Eight new <I>Leptographium</I> species associated with tree-infesting bark beetles in China

Abstract

Leptographium spp. are anamorphs of Grosmannia residing in the order Ophiostomatales. These fungi are typically associated with bark-beetles and are common causal agents of sapstain in lumber and some are important tree pathogens. In this study, Leptographium spp. associated with bark beetles collected during a survey in Jilin and Yunnan provinces of China, were identified. Identifications were achieved using comparisons of morphological characters and DNA sequence data for the ITS2-partial LSU rDNA region, as well as the β-tubulin and EF-1α gene regions. Eight unknown species of Leptographium are recognised and described from conifer and hardwood hosts, associated with beetles including Ips subelongatus, Tomicus yunnanensis, Hylurgops minor, Polygraphus verrucifrons and a Pissodes sp. Six of the new species are morphologically and phylogenetically related to species known to occur in Asia such as G. yunnanense, L. bhutanense, L. bistatum and L. sinoprocerum. The remaining two taxa are related to those in a group containing G. americana and L. abietinum, found in North America. This study also provides the first report of L. pineti on Pinus kesiya in China.

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

“…Group A is the largest group and includes five species, L. bhutanense, L. gracile, L. sinoprocerum, L. sinense and L. longiconidiophorum, while Group C includes two species, L. pini-densiflorae and L. sibiricum. Three of these (L. gracile, L. sinoprocerum, L. sinense) have been reported only from China (Lu et al 2008;Paciura et al 2010; and isolates from the present study). Leptographium longiconidiophorum and L. pini-densiflorae have been recorded only from Japan (Masuya et al 2000; present study), while L. bhutanense is from Bhutan , and L. sibiricum from Russia (Jacobs et al 2000).…”

“…Leptographium longiconidiophorum and L. pini-densiflorae have been recorded only from Japan (Masuya et al 2000; present study), while L. bhutanense is from Bhutan , and L. sibiricum from Russia (Jacobs et al 2000). Most of these species were isolated from pines, but L. gracile (in Group A) has also been collected on spruce (Paciura et al 2010), and L. sibiricum (in Group C) was isolated from Abies (Jacobs et al 2000). The insects associated with species in Groups A and C are mainly weevils and bark beetles, with L. sibiricum being the only exception and collected as an associate of a cerambycid beetle (Jacobs et al 2000).…”

“…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.…”

Phylogeny and taxonomy of species in theGrosmannia serpenscomplex

“…Of the five gene regions used, only ITS2-LSU data did not distinguish among the species. This was not unexpected however because authors (Lim et al 2004, Paciura et al 2010 failed to gain effective resolution of species in the Grosmannia-Leptographium complexes using this gene region. In contrast sequence data from the four protein-coding genes strongly supported the separation of the five species.…”