Expression Of Potassium Transport Protein Gene Family And Characteristic Analysis Of Roots Potassium Uptake Transport Under Drought Stress In Apple

Potassium(K+) is one of important mineral nutrition elements involved in plant physiological processes, and affects the yield and quality of plant. K absorption capacity of plant roots is not only affected by the effective concentration of potassium in the soil, but also is regulated by the highly soil moisture conditions. To analysis the apple K+ uptake characteristics under drought condition, this article screenes the apple K transport protein genes from the level of gene, and analyzes their organs expression characteristics. In water experiment conditions, using the Non- invasive Micro- test Technique to research on the physical growth and the influence of the root K +, H + flow under drought(15% PEG) and low potassium stress. The main results as follows:1. Through the existed apple genome database we screening K + transport protein genes,analyzing the phylogenetic relationship, and using the q RT- PCR detecting the expression characteristics of fruit development process and various organs and tissues in M.hupehensis(pamp) Rehd. Results show there are 65 K + transport protein genes in the apple, including CHX family genes(33), HAK family genes(24), HKT family gene(1) and KEA family genes(7).These genes are highly homologous with Arabidopsis thaliana K+transporter genes.Chromosomal localization found that these K+ transporter genes were distributed in the thirteen of seventeen apple chromosomes unevenly. Quantitative expression analysis showed that most of the K+transporter genes had differential expression pattern. 32 genes had higher expression abundance in root while 12 genes in mature leaves, 11 genes in shoot tips and 19 genes in fruit. The results of study provides the basic data to reveal the apple K + transport protein gene function.2. Under drought stress(15% PEG), through the comprehensive physiological datas,results of leaf relative water content and K + content show that M.hupehensis(pamp)Rehd. is drought sensitive plant, drought stress affect the absorption and utilization of K+, and their growth and development; Under low potassium stress(K: 0.05 m M), root growth is restrained through the comprehensive physiological datas,results of leaf relative water contentand K+content show that K+absorb ability of M.hupehensis(pamp) Rehd.root is improved,K + and H + flow test results also support the judgment.3. Under drought stress, the level of K+ absorption and H+ efflux in M.hupehensis(pamp)Rehd. root is reduced in different degree, when the channel protein inhibitors of Cs Cl and PM H + ATPase inhibitor of Orthovanadate role in it, the later one more inhibition K +absorption and H + efflux, and real-time quantitative PCR results showe that 6 K + transport protein genes expression increase. MDP0000247022 comes from the family of kups responses most obviously. We analysis K+ transport protein genes are induced activation under drought stress, K + / H + reverse transport proteins mainly mediated root K + absorption;M.hupehensis(pamp) Rehd.control group and the low potassium stress group are similar with reduced level of K+ absorption and H+ efflux in roots in Cs Cl and vanadate inhibitors,which reveals K + channel proteins and transporters on the root of K + absorption have the same contribution.