Function Analysis Of Phytase Gene AtMINPP In Arabidopsis

Multiple inositol polyphosphate phosphatase(MINPP) is the currently known phytase which can hydrolyze the phytic acid, and it has been detected commonly exists in bacteria, plants and animals.In plants, MINPP plays a pivotal role in many processes, including stress responses, hormone effects,signal conduction. In order to carry out an in-depth study on the physiological functions of MINPP plays in plants, an homologization gene AtMINPP in Arabidopsis thaliana was analyzed through applying bioinformatics. The analysis of AtMINPP defected mutant atminpp shown that AtMINPP plays an important regulatoy role in many aspects, including growth,development,and signal response. An initial research on the functions of AtMINPP is carried out in this paper, the results are shown as follows:1,AtMINPP consists of 11 exons and encodes 487 amino acids, and it contains the conservative sequence RHGXRXP of signature heptapeptide of histidine phosphatases(HAP) and HAE active site motif. Meanwhile, the gene chip expression spectrum analysis shows that AtMINPP is regulated by many kinds of hormones and environment stress signals. The AtMINPP prokaryotic expression vector was constructed in this paper, and the analysis demostrates that it has the maximum solubility expression level of the interest protein in Transetta (DE3) host bacterium.2, Through analyzing the root system growing phenotype of wild type and mutant atminpp, it can be found that the mutant axial root was comparatively shorter. Then the mutant atminpp phenotype was recovered closely to wild type by overexpressed AtMINPP, which indicated that it was induced by the defection of this gene. Meanwhile, the analysis of GUS report gene expressed which driven by AtMINPP promoter region shown that AtMINPP was peculiarly expressed in root at the initial stage of germination. It reveals that AtMINPP has participated in the growth and development in the process of regulating the root system.3,The rosette leaf phenotype of mutant atminpp obviously generated curl and shrink after 2 weeks in soil culture, and then it became fairly dwarf and emaciate after bolting. The rosette leaf and stock phenotype of mutant atminpp was recovered,and it was unfolding, healthy and strong, which is closely to the wild type by overexpressed AtMINPP. It indicated that AtMINPP has participated in the growth and development in the process of regulating ground plant.4, A further research idicated that mutant atminpp shown more insensitivity to IAA than that to the wild type.The elongate axial root of wild type can be obviously inhibited than that of mutant atminpp from 10 nM to 100 nM IAA. It indicated that AtMINPP mediates the response of the plant to IAA signal, and the phenotype generated by mutant atminpp may relate to the changes in response regulation of IAA signal.