Isolation and Identification of Competitive Fungi on Medium for Black Wood Ear Mushroom in Korea and In Vitro Selection of Potential Biocontrol Agents

Abstract

Black wood ear mushroom (<i>Auricularia auricula-judae</i>) is one of the most economically important mushrooms in China, Japan, and Korea. The cultivation of wood ear mushrooms on artificial substrates is more efficient in terms of time and cost compared with their natural growth on trees. However, if the substrate cultivation is infected by fast-growing fungi, the relatively slow-growing ear mushroom will be outcompeted, leading to economic losses. In this study, we investigated the competitive fungal isolates from substrates infected with fast-growing fungi for the cultivation of ear mushrooms in Jangheung and Sunchon, Korea. We collected 54 isolates and identified them by sequencing their internal transcribed spacer region with morphological identification. Among the isolates, the dominant isolates were <i>Trichoderma</i> spp. (92.6%), <i>Penicillium</i> spp. (5.6%), and <i>Talaromyces</i> sp. (1.8%). To find an appropriate eco-friendly biocontrol agent, we used five <i>Streptomyces</i> spp. and Benomyl, as controls against <i>Trichoderma</i> spp. and <i>Penicillium</i> spp. Among the six <i>Streptomyces</i> spp., <i>Streptomyces</i> sp. JC203-3 effectively controlled the fungi <i>Trichoderma</i> spp. and <i>Penicillium</i> spp., which pose a significant problem for the substrates of black wood ear mushrooms. This result indicated that this <i>Streptomyces</i> sp. JC203-3 can be used as biocontrol agents to protect against <i>Trichoderma</i> and <i>Penicillium</i> spp.