Genome Wide Identification,Characterization And Expression Analysis Of HD-ZIP Gene Family In Cucumis Sativus.L Under Biotic And Abiotic Stresses

In plants,homeodomain–leucine zipper(HD-Zip)transcription factors are considered to play an important role in the growth and developmental processes.The HD-Zip is a class of homeobox proteins containing homeodomain(HD)and leucine zipper(LZ)motif.These two motifs of HD-ZIP family present in all eukaryotic organisms,but their association in a single protein is unique to plants.Based on their structure,sequence conservation,and functional properties,HD-ZIP are further divided into four subfamilies(HD-Zip I,HD-Zip II,HD-Zip III,and HD-Zip IV).In this study,we identified forty HD-ZIP(CsHDZ)genes in cucumber plants from the available cucumber genome database.Additionally,we performed phylogenetic analysis,conserved motif analysis,chromosomal mapping,gene ontology,and transcriptomic analysis.Moreover,we selected 11 genes for real-time PCR(q RT-PCR)expression profiling.We investigated the expression of these 11 genes under abiotic stresses,biotic stress,and hormonal treatments.Further,transient expression of CsHDZ22 was performed in tobacco epidermal cells.The obtained results highlighted the different significant roles of the the HD-ZIP gene family in cucumber.The CsHDZ genes expression analysis made inroads for future functional studies in cucumber plants.The detailed information regarding the main findings of this study is given below.1.We retrieved 40 CsHDZ encoding HD-ZIP proteins from the cucumber genome database.All the genes were renamed as CsHDZ1 to CsHDZ40.The majority of CsHDZ genes are located in the nucleus whereas,CsHDZ05,CsHDZ11,CsHDZ19,CsHDZ30,CsHDZ36,and CsHDZ40 are located in plasma membrane whereas one gene CsHDZ13 resides extracellular.2.The maximum likelihood phylogenetic tree was constructed to gain insightful knowledge about the evolutionary relationship of HD-ZIP proteins from Cucumis sativus,rice,and Arabidopsis.The amino acid sequence 40 CsHDZ,47 At HDZ,and 48 Os HDZ genes were used to construct the phylogenetic tree.Additionally,the HD-ZIP proteins were classified into four subfamilies named HD-ZIP I,HD-ZIP II,HD-ZIP III,and HD-ZIP IV,and the number of cucumber HD-ZIP proteins in each subfamily was measured.Among the four subfamilies,HD-ZIP I subfamily is the largest subfamily that accounted for 13 genes followed by HD-ZIP II 11 genes,HD-ZIP IV 11 genes,and HD-ZIP III 5 genes.3.Heat map data showed that CsHDZ genes expressed in all the tissues suggesting that they are involved in various developmental processes.The in silico biological prediction suggested that CsHDZ genes are active in numerous biological processes such as response to environmental stimuli,developmental activities,metabolic activities,hormonal response,and maturation.Additionally,the clustering of these cis-elements in the promoter region of CsHDZ genes suggested their role in regulating gene expression during different growth stages and environmental stimuli.4.The expression analysis of 11 CsHDZ genes under various abiotic stresses such as heat,cold,drought,and salt stress showed upregulated expression patterns in most of the stress periods.Moreover,the expression analysis under hormones(IAA and ABA)exhibited differential expression trends.Further,under powdery mildew stress the CSHDZ genes showed enhanced expression values except for the CsHDZ08,CsHDZ11,CsHDZ22,and CsHDZ36.5.Transient expression assay of the CsHDZ22 gene in the tobacco epidermis cell was performed.According to the result,the CsHDZ22 resides in the nucleus of the cell.Our results unfolded the biological,molecular,and cellular role of Cucumis sativus CsHDZ genes.In the light of above-mentioned outcomes,it has been deducted that CsHDZ genes in Cucumis sativus genome play an important role in mediating the resistance to various abiotic stresses and powdery mildew stress as well as provide significant clues for functional studies.