Research Area Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a/166-5, 1060 Vienna, Austria.
Appl Environ Microbiol. 2011 Oct;77(20):7217-26. doi: 10.1128/AEM.06027-11. Epub 2011 Aug 19.
Mycoparasitic Trichoderma species have expanded numbers of fungal subgroup C chitinases that contain multiple carbohydrate binding modules and could thus be important for fungal cell wall degradation during the mycoparasitic attack. In this study, we analyzed the gene regulation of subgroup C chitinases in the mycoparasite Trichoderma virens. In addition to regulation by nutritional stimuli, we found complex expression patterns in different parts of the fungal colony, and also, the mode of cultivation strongly influenced subgroup C chitinase transcript levels. Thus, the regulation of these genes is governed by a combination of colony-internal and -external signals. Our results showed completely different expression profiles of subgroup C chitinase genes in T. virens than in a previous study with T. atroviride, although both fungi are potent mycoparasites. Only a few subgroup C chitinase orthologues were found in T. atroviride and T. virens, and even those showed substantially divergent gene expression patterns. Microscopic analysis revealed morphogenetic differences between T. atroviride and T. virens, which could be connected to differential subgroup C chitinase gene expression. The biological function of fungal subgroup C chitinases therefore might not be as clear-cut as previously anticipated. They could have pleiotropic roles and might be involved in both degradation of exogenous chitinous carbon sources, including other fungal cell walls, and recycling of their own cell walls during hyphal development and colony formation.
具有真菌亚群 C 几丁质酶的真菌寄生性 Trichoderma 物种数量增加，这些几丁质酶包含多个碳水化合物结合模块，因此在真菌寄生攻击过程中降解真菌细胞壁时可能很重要。在这项研究中，我们分析了真菌寄生菌 Trichoderma virens 中真菌亚群 C 几丁质酶的基因调控。除了营养刺激的调节外，我们还发现了真菌菌落不同部位的复杂表达模式，并且培养方式也强烈影响亚群 C 几丁质酶转录本水平。因此，这些基因的调控受到菌落内部和外部信号的共同作用。我们的研究结果表明，尽管两种真菌都是有效的真菌寄生菌，但在 T. virens 中的亚群 C 几丁质酶基因表达模式与之前在 T. atroviride 中的研究完全不同。尽管在 T. atroviride 和 T. virens 中发现了少数亚群 C 几丁质酶直系同源物，但即使是这些基因也表现出明显不同的基因表达模式。显微镜分析揭示了 T. atroviride 和 T. virens 之间的形态发生差异，这可能与亚群 C 几丁质酶基因表达的差异有关。因此，真菌亚群 C 几丁质酶的生物学功能可能并不像之前预期的那样明确。它们可能具有多效性作用，并且可能参与降解外源性几丁质碳源，包括其他真菌细胞壁，以及在菌丝发育和菌落形成过程中回收自身细胞壁。
