EST analysis of cDNA libraries from the entomopathogenic fungus Beauveria (Cordyceps) bassiana. II. Fungal cells sporulating on chitin and producing oosporein

Abstract

In the accompanying paper [Cho, E.-M., Liu, L., Farmerie, W. & Keyhani, N. O. (2006). Microbiology 152, 2843-2854], the analysis of expressed sequence tag (EST) libraries derived from homogeneous single-cell populations of aerial conidia, in vitro blastospores and submerged conidia of the entomopathogenic fungus Beauveria (Cordyceps) bassiana has been reported. Here an extended EST analysis is presented of complex cell mixtures derived from fungal cells sporulating on chitin or grown under culture conditions inducing the production of the B. bassiana secondary metabolite, oosporein. Fungal material used for the construction of the libraries included germinating conidia and blastospores, mycelia, as well as cells in various developmental stages. Approximately 2,500 5' end sequences were determined from random sequencing of clones from each library, and were clustered into 277 contigs with 1,069 singlets, and 306 contigs with 1,064 singlets, for the chitin and oosporein libraries, respectively. Almost half (45-50 %) of the sequences in each library displayed either no significant similarity (e value >10(-4)) or similarity to hypothetical proteins found in the NCBI database. Approximately 20-25 % of the sequences in each library could be annotated by gene ontology terms. A comparative analysis between the two libraries, as well as the libraries in the accompanying paper, is presented. A set of 4,360 clustered and unique sequences was characterized. The data are indicative of a highly plastic gene expression repertoire being available to B. bassiana for growth during different environmental and developmental conditions, and provides a dataset for gene discovery and genome annotation.