Identification of genes preferentially expressed during microcycle conidiation of Metarhizium anisopliae using suppression subtractive hybridization.

Microcycle conidiation has been defined as the production of conidia directly by a spore without the intervention of hyphal growth. The molecular mechanisms underlying this process are still poorly understood. Suppression subtractive hybridization was used here to isolate the genes preferentially expressed during microcycle conidiation vs. in normal conidiation hypha of Metarhizium anisopliae CQMa102, a common fungal pathogen of locusts. A total of 1600 clones from the subtracted cDNA library were screened by cDNA array dot blotting and 221 unique expressed sequence tags were identified as being differentially expressed. These genes were found to be homologous genes involved in various cellular processes, including general metabolism, protein synthesis, energy, cell-cycle and DNA processing, cellular transport, transcription, signal transduction and stress response. Real-time reverse transcriptase PCR assay of six randomly selected genes revealed that they are all highly expressed during microcycle conidiation.