Developmentally induced changes in the sclerotial proteome of Sclerotinia sclerotiorum

Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic fungal phytopathogen with a broad host range. The fungus produces sclerotia, long-term survival and dissemination structures that serve as the primary source of inoculum during seasonal crop infection cycles. Herein, we report the first proteomics-based analysis of sclerotial development. A total of 88 protein spots were observed by two-dimensional gel electrophoresis (2-DE) to exhibit significant temporal differences in abundance at three representative stages of sclerotial development, and the identities of these proteins were established using LC-MS/MS. The proteins were classified into several functional categories including metabolism, energy, transcription and protein fate, cell defense, differentiation, and proteins with as of yet unknown functions. In addition, proteins involved in the process of melanogenesis were found to be differentially abundant during sclerotial development, as was the development-specific protein, Ssp. This study provides a starting point towards achieving a comprehensive understanding of the proteins and molecular events associated with sclerotial development.