Swift Current Research and Development Centre, Agriculture and Agri-Food Canada, Box 1030, Swift Current, Saskatchewan S9H 3X2, Canada.
Mycologia. 2022 May-Jun;114(3):476-486. doi: 10.1080/00275514.2022.2051986. Epub 2022 May 18.
The antagonistic activities of three potential biocontrol agents (BCAs), , and , were tested in vitro against the target fungi , and . In vitro dual-culture assay revealed that the BCAs were able to inhibit the mycelial growth of most of the target fungi, with the most common mode of action being mycoparasitism. After 5 d of incubation, depending on the host-parasite interface, biotrophic mycoparasitism was observed via attachment structures on , and . Haustoria and appressoria were formed by and on and , respectively. Clamp-like structures were also produced by both BCAs, depending on the host fungus. formed only contact points on its hosts. Coiling structure was observed with and occasionally in pure culture but more abundantly in the dual-culture assay. After an additional 3 to 5 d of incubation, the BCAs started damaging their host cells. Asexual fruiting bodies of the BCAs spread necrotrophically on and and began destroying their mycelia after the initial 5 d of incubation. Furthermore, mycelial dissolution of by an excreted substance was observed at a distance before direct contact with . The diffuse metabolite assay revealed that the highest inhibition of the three BCAs was on and their least effectiveness was observed on . Overall, these results provide evidence that , and are potential candidates for biological control of the tested target fungi. This constitutes the first report that these three BCAs are able to establish an initial biotrophic relationship followed by a necrotrophic lifestyle. In addition, has not previously been reported as a BCA.
三种潜在生防菌（BCA）、、和的拮抗活性在体外对靶真菌、和进行了测试。体外双培养试验表明，BCA 能够抑制大多数靶真菌的菌丝生长，最常见的作用模式是菌寄生。培养 5d 后，根据宿主-寄生虫界面，通过、上的附着结构观察到生营养菌寄生。和分别在、上形成了吸器和附着胞。BCA 还产生了类似的附着器结构。和仅在其宿主上形成接触点。和偶尔在纯培养中观察到卷曲结构，但在双培养试验中更为丰富。培养 3 至 5d 后，BCA 开始破坏其宿主细胞。BCA 的无性繁殖体在和上呈坏死性扩散，并在最初的 5d 培养后开始破坏其菌丝。此外，在与直接接触之前，通过分泌的物质观察到对的菌丝溶解。弥散代谢物测定表明，三种 BCA 对和的抑制作用最高，对的抑制作用最小。总的来说，这些结果为、和是测试靶真菌生物防治的潜在候选物提供了证据。这是首次报道这三种 BCA 能够建立初始的生营养关系，然后是坏死性生活方式。此外，以前没有报道过作为 BCA。
