Trichoderma reesei is the major filamentous fungus used to produce cellulase and there is huge interest in promoting its ability to produce higher titers of cellulase. Among the many factors affecting cellulase production in T. reesei, the mycelial phenotype is important but seldom studied. Herein, a close homolog of the Neurospora crassa COT1 kinase was discovered in T. reesei and designated TrCOT1, which is of 83.3% amino acid sequence identity. Functional disruption of Trcot1 in T. reesei by RNAi-mediated gene silencing resulted in retarded sporulation on potato dextrose agar and dwarfed colonies on minimal medium agar plates containing glucose, xylan, lactose, xylose, or glycerol as the sole carbon source. The representative mutant strain, SUS2/Trcot1i, also displayed reduced mycelia accumulation but hyperbranching in the MM glucose liquid medium, with hyphal growth unit length values decreased to 73.0 µm/tip compared to 239.8 µm/tip for the parent strain SUS2. The hyperbranching phenotype led to slightly but significantly increased cellulase secretion from 24 to 72 h in a batch culture. However, the cellulase production per unit of mycelial biomass was much more profoundly improved from 24 to 96 h.

中文翻译：

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RNAi 介导的 Trcot1 基因沉默在里氏木霉中诱导超分支表型。

里氏木霉是用于生产纤维素酶的主要丝状真菌，人们对提高其生产更高滴度纤维素酶的能力有着巨大的兴趣。在影响里氏木霉纤维素酶生产的众多因素中，菌丝体表型很重要，但研究很少。在此，在里氏木霉中发现了粗糙脉孢菌COT1 激酶的密切同系物，并将其命名为Tr COT1，其具有 83.3% 的氨基酸序列同一性。里氏木霉中Trcot1的功能破坏通过 RNAi 介导的基因沉默导致马铃薯葡萄糖琼脂上的孢子形成延迟，并导致含有葡萄糖、木聚糖、乳糖、木糖或甘油作为唯一碳源的基本培养基琼脂平板上的菌落矮化。代表性突变菌株 SUS2/Trcot1i 在 MM 葡萄糖液体培养基中也表现出菌丝体积累减少但超分枝，菌丝生长单位长度值降至 73.0 µm/tip，而亲本菌株 SUS2 为 239.8 µm/tip。在分批培养中，超分枝表型导致从 24 小时到 72 小时的纤维素酶分泌略有但显着增加。然而，每单位菌丝体生物量的纤维素酶产量从 24 小时提高到 96 小时更为深刻。