The Arabidopsis pi4kβ1,2 mutant is mutated in the phosphatidylinositol 4-kinase(PI4K)β1 and PI4Kβ2 enzymes which are involved in the biosynthesis of phosphatidylinositol 4-phosphate(PI4P),a minor membrane lipid wit...The Arabidopsis pi4kβ1,2 mutant is mutated in the phosphatidylinositol 4-kinase(PI4K)β1 and PI4Kβ2 enzymes which are involved in the biosynthesis of phosphatidylinositol 4-phosphate(PI4P),a minor membrane lipid with important signaling roles.pi4kβ1,2 plants display autoimmunity and shorter roots.Though the pi4kβ1,2 mutant has been extensively characterized,the source of its autoimmunity remains largely unknown.In this study,through a genetic suppressor screen,we identified multiple partial loss-of-function alleles of signal peptide peptidase(spp)that can suppress all the defects of pi4kβ1,2.SPP is an intramembrane cleaving aspartic protease.Interestingly,pi4kβ1,2 plants display enhanced ER stress response and mutations in SPP can suppress such phenotype.Furthermore,reduced ER stress responses were observed in the spp single mutants.Overall,our study reveals a previously unknown function of PI4Kβand SPP in ER stress and plant immunity.展开更多
基金supported by grants to XL from the National Sciences and Engineering Research Council(NSERC)Discovery programthe NSERCCREATE funded Plant Responses To Eliminate Critical Threats(PRoTECT)program,Canada Research Chairs(CRC)the Canadian Foundation for Innovation(CFI),and scholarships to KTD from the Izaak Walton Killam Memorial Fund of the Killam Trusts and The University of British Columbia’s Four Year Fellowship program。
文摘The Arabidopsis pi4kβ1,2 mutant is mutated in the phosphatidylinositol 4-kinase(PI4K)β1 and PI4Kβ2 enzymes which are involved in the biosynthesis of phosphatidylinositol 4-phosphate(PI4P),a minor membrane lipid with important signaling roles.pi4kβ1,2 plants display autoimmunity and shorter roots.Though the pi4kβ1,2 mutant has been extensively characterized,the source of its autoimmunity remains largely unknown.In this study,through a genetic suppressor screen,we identified multiple partial loss-of-function alleles of signal peptide peptidase(spp)that can suppress all the defects of pi4kβ1,2.SPP is an intramembrane cleaving aspartic protease.Interestingly,pi4kβ1,2 plants display enhanced ER stress response and mutations in SPP can suppress such phenotype.Furthermore,reduced ER stress responses were observed in the spp single mutants.Overall,our study reveals a previously unknown function of PI4Kβand SPP in ER stress and plant immunity.
