Molecular phylogeny and evolution of floral characters of Artemisia and allies (Anthemideae, Asteraceae): evidence from nrDNA ETS and ITS sequences

Taxon (Impact Factor: 3.05). 01/2008; 57(1):66-78.

ABSTRACT To better understand the evolutionary history of the genus Artemisia (Anthemideae, Asteraceae) and its relationships to other genera of the subtribes Artemisiinae, Leucantheminae and Tanacetinae, 63 sequences of the external and 10 of the internal transcribed spacer of nuclear ribosomal DNA (ETS and ITS) were newly generated. Analyses were performed on the combined dataset using maximum parsimony, maximum likelihood and Bayesian inference. The combined analysis supports that all Artemisiinae genera included plus Hippolytia (subtribe Tanacetinae) and Nipponanthemum (subtribe Leucantheminae) constitute a monophyletic group. Within this group, a successive branching shows three monophyletic groups: (1) Nipponanthemum/Hippolytia/Brachanthemum; (2) the Dendranthema group; and (3) the Artemisia/Kaschgaria group. Within the latter, a new sister-group relationship is found between the monophyletic genus Kaschgaria and the Artemisia group, which comprises two main evolutionary lineages: (i) the Dracunculus clade including various Artemisia species and four Asian genera: Filifolium, Mausolea, Neopallasia and Turaniphytum; and (ii) the remaining subgenera of Artemisia plus the two North American genera: Picrothamnus and Sphaeromeria. Within this phylogenetic framework the evolution of two important characters (capitula and pollen type) in the group was inferred. Character reconstruction reveals that discoid capitula and Anthemis pollen type are the ancestral condition in the subtribe. The Artemisia/Kaschgaria lineage probably originated from an ancestor with disciform capitula, central hermaphrodite florets and Artemisia pollen type. Molecular evidence of several biogeographical migration routes of the genus Artemisia is presented.

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    ABSTRACT: Two possible intergeneric putative hybrids between Cancrinia maximowiczii and an interspecific hybrid (Chrysanthemum naktongense × Chrysanthemum ×morifolium ‘Aifen’) were produced without emasculation. The putative hybrids could be identified by ITS sequences and morphological characteristics. The distinct trait of the putative hybrids presented itself by 7-13 white tubular florets bursting out in the outer capitula. Results of flow cytometry analysis and chromosome counting did not support the nature of the putative hybrids. It was found that the ploidy levels of the putative hybrids and parents are diploid, hexaploid and diploid respectively. Whether the paternal parent is a donor of the genome or not, need to be analyzed further by GISH. We propose that C. maximowiczii may be transferred to the subtribe Artemisiinae based on ITS phylogenetic analysis, although the position of the species and the genus Cancrinia could not be confirmed here.
    Genetic Resources and Crop Evolution 02/2014; 62(2). DOI:10.1007/s10722-014-0153-y · 1.48 Impact Factor
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    ABSTRACT: An intergeneric hybrid between Hippolytia kaschgarica (maternal plant) and Nipponanthemum nipponicum (paternal plant) was produced without emasculation for the first time. This proves a close relationship between Hippolytia and Nipponanthemum, once again. The hybrids could be identified by nuclear ribosomal DNA internal transcribed spacer (ITS) sequences and morphological characteristics. The composition of the hybrid capitulum was a mix between both parents. It was basically similar to the maternal plant (Hippolytia) with yellow (actinomorphic) tubular florets, but supplemented with 5-13 white tetramerous, or pentamerous tubular florets bursting out in the outer whirl, being more distinctive and bigger. Instead of ligulate white ray florets of the paternal plant (Nipponanthemum), they were tubular (actinomorphic). The same phenomenon recently appeared in the intergeneric hybrid between Cancrinia maximowiczii (tubular) and the interspecific hybrid of Chrysanthemum naktongense × Chrysanthemum ×morifolium ‘Aifen’ (ligulate, daisy-like). The shape of the achenes of our new hybrid is quite similar to that of the paternal parent with pappus of separate unequal subulate scales, or awns. In the maternal parent, pappus is absent. Similarly to the referred intergeneric hybrid, this new viable hybrid might be used as bridge for breeding multi-generic hybrids within the Compositae tribe Anthemideae. Since the molecular mechanism behind the novel phenotype of the new hybrid has not been explored in Chrysanthemum, this is discussed here with recent findings in Senecio, Gerbera and Helianthus. One of the CYCLOIDEA-like genes that control floral symmetry, CYC2c is required for zygomorphy in normal ligulate ray florets. In novel intergeneric hybrids, ray florets remain actinomorphic (tubular), however. Some causes are tackled.
    Genetic Resources and Crop Evolution 02/2014; 62(2). DOI:10.1007/s10722-014-0150-1 · 1.48 Impact Factor
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    ABSTRACT: To assess temporal origins and diversification of lineages within subtribe Artemisiinae and Artemisia group a penalized likelihood analysis was applied on nrDNA ITS and ETS of 63 representatives. The tree was calibrated at the stem node of the Kaschgaria/Artemisia lineage with the most reliable early Artemisia fossil pollen record from Late Oligocene (23 Ma). The results from this study suggest that the origin of the subtribe goes back to the Late Oligocene (24.6 ± 2.6 Ma) whilst the onset of differentiation of the genus Artemisia and most closely related genera is dated to the Early Miocene (19.8 ± 2.3 Ma). Divergence ages for lineages within the Artemisia group are often between the Early and Middle Miocene, whereas their radiations mostly occurred in the Late Miocene and Pliocene. The temporal context was also used to examine biogeographic and morphological (capitula and pollen type) evolution. Within the Artemisia group all lineages except the North American endemic have colonized the Mediterranean Basin at different epochs from Asian ancestors. Our analyses suggest the divergence of the North American endemic group from Asian ancestors (10.8 ± 1.5 Ma) in the Late Miocene. Homogamous-discoid capitula, characteristic of subgenera Seriphidium and Tridentatae, evolved not only in different geographic regions, but also at different times (2.0 ± 0.8 Ma and 7.9 ± 0.9 Ma respectively) within the Artemisia group. The loss of fertility of central flowers of disciform capitula should be considered as an ancient event in the genus since subgenus Dracunculus is one of the first groups that diverged (17.6 ± 2.1 Ma).
    Collectanea Botanica 12/2011; 30:7-15. DOI:10.3989/collectbot.2011.v30.001


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