Discoloration induced byRaffaelea quercivoraisolates inQuercus serratalogs and its relation to phylogeny: a comparison among isolates with and without the Japanese oak wilt incidence including outside of Japan

Comparison of Sapwood Discoloration in Fagaceae Trees After Inoculation with Isolates of Raffaelea quercivora, Cause of Mass Mortality of Japanese Oak Trees

“…These differences in discoloration may relate to the lower mortality levels of evergreen oaks in the field, because most R. quercivora isolates used in our previous studies were categorized as having low virulence (16,17). The sapwood discoloration widths of these species were comparatively smaller than the deciduous ring-porous Quercus spp.…”

“…The R. quercivora isolates were iso lated from the body surface of P. quercivorus collected in Japan, Taiwan, Vietnam, Thailand, and Indonesia ( Table 1). Phytosanitary certificates and research permissions were obtained from the governmental authorities in each country (16). Isolates with different virulence were selected based on the results of previous studies (Table 1) (16,17).…”

“…However, our understanding about tree-fungus interactions remains limited compared with tree-beetle interactions. Furthermore, Kusumoto et al (16,17) collected fungal isolates from Japan and other Asian countries and showed that the most virulent isolate caused twice as much discoloration in Q. serrata logs than the least virulent isolate. In addition, the authors suggested that the xylem vessel arrangement in fagaceous trees (i.e., ring-, radial-, and diffuse-porous wood) is associated with differences in the tangential spread of sapwood discoloration among host species.…”

New Raffaelea species (Ophiostomatales) from the USA and Taiwan associated with ambrosia beetles and plant hosts

“…Comparison of fungal isolates in this study with known species of Raffaelea revealed that two isolates from Taiwan, Hulcr7167 and Hulcr7176, grouped with R. quercivora . Raffaelea quercivora has been isolated from Platypus quercivorus in Japan, where it is responsible for ongoing epidemics of Japanese oak wilt (Kubono & Ito 2002), as well as in Taiwan (Kusumoto et al 2014). Our isolates of R. quercivora were not isolated from the mycangia or fungal galleries of P. quercivorus , however, but rather from the mycangia of Cyclorhipidion ohnoi and the fungal galleries of Crossotarsus emancipatus from Taiwan.…”

“…in molecular phylogenies of individual rDNA loci (Musvuugwa et al 2015) and additional coding genes (Dreaden et al 2014). Raffaelea quercivora , which is responsible for Japanese oak wilt and associated with Platypus quercivorus (Kubono & Ito 2002, Kusumoto et al 2014), lies within the R. sulphurea complex in Leptographium s. lat. (de Beer & Wingfield 2013, Dreaden et al 2014, Musvuugwa et al 2015).…”