Analysis of EST Sequences of Sclerotinia Homoeocarpa Isolates Generated by High-Throughput Short-Read Illumina Sequencing Technology.

Dollar spot caused by Sclerotinia homoeocarpa is the most economically important disease of turfgrass on golf courses.  Due to intense management requirement of the disease, fungicide resistance to three major chemistries has been reported. Furthermore, current species designation of the pathogen has been controversial.  Recent significant advancement of high-throughput, cost-effective sequencing technologies has been an efficient instrument for genomics studies of ÒorphanÓ organisms like S. homoeocarpa. As a first step toward genomics resource development and biological understanding of the pathogen, two field isolates (WC63 and SD20) of dollar spot with different sensitivities to demethlylation inhibitor fungicides, which were cultured on potato dextrose media were utilized for EST sequences using high-throughput Illumina Genome Analyzer.  The Illumina Genome Analyzer generates hundreds of short sequence reads, typically 36 nucleotides in length.  De novo assembly of EST sequences of two S. homoeocarpa isolates was performed using freely available assembly software called Edena.  Edena generated 430 (a total of 31,732 kb from 881,432 36 mers) and 427 (a total of 34,315 kb from 953,211 36 mers) short contigs ranging 100-1600 bp in size from WC63 and SD20 isolates, respectively.  The first EST collection and annotation databases of S. homoeocarpa will provide valuable genomics resources (EST-SSR marker development, gene discovery, etc.) for researchers in turfgrass and beyond.  Details about analysis of the EST and derived contig sequences and their annotation will be presented.