Abstract:
The ophiostomatoid fungi (Microascales and Ophiostomatales, Ascomycota) are common
associates of Ips typographus, and include tree pathogens and species responsible for
blue-stain of timber. Fungal assemblages associated with I. typographus have varied considerably
between studies but few investigations have attempted to explain this variation.
For this reason, we assessed the overall cultivable fungal diversity associated with I. typographus
in a storm-felled spruce forest in south-eastern Finland. Fungi were isolated from
the individually collected beetles as well as their phoretic mites in spring, summer and
autumn, including different life stages of the beetle (hibernation, dispersal flight and first
generation). The internal transcribed spacer (ITS) gene region was used to identify the
fungi. A total of 32 operational taxonomic units (OTUs) were found and these resided in four
fungal phyla/subphyla (24 Ascomycota, 2 Basidiomycota, 5 Mucoromycotina, 1 Mortierellomycotina)
in association with adult bark beetles. Ophiostomatoid species were the most
commonly detected fungal associates. A generalized linear model analysis showed a clear
association between fungal communities and season, indicating seasonal succession
among I. typographus-associated fungi. The season of sampling appears to be an important
factor that has resulted in inconsistencies between results in previous studies. Many of
these fungi were also found on phoretic mites and their presence or absence could have
influenced variation in patterns of association.
Description:
The sequence data
generated in this study are available in GenBank
database (accession numbers KT896627-
KT896658). Representative isolates of
ophiostomatoid fungi are preserved in the Culture
Collection (CMW) of the Forestry and Agricultural
Biotechnology Institute (FABI), University of Pretoria,
South Africa.