Monophyly of the Conifer Species in the Ceratocystis coerulescens Complex Based on DNA Sequence Data

Partial Interfertility Among theCeratocystisSpecies on Conifers

“…The large size of many of the hybrid ascospores also suggests aneuploidy or polyploidy. The low vigor of the hybrid progeny indicates that such hybrids would not be fit in nature, and we have not seen evidence for naturally occurring hybrids in Ceratocystis species based on isozyme electromorphs , DNA sequences (Witthuhn et al, 1998), or morphology .…”

“…Of the species in the C. coerulescens complex, C. polonica and C. laricicola are the most closely related Witthuhn et al, 1998), but in numerous attempts in crossing these species, perithecia and ascospores were seen in only one instance, and hybrid progeny were recovered only with difficulty. These species are sympatric across Eurasia, with C. polonica associated with bark beetles on Picea and C. laricicola associated with bark beetles on Larix .…”

“…These species are sympatric across Eurasia, with C. polonica associated with bark beetles on Picea and C. laricicola associated with bark beetles on Larix . Although these two groups show very poor interfertility, they cannot be distinguished on morphology , have identical DNA sequences in the internal transcribed spacer regions (ITS) of the rDNA (Witthuhn et al, 1998), and are distinguished by a single isozyme allele . The fact that pairings of strains of these two groups result in misshapen ascospores of low germination percentage and produce progeny of low vigor supports the contention that the two groups are distinct species.…”

“…In studies on the Ceratocystis species that occur primarily on conifers, we identified seven species based on isozyme patterns , DNA sequences of the internal transcribed spacer region (Witthuhn et al, 1998), as well as morphology and ecology Wingfield et al, 1997). These seven species form a monophyletic group (Witthuhn et al, 1998) and are closely related. They cause bluestain of sapwood in members of the Pinaceae, and three of the species are associates of tree-killing bark beetles.…”

Four new Ceratocystis spp. associated with wounds on Eucalyptus, Schizolobium and Terminalia trees in Ecuador

“…C. Moreau species complex (Hedgcock 1906;Van Wyk et al 2006a) and some of the species related to C. coerulescens (Münch) B.K. Bakshi also cause sap stain particularly in conifers (Wingfield et al 1997;Witthuhn et al 1998). Species in the C. fimbriata Ellis & Halst.…”