Arabidopsis local resistance to Botrytis cinerea involves salicylic acid and camalexin and requires EDS4 and PAD2, but not SID2, EDS5 or PAD4.
Salicylic acid (SA) is an important regulator of plant defense responses, and a variety of Arabidopsis mutants impaired in resistance against bacterial and fungal pathogens show defects in SA accumulation, perception, or signal transduction. Nevertheless, the role of SA-dependent defense responses against necrotrophic fungi is currently unclear. We determined the susceptibility of a set of previously identified Arabidopsis mutants impaired in defense responses to the necrotrophic fungal pathogen Botrytis cinerea. The rate of development of B. cinerea disease symptoms on primary infected leaves was affected by responses mediated by the genes EIN2, JAR1, EDS4, PAD2, and PAD3, but was largely independent of EDS5, SID2/ICS1, and PAD4. Furthermore, plants expressing a nahG transgene or treated with a phenylalanine ammonia lyase (PAL) inhibitor showed enhanced symptoms, suggesting that SA synthesized via PAL, and not via isochorismate synthase (ICS), mediates lesion development. In addition, the degree of lesion development did not correlate with defensin or PR1 expression, although it was partially dependent upon camalexin accumulation. Although npr1 mutant leaves were normally susceptible to B. cinerea infection, a double ein2 npr1 mutant was significantly more susceptible than ein2 plants, and exogenous application of SA decreased B. cinerea lesion size through an NPR1-dependent mechanism that could be mimicked by the cpr1 mutation. These data indicate that local resistance to B. cinerea requires ethylene-, jasmonate-, and SA-mediated signaling, that the SA affecting this resistance does not require ICS1 and is likely synthesized via PAL, and that camalexin limits lesion development.
Ferrari
Simone
S
Department of Genetics, Harvard Medical School, Massachusetts General Hospital, Boston, MA 02114, USA.
Plotnikova
Julia M
JM
De Lorenzo
Giulia
G
Ausubel
Frederick M
FM
D017360:Arabidopsis / Q000235:genetics / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D020171:Botrytis / Q000187:drug effects / Q000254:growth & development*; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D023082:Defensins; D005030:Ethylenes / Q000096:biosynthesis; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007113:Immunity, Innate / Q000235:genetics; D007211:Indoles / Q000378:metabolism*; D019751:Intramolecular Transferases / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009713:Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism; D054883:Oxylipins; D010650:Phenylalanine Ammonia-Lyase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism* / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013844:Thiazoles / Q000378:metabolism*; D000094162:Phytoalexins; D010453:Peptide Synthases
D029681:Arabidopsis Proteins; D002265:Carboxylic Ester Hydrolases; D003517:Cyclopentanes; D003577:Cytochrome P-450 Enzyme System; D023082:Defensins; D005030:Ethylenes; D007211:Indoles; D019751:Intramolecular Transferases; D026901:Membrane Transport Proteins; D006899:Mixed Function Oxygenases; D009713:Nucleotidyltransferases; D054883:Oxylipins; D010650:Phenylalanine Ammonia-Lyase; D010940:Plant Proteins; D011956:Receptors, Cell Surface; D020156:Salicylic Acid; D013844:Thiazoles; C455514:EDS5 protein, Arabidopsis; C119963:EIN2 protein, Arabidopsis; C102405:camalexin; D000094162:Phytoalexins; C053376:pathogenesis-related proteins, plant; C011006:jasmonic acid; C036216:ethylene; C417307:PAD3 protein, Arabidopsis; C400766:PAD4 protein, Arabidopsis; C058486:isochorismate synthase; C412831:AT2G46370 protein, Arabidopsis; D010453:Peptide Synthases