Leptographium procerum and the closely related species Leptographium profanum, are ascomycetes
associated with root-infesting beetles on pines and hardwood trees, respectively.
Both species occur in North America where they are apparently native. L. procerum has
also been found in Europe, China New Zealand, and South Africa where it has most probably
been introduced. As is true for many other Leptographium species, sexual states have
never been observed in L. procerum or L. profanum. The objectives of this study were to clone
and characterize the mating type loci of these fungi, and to develop markers to determine
the mating types of individual isolates. To achieve this, a partial sequence of MAT1-2-1 was
amplified using degenerate primers targeting the high mobility group (HMG) sequence. A
complete MAT1-2 idiomorph of L. profanum was subsequently obtained by screening a genomic
library using the HMG sequence as a probe. Long range PCR was used to amplify the
complete MAT1-1 idiomorph of L. profanum and both the MAT1-1 and MAT1-2 idiomorphs
of L. procerum. Characterization of the MAT idiomorphs suggests that the MAT genes are
fully functional and that individuals of both these species are self-sterile in nature with
a heterothallic mating system. Mating type markers were developed and tested on a population
of L. procerum isolates from the USA, the assumed center of origin for this species.
The results suggest that cryptic sexual reproduction is occurring or has recently taken
place within this population.