title: Rice OsPAD4 functions differently from Arabidopsis AtPAD4 in host-pathogen interactions.
abstract: The extensively studied Arabidopsis phytoalexin deficient 4 (AtPAD4) gene plays an important role in Arabidopsis disease resistance; however, the function of its sequence ortholog in rice is unknown. Here, we show that rice OsPAD4 appears not to be the functional ortholog of AtPAD4 in host-pathogen interactions, and that the OsPAD4 encodes a plasma membrane protein but that AtPAD4 encodes a cytoplasmic and nuclear protein. Suppression of OsPAD4 by RNA interference (RNAi) increased rice susceptibility to the biotrophic pathogen Xanthomonas oryzae pv. oryzae (Xoo), which causes bacteria blight disease in local tissue. OsPAD4-RNAi plants also show compromised wound-induced systemic resistance to Xoo. The increased susceptibility to Xoo was associated with reduced accumulation of jasmonic acid (JA) and phytoalexin momilactone A (MOA). Exogenous application of JA complemented the phenotype of OsPAD4-RNAi plants in response to Xoo. The following results suggest that OsPAD4 functions differently than AtPAD4 in response to pathogen infection. First, OsPAD4 plays an important role in wound-induced systemic resistance, whereas AtPAD4 mediates systemic acquired resistance. Second, OsPAD4-involved defense signaling against Xoo is JA-dependent, but AtPAD4-involved defense signaling against biotrophic pathogens is salicylic acid-dependent. Finally, OsPAD4 is required for the accumulation of terpenoid-type phytoalexin MOA in rice-bacterium interactions, but AtPAD4-mediated resistance is associated with the accumulation of indole-type phytoalexin camalexin.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Yinggen
authors.initials: Y
authors.lastname: Ke
authors.forename: Hongbo
authors.initials: H
authors.lastname: Liu
authors.forename: Xianghua
authors.initials: X
authors.lastname: Li
authors.forename: Jinghua
authors.initials: J
authors.lastname: Xiao
authors.forename: Shiping
authors.initials: S
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism / Q000494:pharmacology; D060467:Disease Resistance / Q000235:genetics; D004224:Diterpenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D054884:Host-Pathogen Interactions; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D054883:Oxylipins / Q000378:metabolism / Q000494:pharmacology; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D010940:Plant Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D011523:Protoplasts / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020156:Salicylic Acid / Q000378:metabolism / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D013314:Stress, Mechanical; D014974:Xanthomonas / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D004224:Diterpenes; D008565:Membrane Proteins; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D049452:Green Fluorescent Proteins; C116023:momilactone A; C011006:jasmonic acid; D002265:Carboxylic Ester Hydrolases; C400766:PAD4 protein, Arabidopsis; D020156:Salicylic Acid
keywords: Oryza sativa; Xanthomonas oryzae; bacterial blight; bacterial streak; jasmonate; systemic resistance