The role of hydrophobins in fungal growth and nutrition

Abstract

In our planet, one of the most widely distributed organisms is fungi. The genus Trichoderma is soil-borne filamentous fungi in phylum of Ascomycota. These fungi are described as environmental opportunistic, mycoparasitic and competitive for nutrient and other resources. Among other features, these capabilities of fungi are provided by secreted surface-active proteins. Hydrophobin proteins represent one of the most known self-assembly and surface-active biological molecules secreted by fungi. These small cysteine-rich secreted proteins play a vital function in fungal growth and development as well as in their adaptation to their environment. They enable hydrophilic: hydrophobic interfaces to change forms and adapt to the environment by assembling in amphipathic films. The goal of this study was to understand the role of hydrophobins in fungal growth and nutrition. For this study, two Trichoderma (Hypocreales, Ascomycota) species, namely T. guizhouense and T. harzianum and respective mutants lacking either one or two hydrophobin-encoding genes were selected. By investigating the relationship of hydrophobins and nutrition, qPCR method was applied to determine expression levels of hydrophobins within the different stages of Trichoderma development. Then, the phenotype microarray technique was performed to assess how different hydrophobins influence the growth of Trichoderma on individual carbon sources during the life cycle.In light of these results, it can be stated that hfb4 and hfb10 has an influence of assimilation for some carbon sources. T. guizhouense and T. harzianum with or without these hydrophobins could lead themselves to up-regulation or down-regulation of their carbon uptake metabolism, hence their growth pattern.