Grosmannia and Leptographium spp. associated with conifer-infesting bark beetles in Finland and Russia, including Leptographium taigense sp. nov.

Abstract

Species of Grosmannia with Leptographium anamorphs include important forest pathogens and agents of blue stain in timber. They are commonly found in association with forest pests, such as bark beetles. During a survey of ophiostomatoid fungi in eastern parts of Finland and neighboring Russia, species belonging to the genus Grosmannia were isolated from 12 different bark beetle species infesting Picea abies and Pinus sylvestris, the most economically important conifers in the region. Identification of these fungi was based on morphology, DNA sequence comparisons for three gene regions and phylogenetic analyses. A total of ten taxa were identified. These belonged to six different species complexes in Grosmannia. The phylogenetic analyses provided an opportunity to redefine the G. galeiformis-, L. procerum-, L. lundbergii-, G. piceiperda-, G. olivacea- and G. penicillata-complexes, and to consider the species emerging from the survey within the context of these complexes. The species included G. galeiformis, G. olivacea, L. chlamydatum, L. lundbergii, L. truncatum and a novel taxon, described here as L. taigense sp. nov. In addition, species closely related to G. cucullata, G. olivaceapini comb. nov., G. piceiperda and L. procerum were isolated but their identity could not be resolved. The overall results indicate that the diversity of Grosmannia species in the boreal forests remains poorly understood and that further studies are needed to clarify the status of several species or species complexes.

Mating type markers reveal high levels of heterothallism in Leptographium sensu lato

“…piceiderda B', 'G. piceiperda C' and G. aenigmatica) considered in this study grouped in a single, well supported clade, consistent with the G. piceiperda complex previously defined Linnakoski et al, 2012). This suggests that these species might share a common homothallic ancestor.…”

“…Species in Leptographium sensu lato have been assigned to different complexes based on their relatedness in phylogeny, morphological characters, as well as their ecology Linnakoski et al, 2012). Results of the present study showed that those species belonging to the same complex consistently share the same mode of sexual reproduction.…”

Taxonomy and phylogeny of the Leptographium procerum complex, including Leptographium sinense sp. nov. and Leptographium longiconidiophorum sp. nov.

“…In one of these complexes, L. procerum was the oldest known species and thus became the name-bearing species of the complex. At present, the L. procerum complex includes eight species (Linnakoski et al 2012). Interestingly, apart from L. procerum (Kendrick 1962) and L. profanum described from USA, and L. sibiricum from Russia (Jacobs et al 2000), all other species in the complex have been described from East Asia (Linnakoski et al 2012).…”

“…At present, the L. procerum complex includes eight species (Linnakoski et al 2012). Interestingly, apart from L. procerum (Kendrick 1962) and L. profanum described from USA, and L. sibiricum from Russia (Jacobs et al 2000), all other species in the complex have been described from East Asia (Linnakoski et al 2012). Leptographium pinidensiflorae was described from Japan (Masuya et al 2000), L. bhutanense from Bhutan , and L. sinoprocerum (Lu et al 2008), L. gracile and L. latens (Paciura et al 2010) from China.…”

“…However, Paciura et al (2010) and Linnakoski et al (2012) showed that the ITS2-LSU and bT gene regions have limitations in distinguishing closely related species in the L. procerum complex. Duong et al (2012) thus sequenced an additional two gene regions, calmodulin (CAL) and actin (ACT) and with sequences for five gene regions, were able to successfully delineate morphologically similar but cryptic species in the neighboring G. serpens complex in Leptographium s. l.…”