Differential activation of defense-related genes in susceptible and resistant pepper cultivars infected with Phytophthora capsici
Silvar. C Merino. F Diaz. J
Journal of Plant Physiology ; 2008 [Vol.165] Pages:1120-1124
Abstract
This study investigated the expression pattern of genes encoding for a basic PR-1 protein, a basic b-1,3-glucanase, a peroxidase, and a sesquiterpene cyclase involved in defense responses in three pepper cultivars with different levels of resistance to Phytophthora capsici. All genes were up-regulated in infected stems of the pepper cultivars, with expression being detected 8 h post-inoculation. mRNA levels of these genes increased markedly by 24 h post-inoculation, and maximal induction levels were observed for the PR-1 and sesquiterpene cyclase genes. PR-1, peroxidase, and sesquiterpene genes were always expressed at higher levels in resistant cultivars than in the susceptible cultivar, although up-regulation was observed in both, suggesting that the differences between these pepper genotypes in susceptibility and resistance are a matter of the timing and magnitude of the defense response.
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