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    Evolutionary relationships in Santalales inferred using target capture with Angiosperms353, focusing on Australasian Santalaceae sensu lato
    (CSIRO Publishing, Australia, 2025-08) Anderson BM; Edlund M; James SA; Lepschi BJ; Nickrent DL; Sultan A; Tate JA; Petersen G; Murphy D
    The angiosperm order Santalales comprises more than 2500 species, most of which are hemi- or holoparasitic on other plants, and derive water and nutrients via specialised structures that attach to host roots or stems. The parasitic lifestyle has affected the morphology and genomes of these plants, and classification of the order has been difficult, with outstanding questions about membership of and relationships between families in the order. We chose to focus on improving phylogenetic sampling in the broadly circumscribed Santalaceae sens. lat., with emphasis on Australasian members of Amphorogynaceae and Viscaceae as part of the Genomics for Australian Plants Initiative. We used target capture with the Angiosperms353 bait set to generate a dataset of 318 nuclear loci × 195 samples, including publicly available data from other Santalales families. Phylogenetic inferences using maximum likelihood concatenation and a summary coalescent approach were largely congruent and resolved relationships between most families, agreeing with much of the previous work on the order. Some relationships that have been difficult to resolve remained so, such as branching order among some families in Olacaceae sens. lat. and Santalaceae sens. lat. Denser sampling in Amphorogynaceae and Viscaceae provided new insights into species-level relationships in genera such as Leptomeria and Choretrum, and allowed testing of recent phylogenetic work in Korthalsella. Our new phylogenetic hypothesis is consistent with one origin of root hemiparasitism, two origins of holoparasitism and five origins of aerial parasitism in the order. Although Angiosperms353 was successful, some phylogenetic bias in gene recovery suggests that future studies may benefit from more specific baits and deeper sequencing, especially for Viscaceae.
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    Systematics, biology and ecology of New Zealand's pygmy mistletoes (Korthalsella: Viscaceae) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Ecology at Massey University, Manawatu, New Zealand
    (Massey University, 2014) Sultan, Amir
    New Zealand’s pygmy mistletoes belong to the genus Korthalsella Tieghem, which comprises about 30 species ranging from Malesia to Hawaii, the Marquesas and Henderson Islands in the east, Japan in the north, Australia, New Zealand in the south, and Ethiopia and Madagascar to the west. Mainland Australia, Hawaii, Malesia and Madagascar all have high levels of species richness. This thesis shows that Korthalsella has high levels of regional endemism and has widespread parallelism and supports the biogeographic model of speciation, whereas, the traditional sections based on morphology are not supported. Korthalsella is represented in New Zealand by a monophyletic clade of three species K. clavata (Kirk) Cheeseman, K. lindsayi (Oliver ex J. D. Hooker) Engl., and K. salicornioides (A. Cunningham) Tiegh. Korthalsella clavata and K. lindsayi are both generalists with relatively broad host ranges whereas K. salicornioides is a specialist species with most host records from two myrtaceous genera Kunzea Rchb. (kanuka) and Leptospermum J. R. Forst & G. Forst (manuka). Cross-infection experiments in Korthalsella salicornioides indicate the presence of putative Kunzea- and Leptospermum-specific races with better success rates of seedling survival when maternal and recipient hosts were the same. However, genetic data based on nuclear internal transcribed spacer (ITS) and chloroplast trnQ-rps16 spacer sequences does not support the presence of host related variability and the within-species genetic structure appears to be geographic rather than host-based. My study shows that both cpDNA haplotypes and ITS sequence types are shared between K. clavata and K. lindsayi, which possiby is an outcome of hybridisation and introgression between the two species. Korthalsella salicornioides is an ambophilous species relying both on insects and on wind for effective pollination, whereas K. lindsayi is an anemophilous species. This study confirms the presence of explosive seed discharge in both species with dispersal distances ranging up to 4 and 7 m in K. lindsayi and K. salicornioides, respectively. However, dispersal distances of around 1 m are more typical. This study also describes the first account of clonal propagation by means of proliferation of endophyte and formation of adventitious sprouts in these species. Several new natural enemies specialising on New Zealand Korthalsella were discovered - two specialist armoured scales (Leucaspis albotecta Henderson and L. trilobata Henderson), a felt scale (Eriococcus korthalsellae Henderson), and two pathogenic ascomycetes Guignardia korthalsellae Sultan, Johnston, Park & Robertson and Rosenscheldiella korthalsellae Sultan, Johnston, Park & Robertson. Other natural enemies include a specialist gall mite Aceria korelli Manson, whereas generalists include native and adventive scale insects and generalist Lepidoptera. Demographic study of several populations revealed that all species have high growth rates and high ramet turnover. Korthalsella salicornioides and K. clavata had relatively stable recruitment rates in all size/stage classes whereas K. lindsayi populations were apparently declining at the two study sites.