Primary Study On The Function Of Protein Tyrosine Kinase Candidate Genes And The Drought Resistance Of Their Mutants In Arabidopsis Thaliana

Tyrosine reversible phosphorylation of protein catalyzed by PTK (protein tyrosine kinase) and PTP (protein tyrosine phosphatase) plays a important role in cellular signal transduction of animal cell. However, the PTK/PTP signaling cascade has not yet been discovered in plant cells. In recent years, some pharmacological experiments show that tyrosine reversible phosphorylation maybe exist in plant, and take part in plant stress signal transduction. Meanwhile several protein tyrosine phosphatases have been discovered in plant cells, which also indicate possible existence of protein tyrosine kinases in plant cells. In this study, we analyzed the function of PTK candidate gene and their relationship with the drought tolerance of plant in Arabidopsis thaliana, in order to obtain genes related to drought tolerance .Thirty candidate genes encoding protein tyrosine kinase were found in Arabidopsis thaliana by blasting of conserved amino acid sequences of PTK in animal cells. With bioinformatics analysis, some of genes responded to osmotic stress, cold and salt stress in transcriptional level, but not to wound, oxidation and toxic stress. Four genes AT4g23050, AT4g24480, AT4g38470 and AT5g57610 were related to stress adaptation in plant cells, because the stress of osmosis, heat, cold and salt could all induce the expression of these genes.Drought resistant analysis of 47 mutants showed: compared with their wild types, ATlg67890, AT4g38470 and AT5g58950 gene's mutants were more drought resistant; ATlgl6270, ATlgl8160, ATlg73660, ATlg79570, AT2gl7700, AT2g35050, AT3g01490, AT3g06620, AT3g06640, and AT3g22750 gene's mutants were less drought tolerance; and the others were showed no difference. The more scientific drought and heat resistant experiments were done further, their results showed: compared with wild type, AT4g38470 gene's mutants were more drought resistant, but were more sensitive to heat stress.In order to study physiological and biochemical characteristics of proteins encoded by AT4g23050 and AT4g38470, we have constructed two vectors named p426GAL-23050 and p426GAL-38470, which could be expressed in yeast and obtained recombinant protein of AT4g23050.