Transcriptomic profilling of sweet basil (Ocimum basilicum) downy mildew (Peronospora belbahrii) infection

Applying a metatranscriptomic analysis pipeline (Guo et al. 2016 Frontiers in Plant Science), we are the first to analyze the host-pathogen metatranscriptome of the basil downy mildew system. RNA-sequencing technology was utilized to gain access to the full array of expressed transcripts from both O. basilicum and P. belbahrii. This RNA-seq workflow has allowed us to identity nearly 3,000 candidate P. belbahrii genes expressed in planta, as well as 1,267 and 2,798 candidate O. basilicum genes induced or suppressed respectively under P. belbahrii infection (five days post inoculation). Up-regulated candidate genes are highly enriched for biological processes such as biotic and abiotic stress responses whereas down-regulated genes are enriched for metabolism and photosynthesis, suggesting that basil plants actively respond to pathogen infection with transcriptome reprogramming. RNAseq data were generated from O. basilicum plants either uninfected or infected with P. belbahrii at 5 days post inoculation.