Abstract
Mature plant of N. benthamiana, a model Solanaceae plant, is resistant against potato blight pathogen P. infestans, whereas young plant is susceptible to this pathogen. Analysis with virus-induced gene silencing (VIGS) revealed that genes for SGT1 and HSP90 (required for accumulation of R-proteins), Gβ and RAC (trimetric and small G proteins), ICS1 (salicylic acid biosynthesis), EIN2 (ethylene signaling factor), and ethylene-regulated EAS and EAH (phytoalexin biosynthesis) are essential for resistance of N. benthamiana to P. infestans. In this study, we employed VIGS-based screening to isolate novel defense-related genes from N. benthamiana. Leaves of N. benthamiana were treated with INF1, an elicitor protein derived from P. infestans, for 1 to 12 hours and cDNA for INF1-induced genes were enriched by subtractive hybridization. Resultant cDNA was normalized and cloned into VIGS vector pTV00 to generate VIGS library. With this library, we isolated VIGS-induced N. benthamiana plants showing stunting of plant, chlorosis or spontaneous cell death in leaves. We also report the results of screening for gene-silenced plants showing reduced resistance to P. infestans.
