Intracellular beta-Glucosidases CEL1a and CEL1b Are Essential for Cellulase Induction on Lactose in Trichoderma reesei

文献类型： 外文期刊

第一作者： Xu, Jintao

作者： Xu, Jintao;Zhao, Guolei;Kou, Yanbo;Zhang, Weixin;Chen, Guanjun;Liu, Weifeng;Zhou, Qingxin

作者机构：

期刊名称：EUKARYOTIC CELL （ 影响因子：2.992； 五年影响因子：3.167 ）

ISSN： 1535-9778

年卷期： 2014 年 13 卷 8 期

页码：

收录情况： SCI

摘要： Lactose (1,4-O-beta-D-galacto-pyranosyl-D-glucose) induces cellulolytic enzymes in Trichoderma reesei and is in fact one of the most important soluble carbon sources used to produce cellulases on an industrial level. The mechanism underlying the induction is, however, not fully understood. In this study, we investigated the cellular functions of the intracellular beta-glucosidases CEL1a and CEL1b in the induction of cellulase genes by lactose in T. reesei. We demonstrated that while CEL1a and CEL1b were functionally equivalent in mediating the induction, the simultaneous absence of these intracellular beta-glucosidases abolished cbh1 gene expression on lactose. D-Galactose restored the efficient cellulase gene induction in the Delta cel1a strain independently of its reductive metabolism, but not in the Delta cel1a Delta cel1b strain. A further comparison of the transcriptional responses of the Delta cel1a Delta cel1b strain complemented with wild-type CEL1a or a catalytically inactive CEL1a version and the Delta cel1a strain constitutively expressing CEL1a or the Kluyveromyces lactis beta-galactosidase LAC4 showed that both the CEL1a protein and its glycoside hydrolytic activity were indispensable for cellulase induction by lactose. We also present evidence that intracellular beta-glucosidase-mediated lactose induction is further conveyed to XYR1 to ensure the efficiently induced expression of cellulase genes.

分类号： Q93

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