Abstract:
Leptographium procerum (Ophiostomatales,
Ascomycota) is a well-known fungal associate
of pine root-infesting bark beetles and weevils, occurring
in several countries of the world. The fungus is not
a primary pathogen but has been associated with white
pine root decline in the USA and with serious damage
caused by the introduced red turpentine beetle (RTB)
Dendroctonus valens in China. Several species closely
related to L. procerum have been described during the
past decade. The aim of this study was to reevaluate
species boundaries in the L. procerum complex using
multigene phylogenetic analyses and morphological
comparisons. Phylogenetic analyses of seven gene
regions (ITS2-LSU, actin, b-tubulin, calmodulin,
translation elongation factor 1-a, and the mating
type genes MAT1-1-3 and MAT1-2-1) distinguished between nine species in the complex. These included
L. procerum, L. bhutanense, L. gracile, L. profanum,
L. pini-densiflorae, L. sibiricum, L. sinoprocerum, as
well as two new species described here as Leptographium
sinense sp. nov. from Hylobitelus xiaoi on Pinus
elliottii in China, and Leptographium longiconidiophorum
sp. nov. from Pinus densiflora in Japan.
Leptographium latens is reduced to synonymy with
L. gracile, and an epitype is designated for L.
procerum, because a living culture associated with
the holotype of L. procerum did not exist. Amplification
patterns of the mating type genes suggest that
all known species in the L. procerum complex are
heterothallic, although sexual states have not been
observed for any of the species. The results also suggest
that Eastern Asia is most probably the centre of species
diversity for the L. procerum complex.
