C,D,and E clades.Seven GHMAPK genes(GH_A07G1527,GH_D02G1138,GH_D03G0121,GH_D03G1517,GH_D05G1003,GH_D11G0040,and GH_D12G2528)were selected and specific tissue expression and profiling under drought and salt stress were performed.The qPCR analysis result shows that the genes are expressed in both the vegetative and reproductive parts of the plant.Also,the qPCR analysis showed that the genes were highly upregulated under drought treatment while only 5 genes were upregulated in salt treatment and two were downregulated respectively.GH_D03G1517 gene was identified and characterized.Tissue-specific expression and profiling under drought and salt stress were performed using qPCR.GH_D03G1517 was predominantly expressed in young leaf and root parts of the plant as shown by qPCR.Subcellular localization analysis by the Green Fluorescence Protein method revealed that GH_D03G1517 was distributed in the nucleus and cytoplasm.GH_D03G1517 overexpressed Arabidopsis plants exhibit drought and salt tolerance,with less oxidant and higher antioxidant enzymes.In the GH_D03G1517 overexpressed plants,physiological parameters were relatively stable with an unstable concentration in wild type plants.Stress-responsive genes: Abre binding factor4,Stress-induced protein1,Ras-related protein18,and Desiccation-responsive22 were found upregulated in the GH_D03G1517-transformed lines and downregulated in wild type.VIGS technique showed that GH_D03G1517 silenced cotton plants had high levels of oxidant and lower antioxidant enzymes,with poorly developed physiological parameters.The expression level of three drought stress-responsive genes revealed downregulated profile expression.The findings of this research showed that the GH_D03G1517 gene drought and salt stress tolerance and can serve as a technique in crop molecular improvement for stress tolerance in cotton.Lastly,three abiotic stress tolerance(cold,drought and salt)study was carried out on Gh_D05G3876transformed Arabidopsis plants.Gene expression and phenotypic analysis of the transformed plants were analyzed under cold,drought,and salt stress.Physiological parameters such as Relative water content,Leaf water loss,chlorophyll content,and ion leakage showed that overexpressed plants possess more stable content for normal growth compared with the Wild type plants.Also,Gh_D05G3876 overexpressed plants showed a higher level of antioxidant activities and a lower level of oxidant activities.Silencing Gh_D05G3876 in cotton inhibited its tolerance to drought stress.Our research findings strongly suggest that Gh_D05G3876 can be regarded as a key factor for abiotic stress tolerance in cotton plants.