Plant Pathology and Microbiology, Statistics
Journal or Book Title
Molecular Plant-Microbe Interactions
Nonspecific recognition of pathogen-derived general elicitors triggers the first line of plant basal defense, which in turn, preconditions the host towards resistance or susceptibility. To elucidate how basal defense responses influence the onset of Mla (mildew resistance locus a)-specified resistance, we performed a meta-analysis of GeneChip mRNA expression for 155 basal defense-related genes of barley (Hordeum vulgare) challenged with Blumeria graminis f. sp. hordei, the causal agent of powdery mildew disease. In plants containing the fast-acting Mla1, Mla6, or Mla13 alleles, transcripts hyper-accumulated from 0 to 16 h after inoculation (hai) in both compatible and incompatible interactions. Suppression of basal defense-related transcripts was observed after 16 hai only in compatible interactions, whereas these transcripts were sustained or increased in incompatible interactions. By contrast, in plants containing wild-type and mutants of the delayed-acting Mla12 allele, an early hyper-induction of transcripts from 0 to 8 hai was observed, but the expression of many of these genes is markedly suppressed from 8 to 16 hai. These results suggest that the inhibition of basal defense facilitates the development of haustoria by the pathogen, consequently delaying the onset of host resistance responses. Thus, we hypothesize that the regulation of basal defense influences host-cell accessibility to the fungal pathogen and drives allelic diversification of gene-specific resistance phenotypes.
This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 2006.
Caldo, Rico A.; Nettleton, Dan; Peng, Jiqing; and Wise, Roger P., "Stage-Specific Suppression of Basal Defense Discriminates Barley Plants Containing Fast- and Delayed-Acting Mla Powdery Mildew Resistance Alleles" (2006). Statistics Publications. 211.