Department of Chemistry, Werner Siemens Chair of Synthetic Biotechnology, TUM School of Natural Sciences, Technical University of Munich (TUM), Garching, Germany.
Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany.
Microbiologyopen. 2023 Oct;12(5):e1386. doi: 10.1002/mbo3.1386.
Lichens are symbiotic associations consisting of a photobiont (algae or cyanobacteria) and a mycobiont (fungus), which together generate a variety of unique secondary metabolites. To access this biosynthetic potential for biotechnological applications, deeper insights into the biosynthetic pathways and corresponding gene clusters are necessary. Here, we provide a comparative view of the biosynthetic gene clusters of three lichen mycobionts derived from Hypogymnia physodes, Hypogymnia tubulosa, and Parmelia sulcata. In addition, we present a high-quality PacBio metagenome of Parmelia sulcata, from which we extracted the mycobiont bin containing 214 biosynthetic gene clusters. Most biosynthetic gene clusters in these genomes were associated with T1PKSs, followed by NRPSs and terpenes. This study focused on biosynthetic gene clusters related to polyketide synthesis. Based on ketosynthase homology, we identified nine highly syntenic clusters present in all three species. Among the four clusters belonging to nonreducing PKSs, two are putatively linked to lichen substances derived from orsellinic acid (orcinol depsides and depsidones, e.g., lecanoric acid, physodic acid, lobaric acid), one to compounds derived from methylated forms of orsellinic acid (beta orcinol depsides, e.g., atranorin), and one to melanins. Five clusters with orthologs in all three species are linked to reducing PKSs. Our study contributes to sorting and dereplicating the vast PKS diversity found in lichenized fungi. High-quality sequences of biosynthetic gene clusters of these three common species provide a foundation for further exploration into biotechnological applications and the molecular evolution of lichen substances.
地衣是由光合生物（藻类或蓝细菌）和菌根生物（真菌）组成的共生联合体，共同产生各种独特的次生代谢物。为了将这种生物合成潜力应用于生物技术，有必要深入了解生物合成途径和相应的基因簇。在这里，我们提供了三个地衣菌根真菌（Hypogymnia physodes、Hypogymnia tubulosa 和 Parmelia sulcata）的生物合成基因簇的比较视图。此外，我们还提供了 Parmelia sulcata 的高质量 PacBio 宏基因组，从中提取了包含 214 个生物合成基因簇的菌根生物 bin。这些基因组中的大多数生物合成基因簇与 T1PKSs 相关，其次是 NRPSs 和萜类化合物。本研究重点关注与聚酮合成相关的生物合成基因簇。基于酮合酶同源性，我们在所有三个物种中都鉴定出了九个高度同源的簇。在属于非还原 PKS 的四个簇中，有两个可能与来源于 orsellinic 酸（orcinol 去甲二萜和去甲二酮，例如，lecanoric 酸、physodic 酸、lobaric 酸）的地衣物质有关，一个与来源于甲基化 orsellinic 酸的化合物（beta orcinol 去甲二萜，例如，atranorin）有关，一个与黑色素有关。在所有三个物种中都有同源物的五个簇与还原 PKS 有关。我们的研究有助于对地衣真菌中发现的大量 PKS 多样性进行分类和去冗余。这三个常见物种的生物合成基因簇的高质量序列为进一步探索生物技术应用和地衣物质的分子进化提供了基础。
