BackgroundThe Ceratocystis genus harbors a large number of phytopathogenic fungi that cause xylem parenchyma degradation and vascular destruction on a broad range of economically important plants. Ceratocystis cacaofunesta is a necrotrophic fungus responsible for lethal wilt disease in cacao. The aim of this work is to analyze the genome of C. cacaofunesta through a comparative approach with genomes of other Sordariomycetes in order to better understand the molecular basis of pathogenicity in the Ceratocystis genus.ResultsWe present an analysis of the C. cacaofunesta genome focusing on secreted proteins that might constitute pathogenicity factors. Comparative genome analyses among five Ceratocystidaceae species and 23 other Sordariomycetes fungi showed a strong reduction in gene content of the Ceratocystis genus. However, some gene families displayed a remarkable expansion, in particular, the Phosphatidylinositol specific phospholipases-C (PI-PLC) family. Also, evolutionary rate calculations suggest that the evolution process of this family was guided by positive selection. Interestingly, among the 82 PI-PLCs genes identified in the C. cacaofunesta genome, 70 genes encoding extracellular PI-PLCs are grouped in eight small scaffolds surrounded by transposon fragments and scars that could be involved in the rapid evolution of the PI-PLC family. Experimental secretome using LC–MS/MS validated 24% (86 proteins) of the total predicted secretome (342 proteins), including four PI-PLCs and other important pathogenicity factors.ConclusionAnalysis of the Ceratocystis cacaofunesta genome provides evidence that PI-PLCs may play a role in pathogenicity. Subsequent functional studies will be aimed at evaluating this hypothesis. The observed genetic arsenals, together with the analysis of the PI-PLC family shown in this work, reveal significant differences in the Ceratocystis genome compared to the classical vascular fungi, Verticillium and Fusarium. Altogether, our analyses provide new insights into the evolution and the molecular basis of plant pathogenicity.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-4440-4) contains supplementary material, which is available to authorized users.

a Fungal and oomycete diseases are responsible for significant economic losses of cacao crops worldwide.Such diseases are caused mainly by the fungus Moniliophthora perniciosa, and the oomycetes Phytophthora citrophtora, P. capsici, and P. palmivora. The endophytic bacterium Burkholderia seminalis has showed antagonistic action against several plant pathogens. Herein, desorption electrospray ionization mass spectrometry imaging (DESI-MSI) was applied to map spatial metabolic distributions from B. seminalis and cacao pathogen monocultures, as well as to monitor interkingdom interactions of the endophytic bacterium with the fungus and oomycetes. DESI-MSI was successful in the direct analysis of fungus and oomycete pathogens on dehydrated agar plate, detecting several phospholipids and other unidentified metabolites. Chemical defense of B. seminalis against cacao pathogens was evidenced by the detection of partially diffuse rhamnolipid, which probably act in synergism with other unidentified diffuse metabolites.

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