Differential transcriptomic profiling of filamentous fungus during solid-state and submerged fermentation and identification of an essential regulatory gene PoxMBF1 that directly regulated cellulase and xylanase gene expression
Differential transcriptomic profiling of filamentous fungus during solid-state and submerged fermentation and identification of an essential regulatory gene PoxMBF1 that directly regulated cellulase and xylanase gene expression
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丝状真菌在固态和深层发酵过程中的差异转录组分析以及直接调节纤维素酶和木聚糖酶基因表达的必需调控基因 PoxMBF1 的鉴定
DOI：
10.1186/s13068-019-1445-4
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发表时间：
2019
影响因子：
6.3
通讯作者：
Feng Jia-Xun
中科院分区：
文献类型：
--
作者：
Zhao Shuai;Liu Qi;Wang Jiu-Xiang;Liao Xu-Zhong;Guo Hao;Li Cheng-Xi;Zhang Feng-Fei;Liao Lu-Sheng;Luo Xue-Mei;Feng Jia-Xun
背景：固态发酵（SSF）模拟土壤真菌的自然腐烂环境，可用于研究植物生物量降解酶的生产。然而，真菌基因在SSF过程中的转录调控知识仍然有限。本文对丝状真菌草酸青霉（penicillium oxalicumstrain HP7-1）在含有麦麸加稻草（WR）的培养基中培养，在SSF （WR_SSF）和深层发酵（WR_SmF；对照）条件下进行转录谱分析。通过比较转录组学和遗传学分析，鉴定了在SSF过程中调节真菌纤维素酶和木聚糖酶基因表达的新型关键转录因子。结果：WR_SSF处理下主要纤维素酶基因的表达高于WR_SmF处理，而与柠檬酸循环相关的基因在WR_SSF处理下表达受到抑制。从p的转录组学分析中筛选出56个纤维素酶生产的候选调控基因。oxalicumHP7-1基因在亲本菌株∆PoxKu70中进行敲除实验，得到43个缺失突变体，其中18个在前期研究中构建。酶活性测定揭示了14个新的参与纤维素酶生产的调控基因。oxalicumduring社保基金。值得注意的是，编码多蛋白桥接因子1的重要调控基因poxmbf1的缺失导致SSF和SmF诱导后2天的纤维素酶和木聚糖酶产量翻倍。在SSF和SmF过程中，poxmbf1动态和差异调节纤维素酶和木聚糖酶基因亚群的转录，并赋予抗逆性。重要的是，PoxMBF1在体外特异性结合主要纤维素酶和木聚糖酶基因的启动子。结论：我们揭示了p的差异转录调控。在SSF和SmF过程中，发现了一种新的TF PoxMBF1，它直接调节SSF和SmF过程中纤维素酶和木聚糖酶基因的表达。这些发现扩大了我们对真菌发酵过程中纤维素酶和木聚糖酶基因表达调控机制的理解。
Background:Solid-state fermentation (SSF) mimics the natural decay environment of soil fungi and can be employed to investigate the production of plant biomass-degrading enzymes. However, knowledge on the transcriptional regulation of fungal genes during SSF remains limited. Herein, transcriptional profiling was performed on the filamentous fungusPenicillium oxalicumstrain HP7-1 cultivated in medium containing wheat bran plus rice straw (WR) under SSF (WR_SSF) and submerged fermentation (WR_SmF; control) conditions. Novel key transcription factors (TFs) regulating fungal cellulase and xylanase gene expression during SSF were identified via comparative transcriptomic and genetic analyses.Results:Expression of major cellulase genes was higher under WR_SSF condition than that under WR_SmF, but the expression of genes involved in the citric acid cycle was repressed under WR_SSF condition. Fifty-six candidate regulatory genes for cellulase production were screened out from transcriptomic profiling ofP.oxalicumHP7-1 for knockout experiments in the parental strain ∆PoxKu70, resulting in 43 deletion mutants including 18 constructed in the previous studies. Enzyme activity assays revealed 14 novel regulatory genes involved in cellulase production inP.oxalicumduring SSF. Remarkably, deletion of the essential regulatory genePoxMBF1, encoding Multiprotein Bridging Factor 1, resulted in doubled cellulase and xylanase production at 2 days after induction during both SSF and SmF.PoxMBF1dynamically and differentially regulated transcription of a subset of cellulase and xylanase genes during SSF and SmF, and conferred stress resistance. Importantly, PoxMBF1 bound specifically to the putative promoters of major cellulase and xylanase genes in vitro.Conclusions:We revealed differential transcriptional regulation ofP.oxalicumduring SSF and SmF, and identified PoxMBF1, a novel TF that directly regulates cellulase and xylanase gene expression during SSF and SmF. These findings expand our understanding of regulatory mechanisms of cellulase and xylanase gene expression during fungal fermentation.