Expression of Biomass-Degrading Enzymes Is a Major Event during Conidium Development in Trichoderma reesei
Expression of Biomass-Degrading Enzymes Is a Major Event during Conidium Development in Trichoderma reesei
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DOI：
10.1128/ec.05014-11
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发表时间：
2011-11-01
期刊：
影响因子：
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通讯作者：
Kubicek, Christian P.
中科院分区：
文献类型：
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作者：
Metz, Benjamin;Seidl-Seiboth, Verena;Kubicek, Christian P.
分生孢子在许多丝状真菌的生命周期中起着至关重要的作用，是在不利条件下生存的主要手段。为了研究里氏木霉从生长的菌丝到分生孢子的转变过程中发生的转录变化，进行了微阵列实验。总共 900 个不同的基因被分类为差异表达，相对于它们在分生孢子形成时间零时的表达，至少在分析的时间点之一。上调基因中代表性较高的主要功能类别（FunCat）涉及溶质转运、代谢、转录调控、次级代谢物合成、脂肪酶、蛋白酶，特别是纤维素酶和半纤维素酶。下调基因中比例过高的类别尤其是与核糖体和线粒体功能相关的基因。纤维素酶和半纤维素酶基因的上调依赖于正转录调节因子XYR1的功能，但XYR1对分生孢子本身没有影响。至少 20% 的显着调控基因非随机分布在里氏木霉基因组内，表明分生孢子形成调控中存在表观遗传成分。在此过程中纤维素酶和半纤维素酶的显着上调，以及里氏木霉孢子中纤维素酶和半纤维素酶含量的显着上调，有助于推测水解植物生物量的能力是这种真菌的主要特征，使其能够在面临不利条件一段时间后打破休眠并重新启动营养生长。
The conidium plays a critical role in the life cycle of many filamentous fungi, being the primary means for survival under unfavorable conditions. To investigate the transcriptional changes taking place during the transition from growing hyphae to conidia in Trichoderma reesei, microarray experiments were performed. A total of 900 distinct genes were classified as differentially expressed, relative to their expression at time zero of conidiation, at least at one of the time points analyzed. The main functional categories (FunCat) overrepresented among the upregulated genes were those involving solute transport, metabolism, transcriptional regulation, secondary metabolite synthesis, lipases, proteases, and, particularly, cellulases and hemicellulases. Categories overrepresented among the downregulated genes were especially those associated with ribosomal and mitochondrial functions. The upregulation of cellulase and hemicellulase genes was dependent on the function of the positive transcriptional regulator XYR1, but XYR1 exerted no influence on conidiation itself. At least 20% of the significantly regulated genes were nonrandomly distributed within the T. reesei genome, suggesting an epigenetic component in the regulation of conidiation. The significant upregulation of cellulases and hemicellulases during this process, and thus cellulase and hemicellulase content in the spores of T. reesei, contributes to the hypothesis that the ability to hydrolyze plant biomass is a major trait of this fungus enabling it to break dormancy and reinitiate vegetative growth after a period of facing unfavorable conditions.