title: Rewiring mitogen-activated protein kinase cascade by positive feedback confers potato blight resistance.
abstract: Late blight, caused by the notorious pathogen Phytophthora infestans, is a devastating disease of potato (Solanum tuberosum) and tomato (Solanum lycopersicum), and during the 1840s caused the Irish potato famine and over one million fatalities. Currently, grown potato cultivars lack adequate blight tolerance. Earlier cultivars bred for resistance used disease resistance genes that confer immunity only to some strains of the pathogen harboring corresponding avirulence gene. Specific resistance gene-mediated immunity and chemical controls are rapidly overcome in the field when new pathogen races arise through mutation, recombination, or migration from elsewhere. A mitogen-activated protein kinase (MAPK) cascade plays a pivotal role in plant innate immunity. Here we show that the transgenic potato plants that carry a constitutively active form of MAPK kinase driven by a pathogen-inducible promoter of potato showed high resistance to early blight pathogen Alternaria solani as well as P. infestans. The pathogen attack provoked defense-related MAPK activation followed by induction of NADPH oxidase gene expression, which is implicated in reactive oxygen species production, and resulted in hypersensitive response-like phenotype. We propose that enhancing disease resistance through altered regulation of plant defense mechanisms should be more durable and publicly acceptable than engineering overexpression of antimicrobial proteins.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Yamamizo
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kuchimura
authors.forename: Akira
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Shinpei
authors.initials: S
authors.lastname: Katou
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Kawakita
authors.forename: Jonathan D G
authors.initials: JD
authors.lastname: Jones
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Doke
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yoshioka
mesh_terms: D017930:Genes, Reporter; D007113:Immunity, Innate; D020935:MAP Kinase Signaling System; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D010838:Phytophthora / Q000472:pathogenicity; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D011198:Solanum tuberosum / Q000201:enzymology / Q000235:genetics* / Q000382:microbiology; D013729:Terpenes / Q000737:chemistry / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics; D015854:Up-Regulation
chemical_list: D010940:Plant Proteins; D013729:Terpenes; D020928:Mitogen-Activated Protein Kinases; C106405:SA-induced protein kinase; D020929:Mitogen-Activated Protein Kinase Kinases