Effects of urate, a natural inhibitor of peroxynitrite-mediated toxicity, in the response of Arabidopsis thaliana to the bacterial pathogen Pseudomonas syringae.
Urate, a natural peroxynitrite scavenger, has been used to investigate the possible role of peroxynitrite during plant-pathogen interactions. Urate greatly reduced lesion formation in Arabidopsis leaves treated with an abiotic peroxynitrite-generating system or with a peroxynitrite solution, indicating that it can act as an effective scavenger in planta. In the interaction with the avirulent Pseudomonas syringae pv. phaseolicola (avrRPM1+), cell death in the inoculated area was strongly reduced by urate, without compromising disease resistance. In contrast, urate promoted discrete cell death in response to an isogenic Pseudomonas syringae (avrRPM1-), which did not trigger an HR when inoculated alone, and it induced resistance and arrest of pathogen growth. Scavenging of peroxynitrite did not modify the response of Arabidopsis to an avirulent strain of Xanthomonas campestris pv campestris, that showed a high resistance to NO and peroxynitrite. Our data indicate that peroxynitrite plays a significant role in the responses of plants to Pseudomonas syringae.
Alamillo
J M
JM
Laboratorio de Bioquímica, Departamento de Biotecnología, UPM, E.T.S. Ingenieros Agrónomos, E-28040 Madrid, Spain.
García-Olmedo
F
F
D017360:Arabidopsis / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*; D029681:Arabidopsis Proteins; D015152:Blotting, Northern; D016923:Cell Death; D009566:Nitrates / Q000037:antagonists & inhibitors* / Q000633:toxicity; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010544:Peroxidases / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics; D011549:Pseudomonas / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity*; D018749:RNA, Plant / Q000032:analysis; D014527:Uric Acid / Q000378:metabolism / Q000494:pharmacology*; D014774:Virulence; D016959:Xanthomonas campestris / Q000472:pathogenicity
D029681:Arabidopsis Proteins; D009566:Nitrates; D020030:Nitric Oxide Donors; D010940:Plant Proteins; D018749:RNA, Plant; C095014:RPM1 protein, Arabidopsis; D009599:Nitroprusside; C039642:peroxynitric acid; D014527:Uric Acid; D009569:Nitric Oxide; D010544:Peroxidases