Dual RNA sequencing reveals the transcriptomic and cellular response of Cannabis sativa to infection by the fungal pathogen Sclerotinia sclerotiorum

Known to infect more than 600 plant species worldwide, Sclerotinia sclerotiorum is a necrotrophic fungal pathogen, and the causative agent of white mold. With recent infection reports documented across North America, Cannabis sativa is known to be susceptible to Sclerotinia infection. Resulting from legal constraints associated with C. sativa, little is known about the Cannabis-Sclerotinia pathosystem, particularly in how the plant responds to pathogen attack at the cellular and molecular levels. Our anatomical study revealed initial infection and degradation of the epidermis and cortical parenchyma, followed by widespread infection of the vascular phloem. Dual RNA sequencing of the C. sativa cola provided a detailed transcriptomic profile of this pathosystem directly at the site of infection over time. Differential gene expression analysis revealed large-scale transcriptional shifts resulting from rapid infection. Gene ontology term enrichment identified processes associated with plant defense and signal transduction cascades during C. sativa infection while processes associated with redox control and sugar catabolism were enriched in the S. sclerotiorum pathogen. Taken together, this study revealed transcriptional reprogramming in both the host plant and fungal pathogen associated with floral infection in space and time.