title: Plant Aquaporin AtPIP1;4 Links Apoplastic H2O2 Induction to Disease Immunity Pathways.
abstract: Hydrogen peroxide (H2O2) is a stable component of reactive oxygen species, and its production in plants represents the successful recognition of pathogen infection and pathogen-associated molecular patterns (PAMPs). This production of H2O2 is typically apoplastic but is subsequently associated with intracellular immunity pathways that regulate disease resistance, such as systemic acquired resistance and PAMP-triggered immunity. Here, we elucidate that an Arabidopsis (Arabidopsis thaliana) aquaporin (i.e. the plasma membrane intrinsic protein AtPIP1;4) acts to close the cytological distance between H2O2 production and functional performance. Expression of the AtPIP1;4 gene in plant leaves is inducible by a bacterial pathogen, and the expression accompanies H2O2 accumulation in the cytoplasm. Under de novo expression conditions, AtPIP1;4 is able to mediate the translocation of externally applied H2O2 into the cytoplasm of yeast (Saccharomyces cerevisiae) cells. In plant cells treated with H2O2, AtPIP1;4 functions as an effective facilitator of H2O2 transport across plasma membranes and mediates the translocation of externally applied H2O2 from the apoplast to the cytoplasm. The H2O2-transport role of AtPIP1;4 is essentially required for the cytoplasmic import of apoplastic H2O2 induced by the bacterial pathogen and two typical PAMPs in the absence of induced production of intracellular H2O2 As a consequence, cytoplasmic H2O2 quantities increase substantially while systemic acquired resistance and PAMP-triggered immunity are activated to repress the bacterial pathogenicity. By contrast, loss-of-function mutation at the AtPIP1;4 gene locus not only nullifies the cytoplasmic import of pathogen- and PAMP-induced apoplastic H2O2 but also cancels the subsequent immune responses, suggesting a pivotal role of AtPIP1;4 in apocytoplastic signal transduction in immunity pathways.
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Tian
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Ji
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Junyi
authors.initials: J
authors.lastname: Xie
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Qinglei
authors.initials: Q
authors.lastname: Qiu
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China dshen@njau.edu.cn hsdong@njau.edu.cn.
authors.forename: Dan
authors.identifier: 0000-0003-4739-1814
authors.initials: D
authors.lastname: Shen
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China dshen@njau.edu.cn hsdong@njau.edu.cn.
authors.forename: Hansong
authors.identifier: 0000-0003-2820-9159
authors.initials: H
authors.lastname: Dong
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D060467:Disease Resistance / Q000276:immunology; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D000069452:Pathogen-Associated Molecular Pattern Molecules; D010935:Plant Diseases / Q000276:immunology*; D057865:Plant Immunity; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000472:pathogenicity; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics
chemical_list: D020346:Aquaporins; D029681:Arabidopsis Proteins; C000611205:PIP1;4 protein, Arabidopsis; D000069452:Pathogen-Associated Molecular Pattern Molecules; D006861:Hydrogen Peroxide