Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Resolving reticulate evolutionary histories of polyploid species of Azorella (Apiaceae) endemic to New Zealand(Elsevier Inc, USA, 2026-01) Ning W; Meudt HM; Nicolas AN; Plunkett GM; Heenan PB; Lee WG; Tate JAGenera with species of multiple ploidy levels provide models to understand successive rounds of whole genome duplication leading to intricate reticulate relationships of polyploid plant species. Here, we studied 17 polyploid taxa (species, subspecies, or varieties) in Azorella (Apiaceae) sections Schizeilema and Stilbocarpa that are mostly endemic to New Zealand. Using phylogenomic approaches, our goals were to resolve species relationships, determine the origins of the higher-level polyploids (6x and 10x), and assess the biogeography of the New Zealand Azorella species. Phylogenomic analysis of Anigosperms353 baits-captured Hyb-Seq data, together with comparison of phylogenies reconstructed using genome-skimming retrieved nrDNA and plastome sequences, showed that species diversification within New Zealand may relate to multiple origins from South America, which has been further shaped by additional rounds of polyploidy as well as hybridization or introgression. The two Azorella sections in New Zealand likely resulted from different biogeographic events from South America − one to the subantarctic islands (section Stilbocarpa) and a second to the South Island (section Schizeilema). In addition, within section Schizeilema, species have dispersed from the South Island (New Zealand) to Australia, the subantarctic islands, and the North Island (New Zealand). Our combined approach of phylogenomic analyses of plastome and nuclear locus-based data, together with SNP-based network approaches allowed us to determine the origins of some higher-level polyploids in New Zealand Azorella and revealed a more complex picture of historical and ongoing polyploidy and hybridization within these lineages.Item Forget-me-not phylogenomics: Improving the resolution and taxonomy of a rapid island and mountain radiation in Aotearoa New Zealand (Myosotis; Boraginaceae)(Elsevier Inc., 2024-11-22) Meudt HM; Pearson S; Ning W; Prebble JM; Tate JAIsland and mountain systems represent natural laboratories for studies of species radiations, but they often present several challenges for phylogenetic inference and species delimitation. The southern hemisphere forget-me-nots (Myosotis, Boraginaceae) comprise a geologically recent radiation centred in New Zealand, a mountainous archipelago, with about 50 species that are morphologically and ecologically divergent but lack genetic variation sufficient to resolve phylogenetic relationships and species boundaries using standard DNA Sanger sequencing markers, AFLPs, or microsatellites. Many of these Myosotis species are geographically restricted in alpine areas, uncommon or threatened, have polyploid and dysploid genomes, and are of high taxonomic and conservation priority. Here we present phylogenomic analyses using target-capture of Angiosperms353 baits, and genome skimming of whole plastomes and nrDNA, to improve resolution of the radiation, explore biogeographic and morphological patterns within it, and address specific taxonomic questions for each species. Our comprehensive sampling includes over 300 individuals representing nearly all species from Aotearoa New Zealand and Australia, which is ∼ 2-3 × more taxon sampling and ∼ 80-120 × more molecular data than previously published for Myosotis. Exploration of different data filtering, curation and analyses (coalescent vs. concatenation) improved the resolution of the Angiosperms353 tree, which despite short backbone branches with low support values, showed taxonomic and geographic patterns, including multiple switches between ebracteate and bracteate inflorescences and multiple expansions within New Zealand from Te Waipounamu South Island to Te Ika-a-Māui North Island, Rakiura Stewart Island, subantarctic islands, and Australia. Some of these patterns were also seen in the genome skimming datasets, and comparison of the three datasets was useful for improving our understanding of the taxonomy and resolution of this radiation. Although this phylogenomic study does not fully overcome all of the challenges regarding species delimitation of this rapid island and mountain species radiation, it nevertheless makes an important contribution to an integrative taxonomic revision of the southern hemisphere species of Myosotis.