Comparative transcriptomics reveal conserved modules of plant defence against different pathogens in Strawberry

Strawberry (Fragaria xananassa) is an economically important high-value crop that is susceptible to three most devastating pathogens with different lifestyles - a necrotrophic fungus Botrytis cinerea causing grey mold, a hemibiotrophic oomycete Phytophthora cactorum causing crown/root rot, and a biotrophic fungus Podosphaera aphanis causing powdery mildew. Studies on individual plant-pathogen interactions are only sufficient for developing disease resistant strawberry varieties to a particular pathogen. However, each of these pathogens have the potential to co-infect strawberry at a given point of time. Therefore, understanding how these pathogens manipulate strawberrys defences and how it responds to these pathogens is essential for developing broad-spectrum disease resistant varieties. Here, in the diploid model Fragaria vesca, we performed comparative transcriptome analysis between each of these pathogen infections to identify 501 Common Responsive (CoRe) genes targeted against these pathogens. Furthermore, about 80% of these CoRe set are upregulated upon infection by all three pathogens indicating a similar transcriptional response of F. vesca independent of pathogens lifestyle. These upregulated CoRe set include genes from well-known defence responsive pathways such as calcium and MAP kinase signalling, WRKY transcription factors, pathogenesis-related allergen genes and hormone and terpene biosynthetic genes. These novel insights into F. vescas defences might serve as a basis for engineering plants with broad spectrum resistance.