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Correlation of defense gene induction defects with powdery mildew susceptibility in Arabidopsis enhanced disease susceptibility mutants
Author(s) -
Reuber T. Lynne,
Plotnikova Julia M.,
Dewdney Julia,
Rogers Elizabeth E.,
Wood William,
Ausubel Frederick M.
Publication year - 1998
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1998.00319.x
Subject(s) - powdery mildew , mutant , hla b , arabidopsis , biology , gene , genetics , botany , allele
Summary We investigated the relative importance of specificArabidopsis thalianagenes in conferring resistance to bacterial versus fungal pathogens. We first developed a pathosystem involving the infection ofArabidopsisaccession Columbia with a virulent isolate of the obligate biotrophic fungal pathogenErysiphe orontii. E. orontiielicited the accumulation of mRNAs corresponding to the defense‐related genesPR1, BGL2 (PR2), PR5 and GST1, but did not elicit production of the phytoalexin camalexin or the accumulation of defensin (PDF1.2) or thionin (THI2.1) mRNAs. We tested a set of 15 previously isolatedArabidopsisphytoalexin deficient(pad),non‐expresser ofPR (npr) andenhanced disease susceptibility(eds)mutants that are more susceptible toPseudomonas syringaefor their susceptibility toE. orontii.Four of these mutants (pad4–1, npr1–1, eds5–1 anda doublenpr1–1 eds5–1mutant) as well asArabidopsislines carrying anahGtransgene exhibited enhanced susceptibility toE. orontiiand reduced levels ofPRgene expression.Comparison of thePRgene induction patterns in response toE. orontiiin the various mutants and in thenahGtransgenics suggests the existence ofNPR1‐independent salicylate‐dependent andNPR1‐independent salicylate‐independent defense gene activation pathways. Eleven otheredsandpadmutants did not show measurable enhanced susceptibility toE. orontii, suggesting that these mutants are defective in factors that are not important for the limitation ofE. orontiigrowth.