Abstract Detail

Mycological Section

Wang, Yan [1], White, Merlin [2], Moncalvo, Jean-Marc [3].

Preliminary analyses of four Harpellales (gut fungi) genomes offers insight into these obligate gut symbionts of aquatic insects.

Harpellales is a group of obligate, symbiotic fungi or trichomycetes that colonize the digestive tracts of arthropods, thus known as gut fungi. This Order contains about 200 described species. Smittium, with 82 species, is the largest genus of the group. We present the first descriptive report of four Harpellales genomes, and preliminary results from comparative analyses with other fungi, particularly those that are obligatorily associated with insects such as the entomopathogenic Metarhizium, Beauvaria and Cordyceps for which genomes are available. The goals of this research are to eventually detect genetic elements that are unique to insect-associated fungi and genetic differences between insect-symbionts and insect-pathogens. Genome-wide data were obtained for two strains from the Smittium culicis species complex, one strain of S. mucronatum, and one strain of Zancudomyces culisetae. DNAs were isolated from cultures grown in BHIGTv broth. Two libraries (paired-end and 5kb mate pair) were prepared for S. culicis GSMNP, whereas only paired-end library was prepared for the other three strains. The libraries were sequenced using an Illumina HiSeq 2500 platform. Raw sequence reads were quality trimmed and assembled with RAY (v.2.3.1). Gene prediction employed AUGUSTUS (v3.1) using the available genome of Conidiobolus coronatus as the trainer. Gene functions were annotated by using Blast2GO (v3.0) and InterProScan (v5.8-49.0) against the nonredundant database in NCBI and protein signature databases in EBI. CEGMA (v2.4.010312) was used to identify the presence of core eukaryotic protein-coding genes. Illumina data assemblies in RAY resulted in several thousands scaffolds, however, CEGMA identified the presence of >90% of either complete or partial core eukaryotic protein-coding genes, which is a good indication that most of the genome sequences were recovered. Preliminary results indicate wide variation in genome sizes within the four Harpellales species examined. The three Smittium genomes are significantly larger than Z. culisetae, but genome sizes were not correlated with the predicted number of coding genes. The predicted gene densities from four Harpellales genomes appear to be low in comparison to entomopathogenic fungi and other fungi in general. They also appear to harbor low GC contents (~30%). In this poster we will present results from our latest investigations.

1 - University of Toronto, Department of Ecology and Evolutionary Biology, 25 Willcocks St, Toronto, ON, M5S 3B2, Canada
2 - Boise State University, Department of Biological Sciences, 1910 University Drive, Boise, ID, 83725, USA
3 - Royal Ontario Museum, Department of Natural History, 100 Qween's park, Toronto, ON, M5S 2C6 , Canada

Keywords:
Smittium
Kickxellomycotina
zygomycete
Comparative Genomics.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PMY020
Abstract ID:1340
Candidate for Awards:MSA Best Poster Presentation Award by a Graduate Student