Fungi Isolated from Pine Wood Nematode, Its Vector Japanese Pine Sawyer, and the Nematode-Infected Japanese Black Pine Wood in Korea

Abstract

Pine tree death caused by pine wood nematode (PWN) involves phoretic relationships between PWN and its vector Japanese pine sawyer beetle (JPS). In an effort to understand the diversity of fungi involved in PWN life cycle, a total of 176 fungal isolates were collected from PWNs, adults and larvae of JPS, PWN-diseased Japanese black pine that was cut down in 2005 at Jinju, Korea. Based on microscopic observation and colony morphology, and sequence analysis of the ITS rDNA, the fungal isolates were identified at the level of genus. Three genera including Mucor, Ophiostoma, and Penicillium were identified from PWN. Two genera of Ophiostoma and Penicillium were discovered from JPS larvae. From JPS adult beetles, nine genera of Aspergillus, Gibberella, Hypocrea, Irpex, Leptosphaeria, Ophiostoma, Penicillium, and Plectosphaerella and unknown basidiomycetes were found. Ten genera from PWN-infected wood were confirmed as Bionectria, Botrytis, Camarops, Fusarium, Hypocrea, Nectrtia, Mucor, Ophiostoma, Penicillium, and Trichoderma. Penicillium and Ophiostoma were commonly distributed on PWN and its vector and host. This is first report of the fungi associated with PWN and its vector and host in Korea.

A native fungal symbiont facilitates the prevalence and development of an invasive pathogen–native vector symbiosis

“…Ophiostomatoid fungi were isolated from the pinewood nematode and its vector in South Korea. However, it is possible that the fungi might be introduced into pine trees by secondary bark beetle colonization of the trees (Donald et al 2003, Hyun et al 2007). Here we demonstrate that Sporothrix sp.…”

“…Importantly, these dying pine trees were infested with bark beetles (Coleoptera: Scolytinae) that carry a wide range of ophiostomatoid (blue stain) fungi (Donald et al 2003). It is these fungi, including Ophiostoma ips, O. minus, and Ceratocystis sp., reported from wood infested with the nematode and vector beetles in Japan, Korea, and America, that provide food for the mycophagous phase of the nematode life cycle (Kobayashi et al 1974, Wingfield 1987, Hyun et al 2007). Ophiostomatoid fungi identified in dead trees positively influence reproduction of the pinewood nematode and the interactions of nematode and host pine trees (Maehara 2008, Maehara and Futai 2000, Niu et al 2012.…”

Hyperspectral Analysis of Pine Wilt Disease to Determine an Optimal Detection Index

“…Pine wilt disease, caused by Bursaphelenchus xylophilus, the pine wood nematode (PWN), is one of the most damaging emerging pest problems in forests around the world [1][2][3][4][5]. Since PWN is highly pathogenic, 80% of infested red pine trees die in the first year and the remaining 20% die in the second year; red pine mortality thus quickly reaches 100%.…”

Ophiostoma ipsfrom Pinewood Nematode Vector, Japanese Pine Sawyer Beetle (Monochamus alternatus), in Korea

“…However, it is not yet known which fungal species are associated with the ecosystem of PWN in Korea. In a recent survey of fungi associated with the PWN life cycle eight genera, including Ophiostoma , were isolated from JPS [4]. This study was undertaken to identify one of the Ophiostoma species associated with JPS.…”

“…Initially, three Ophiostoma isolates with very similar colony morphology were selected for this study from the fungal cultures isolated from JPS in the previous study [4]. When we observed their mycelial and spore structures in detail using microscopes, the three isolates were almost the same.…”