title: An Interspecies Comparative Analysis of the Predicted Secretomes of the Necrotrophic Plant Pathogens Sclerotinia sclerotiorum and Botrytis cinerea.
abstract: Phytopathogenic fungi form intimate associations with host plant species and cause disease. To be successful, fungal pathogens communicate with a susceptible host through the secretion of proteinaceous effectors, hydrolytic enzymes and metabolites. Sclerotinia sclerotiorum and Botrytis cinerea are economically important necrotrophic fungal pathogens that cause disease on numerous crop species. Here, a powerful bioinformatics pipeline was used to predict the refined S. sclerotiorum and B. cinerea secretomes, identifying 432 and 499 proteins respectively. Analyses focusing on S. sclerotiorum revealed that 16% of the secretome encoding genes resided in small, sequence heterogeneous, gene clusters that were distributed over 13 of the 16 predicted chromosomes. Functional analyses highlighted the importance of plant cell hydrolysis, oxidation-reduction processes and the redox state to the S. sclerotiorum and B. cinerea secretomes and potentially host infection. Only 8% of the predicted proteins were distinct between the two secretomes. In contrast to S. sclerotiorum, the B. cinerea secretome lacked CFEM- or LysM-containing proteins. The 115 fungal and oomycete genome comparison identified 30 proteins specific to S. sclerotiorum and B. cinerea, plus 11 proteins specific to S. sclerotiorum and 32 proteins specific to B. cinerea. Expressed sequence tag (EST) and proteomic analyses showed that 246 S. sclerotiorum secretome encoding genes had EST support, including 101 which were only expressed in vitro and 49 which were only expressed in planta, whilst 42 predicted proteins were experimentally proven to be secreted. These detailed in silico analyses of two important necrotrophic pathogens will permit informed choices to be made when candidate effector proteins are selected for function analyses in planta.
authors.affiliation: Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom.
authors.forename: Steph
authors.initials: S
authors.lastname: Heard
authors.affiliation: Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom.
authors.forename: Neil A
authors.initials: NA
authors.lastname: Brown
authors.affiliation: Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom.
authors.forename: Kim
authors.initials: K
authors.lastname: Hammond-Kosack
mesh_terms: D001203:Ascomycota / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D020171:Botrytis / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D015825:Chromosomes, Fungal; D019295:Computational Biology; D020224:Expressed Sequence Tags; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D054884:Host-Pathogen Interactions; D058977:Molecular Sequence Annotation; D005810:Multigene Family; D010944:Plants / Q000382:microbiology; D040901:Proteomics; D013045:Species Specificity
chemical_list: D005656:Fungal Proteins