The proteome of the phytopathogenic fungus Sclerotinia sclerotiorum.

In order to gain a more thorough understanding of the phytopathogenic fungus, Sclerotinia sclerotiorum, we initiated a proteome-level study of the fungal mycelia and secretome. To our knowledge, this is the first comprehensive proteome-level study of this fungus. Extracted mycelial proteins and secreted proteins collected from liquid culture were separated using 2-DE and annotated following ESI-q-TOF MS/MS. Fifty-two secreted proteins were reproducibly present in three biological replicates and 18 of them were identified by MS/MS while over 200 mycelial proteins were reproducibly present in three independent extractions and approximately half of them were identified. Many of the annotated secreted proteins were cell wall degrading enzymes that had been previously identified as pathogenicity or virulence factors of S. sclerotiorum; however, the contribution to the virulence of S. sclerotiorum of one of the identified proteins, alpha-L-arabinofuranosidase, is yet to be analyzed. Furthermore, previous comprehensive EST studies did not detect the presence of the alpha-L-arabinofuranosidase transcript, which demonstrates the merit of performing proteome-level research. All of the secreted and mycelial proteins identified were functionally classified, and the known and proposed roles in disease initiation or progression for many of them are discussed.