This expanded survey of ITS sequences represents the largest analysis of molecular data ever attempted on Eucalyptus. Sequences of the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA were included in an analysis of 90 species of Eucalyptus s.s. and 28 species representing eight other genera (Allosyncarpia, Angophora, Arillastrum, Corymbia, Eucalyptopsis, Stockwellia, Lophostemon and Metrosideros). The results of the study indicate that Angophora and Corymbia form a well-supported clade that is highly differentiated from Eucalyptus s.s. Corymbia species are divided between two clades, one of which may be the sister to Angophora. Allosyncarpia, Arillastrum, Eucalyptopsis and ‘Stockwellia’ are also highly differentiated from Eucalyptus s.s. If the genus Eucalyptus is to be expanded to include Angophora and Corymbia(sensu Brooker 2000), ITS data suggest that Allosyncarpia, Eucalyptopsis, ‘Stockwellia’ and potentially Arillastrum should also be included in Eucalyptus s.l. The ITS data suggest that subg. Symphyomyrtus is paraphyletic and that subg. Minutifructus should be included within it. Within subg.Symphyomyrtus, only sect. Maidenaria appears to be monophyletic. Sections Adnataria and Dumaria are probably monophyletic; sections Exsertaria and Latoangulatae are very close and probably should be combined in a single section. Section Bisectae is polyphyletic and is divided into two distinct lineages. The phylogenetic groups depicted by ITS data are consistent with the frequency of natural inter-specific hybridisations as well as data from controlled crosses within subgenus Symphyomyrtus. The ITS data illustrate that subg. Idiogenes and western Australian monocalypts are early evolutionary lines relative to E. diversifolia, E. rubiginosa (monotypic subg. Primitiva) and the eastern monocalypts and that subg. Primitiva should be sunk into subg. Eucalyptus. Subgenus Eudesmia may be monophyletic, grouping with subgenera Idiogenes and Eucalyptus. Further work is required to confirm the phylogenetic positions of the monotypic subgenera Alveolata, Cruciformes, Acerosae and Cuboidea.

Variation in the chloroplast genome of 44 accessions representing 14 Eucalyptus L'Hér. species from the series Viminales (sensu Pryor and Johnson 1971) was investigated. Southern analysis of the chloroplast genomes restricted with 12 enzymes revealed 20 restriction-site polymorphisms of which 7 were autapomorphic to individual trees. The 13 informative restriction-site polymorphisms were distributed between individuals of different species, but none was species-specific. Fourteen chloroplast haplotypes were identified for south-eastern Australian individuals. In endemic Tasmanian species, five haplotypes were identified. Chloroplast haplotypes appear to have a mosaic distribution in south-eastern Australia, more closely associated with geographical regions than with morphological species boundaries. The biogeographic distribution of chloroplast haplotypes may be explained by a combination of interspecific hybridisation and introgression, and convergent evolution. The lack of species-specificity of cpDNA variation indicates that, although cpDNA is not appropriate for species-level phylogeny analysis in the series Viminales, it may provide useful information in studies of biogeography and gene flow in Eucalyptus.

No abstract

We present a set of 35 chloroplast microsatellite primers for Eucalyptus. Ten of the microsatellites displayed intraspecific polymorphism, and identified nine haplotypes among 16 Eucalyptus globulus individuals. Primer conservation was high, with a polymerase chain reaction (PCR) success rate of 98% when tested on four other Eucalyptus species and seven additional myrtaceous genera. Chloroplast microsatellites have applications in phylogeographic studies, fingerprinting and progeny analysis.