title: Alpha-picolinic acid, a fungal toxin and mammal apoptosis-inducing agent, elicits hypersensitive-like response and enhances disease resistance in rice.
abstract: Alpha-picolinic acid (PA), a metabolite of tryptophan and an inducer of apoptosis in the animal cell, has been reported to be a toxin produced by some of plant fungal pathogens and used in screening for disease resistant mutants. Here, we report that PA is an efficient apoptosis agent triggering cell death of hypersensitive-like response in planta. Confirmed by Fluorescence Activated Cell Sorter (FACS), rice suspension cells and leaves exhibited programmed cell death induced by PA. The PA-induced cell death was associated with the accumulation of reactive oxygen species that could be blocked by diphenylene iodonium chloride, indicating that the generation of reactive oxygen species was NADPH-oxidase dependent. We also demonstrated the induction of rice defense-related genes and subsequent resistant enhancement by PA against the rice blast fungus Magnaporthe grisea. Hence, it was concluded that the PA-stimulated defense response likely involves the onset of the hypersensitive response in rice, which also provides a simple eliciting tool for studying apoptosis in the plant cell.
authors.affiliation: SHARF and National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Hai Kuo
authors.initials: HK
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Bi Zeng
authors.initials: BZ
authors.lastname: Mao
authors.forename: Qun
authors.initials: Q
authors.lastname: Li
authors.forename: Zu Hua
authors.initials: ZH
authors.lastname: He
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D015152:Blotting, Northern; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D007113:Immunity, Innate / Q000187:drug effects; D020082:Magnaporthe / Q000254:growth & development; D009861:Onium Compounds / Q000494:pharmacology; D012275:Oryza / Q000235:genetics / Q000382:microbiology / Q000502:physiology*; D010848:Picolinic Acids / Q000494:pharmacology*; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics; D011523:Protoplasts / Q000737:chemistry / Q000187:drug effects
chemical_list: D004791:Enzyme Inhibitors; D009861:Onium Compounds; D010848:Picolinic Acids; D010940:Plant Proteins; C007517:diphenyleneiodonium; D006861:Hydrogen Peroxide; C030614:picolinic acid