Feldman Daria, Kowbel David J, Cohen Adi, Glass N Louise, Hadar Yitzhak, Yarden Oded
1Department of Plant Pathology and Microbiology, The R.H. Smith Faculty Agriculture, Food and Environment, The Hebrew University of Jerusalem, 7600001 Rehovot, Israel.
2Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720 USA.
Biotechnol Biofuels. 2019 Sep 4;12:210. doi: 10.1186/s13068-019-1550-4. eCollection 2019.
Biofuels derived from lignocellulosic biomass are a viable alternative to fossil fuels required for transportation. Following plant biomass pretreatment, the furan derivative furfural is present at concentrations which are inhibitory to yeasts. Detoxification of furfural is thus important for efficient fermentation. Here, we searched for new genetic attributes in the fungus that may be linked to furfural tolerance. The fact that furfural is involved in the natural process of sexual spore germination of and that this fungus is highly amenable to genetic manipulations makes it a rational candidate for this study.
Both hypothesis-based and unbiased (random promotor mutagenesis) approaches were performed to identify genes associated with the response to furfural. Changes in the transcriptional profile following exposure to furfural revealed that the affected processes were, overall, similar to those observed in . was more tolerant (by ~ 30%) to furfural when carboxymethyl cellulose was the main carbon source as opposed to sucrose, indicative of a link between carbohydrate metabolism and furfural tolerance. We also observed increased tolerance in a Δ- mutant (CRE-1 is a key transcription factor that regulates the ability of fungi to utilize non-preferred carbon sources). In addition, analysis of aldehyde dehydrogenase mutants showed that - (NCU00378) was involved in tolerance to furfural as well as the predicted membrane transporter NCU05580 (-), a homolog of in . Further to the rational screening, an unbiased approach revealed additional genes whose inactivation conferred increased tolerance to furfural: (i) NCU02488, which affected the abundance of the non-anchored cell wall protein NCW-1 (NCU05137), and (ii) the zinc finger protein NCU01407.
We identified attributes in associated with tolerance or degradation of furfural, using complementary research approaches. The manipulation of the genes involved in furan sensitivity can provide a means for improving the production of biofuel producing strains. Similar research approaches can be utilized in and other filamentous fungi to identify additional attributes relevant to other furans or toxic chemicals.
源自木质纤维素生物质的生物燃料是交通运输所需化石燃料的可行替代品。植物生物质预处理后，呋喃衍生物糠醛会以抑制酵母的浓度存在。因此，糠醛的解毒对于高效发酵很重要。在此，我们在该真菌中寻找可能与糠醛耐受性相关的新遗传特性。糠醛参与该真菌有性孢子萌发的自然过程，且该真菌非常适合进行基因操作，这使其成为本研究的合理候选对象。
采用基于假设和无偏见（随机启动子诱变）的方法来鉴定与对糠醛反应相关的基因。暴露于糠醛后转录谱的变化表明，总体而言，受影响的过程与在[具体真菌名称未给出]中观察到的相似。当羧甲基纤维素作为主要碳源而非蔗糖时，[具体真菌名称未给出]对糠醛的耐受性更高（约高30%），这表明碳水化合物代谢与糠醛耐受性之间存在联系。我们还在一个Δ - 突变体中观察到耐受性增加（CRE - 1是调节真菌利用非首选碳源能力的关键转录因子）。此外，对醛脱氢酶突变体的分析表明，[具体基因名称未给出]（NCU00378）参与对糠醛的耐受性，以及预测的膜转运蛋白NCU05580（[具体基因名称未给出]），它是[另一具体真菌名称未给出]中[具体基因名称未给出]的同源物。除了合理筛选外，无偏见方法还揭示了其他基因，其失活赋予对糠醛更高的耐受性：（i）NCU02488，它影响非锚定细胞壁蛋白NCW - 1（NCU05137）的丰度，以及（ii）锌指蛋白NCU01407。
我们使用互补研究方法在[具体真菌名称未给出]中鉴定了与糠醛耐受性或降解相关的特性。对涉及呋喃敏感性的基因进行操作可为改善生物燃料生产菌株的生产提供一种手段。类似的研究方法可用于[具体真菌名称未给出]和其他丝状真菌，以鉴定与其他呋喃或有毒化学物质相关的其他特性。
