Suppressive subtractive hybridization and differential screening identified genes differentially expressed in yeast and mycelial forms of Ophiostoma piceae

Abstract

Ophiostoma piceae is a sap-staining fungus that colonizes and discolours wood. It has been established that the mycelium form but not the yeast form becomes pigmented in vitro. Suppressive subtractive hybridization PCR was used to isolate transcripts specifically upregulated in either the yeast or mycelial forms of O. piceae. Subtracted cDNAs were cloned and transformed into Escherichia coli. The yeast and mycelium specific clones were then screened by differential screening to reduce the possibility of isolating false positive clones and the differential expression of the two sets of cDNAs was confirmed by reverse Northern hybridization. Numerous genes appear to be specifically expressed in either the yeast or mycelial forms. Sequence analysis identified several cDNAs similar to known genes. However, a few cDNAs showed no similarity to sequences in the public databases.