The genome of the emerging barley pathogen Ramularia collo-cygni. (December 2016)

• Record Type: Journal Article
• Authors: McGrann, Graham; Andongabo, Ambrose; Sjökvist, Elisabet; Trivedi, Urmi; Dussart, Francois; Kaczmarek, Maciej; Mackenzie, Ashleigh; Fountaine, James; Taylor, Jeanette; Paterson, Linda; Gorniak, Kalina; Burnett, Fiona; Kanyuka, Kostya; Hammond-Kosack, Kim; Rudd, Jason; Blaxter, Mark; Havis, Neil
• Is Part Of: BMC genomics. Volume 17:Number 1(2016)
• Page Start: 1
• Page End: 17
• Publication Date: 2016-12
• Subjects: Ramularia leaf spot -- Dothideomycetes -- Rubellin toxin -- Endophyte -- Necrotroph -- Whole genome sequencing; Genomes -- Periodicals; Gene mapping -- Periodicals; Genomics -- Periodicals; Base Sequence -- Periodicals; Chromosome Mapping -- Periodicals; Genetic Techniques -- Periodicals; Sequence Analysis, DNA -- Periodicals; 572.8605
• DOI: 10.1186/s12864-016-2928-3
• Languages: English
• ISSNs: 1471-2164

Abstract

Abstract Background Ramularia collo -cygni is a newly important, foliar fungal pathogen of barley that causes the disease Ramularia leaf spot. The fungus exhibits a prolonged endophytic growth stage before switching life habit to become an aggressive, necrotrophic pathogen that causes significant losses to green leaf area and hence grain yield and quality. Results TheR. collo -cygni genome was sequenced using a combination of Illumina and Roche 454 technologies. The draft assembly of 30.3 Mb contained 11, 617 predicted gene models. Our phylogenomic analysis confirmed the classification of this ascomycete fungus within the family Mycosphaerellaceae, order Capnodiales of the class Dothideomycetes. A predicted secretome comprising 1053 proteins included redox-related enzymes and carbohydrate-modifying enzymes and proteases. The relative paucity of plant cell wall degrading enzyme genes may be associated with the stealth pathogenesis characteristic of plant pathogens from the Mycosphaerellaceae. A large number of genes associated with secondary metabolite production, including homologs of toxin biosynthesis genes found in other Dothideomycete plant pathogens, were identified. Conclusions The genome sequence ofR. collo -cygni provides a framework for understanding the genetic basis of pathogenesis in this important emerging pathogen. The reduced complement of carbohydrate-degrading enzyme genes is likely to reflect a strategy to avoid detection by host defences during its prolonged asymptomatic growth. Of particular interest will be the analysis ofR. collo -cygni gene expression during interactions with the host barley, to understand what triggers this fungus to switch from being a benign endophyte to an aggressive necrotroph.