The effects of infection with wild-type or mutant cucumber mosaic virus on the Arabidopsis transcriptome

The cucumber mosaic virus (CMV) 2b counter-defense protein disrupts plant antiviral mechanisms mediated by RNA silencing and salicylic acid (SA). Using NASC ATH-1 microarrays to investigate defensive gene expression in 2b-transgenic Arabidopsis thaliana plants we found that, surprisingly, 2b inhibited expression of few SA-regulated genes and in some instances enhanced the effect of SA on certain genes. Strikingly, the 2b protein inhibited changes in the expression of 90% of genes regulated by jasmonic acid (NASCARRAYS-415: Lewsey et al. Molec. Plant-Microbe Interact. vol. 23, in press). We will extend this work to understand the effects of the 2b protein on plant gene expression during an authentic viral infection. By comparing the effects on the transcriptome of infection by wild-type CMV and the 2b gene deletion mutant, CMV2b, we will reveal not only the influence of the 2b protein but also the effects of its interactions with other viral gene products (and the process of infection itself), on the host transcriptome.

9