Functional Analysis Of GhPNP1and GhRAX3 Enhances Drought Tolerance In Cotton

Cotton is the most important cash crop around of the world.since cotton is widely planted in arid and semi-arid regions,so that water supply shortage has become one of the major limiting factors affecting cotton yield and quality,that has impact on growth of cotton agricultural economy.it is very important to solve the drought damage to the crops actively.With the deepening of modern agricultural technology research in genetic and molecular level,the study of stress resistance gene has become the main direction of our resolve to abiotic stress.Plant defense-related genes is mainly divided into five categories: namely NAC transcription factor,bZIP transcription factors,AP2 / ERF transcription factor,WRKY transcription factor,and MYB(v-myb avianmyeloblastosis viral oncogene homolog)Transcription factor,they are able to play a key role in plant disease resistance and defense responses regulatory process.GhRAX3 is drought-induced gene expression GbMYB5 have genetic relationship,studies have shown that the gene MYB class family is critical to environmental stresses on plant response.The GhPNP1 gene encoded protein is widely distributed in the PNP category of biological cells involved in homeostasis important intracellular protein molecule,domestic and overseas on cotton in the physiological mechanism of PNP-like protein has not been reported.The virus induced gene silence vector was constructed and the silenced cotton plants were obtained.PEG simulating drought stress treatment was used to determine the drought tolerance of silenced cotton plants and test the several physiological index related to stress tolerance,such as water loss rate,relative water content,MDA content,T-AOC level and electrolyte leakage in silenced cotton plants.on the basis of previous studies,the analysis of the gene after GhPNP1 and GhRAX3 gene silenced using gene silencing Austrian upland cotton 3503.silenced after 25 days with 18% PEG(polyethylene glycol 6000)nutrient solution GhPNP1 and GhRAX3 silenced and empty vector plant.We found that around GhPNP1 treatment group and empty vector gene silencing significantly different plants,wilting silent group of serious,GhRAX3 silence group plants also appeared the same phenotype,indicating GhPNP1 and GhRAX3 genes induced in response to drought stress,there is a certain correlation between drought resistance plants.Using physiological and biochemical parameters deeply measured on GhPNP1 and GhRAX3 gene analysis.First detected cotton plants GhPNP1 and GhRAX3 geneexpression is induced in response under the drought tolerance,in 18%(v / v)PEG6000 induction treatment for 0.5 h GhRAX3 that is significantly upregulated 5 fold increase in expression after 48 h up to 33 times.GhPNP1 expresses in roots,stems and leaves,the expressing amount in stem is higher,as expressed in the root volume of 1.8times.Unified to the seedling age of 25 days of GhPNP1 and GhRAX3 silent group and empty vector group of cotton plants and wild type not silence plants,18% PEG treatment for 36 hours respectively,Sampling every 8 hours,Determination of water loss rate,relative water content and T-AOC(total antioxidant capacity,including SOD,POD,etc.),ion leakage rate in leaf and plant physiological indexes related to plant.Experiments show that the drought resistance of cotton plant significantly reduced after the silencing of gene GhPNP1 and GhRAX3.In dry conditiongs,the MDA content,ion leakage rate,leaf water loss rate of plants silence is significantly higher than wild type cotton plants;The silence of the plant total antioxidant capacity T-AOC,relative water content was significantly lower than control plants not silence.This study from cotton in cloning an R2R3 MYB-a plant natriuretic peptides an d encoding genes,through the analysis of the function of the two genes as well as a va riety of gene silencing after drought stress treatment associated with the physiological and biochemical and phenotypic observation to determine the drought resistance funct ion of GhPNP1 and GhRAX3 genes.GhPNP1 and GhRAX3 raised expression induce d by drought stress,silence after the drought tolerance of plants to reduce.Speculation GhPNP1 and GhRAX3 may through the downstream signaling pathways involved in cotton of drought stress,the effect of drought stress on the drought tolerance of cotton is adjustment.