School of Ecology and Conservation, University of Agricultural Sciences, GKVK Campus, Bengaluru, 560065, India; School of Biosciences and Technology, Vellore Institute of Technology, Vellore, 632014, India.
School of Biosciences and Technology, Vellore Institute of Technology, Vellore, 632014, India.
Microbiol Res. 2021 Jan;242:126595. doi: 10.1016/j.micres.2020.126595. Epub 2020 Sep 17.
Antagonism of plant pathogenic fungi by endophytic fungi is a well-known phenomenon. In plate assays, the antagonism could be due to mycoparasitism, competition for space or antibiosis, involving a chemical diffusate, or a volatile organic compound (VOC). In this study, we demonstrate that besides mycoparasitism, VOCs play a major role in antagonism of pathogenic fungi by four endophytic fungi belonging to the genus Trichoderma. Using a double-plate assay, we show that all the four endophytic Trichoderma species significantly inhibited mycelial growth of three of the four pathogens, (Sclerotinia sclerotiorum-TSS, Sclerotium rolfsii-CSR and Fusarium oxysporum-CFO), while that of Macrophomina phaseolina-CMP was not affected. GC-MS analysis of the pure cultures of one of the endophytic fungi studied, namely, Trichoderma longibrachiatum strain 2 (Acc. No. MK751758) and the pathogens, F. oxysporum-CFO and M. phaseolina-CMP revealed the presence of several VOCs including hydrocarbons, alcohols, ketones, aldehydes, esters, acids, ethers and different classes of terpenes. In mixed double plates, where the endophyte was grown along with either of the two plant pathogens, F. oxysporum-CFO or M. phaseolina-CMP, there was an induction of a number of new VOCs that were not detected in the pure cultures of either the endophyte or the pathogens. Several of these new VOCs are reported to possess antifungal and cytotoxic activity. We discuss these results and highlight the importance of such interactions in endophyte-pathogen interactions.
植物病原真菌的拮抗作用是一种众所周知的现象。在平板测定中，拮抗作用可能是由于真菌寄生、空间竞争或抗生性引起的，涉及化学扩散物或挥发性有机化合物（VOC）。在这项研究中，我们证明了除了真菌寄生作用外，VOCs 在四种内生真菌（属于 Trichoderma 属的真菌）对病原真菌的拮抗作用中起主要作用。使用双平板测定法，我们表明所有四种内生 Trichoderma 种都显著抑制了三种病原体（Sclerotinia sclerotiorum-TSS、Sclerotium rolfsii-CSR 和 Fusarium oxysporum-CFO）的菌丝生长，而 Macrophomina phaseolina-CMP 的菌丝生长不受影响。对所研究的内生真菌之一，即 Trichoderma longibrachiatum 菌株 2（Acc. No. MK751758）和病原体 F. oxysporum-CFO 和 M. phaseolina-CMP 的纯培养物进行 GC-MS 分析，发现了几种 VOC，包括碳氢化合物、醇、酮、醛、酯、酸、醚和不同类别的萜烯。在混合双板中，内生真菌与两种植物病原体之一，即 F. oxysporum-CFO 或 M. phaseolina-CMP 一起生长，会诱导产生许多在纯培养物中未检测到的新 VOC内生菌或病原体。这些新 VOC 中的几种被报道具有抗真菌和细胞毒性活性。我们讨论了这些结果，并强调了这种相互作用在内生菌-病原体相互作用中的重要性。
