title: Comparative genomics of Beauveria bassiana: uncovering signatures of virulence against mosquitoes.
abstract: Entomopathogenic fungi such as Beauveria bassiana are promising biological agents for control of malaria mosquitoes. Indeed, infection with B. bassiana reduces the lifespan of mosquitoes in the laboratory and in the field. Natural isolates of B. bassiana show up to 10-fold differences in virulence between the most and the least virulent isolate. In this study, we sequenced the genomes of five isolates representing the extremes of low/high virulence and three RNA libraries, and applied a genome comparison approach to uncover genetic mechanisms underpinning virulence.
  
  
  
  A high-quality, near-complete genome assembly was achieved for the highly virulent isolate Bb8028, which was compared to the assemblies of the four other isolates. Whole genome analysis showed a high level of genetic diversity between the five isolates (2.85-16.8 SNPs/kb), which grouped into two distinct phylogenetic clusters. Mating type gene analysis revealed the presence of either the MAT1-1-1 or the MAT1-2-1 gene. Moreover, a putative new MAT gene (MAT1-2-8) was detected in the MAT1-2 locus. Comparative genome analysis revealed that Bb8028 contains 163 genes exclusive for this isolate. These unique genes have a tendency to cluster in the genome and to be often located near the telomeres. Among the genes unique to Bb8028 are a Non-Ribosomal Peptide Synthetase (NRPS) secondary metabolite gene cluster, a polyketide synthase (PKS) gene, and five genes with homology to bacterial toxins. A survey of candidate virulence genes for B. bassiana is presented.
  
  
  
  Our results indicate several genes and molecular processes that may underpin virulence towards mosquitoes. Thus, the genome sequences of five isolates of B. bassiana provide a better understanding of the natural variation in virulence and will offer a major resource for future research on this important biological control agent.
authors.affiliation: Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.|Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
authors.forename: Claudio A
authors.initials: CA
authors.lastname: Valero-Jiménez
authors.affiliation: Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
authors.forename: Luigi
authors.initials: L
authors.lastname: Faino
authors.affiliation: Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.|Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
authors.forename: Daphne
authors.initials: D
authors.lastname: Spring In't Veld
authors.affiliation: Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
authors.forename: Sandra
authors.initials: S
authors.lastname: Smit
authors.affiliation: Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands. bas.zwaan@wur.nl.
authors.forename: Bas J
authors.initials: BJ
authors.lastname: Zwaan
authors.affiliation: Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands. jan.vankan@wur.nl.
authors.forename: Jan A L
authors.initials: JA
authors.lastname: van Kan
mesh_terms: D000818:Animals; D052982:Beauveria / Q000145:classification / Q000235:genetics / Q000502:physiology*; D055028:Comparative Genomic Hybridization; D009033:Culicidae / Q000382:microbiology*; D005656:Fungal Proteins / Q000235:genetics; D049770:Genes, Mating Type, Fungal / Q000235:genetics; D014644:Genetic Variation; D016681:Genome, Fungal; D010453:Peptide Synthases / Q000235:genetics; D010802:Phylogeny; D048630:Polyketide Synthases / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D014774:Virulence / Q000235:genetics*
chemical_list: D005656:Fungal Proteins; D048630:Polyketide Synthases; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase
keywords: Beauveria bassiana; Comparative genomics; Genome sequencing; Virulence