Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
College of Biological Sciences, China Agricultural University, Beijing 100193, P.R, China.
J Microbiol Biotechnol. 2020 Feb 28;30(2):206-215. doi: 10.4014/jmb.1909.09050.
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 , the mycelial phenotype is important but seldom studied. Herein, a close homolog of the COT1 kinase was discovered in and designated COT1, which is of 83.3% amino acid sequence identity. Functional disruption of in 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.
是生产纤维素酶的主要丝状真菌，人们对提高其生产纤维素酶的能力非常感兴趣。在影响 的纤维素酶生产的众多因素中，菌丝体表型很重要，但很少研究。在此，在 中发现了一个与 COT1 激酶密切同源的基因，并将其命名为 COT1，其氨基酸序列同一性为 83.3%。通过 RNAi 介导的基因沉默对 中的 进行功能缺失，导致在土豆葡萄糖琼脂上的产孢延迟，以及在含有葡萄糖、木聚糖、乳糖、木糖或甘油作为唯一碳源的最低培养基琼脂平板上的菌落矮小。代表性的突变株 SUS2/Trcot1i 也表现出在 MM 葡萄糖液体培养基中菌丝体积累减少但分枝过度，与亲本菌株 SUS2 相比，菌丝生长单位长度值从 239.8 µm/尖端降低到 73.0 µm/尖端。分枝过度表型导致分批培养中纤维素酶的分泌从 24 小时略微但显著增加到 72 小时。然而，从 24 小时到 96 小时，每单位菌丝体生物质的纤维素酶产量得到了更显著的提高。
