State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China.
Analysis Center of Agrobiology and Environmental Science, Zhejiang University, Hangzhou, China.
Microbiologyopen. 2019 Apr;8(4):e00666. doi: 10.1002/mbo3.666. Epub 2018 Jun 21.
The endophytic fungi Muscodor spp. produce volatile organic compounds (VOCs) which can inhibit and even kill pathogenic fungi, bacteria, and nematodes. Nine endophytic fungal strains, isolated from the shoots of gramineous plants including Arthraxon hispidus, Eleusine indica, Oplismenus undulatifolius, and Oryza granulata, were identified as Muscodor through phylogenetic analysis of the internal transcribed spacer. Through an SPSS K-means cluster analysis, the nine Muscodor strains were divided into four groups based on the antifungal activities of the VOCs produced by these fungi determined by a two-section confrontation test. The first group contains the strains Y-L-54, W-S-41, Y-S-35, W-T-27, and Y-L-56, which showed the strongest activity. The second and third groups contain W-S-35 and Y-L-43, which showed stronger and moderate activity, respectively. The fourth group contains W-S-38 and N-L-7, which were the weakest in inhibiting the tested pathogens. Thirty-five compounds and the relative amounts of VOCs were determined by SPME-GC-MS and comparison with the NIST14 mass spectrometry database and Agilent MassHunter qualitative and quantitative analyses. These 35 compounds were classified into two different categories: (a) the product of fatty acid degradation, and (b) the intermediate and final metabolite of the metabolic pathway with the precursor of mevalonic acid. SPSS clustering analysis showed that the chemical components of VOCs might be correlated with their bioactivity rather than their phylogenetic assignment and some of the identified compounds might be responsible for antifungal activity. In conclusion, new Muscodor endophytes were recorded in tropical gramineous plants and a number of strains showed remarkable bioactive properties. Therefore, they have important potential applications in the fields of plant disease control.
内生真菌 Muscodor 属产生挥发性有机化合物（VOCs），可以抑制甚至杀死病原真菌、细菌和线虫。从禾本科植物的茎中分离到的 9 株内生真菌菌株，通过对其内部转录间隔区的系统发育分析，鉴定为 Muscodor。通过 SPSS K-均值聚类分析，根据这些真菌产生的 VOCs 的抗真菌活性，将 9 株 Muscodor 菌株分为 4 组，通过两节对峙试验确定。第一组包含 Y-L-54、W-S-41、Y-S-35、W-T-27 和 Y-L-56 菌株，其活性最强。第二组和第三组包含 W-S-35 和 Y-L-43 菌株，其活性分别较强和中等。第四组包含 W-S-38 和 N-L-7 菌株，它们对测试的病原体抑制作用最弱。通过 SPME-GC-MS 并与 NIST14 质谱数据库和 Agilent MassHunter 定性和定量分析进行比较，确定了 35 种化合物和 VOCs 的相对含量。这些化合物分为两类：（a）脂肪酸降解产物，（b）以甲羟戊酸前体为起始物的代谢途径的中间和最终代谢物。SPSS 聚类分析表明，VOCs 的化学成分可能与其生物活性相关，而不是与其系统发育分配相关，一些鉴定出的化合物可能与抗真菌活性有关。总之，在热带禾本科植物中记录了新的 Muscodor 内生真菌，一些菌株表现出显著的生物活性特性。因此，它们在植物病害防治领域具有重要的潜在应用价值。
