Comparative gene expression profiles of Trichoderma harzianum proteases during in vitro nematode egg-parasitism

Abstract The parasitism of nematodes by Trichoderma harzianum involves the production and co-ordinated secretion of various eggshell-degrading enzymes. While several protease-encoding genes of Trichoderma spp. have been characterized under different biocontrol conditions, their functional role in the nematode egg-infection process has been poorly understood to date. The present study was carried out to investigate the role and importance of different proteases implicated in nematode egg-parasitism. Parallel expressional characterization of 13 peptidase-encoding genes clearly suggests that the highly transcribed genes encoding acidic serine protease pra1 ; aspartic protease p6281 and p9438 ; metalloendopeptidase p7455 and the most prominently induced sedolisin serine protease p5216 were co-expressed and they may play pivotal roles in the egg-parasitic process. In addition, gene expression profiles indicated similarities (e.g. p1324 ) as well as characteristic differences (e.g. p5216 , p7455 , p9438 , p5431 , prb1 , SS10 and SA76 ) between egg-parasitism and other biocontrol-related processes. These results underline the diversity and the functional specialization of fungal protease genes and reveal new insights into the host-pathogen interaction between nematode eggs and T. harzianum .