Gene expression during Ustilago maydis diploid filamentous growth: EST library creation and analyses

Abstract

Ustilago maydis is an important model system for the plant pathogenic smut and rust fungi. Critical to the continued development of this model is establishing genomic resources. We have constructed a cDNA library from a forced diploid culture of U. maydis growing as filaments and have generated 7455 ESTs that are assembled into 3074 contiguous sequences. This represents as much as 46% of the coding capacity predicted for U. maydis. BLAST searches with a similarity cutoff of E </= 10(-5), allow us to annotate 59% of the contigs based upon matches in the NCBI nr and dbEST databases. These annotated sequences provide information on mature mRNAs that will aid with gene prediction in the U. maydis genome sequence. Functional categorization and comparative analyses of the sequences provides gene identities, expression information and a solid base for future research in this model fungal pathogen.