Identification of Mycoparasitism-Related Genes in Trichoderma atroviride

A high-throughput sequencing approach was utilized to carry out a comparative transcriptome analysis ofTrichoderma atroviride IMI206040 during mycoparasitic interactions with the plant-pathogenic fungusRhizoctonia solani . In this study, transcript fragments of 7,797Trichoderma genes were sequenced, 175 of which were host responsive. According to the functional annotation of these genes by KOG (eukaryotic orthologous groups), the most abundant group during direct contact was “metabolism.” Quantitative reverse transcription (RT)-PCR confirmed the differential transcription of 13 genes (includingswo1 , encoding an expansin-like protein;axe1 , coding for an acetyl xylan esterase; and homologs of genes encoding the aspartyl proteasepapA and a trypsin-like protease,pra1 ) in the presence ofR. solani . An additional relative gene expression analysis of these genes, conducted at different stages of mycoparasitism againstBotrytis cinerea andPhytophthora capsici , revealed a synergistic transcription of various genes involved in cell wall degradation. The similarities in expression patterns and the occurrence of regulatory binding sites in the corresponding promoter regions suggest a possible analog regulation of these genes during the mycoparasitism ofT. atroviride . Furthermore, a chitin- and distance-dependent induction ofpra1 was demonstrated.