The proteome of the phytopathogenic fungusSclerotinia sclerotiorum

Abstract

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.

An optimized microplate assay system for quantitative evaluation of plant cell wall–degrading enzyme activity of fungal culture extracts

“…While the T. reesei enzyme system is quite efficient at degrading pure cellulose, there are opportunities to complement its enzyme systems with novel enzymes from other species. The fact that the plant pathogenic fungi used in this study compared favorably to T. reesei is supported by genomic and proteomic analyses demonstrating that plant pathogenic fungi are rich reservoirs of multiple classes of enzymes involved in cell wall breakdown (Martinez et al, 2008;Paper et al, 2007;Phalip et al, 2005;Yajima and Kav, 2006). Identifying superior species and isolates is an important first step to obtaining novel cellulolytic enzymes.…”

Identification and Characterization of Sclerotinia sclerotiorum NADPH Oxidases

“…Sclerotinia sclerotiorum is an economically important necrotrophic fungal pathogen with a worldwide distribution of more than 400 dicotyledonous host species (42). Included among these hosts are several agriculturally important plants, including soybean, canola, and sunflower (15).…”

Plant Root Secretions and Their Interactions with Neighbors

“…These effectors have been found in the secretome of different oomycetes (Kamoun 2006). Among the secretomes studied on plant pathogenic fungi are those from Fusarium graminearum, and Sclerotinia sclerotiorum (Phalip et al 2005;Yajima and Kav 2006). In F. graminearum secretome, in the presence of Humulus lupulus L. cell wall, were identified 84 proteins (Phalip et al 2005) which 45% of them are actually involved in cell wall degradation and the most abundant proteins were cellulases, endoglucanases, proteases, and chitinases.…”

“…In F. graminearum secretome, in the presence of Humulus lupulus L. cell wall, were identified 84 proteins (Phalip et al 2005) which 45% of them are actually involved in cell wall degradation and the most abundant proteins were cellulases, endoglucanases, proteases, and chitinases. In S. sclerotiorum were identified 18 secreted proteins from the liquid culture of this fungus (Yajima and Kav 2006) where L-arabinofuranosidase was one of the most abundant in the secretome but not in the mycelia. This protein is much known for its function in the virulence process of this fungus.…”