木质纤维素资源高效生物降解转化中的关键科学问题研究

曲音波 钟耀华 秦玉琪 严兴 田朝光

摘 要：以高产木质纤维素降解酶的里氏木霉、草酸青霉，以及丝状真菌遗传学研究的模式菌粗糙脉孢菌为研究对象，分别对碳源感应（诱导物形成和转运）、信号传递、基因转录水平调控、蛋白分泌、酶系重构这5个调控木质纤维素酶高效降解木质纤维素的主要内容进行了深入研究。研究发现调控丝状真菌纤维素酶合成分泌的新基因。草酸青霉中3个纤维寡糖转运蛋白CdtC，CdtD与CdtG，和粗糙脉孢菌中两个纤维寡糖转运蛋白CDT-1和CDT-2。通过调控真菌细胞将诱导物运输入细胞这一重要的生理过程，参与纤维素酶合成的调控。发现关键信号蛋白TrRas2通过信号调控纤维素酶基因的表达。发现多个在转录水平调控纤维素酶基因和半纤维素酶基因转录的调控蛋白，包括AmyR、ClrB、CreA、CER-1、CER2、HCR-1等，它们或单独作用，或协同作用，共同调控纤维素酶基因转录水平的表达。发现了10个关键功能蛋白11个转录调控蛋白参与了与丝状真菌纤维素酶高效分泌相关的UPR信号通路，对以上关键蛋白功能的研究将是解析丝状真菌纤维素酶高效分泌的分子机制的基础。筛选出有效提高木质纤维素水解效率的协同因子：包括草酸青霉多糖单加氧酶（PMO）、木质素降解相关酶漆酶LacA。在元基因组的研究中，发现了多个新的、有潜在协同效应的纤维素酶和半纤维素酶基因，并已经用于里氏木霉游离酶系的重构。

关键词：草酸青霉 里氏木霉 粗糙脉孢菌 糖转运蛋白 转录调控蛋白 分泌 重构

Abstract：Our research objects are Trichoderma reesei， Penicillium oxalicum and. Neurospora crassa. The research is focused on carbon source induction， signal pathway， transcriptional regulation， protein secretion， and enzyme reconstruction. Many important genes which encode proteins regulating the expression of cellulase and hemicellulase genes were observed. Three cellodextrin transporters （CdtC， CdtD， and CdtG） founcd in P. oxalicum and two cellodextrin transporters （CDT1 and CDT2） found in N. crassa were reported playing important roles in cellulase induction in the cellulolytic fungus. The Ras2 in T. reesei regulates expression of cellulase genes through the signal pathway. Many transcription proteins were observed including AmyR， ClrB， CreA， CER-1， CER2， and HCR-1. They are involved in transcriptional regulation of expression of cellulase genes. 10 Key proteins and 11 transcription proteins were reported to be involved in UPR pathway which is relating with the high secretion of cellulolytic fungus. Some synergic proteins including polysaccharide monooxygenases （PMOs） in P. oxalicum and laccase in T. reesei were reported enhancing traditional cellulase activity. Many new cellulase and hemicellulase genes were found in metagenome research and some of them have been used in reconstruction of cellulolytic enzymes.

Key Words：Penicillium oxalicum；Trichoderma reesei；Neurospora crassa；Cellodextrin transporters；Transcription proteins；Secretion； Reconstruction

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