Role of phosphatidic acid and AGC kinases in plant/microbe interactions and under stress

内生真菌Piriformospora indica是Sebacinales的一种可培养的担子菌，在包括拟南芥在内的许多植物物种的根部定殖，并促进它们的生长、生物量和种子生产。基于对拟南芥突变体的遗传筛选，这些突变体不响应P. indica，我们确定了促进生长所需的激酶级联。该真菌刺激根细胞中磷脂酸（PA）的合成，从而激活3-磷酸肌醇依赖性蛋白激酶1（PDK 1），随后激活氧化信号诱导1（OXI 1）和有丝分裂原激活蛋白激酶3和-6。此外，AGC 2 -2，OXI 1的同源物，是生长反应所必需的。在这个提议中，该途径对有益的（P. indica）和致病的（A.将分析植物/微生物相互作用、诱导的系统抗性和非生物胁迫反应（干旱、盐、寒冷）。将在生物化学和分子水平上分析PA合成或该途径激酶受损的微生物和应力暴露突变体的适应性。比较分析将确定PA-PDK 1-OXI 1/AGC 2 -2信号通路在植物/微生物相互作用和非生物胁迫下的作用。

The endophytic fungus Piriformospora indica, a cultivable basidiomycete of Sebacinales, colonizes the roots of many plant species including Arabidopsis and promotes their growth, biomass and seed production. Based on a genetic screen for Arabidopsis mutants which do not respond to P. indica, we identified a kinase cascade that is required for growth promotion. The fungus stimulates the synthesis of phosphatidic acid (PA) in root cells which activates 3-PHOSPHOINOSITIDE-DEPENDENT PROTEIN KINASE1 (PDK1) followed by OXIDATIVE SIGNAL INDUCIBLE1 (OXI1) and the MITOGEN-ACTIVATED PROTEIN KINASES 3 and -6. Furthermore, AGC2-2, a homolog of OXI1, is required for the growth response. In this proposal, the role of this pathway for beneficial (P. indica) and pathogenic (A. brassica) plant/microbe interactions, induced systemic resistance and abiotic stress responses (drought, salt, cold) will be analysed. The fitness of microbe- and stress-exposed mutants impaired in PA synthesis or kinases of this pathway will be analysed at biochemical and molecular levels. The comparative analysis will define the role of the PA-PDK1- OXI1/AGC2-2 signalling pathway in plant/microbe interactions and under abiotic stress.