Potato cDNA microarrays produced by TIGR were demonstrated to be able to cross-hybridize with N. benthamiana mRNA. It provided a powerful tool for gene expression profiling analysis on VIGS N. benthamiana plants. Gene expression profiles of NPK1- and SGT1- silenced plants were analyzed by using 5K cDNA arrays with biological triplicates. A list of differentially expressed genes was obtained and subjected to further analysis. Several genes have already been analyzed by VIGS. Experiments will be repeated using 10K arrays to analyze expression profiling on NPK1- and SGT1-silenced plants before and after TMV challenge, in order to gain more significant and informative data.