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Featured researches published by Akiko Soejima.


American Journal of Botany | 2006

Phylogenetic analysis of the grape family (Vitaceae) based on three chloroplast markers

Akiko Soejima; Jun Wen

Seventy-nine species representing 12 genera of Vitaceae were sequenced for the trnL-F spacer, 37 of which were subsequently sequenced for the atpB-rbcL spacer and the rps16 intron. Phylogenetic analysis of the combined data provided a fairly robust phylogeny for Vitaceae. Cayratia, Tetrastigma, and Cyphostemma form a clade. Cyphostemma and Tetrastigma are each monophyletic, and Cayratia may be paraphyletic. Ampelopsis is paraphyletic with the African Rhoicissus and the South American Cissus striata nested within it. The pinnately leaved Ampelopsis form a subclade, and the simple and palmately leaved Ameplopsis constitutes another with both subclades containing Asian and American species. Species of Cissus from Asia and Central America are monophyletic, but the South American C. striata does not group with other Cissus species. The Asian endemic Nothocissus and Pterisanthes form a clade with Asian Ampelocissus, and A. javalensis from Central America is sister to this clade. Vitis is monophyletic and forms a larger clade with Ampelocissus, Pterisanthes, and Nothocissus. The eastern Asian and North American disjunct Parthenocissus forms a clade with Yua austro-orientalis, a species of a small newly recognized genus from China to eastern Himalaya. Vitaceae show complex multiple intercontinental relationships within the northern hemisphere and between northern and southern hemispheres.


Botany | 2007

Phylogeny of Vitaceae based on the nuclear GAI1 gene sequences

Jun WenJ. Wen; Ze-Long NieZ.-L. Nie; Akiko Soejima; Ying MengY. Meng

Phylogenetic analysis of 105 nuclear GA11 sequences of Vitaceae provided a fairly robust phylogeny, largely congruent with the recently published chloroplast data of the family. In the GA11 phylogeny, Cayratia Juss., Tetrastigma (Miq.) Planch., and Cyphostemma (Planch.) Alston form a clade. Cyphostemma and Tetrastigma are both monophyletic, and Cayratia is paraphyletic. Ampelopsis Michx is paraphyletic with the African Rhoicissus Planch. and the South American Cissus striata Ruiz & Pav. and its close relatives (e.g., Cissus simsiana Roem. & Schult.) nested within it. The pinnately leaved Ampelopsis forms a subclade, and the simple and palmately leaved Ampelopsis constitutes another subclade. All species of Cissus L. sampled from Asia, Africa, and Central and South America (except the C striata complex) form a monophyletic group. Pterisanthes Blume of southeastern Asia forms a clade with the Asian Ampelocissus Planch. Vitis L. is monophyletic and forms a larger clade with the tropical Ampelocissus and Pterisanthes. Parthenocissus Planch., forms a clade with Yua C.L. Li, with each genus reportedly monophyletic. Cissus from the Old World is paraphyletic with the neotropical core Cissus nested within it. The basal grade of Cissus consists of taxa from Africa. The African-Asian biogeographic relationships are complex, with several intercontinental disjunctions. The Northern Hemisphere Ampelopsis is most closely related to the South American C. striata complex and the African Rhoicissus.


American Journal of Botany | 2011

Biogeographic disjunction between eastern Asia and North America in the Adiantum pedatum complex (Pteridaceae)

Jin-Mei Lu; De-Zhu Li; Sue Lutz; Akiko Soejima; Ting-Shuang Yi; Jun Wen

PREMISE OF THE STUDY Biogeographic analyses of ferns with an eastern Asian-North American disjunction are few. The Adiantum pedatum complex has such a disjunct distribution. The monophyly of the complex needs to be tested and diversification history of the four species needs to be reconstructed. METHODS Plastid (atpA, atpB, rbcL, trnL-F, and rps4-trnS) sequences of 100 accessions representing the biogeographic diversity of Adiantum were analyzed with parsimony and Bayesian inference. Biogeography of the Adiantum pedatum complex was inferred using programs DIVA and LAGRANGE. Divergence times of clades were estimated with the program BEAST. KEY RESULTS The A. pedatum complex is monophyletic and sister to the eastern Asian A. edentulum. Accessions of A. pedatum do not form a clade; instead three subgroups are recognizable. The clade of A. aleuticum and A. viridimontanum is nested within A. pedatum. The Asian A. myriosorum is sister to the A. pedatum-A. aleuticum clade. Both DIVA and LAGRANGE analyses suggest an eastern Asian origin of the A. pedatum complex. The age of the crown A. pedatum complex is dated to be at 4.27 (2.24-6.57) million years ago. CONCLUSIONS The currently recognized eastern Asian-North American disjunct species A. pedatum needs to be segregated into three species, corresponding to populations in eastern North America, China, and Japan. The eastern Asian-North American disjunction in the complex is inferred to be the result of two intercontinental migrations, one from eastern Asia into North America in the late Tertiary and the other from North America back to eastern Asia in the Pleistocene.


Journal of Plant Research | 1994

Allozyme Diversity and the Evolution of Symplocos (Symplocaceae) on the Bonin (Ogasawara) Islands

Akiko Soejima; Hidetoshi Nagamasu; Motomi Ito; Mikio Ono

To study the origin and speciation of plants in oceanic islands, electrophoretic analyses have been done on three endemic species ofSymplocos in the Bonin Islands as well as on three other species;S. kuroki, S. nakaharae andS. tanakae which are considered to be closely related to the Bonin endemics. There occur three species:S. kawakamii, S. pergracilis andS. boninensis in Bonin. The genusSymplocos is one which is considered to be diversified in the Bonin Islands.Seven enzyme systems presumed to be encoded by 18 loci were examined. The genetic diversity was low in the island species, as reported in some oceanic island plants of Hawaii and the Bonin Islands. The three endemics share high genetic identities and they clustered together in the tree drawn by the UPGMA method, suggesting that they are a monophyletic group, that is, they result from a single introduction.


Taxon | 2007

Phylogeny of Nolana (Nolaneae, Solanoideae, Solanaceae) as inferred from granule-bound starch synthase I (GBSSI) sequences

Michael O. Dillon; Tieyao Tu; Akiko Soejima; Ting-Shuang Yi; Zelong Nie; Alan Tye; Jun Wen

The phylogenetic relationships of Nolana (Nolaneae, Solanaceae) were constructed using partial sequences (ca. 891 bp) of the granule-bound starch synthase I (GBSSI) or the waxy gene. Nolana, with 89 species, is primarily distributed in coastal Chile (49 spp.) and Peru (43 spp.), and of these, four species are recorded in Peru and Chile, and another from the Galapagos Islands, Ecuador. Our phylogenetic analysis, utilizing a sampling of 63 of the 89 species, supports the monophyly of Nolana and recovered three clades with 95%-100% bootstrap support. Nolana sessiliflora is the sister taxon to the remainder of the genus. Two large, highly supported clades are evident; one containing taxa from Chile, Peru and the Galapagos Islands, and another containing taxa from Chile and Peru. Nolana galapagensis, an endemic to the Galapagos Islands, is suggested to be sister to N. arenicola in a clade that also includes N. adansonii from southern Peru and northern Chile. These two species differ substantially in habitat preference, habit, leaf shape, and mericarp morphology. The monophyly is confirmed for a morphologically cohesive group composed of N. acuminata, N. baccata, N. elegans, N. reichei, N. parviflora, N. pterocarpa, and N. paradoxa, a clade of essentially Chilean species.


Journal of Plant Research | 1997

Allozyme diversity ofPittosporum (Pittosporaceae) on the Bonin (Ogasawara) Islands

Motomi Ito; Akiko Soejima; Mikio Ono

The genusPittosporum includes about 160 species. Four species ofPittosporum occur in the Bonin Islands, and all of these are endemic to the islands. Electrophoretic studies of the four endemic species,P. tobira, from the Japanese mainland, andP. lutchuense var.denudatum from the Ryukyu Islands, were used to determine the origin and speciation pattern of the endemic species.259 individuals were sampled from ten populations. Twenty loci in nine enzyme systems were resolved and used to calculate the gene frequencies for each population. A low genetic diversity was observed in three of the Bonin Island species, as is reported for other oceanic island plants. The exception,P. boninense, has the largest population size and widest distribution. A dendrogram generated by the UPGMA method shows two clusters. One consists of only the Bonin endemics, suggesting a monophyletic origin for these species.


Journal of Systematics and Evolution | 2008

Phylogeny and putative hybridization in the subtribe Paranepheliinae (Liabeae, Asteraceae), implications for classification, biogeography, and Andean orogeny

Akiko Soejima; Jun Wen; Mario Zapata; Michael O. Dillon

The nuclear ribosomal ITS region and the chloroplast trnL-trnF (trnLF) intergenic region were se- quenced for 45 accessions of Paranephelius and six accessions of Pseudonoseris, the two genera of the subtribe Paranepheliinae (Liabeae, Asteraceae) distributed in the alpine regions of the Andes. This data set was used to estimate relationships between these genera and within each genus to aid in evaluating morphological variation and classification. Our results with both ITS and trnLF markers support the monophyly of subtribe Paranephelii- nae, and place Pseudonoseris discolor as the first diverged taxon sister to the clade containing Paranephelius. Pseudonoseris szyszylowiczii exhibited intraspecific divergence supporting intergeneric hybridization between Pseudonoseris and Paranephelius. Within Paranephelius, genetic divergence is low and not adequate to fully resolve phylogenetic relationships at the species level, but two genetically and morphologically recognizable groups were revealed by the ITS data. Several accessions possessing multiple ITS sequences represent putative hybrids between the two groups. These putative hybrids have caused some taxonomic confusion and difficulties in establishing species boundaries in Paranephelius. The divergence time estimates based on ITS sequences indi- cated that the stem of subtribe Paranepheliinae dates to 13 million years ago, but the diversification of the crown clade of the extant members began in the early Pleistocene or late Pliocene, perhaps associated with the uplift of the Andes and the climatic changes of global cooling.Sequences of the chloroplast ndhF gene and the nuclear ribosomal ITS regions are employed to reconstruct the phylogeny of Prunus (Rosaceae), and evaluate the classification schemes of this genus. The two data sets are congruent in that the genera Prunus s.l. and Maddenia form a monophyletic group, with Maddenia nested within Prunus. However, the ndhF data set is incongruent with the ITS data supporting two major groups within Prunus: one consisting of subgenera Laurocerasus (including Pygeum) and Padus as well as the genus Maddenia and another of subgenera Amygdalus, Cerasus, and Prunus. The ITS data, on the other hand, support a clade composed of subgenera Amygdalus and Prunus and Prunus sect. Microcerasus in addition to a paraphyletic grade of subgenera Laurocerasus and Padus (and the genus Maddenia) taxa. In general, the subgeneric classifications of Prunus s.l. are not supported. The ITS and ndhF phylogenies differ mainly in interspecific relationships and the relative position of the Padus/Laurocerasus group. Both ITS and ndhF data sets suggest that the formerly recognized genus Pygeum is polyphyletic and that the distinction of the subgenera Padus and Laurocerasus is not supported. The biogeographic interactions of the temperate and tropical members in the Padus/Laurocerasus/Maddenia alliance including Pygeum are shown to be highly dynamic and complex.


Journal of Plant Research | 1995

A chloroplast-DNA phylogeny of Kalimeris and Aster, with reference to the generic circumscription.

Motomi Ito; Akiko Soejima; Mitsuyasu Hasebe; Kuniaki Watanabe

RFLPs of cpDNA of five species and one variety ofKalimeris, and elght species ofAster from Japan were investigated. Approximately 290 restriction sites were surveyed using 16 restriction enzymes. A total of 52 restriction site mutations was detected, and 21 of them were phylogenetically informative. Wagner parsimony analysis resulted in only one most parsimonious tree.In the tree obtained,Kalimeris sensu Kitamura is a colyphyletic group;K. miqueliana belongs to a different clade than the remaining species ofKalimeris. This result suggests that the shortening of the pappus has occurred in parallel in different evolutionary line. Thus, it is not appropriate to extend the generic circumscription ofKalimeris to includeK. miqueliana, based on pappus length. The sister group ofKalimeris, exceptK. miqueliana, is theAster ageratoides group.Aster ovatus is included in theKalimeris clade and it is suggested that it represents an amphidiploid with someKalimeris species as its maternal parent.


Journal of Plant Research | 2004

Phylogenetic analysis of Asian Symplocos (Symplocaceae) based on nuclear and chloroplast DNA sequences

Akiko Soejima; Hidetoshi Nagamasu

Thirty species and one variety of Symplocos (Symplocaceae), including all taxa distributed in Japan, were phylogenetically analyzed with DNA sequence data. The evolution of morphological characters is discussed on the basis of the phylogenetic relationships obtained. All species were Asian, except one, S. austromexicana, from Mexico. The nuclear ribosomal internal transcribed spacer (ITS) region and two intergenic spacer regions, between trnL and trnF, and between trnH and psbA of chloroplast DNA were used. The topologies of trees obtained from ITS and the chloroplast intergenic spacers are largely congruent. S. sonoharae, the representative of the subgenus Symplocos in Asia, was sister to all other species. The position of the American species, S. austromexicana, which also belongs to the subgenus Symplocos, was not well resolved. The phylogenetic tree based on combined sequence data largely supports the monophyletic origin of the infrageneric sections proposed earlier. However, the phylogenetic relationship between them is not well resolved, probably due to rapid diversification. The section Palura, a deciduous group, is well defined in the DNA analysis, suggesting its independent status in the genus Symplocos. In spite of their morphological divergence, the three endemic species of the Bonin Islands are monophyletic. The occurrence of curved seeds seems to be homoplastic, scattered over the phylogenetic tree without showing a particular infrageneric relationship.


Annals of the Missouri Botanical Garden | 2007

CHROMOSOME NUMBERS AND KARYOTYPES IN ASTERACEAE1

Kuniaki Watanabe; Tetsukazu Yahara; Goro Hashimoto; Yoshimi Nagatani; Akiko Soejima; Takayuki Kawahara; Miyuki Nakazawa

Abstract Chromosome numbers were determined from microsporocytes (meiotic counts) and root-tip cells (mitotic counts) in 201 collections of 51 genera and 119 specific and infraspecific taxa belonging to nine tribes of Asteraceae and Acicarpha spathulata R. Br. of Calyceraceae from Australia, Bolivia, Brazil, Chile, Mexico, and the United States. These include the first reports and new numbers for the basal members of the Barnadesieae and Mutisieae. First reports are provided for 45 taxa, including five genera, Dasyphyllum HBK (2n = 54), Dithyrostegia A. Gray (2n = 14), Epitriche Turcz. (2n = 10), Revealia R. M. King & H. Rob. (2n = 22), and Stifftia J. C. Mikan (2n = 54). In addition, new chromosome numbers are established at the generic level in the genera Barnadesia Mutis (2n = 54), Eremanthus Less. (2n = 34, 30), Macvaughiella R. M. King & H. Rob. (2n = 24), and Trichocline Cass. (2n = 38), and in 12 additional species. Remaining counts augment and agree with previously reported determinations. The base chromosome numbers of Calyceraceae and Asteraceae are discussed in published records and our original counts.

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Jun Wen

Chinese Academy of Sciences

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Mikio Ono

Tokyo Metropolitan University

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Takako Nishino

Osaka Prefecture University

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Jun Wen

Chinese Academy of Sciences

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