Project description:Rhizopus delemar is an invasive fungal pathogen, responsible for the frequently fatal disease mucormycosis. Germination, a crucial mechanism by which spores of Rhizopus delemar infect and cause disease, is a key developmental process that transforms the dormant spore state into a vegetative one. Understanding the molecular mechanisms which underpin this transformation may be key to controlling mucormycosis; however, the regulation of germination remains poorly understood. This study describes the transcriptional changes which take place over the course of germination.
Project description:Soft rot or Rhizopus rot, caused by the fungal pathogen Rhizopus stolonifer, is an aggressive postharvest disease that affects many fruit and vegetables. We proposed that R. stolonifer displays a necrotrophic behavior when infecting fruit, actively killing the host tissues to complete its life cycle. We tested this hypothesis by identifying R. stolonifer infection strategies when interacting with four fruit hosts (tomato, grape, strawberry, and plum). First, we generated a complete and highly contiguous genome assembly for R. stolonifer using PacBio sequencing, of 45.02 Mb in size, an N50 of 2.87Mb, and 12,644 predicted loci with protein-coding genes. We then performed a transcriptomic analysis to identify genes preferentially used by R. stolonifer when growing in fruit versus culture media, and then classified these host-related genes into clusters according to their expression patterns across four time points. Based on the expression data, we determined that R. stolonifer deploys infection mechanisms characteristic of necrotrophs, including a suite of oxidases, proteases, and cell wall degrading enzymes, when it is actively breaking down tissues of all four fruit hosts. Better understanding R. stolonifer – fruit host interactions can support better diagnostic tools and efficient management strategies in postharvest.
