Abstract
Pleosporales is the largest order in the fungal class Dothideomycetes. We report the 36,814,818-bp draft genome sequence and gene annotation of UM1110, a Pleosporales isolate associated with unclassified genera that is potentially a new fungal species. Analysis of the genome sequence led to the finding of genes associated with fungal adhesive proteins, secreted proteases, allergens, and pseudohyphal development.
GENOME ANNOUNCEMENT
Pleosporales is the largest order in the fungal class Dothideomycetes, which is estimated to comprise more than 4,700 species (9). Isolate UM1110, cultured from human nasopharyngeal aspirate, was identified as a Pleosporales species by macro- and microscopic morphology, internal transcribed spacer (ITS)-based PCR amplification, and ITS sequence-based phylogenetic analysis. It shows septate branched hyphae falling apart into rectangular arthroconidia and is potentially a new species of an unclassified Pleosporales genus.
The Pleosporales isolate UM1110 genomic DNA was sequenced to a 100-fold depth of coverage using the Illumina Genome Analyzer GAIIx by employing the next generation sequencing strategy on a 300-bp DNA insert-size library. The genome was assembled into 491 scaffolds (1 kb; N50, 312 kb) comprising 60,208 contigs by using the SOAPdenovo version 1.05 assembler (2). The assembled genome size is 36,814,818 bp, with a G+C content of 51.14%. A total of 14,074 genes, 13,165 (93.54%) of which are longer than 100 amino acids, was predicted using GeneMark-ES version 2.3 (7). Putative functions were successfully assigned to 7,400 (52.58%) genes based on sequence similarity searches against Swiss-Prot protein sequence database.
A preliminary analysis revealed an abundance of genes encoding serine-rich adhesion platelet proteins, which are key components in platelet adhesion commonly found in staphylococcal and streptococcal bacteria (10). These adhesive proteins probably contribute toward host cell adhesion and binding. Also present were genes encoding secreted proteases, like subtilisins and metalloproteases (8), which constitute a significant part of fungal secretomes (4) and are likely to be virulence-related factors, as well as genes associated with allergic reactivity, such as those encoding aldehyde dehydrogenase (Alt a 10), a putative glycosidase (crf1 [coding for Asp f 9]), and thioredoxin-like protein (Fus c 2), commonly known as fungal allergens (1). An interesting feature noted was the presence of hyphal growth protein 1, flocculation (FLO11), and pseudohyphal development (EPD1) genes, which are involved in fungal pseudohyphal development (3, 5). This suggests that UM1110 could have the ability to exist as both filamentous pseudohyphae and yeast cells, a pathogenicity mechanism employed by dimorphic fungi to survive inside mammalian hosts (6).
Nucleotide sequence accession number.
The nucleotide sequence of the Pleosporales isolate UM1110 genome has been deposited in DDBJ/EMBL/GenBank under accession no. AJMS00000000.
ACKNOWLEDGMENTS
This study was supported by research grants UM.C/625/1/HIR/004 and UM.C/HIR/MOHE/MED/02 from the University of Malaya.
K.P.N., Y.F.N., and H.H. conceived the project and contributed to the writing and editing of the manuscript. K.P.N., T.S.S.-H., C.L.C., and S.L.N. were responsible for the isolation, identification, and DNA extraction. S.M.Y., C.C.H., K.W.L., and W.Y.Y. performed the genome sequencing and bioinformatics analysis.
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