Gene expression profiles unique to chile (Capsicum annuum L.) resistant to Phytophthora root rot
Richins. R. D Micheletto. S O’Connell. M. A
Plant Science ; 2010 [Vol.178] Pages:192-201
Abstract
Transcriptome profiling in chile (Capsicum annuum) roots was used to determine those genes with expression profiles correlated with a resistance phenotype to the pathogen, Phytophthora capsici. Two microarrays were generated; a 10K element array printed with cDNAs from a library of transcripts expressed in Criollo de Morelos-334 variety of C. annuum 6 h post-challenge with P. capsici and a 2K element array printed with sequenced cDNA clones selected based on their preliminary patterns of expression. This second array was enriched for clones that were differentially expressed in susceptible (New Mexico 6-4) vs. resistant (CM334) varieties of C. annuum. Gene expression profiles were revaluated at 0, 4 and 24 h post-inoculation. Control treatments included samples collected at 0, 4, and 24 h post-mock-inoculation. In addition to the parental CM334, a resistant backcross line (01-1688) was also used to identify gene expression patterns associated with the resistance phenotype. Based on a principal component analysis, CM334 samples showed the most significant transcription induction at 4 and 24 h post-inoculation, while the predominant variability in the susceptible line was in genes repressed at 24 h. A set of 168 genes with significant changes in expression following P. capsici challenge was identified; of these, 22 were uniquely expressed only in the resistant lines (CM334 or 01-1688). This set of genes represent candidates for further study as markers for recurrent selection programs and as candidate genes for the mechanism of disease resistance.
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