Fungal associates of the lodgepole pine beetle, Dendroctonus murrayanae

Abstract

Bark beetles are well known vectors of ophiostomatoid fungi including species of Ophiostoma, Grosmannia and Ceratocystis. In this study, the most common ophiostomatoid fungi associated with the lodgepole pine beetle, Dendroctonus murrayanae, were characterized. Pre-emergent and post-attack adult beetles were collected from lodgepole pines at four sites in British Columbia, Canada. Fungi were isolated from these beetles and identified using a combination of morphology and DNA sequence comparisons of five gene regions. In all four populations, Grosmannia aurea was the most common associate (74-100% of all beetles) followed closely by Ophiostoma abietinum (29-75%). Other fungi isolated, in order of their relative prevalence with individual beetles were an undescribed Leptographium sp. (0-13%), Ophiostoma ips (0-15%), Ophiostoma piliferum (0-11%), a Pesotum sp. (0-11%) and Ophiostoma floccosum (0-1%). Comparisons of the DNA sequences of Leptographium strains isolated in this study, with ex-type isolates of G. aurea, Grosmannia robusta, Leptographium longiclavatum, and Leptographium terebrantis, as well as with sequences from GenBank, revealed a novel lineage within the Grosmannia clavigera complex. This lineage included some of the D. murrayane isolates as well as several isolates from previous studies referred to as L. terebrantis. However, the monophyly of this lineage is not well supported and a more comprehensive study will be needed to resolve its taxonomic status as one or more novel taxa.

Phylogeny and taxonomy of species in theGrosmannia serpenscomplex

“…Our results thus suggest that a more accurate position for delineating species would be around 0.9 on the x axis in the dendrogram presented by Zambino and Harrington (1992). This also would reflect more accurately the cut-off for species in the G. clavigera complex further down on their cladogram as delimited in several multigene and population studies (Alamouti et al 2011, Lee et al 2005, Roe et al 2010, Six et al 2011.…”

Large Shift in Symbiont Assemblage in the Invasive Red Turpentine Beetle

“…Similarly, O. abietinum , which is shared between China and ENA, is cosmopolitan, symbiotic with a wide diversity of bark beetles [82,85-87], and is an occasional associate of D. valens in China and ENA (0 to 2.3% and 0.7% respectively). In contrast, the other two species shared between China and ENA, G. koreana and L. procerum , have much more limited ranges.…”

A major symbiont shift supports a major niche shift in a clade of tree‐killing bark beetles

“…Within Dendroctonus, species in the basal clades feed in phloem, do not possess mycangia, and are mainly associated with opportunistic fungi, although exceptions exist (Six and Bentz, 2003;Six et al, 2011). In these cases, the fungi may be carried in pits that act as mycangia, resulting in relatively consistent vertical transmission.…”