Molecular Cloning Of Gossypium Hirsutum Sucrose Non-fermenting1-related Protein Kinases2GhSnRK2Gene And Its Functional Analysis

Abiotic stress has been responsible for the reduction in yield of most major crop plant worldwide; Plants are regularly exposed to changes in environmental conditions which they perceive as stresses when it becomes detrimental. However, the occurrence of abiotic stress response in plants metabolism, efficiency and sustainability is attaining substantial significance in the contemporary world. Initiation of abiotic stress in plant activate some initial sensors, which then activate protein signaling pathways, resulting in stress-responsive gene expression and physiological changes. Continuous exposure to these abiotic stresses results in altered metabolism and damage to biomolecules. Plants develop defense mechanisms to tolerate these stresses by upregulation of enzymatic and non-enzymatic antioxidants, compatible solutes and osmolytes molecules. However, the use of modern genetics approaches in effectively dealing with abiotic stress complications has been the major focus of plant molecular biologists.In the present study, expression vector pCAMBIA2301, that carries GhSnRK2gene, was transformed into Arabidopsis thaliana by Agrobacterium tumifascen GV3101mediated transformation. About40resistant transgenic plants were obtained. RT-PCR analyses showed that GhSnRK2gene had been integrated into the Arabidopsis genome of the transgenic plants and was well expressed in offspring seed of different transgenic lines. Subcellular localization of GhSnRK2-GFP protein revealed that, green fluorescent protein (GFP) signals were localized in the nuclei. In contrast to wild-type plants, the transgenic plants overexpressing GhSnRK2showed increased tolerance to drought, cold, abscisic acid and salt stress, suggesting that GhSnRK2acts as a positive regulator in response to cold and drought stress. GhSnRK2gene was induced by10%PEG treatment. Plants overexpressing GhSnRK2revealed evidence of reduced water loss, elevated relative water content and proline accumulation. Tissue specificity analysis revealed that GhSnRK2gene is abundantly expressed in the root. Under normal and stressed conditions, stress inducible genes; RD29A, RD29B, P5CS1, ABI3, CBF1and ABI5showed increased expression level in the GhSnRK2overexpressed plants than Wild-type. Virus induced gene silencing was further used to elucidate the function of GhSnRK2gene in cotton plants. It was observed from the result that transcript level of GhSnRK2gene was downregulated in VIGS plant. Drought stress assay demonstrated that silencing GhSnRK2gene alleviated drought tolerance in cotton plant. Hence, VIGS technique can inevitably be used as an effective means to study gene function by knocking down expression of distinctly expressed genes. This research suggested that through gene manipulation approaches, inception of GhSnRK2gene functions will permit enhancement of plant tolerance to abiotic stress...