Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: The Arabidopsis pop2-1 mutant reveals the involvement of GABA transaminase in salt stress tolerance | Renault et al. BMC Plant Biology 2010 10 20 http 1471-2229 10 20 BMC Plant Biology RESEARCH ARTICLE Open Access The Arabidopsis pop2-1 mutant reveals the involvement of GABA transaminase in salt stress tolerance 2 1 2 1 Hugues Renault Valérie Roussel Abdelhak El Amrani Matthieu Arzel David Renault Alain Bouchereau Carole Deleu 1 Abstract Background GABA y-aminobutyric acid is a non protein amino acid that has been reported to accumulate in a number of plant species when subjected to high salinity and many other environmental constraints. However no experimental data are to date available on the molecular function of GABA and the involvement of its metabolism in salt stress tolerance in higher plants. Here we investigated the regulation of GABA metabolism in Arabidopsis thaliana at the metabolite enzymatic activity and gene transcription levels upon NaCl stress. Results We identified the GABA transaminase GABA-T the first step of GABA catabolism as the most responsive to NaCl. We further performed a functional analysis of the corresponding gene POP2 and demonstrated that the previously isolated loss-of-function pop2-1 mutant was oversensitive to ionic stress but not to osmotic stress suggesting a specific role in salt tolerance. NaCl oversensitivity was not associated with overaccumulation of Na and Cl- but mutant showed a slight decrease in K . To bring insights into POP2 function a promoter-reporter gene strategy was used and showed that POP2 was mainly expressed in roots under control conditions and was induced in primary root apex and aerial parts of plants in response to NaCl. Additionally GC-MS- and UPLC-based metabolite profiling revealed major changes in roots of pop2-1 mutant upon NaCl stress including accumulation of amino acids and decrease in carbohydrates content. Conclusions GABA metabolism was overall up-regulated in response to NaCl in Arabidopsis. Particularly GABA-T was found to play a pivotal function and impairment .
