New Leptographium species from Indonesia and Eastern North America

Ophiostomatoid fungi associated with conifer-infesting beetles and their phoretic mites in Yunnan, China

The Ophiostomatales is an Ascomycete order of fungi that accommodates several tree pathogens and many species that degrade wood. These fungi are commonly vectored by Scolytine bark and ambrosia beetles. In recent years it has also been shown that hyperphoretic mites on these beetles can vector some Ophiostomatales. Little is known regarding the Ophiostomatales in China and we have consequently explored the diversity of these fungi associated with conifer-infesting beetles and mites in Yunnan province. Galleries and beetles were collected for 17 beetle species, while 13 mite species were obtained from six of these beetle species. Collectively, 340 fungal isolates were obtained, 45 from beetles, 184 from mites, 56 from galleries and 55 isolates where the specific niche was not clear. DNA sequences for five gene regions (ITS, LSU, BT, EF, and CAL) were determined for fungal isolates representing different morphological groups. Phylogenetic analyses confirmed the presence of 19 fungal taxa, including five novel species described here as Ophiostoma acarorumsp. nov., Ophiostoma brevipilosisp. nov., Graphilbum kesiyaesp. nov., Graphilbum puerensesp. nov., and Leptographium ningerensesp. nov.Ophiostoma ips was the most frequently isolated species, representing approximately 31% of all isolates. Six of 19 taxa were present on mites, beetles and in the galleries of the beetles, while three species were found on mites and galleries. Two species were found only on mites and one species only on a beetle. Although the numbers of beetles and mites were insufficient to provide statistical inferences, this study confirmed that mites are important vectors of the Ophiostomatales in China. We hypothesize that these mites are most likely responsible for horizontal transfer of fungal species between galleries of different beetle species. The fact that half of the fungal species found were new to science, suggests that the forests of east Asia include many undescribed Ophiostomatales yet to be discovered.

Leptographium profanumsp.nov., a new species from hardwood roots in North America

Species of Leptographium are anamorphs of Ophiostoma and best known as associates of tree-infesting bark beetles. The majority of these fungi and their insect associates are found on conifers where they typically cause sap-stain of lumber. A small number of species are also known as tree pathogens. Relatively few Leptographium species are found on angiosperm trees. Species described from these niches have increased in recent years. The objective of this study was to characterize a Leptographium species isolated from the roots of various hardwood trees in the southeastern United States. Morphology of this fungus differed from that of other Leptographium species. Comparisons of DNA sequences for part of the ITS2–28S ribosomal DNA region, the β-tubulin, and the elongation 1-α gene regions also showed that this fungus represents an undescribed taxon. The fungus is thus described as Leptographium profanum sp.nov.