On the origin of the invasive olives (Olea europaea L., Oleaceae).

The olive tree (Olea europaea) has successfully invaded several regions in Australia and Pacific islands. Two olive subspecies (subspp. europaea and cuspidata) were first introduced in these areas during the nineteenth century. In the present study, we determine the origin of invasive olives and investigate the importance of historical effects on the genetic diversity of populations. Four invasive populations from Australia and Hawaii were characterized using eight nuclear DNA microsatellites, plastid DNA markers as well as ITS-1 sequences. Based on these data, their genetic similarity with native populations was investigated, and it was determined that East Australian and Hawaiian populations (subsp. cuspidata) have originated from southern Africa while South Australian populations (subsp. europaea) have mostly derived from western or central Mediterranean cultivars. Invasive populations of subsp. cuspidata showed significant loss of genetic diversity in comparison to a putative source population, and a recent bottleneck was evidenced in Hawaii. Conversely, invasive populations of subsp. europaea did not display significant loss of genetic diversity in comparison to a native Mediterranean population. Different histories of invasion were inferred for these two taxa with multiple cultivars introduced restoring gene diversity for europaea and a single successful founder event and sequential introductions to East Australia and then Hawaii for cuspidata. Furthermore, one hybrid (cuspidata x europaea) was identified in East Australia. The importance of hybridizations in the future evolution of the olive invasiveness remains to be investigated

The New Zealand alpine endemic Montigena novae-zelandiae (Fabaceae) shares rhizobial symbionts with Carmichaelia and Clianthus

Thirteen rhizobial strains isolated from New Zealand Carmichaelia spp., Clianthus puniceus, Montigena novae-zelandiae (Montigena) and Sophora spp. and the Australian Swainsona galegifolia in the current or previous studies were tested for their ability to nodulate Montigena. Only rhizobial strains isolated from Carmichaelia spp., and those from Clianthus puniceus that produced functional nodules on their original host, and strains from Montigena produced functional nodules on Montigena. Strains that produced functional nodules on Sophora spp. or Swainsona galegifolia did not nodulate Montigena. Strains that nodulated Montigena, identified here or previously as Mesorhizobium spp., had variable 16S ribosomal RNA, recA and glnII but specific nifH, nodA and nodC genes. Results indicate that Montigena shares rhizobia with its closely related Carmichaelia and Clianthus but not Sophora spp. or Swainsona galegifolia and that the ability of different rhizobial strains to produce functional nodules on Montigena, Carmichaelia and Clianthus puniceus is likely to be dependent on specific symbiosis genes. © 2013 The Royal Society of New Zealand

Relationships, gene flow and species boundaries among New Zealand <i>Fuscospora</i> (Nothofagaceae: southern beech)

<div><p>We analysed DNA profiles at eight simple sequence repeat (SSR) loci for 449 individuals of <i>Fuscospora</i> species from New Zealand. The two species with serrated leaves (<i>F. fusca</i> and <i>F. truncata</i>) are clearly distinct genetically despite the occurrence of wild hybrids. Further, from our results, we infer that they are no more closely related to each other than they are to either of the entire-leaved species (<i>F. cliffortioides</i> and <i>F. solandri</i>). Although genetic groups corresponding with <i>F. cliffortioides</i> and <i>F. solandri</i> can be distinguished, our data suggest that considerable admixture may occur between them in some areas. Nonetheless, the broadly sympatric distribution of these two genetic groups, and their consistency with morphological and ecological groups, support their recognition at species rank rather than their treatment as varieties of one variable species.</p></div

Absence of hybridisation between <i>Fuscospora</i> species at a site in Arthur's Pass National Park, New Zealand

<div><p>We analysed simple sequence repeat markers for a selection of red beech (<i>Fuscospora fusca</i>) and mountain beech (<i>Fuscospora cliffortioides</i>) trees growing together and for seeds collected from them. Our analysis detected neither hybrid trees nor hybrid seeds within our sample. We suggest pre-zygotic reproductive isolating mechanisms such as differences in flowering time may be important in maintaining boundaries between <i>Fuscospora</i> species despite extensive sympatry.</p></div