Institute of Biology and Ecology, Faculty of Science, Pavol Jozef Šafárik University in Košice, Košice, Slovak Republic.
Institute of Environmental Research (INFU), Department of Chemistry and Chemical Biology, Technische Universität Dortmund, Dortmund, Germany.
Planta Med. 2020 Sep;86(13-14):997-1008. doi: 10.1055/a-1130-4703. Epub 2020 Apr 15.
Medicinal plants of the genus are rich sources of bioactive naphthodianthrones, which are unique in the plant kingdom, but quite common in fungal endophytes. Cultivable endophytic fungi were isolated from 14 different spp. originating from seeds grown under conditions and further acclimated to outdoor conditions. Among 37 fungal isolates yielded from the aerial and underground plant organs, 25 were identified at the species level by the fungal barcode marker internal transcribed spacer rDNA and protein-coding gene region of . Ten of them were isolated from spp. for the first time. The axenic cultures of the isolated endophytes were screened for the production of extracellular enzymes, as well as bioactive naphthodianthrones and their putative precursors by Bornträger's test and HPLC-HRMS. Traces of naphthodianthrones and their intermediates, emodin, emodin anthrone, skyrin, or pseudohypericin, were detected in the fungal mycelia of and isolated from and , respectively. Traces of emodin, hypericin, and pseudohypericin were released in the broth by , and during submerged fermentation. These endophytes were isolated from several hypericin-producing spp. Taken together, our results reveal the biosynthetic potential of cultivable endophytic fungi harbored in plants as well as evidence of the existence of remarkable plant-endophyte relationships in selected non-native ecological niches. A possible role of the extracellular enzymes in plant secondary metabolism is discussed.
该属植物是生物活性萘并二蒽酮的丰富来源，在植物界中是独特的，但在真菌内生菌中却很常见。从 14 种不同的 种中分离出可培养的内生真菌，这些种源自在受控条件下生长的种子，并进一步适应室外条件。从气生和地下植物器官中分离出的 37 个真菌分离物中，有 25 个通过真菌条形码标记内部转录间隔区 rDNA 和 编码蛋白基因区域在种水平上得到鉴定。其中 10 个是首次从 种中分离出来的。通过 Bornträger 试验和 HPLC-HRMS 对分离出的内生真菌的胞外酶以及生物活性萘并二蒽酮及其潜在前体进行了筛选。在从 和 中分离出的 和 内生真菌的真菌菌丝体中检测到萘并二蒽酮及其中间体大黄素、大黄素蒽酮、斯基林或伪血根碱的痕迹。在液体深层发酵过程中， 和 分别从 和 中释放出大黄素、金丝桃素和伪金丝桃素。这些内生真菌是从几种产生金丝桃素的 种中分离出来的。总之，我们的研究结果揭示了可培养内生真菌在 植物中所具有的生物合成潜力，以及在选定的非本地生态位中存在显著的植物-内生菌关系的证据。还讨论了胞外酶在植物次生代谢中的可能作用。
