木質(zhì)纖維素資源高效生物降解轉(zhuǎn)化中的關(guān)鍵科學(xué)問(wèn)題研究

曲音波 鐘耀華 秦玉琪 嚴(yán)興 田朝光

摘 要：以高產(chǎn)木質(zhì)纖維素降解酶的里氏木霉、草酸青霉，以及絲狀真菌遺傳學(xué)研究的模式菌粗糙脈孢菌為研究對(duì)象，分別對(duì)碳源感應(yīng)（誘導(dǎo)物形成和轉(zhuǎn)運(yùn)）、信號(hào)傳遞、基因轉(zhuǎn)錄水平調(diào)控、蛋白分泌、酶系重構(gòu)這5個(gè)調(diào)控木質(zhì)纖維素酶高效降解木質(zhì)纖維素的主要內(nèi)容進(jìn)行了深入研究。研究發(fā)現(xiàn)調(diào)控絲狀真菌纖維素酶合成分泌的新基因。草酸青霉中3個(gè)纖維寡糖轉(zhuǎn)運(yùn)蛋白CdtC，CdtD與CdtG，和粗糙脈孢菌中兩個(gè)纖維寡糖轉(zhuǎn)運(yùn)蛋白CDT-1和CDT-2。通過(guò)調(diào)控真菌細(xì)胞將誘導(dǎo)物運(yùn)輸入細(xì)胞這一重要的生理過(guò)程，參與纖維素酶合成的調(diào)控。發(fā)現(xiàn)關(guān)鍵信號(hào)蛋白TrRas2通過(guò)信號(hào)調(diào)控纖維素酶基因的表達(dá)。發(fā)現(xiàn)多個(gè)在轉(zhuǎn)錄水平調(diào)控纖維素酶基因和半纖維素酶基因轉(zhuǎn)錄的調(diào)控蛋白，包括AmyR、ClrB、CreA、CER-1、CER2、HCR-1等，它們或單獨(dú)作用，或協(xié)同作用，共同調(diào)控纖維素酶基因轉(zhuǎn)錄水平的表達(dá)。發(fā)現(xiàn)了10個(gè)關(guān)鍵功能蛋白11個(gè)轉(zhuǎn)錄調(diào)控蛋白參與了與絲狀真菌纖維素酶高效分泌相關(guān)的UPR信號(hào)通路，對(duì)以上關(guān)鍵蛋白功能的研究將是解析絲狀真菌纖維素酶高效分泌的分子機(jī)制的基礎(chǔ)。篩選出有效提高木質(zhì)纖維素水解效率的協(xié)同因子：包括草酸青霉多糖單加氧酶（PMO）、木質(zhì)素降解相關(guān)酶漆酶LacA。在元基因組的研究中，發(fā)現(xiàn)了多個(gè)新的、有潛在協(xié)同效應(yīng)的纖維素酶和半纖維素酶基因，并已經(jīng)用于里氏木霉游離酶系的重構(gòu)。

關(guān)鍵詞：草酸青霉 里氏木霉 粗糙脈孢菌 糖轉(zhuǎn)運(yùn)蛋白 轉(zhuǎn)錄調(diào)控蛋白 分泌 重構(gòu)

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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