Till Petra, Pucher Marion E, Mach Robert L, Mach-Aigner Astrid R
1Christian Doppler Laboratory for Optimized Expression of Carbohydrate-active Enzymes, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria.
2Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria.
Biotechnol Biofuels. 2018 Mar 23;11:78. doi: 10.1186/s13068-018-1081-4. eCollection 2018.
Due to its capability to secrete large quantities of plant biomass degrading enzymes (PBDE), is widely applied for industrial purposes. In nature, expression of PBDE is efficiently regulated in this fungus. Several factors involved in this regulatory network have been identified. However, most of them are transcription factors. Long noncoding RNAs (lncRNAs) emerged as common players acting on epigenetic or transcriptional regulation in several eukaryotic organisms. To date, no lncRNA has been described in filamentous fungi.
A lncRNA termed was identified in QM9414. In this study, it was characterized and evidence for its regulatory impact on cellulase expression was provided. Interestingly, different versions of were identified in different strains (namely, QM6a, QM9414, and Rut-C30), varying in terms of RNA length. Remarkably, considerable longer variants of this lncRNA are present in hypercellulolytic strains compared to the wild-type strain QM6a. Based on these results, a correlation between RNA length and the functional impact of on PBDE expression was supposed. This assumption was verified by overexpressing the most abundant versions identified in QM6a, QM9414, and Rut-C30. Such overexpression on the one hand was suitable for regaining the function in disruption strains, and on the other hand resulted in notably higher cellulase activities in QM6a, especially by the expression of longer versions.
With for the first time the regulatory role of a lncRNA in filamentous fungi was uncovered. Besides this, a new player involved in the complex regulation of PBDE expression in was identified. Due to its enhancing effect on cellulase activity, was shown to be not only interesting for basic research, but also a promising candidate for expanding the set of biotechnological tools for industrial application of .
由于其能够分泌大量植物生物质降解酶（PBDE），因此被广泛应用于工业用途。在自然界中，这种真菌中PBDE的表达受到有效调控。已经确定了参与该调控网络的几个因素。然而，其中大多数是转录因子。长链非编码RNA（lncRNA）在几种真核生物中作为表观遗传或转录调控的常见参与者出现。迄今为止，丝状真菌中尚未描述lncRNA。
在QM9414中鉴定出一种名为 的lncRNA。在本研究中，对其进行了表征，并提供了其对纤维素酶表达调控影响的证据。有趣的是，在不同菌株（即QM6a、QM9414和Rut-C30）中鉴定出了不同版本的 ，其RNA长度不同。值得注意的是，与野生型菌株QM6a相比，高纤维素分解菌株中存在相当长的这种lncRNA变体。基于这些结果，推测RNA长度与 对PBDE表达的功能影响之间存在相关性。通过过表达在QM6a、QM9414和Rut-C30中鉴定出的最丰富的 版本，验证了这一假设。一方面，这种 过表达适用于在 破坏菌株中恢复功能，另一方面，导致QM6a中的纤维素酶活性显著提高，特别是通过较长版本的 表达。
首次发现了lncRNA在丝状真菌中的调控作用。除此之外，还鉴定出了参与 中PBDE表达复杂调控的一个新因子。由于其对纤维素酶活性的增强作用， 不仅对基础研究具有重要意义，而且是扩展 工业应用生物技术工具集的一个有前途的候选者。
