ABSTRACT: Comparative genomics including the basal pathogen Peronospora belbahrii reveal common evolutionary patterns and the monophyly of downy mildews in a paraphyletic Phytophthora
Project description:Basil downy mildew (BDM) caused by Peronospora Belbahrii leads to losses in sweet basil cultivation across the world. Though resistant cultivars of basil exist, the formation of sterile offspring and the introduction of unwanted phenotypic and chemotypic traits slows breeding. Previous work by the Simon lab at Rutgers University identified pair of sweet basil cultivars; one resistant to BDM, MRI, and one susceptible, SB22. They predicted that three genes in MRI confer increased BDM resistance. RNA from infected MRI and SB22 plants was harvested during the first 3 days of infection at 4 timepoints in order to capture as many early phases of plant-pathogen interaction as possible. The goal is to develop resistance markers for use in breeding experiments.
Project description: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.
