Youngbae Suh

Phylogenetic relationships in family Magnoliaceae inferred from ndhF sequences

The ndhF sequences of 99 taxa, representing all sections in extant Magnoliaceae, were analyzed to address phylogenetic questions in the family. Magnolia macrophylla and M. dealbata, North American species of Magnolia section Rytidospermum, are placed at the base in the subfamily Magnolioideae although its supporting value is low. In the remaining taxa, several distinctive lineages are recognized: (1) Magnolia, the biggest genus in the family, is not monophyletic; (2) Michelia, including section Maingola of Magnolia subgenus Magnolia, is closely related with Elmerrillia and sections Alcimandra and Aromadendron of Magnolia subgenus Magnolia; (3) the associates of Michelia are grouped with Magnolia subgenus Yulania and section Gynopodium of Magnolia subgenus Magnolia; (4) Pachylarnax forms a clade with sections Manglietiastrum and Gynopodium of Magnolia; (5) a well-supported Manglietia clade is recognized; (6) Caribbean species of section Theorhodon of Magnolia subgenus Magnolia, which are section Splendentes sensu Vázquez-Garcia, are closely allied with New World members of Magnolia subgenus Talauma; and (7) section Rytidospermum of Magnolia subgenus Magnolia and subgenus Talauma are polyphyletic. The separated clades in the molecular tree are considerably different from traditional taxonomic dispositions in the family. The molecular data strongly suggest that a taxonomic realignment of infrafamilial delimitations and compositions should be considered.

DNA sequences from Miocene fossils: an ndhF sequence of Magnolia latahensis (Magnoliaceae) and an rbcL sequence of Persea pseudocarolinensis (Lauraceae)

We report a partial ndhF sequence (1528 bp) of Magnolia latahensis and a partial rbcL sequence (699 bp) of Persea pseudocarolinensis from the Clarkia fossil beds of Idaho, USA (Miocene; 17-20 million years [my] BP). The ndhF sequence from M. latahensis was identical to those of extant M. grandiflora, M. schiediana, M. guatemalensis, and M. tamaulipana. Parsimony analysis of the ndhF sequence of M. latahensis and previously reported ndhF sequences for Magnoliaceae placed M. latahensis within Magnolia as a member of the Theorhodon clade. This result is reasonable considering that: (1) the morphology of M. latahensis is very similar to that of extant M. grandiflora, and (2) a recent molecular phylogenetic study of Magnoliaceae showed that the maximum sequence divergence of ndhF among extant species is very low (1.05% in subfamily Magnolioideae) compared with other angiosperm families. We reanalyzed the previously reported rbcL sequence of M. latahensis with sequences for all major lineages of extant Magnoliales and Laurales. This sequence is sister to Liriodendron, rather than grouped with a close relative of M. grandiflora as predicted by morphology and the results of the ndhF analysis, possibly due to a few erroneous base calls in the sequences. The rbcL sequence of P. pseudocarolinensis differed from rbcL of extant Persea species by 3-6 nucleotides and from rbcL of extant Sassafras albidum by two nucleotides. Phylogenetic analyses of rbcL sequences for all major lineages of Magnoliales and Laurales placed the fossil P. pseudocarolinensis within Lauraceae and as sister to S. albidum. These results reinforce the suggestion that Clarkia and other similar sites hold untapped potential for molecular analysis of fossils.

Phylogenetic Relationships of Maples (Acer L.; Aceraceae) Implied by Nuclear Ribosomal ITS Sequences

Acer. ITS 1 sequences in twenty-eight species of Acer and a species of Dipteronia in the family Aceraceae ranged from 220 to 242 bp and ITS 2 sequences from 215 to 251 bp. The size of the 5.8S coding region was 164 bp for all species examined in the family. Phylogenetic analysis of ITS sequences placed a very robust clade of section Palmata at the base of the tree. Three species of section Parviflora sensu de Jong (1994), A. spicatum, A. distylum and A. nipponicum, did not form a monophyletic clade. Acer spicatum was separated from the robust clade of A. distylum and A. nipponicum. Molecular tree strongly supports the close relationship among section Platanoidea, Glabra series Arguta, and section Macrantha. The close relationship between sections Pentaphylla and Trifoliata was also strongly suggested in ITS tree. Sections Rubra and Hyptiocarpa appeared to be closely allied with each other. The average rate of nucleotide substitution was estimated as (8.0±1.9)×10−11 substitutions per site per year for ITS 1 and (9.0±1.6) ×10−11 for ITS 2.

Phylogeny of Magnoliaceae Based on Ten Chloroplast DNA Regions

Phylogenetic analyses of ten chloroplast DNA regions, ndhF, rbcL, matK, ORF350, trnL intron, trnL-trnF, trnH-psbA, rbcL-atpB, trnK 5′ intron, and trnK 3′ intron (8,719 bp in aligned sequences) from 48 selected taxa were carried out to address phylogenetic questions in the family Magnoliaceae. The major clades in the molecular tree are considerably different from the currently suggested classification system and from the traditionally recognized subgroups in the family. Eleven major clades were recognized with strong support in the subfamily Magnolioideae: (1) MICHELIA clade: Michelia, Elmerrillia, sect. Maingola, sect. Alcimandra, and sect. Aromadendron, (2) YULANIA clade: subgen. Yulania, (3) GYNOPODIUM clade: Pachylarnax, sect. Manglietiastrum, and sect. Gynopodium, (4) KMERIA clade: Kmeria, (5) THEORHODON clade: sect. Theorhodon sensu stricto (excluding sect. Splendentes, which was recently separated from sect. Theorhodon) and sect. Magnolia, (6) GWILLIMIA clade: sect. Gwillimia, sect. Lirianthe, and sect. Blumiana, (7) TALAUMA clade: sect. Talauma and sect. Splendentes, (8) MANGLIETIA clade: Manglietia, (9) RYTIDOSPERMUM clade: sect. Rytidospermum sensu stricto (excluding Magnolia fraseri, M. macrophylla, and M. dealbata) and sect. Oyama, (10) FRASERI clade: M. fraseri, and (11) MACROPHYLLA clade: M. macrophylla and M. dealbata. The recognition of eleven major clades in the subfamily Magnolioideae in this study is in good agreement with previous molecular studies based on less sampling or fewer DNA regions. All of these eleven clades were highly supported with bootstrap values exceeding 80% in both maximum parsimony and maximum likelihood analyses and with posterior probabilities exceeding 0.98 in a Bayesian analysis. However, detailed relationships among the major clades were weakly supported. The molecular data suggest that the taxonomic circumscription of infrafamilial delimitations and compositions should be reconsidered.

PHYLOGENETIC UTILITY OF rbc S SEQUENCES: AN EXAMPLE FROM ANTITHAMNION AND RELATED GENERA (CERAMIACEAE, RHODOPHYTA)

We report the potential phylogenetic utility of the small RUBISCO subunit (rbc S) sequences from a sampling of Antithamnion and related genera in ceramiacean algae. The size of rbc S was 417 bp for all taxa examined. Analyses of the DNA sequence data indicated that pairwise divergences of rbc S sequences were 3.3%–9.8% among species of Antithamnion, and ranged from 13.6% to 18.0% between Antithamnion and related genera. Phylogenetic analyses fully resolved relationships at the intrageneric level with statistical significance supported by high bootstrap values. Two subgenera of Antithamnion, Pteroton and Antithamnion, were clearly distinguished in the molecular tree. In the clade of subgenus Pteroton, A. aglandum was allied with A. callocladum and separated from A. nipponicum. In the pairwise distance comparison of sequence variation, Ceramium showed the greatest genetic distances among genera examined in the study. All phylogenetic trees generated by the maximum parsimony, neighbor joining, and maximum likelihood were completely congruent in topology with high confidence.

PHYLOGENETIC RELATIONSHIPS OF SARGASSUM SUBGENUS BACTROPHYCUS (SARGASSACEAE, PHAEOPHYCEAE) INFERRED FROM RDNA ITS SEQUENCES

Sargassum, the largest genus in Phaeophyceae with more than 400 described species, is distributed in the tropical to temperate regions of all around the world (Yoshida 1983). Agardh (1889) divided genus Sargassum into five subgenera: Phyllotrichia, Schizophycus, Bactrophycus, Arthrophycus and Sargassum (= Eusargassum), and these subgenera are further subdivided into sections, subsections and series (Phillips 1995). Among the subgenera of Sargassum, Bactrophycus is known only in the eastern Asiatic region, where it is considered as an ecologically important group by forming massive vegetations at subtidal and lower intertidal zones (Tseng et al. 1985). On the basis of basal morphology, stem, main branch and reproductive structures, Yoshida (1983) subdivided subgenus Bactrophycus into four sections: Spongocarpus, Teretia, Halochloa, and Repentia. Tseng (1985) added a fifth section Phyllocystae, but it was transferred to the subgenus Sargassum on the basis of molecular data as well as the morphology of receptacles and basal leaves (Stiger et al. 2000). In result, thirty-one species in four sections of subgenus Bactrophycus have been described to date (Tseng et al. 1985; Stiger et al. 2000). Since species of Bactrophycus show a wide range of morphological variation like other subgenera of genus Sargassum, it is difficult to elucidate phylogenetic relationships with morphological characters (Kilar et al. 1992). Therefore, there are a few studies available on phylogenetic relationships in the genus even though extensive studies have been carried out on morphological aspects (Yendo 1907; Setchell 1933, 1936; Okamura 1936; Yoo 1976; Yoshida Algae Volume 17(4): 235-247, 2002

Determination of five active compounds in Artemisia princeps and A. capillaris based on UPLC-DAD and discrimination of two species with multivariate analysis.

Five active compounds, chlorogenic acid, 3,5-di-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid, jaceosidin, and eupatilin, in Artemisia princeps (Compositae) were simultaneously determined by ultra-performance liquid chromatography connected to diode array detector. The morphological resemblance between A. princeps and A. capillaris makes it difficult to properly identify species properly. It occasionally leads to misuse or misapplication in Korean traditional medicine. In the study, the discrimination between A. princeps and A. capillaris was optimally performed by the developed validation method, which resulted in definitely a difference between two species. Also, it was developed the most reliable markers contributing to the discrimination of two species by the multivariate analysis methods, such as a principal component analysis and a partial least squares discrimination analysis.

Molecular evidence for recognizing Antithamnion sparsum (Ceramiales, Rhodophyta) at the species level

S.-R. Lee, I. K. Lee and Y. Suh. 2005. Molecular evidence for recognizing Antithamnion sparsum (Ceramiales, Rhodophyta) at the species level. Phycologia 44: 530–535. The nucleotide sequences of rbcS and Rubisco spacer in the chloroplast genome, and the internal transcribed spacer (ITS) 1 and the small subunit ribosomal DNA in the nuclear genome were determined to clarify the taxonomic relationships of Antithamnion sparsum with its close allies. The species has been often considered to be conspecific with A. densum, but this taxonomic placement still remains to be confirmed. Phylogenetic analyses based on multiple molecular markers clearly distinguished A. sparsum from A. densum. In addition, the Atlantic A. densum from Kerry, Ireland, was clearly separated from the North Pacific A. defectum from San Juan Island, Washington. Comparative analyses of four DNA regions showed that the rbcS region provided the most useful information with the highest resolution and statistical support among the four DNA regions studied. Molecular evidence strongly suggests that A. sparsum should be treated as an independent species.

Allozyme Variation and Genetic Relationships among Species of Cimicifuga (Ranunculaceae) from Korea.

Allozyme investigation of the five Cimicifuga taxa in Korea was conducted to assess genetic and clonal diversity within populations and genetic divergence among populations and taxa. Levels of allozyme variation maintained in Korean Cimicifuga taxa were comparable to those for most herbaceous perennials. In general, samples excluding copies of the same multilocus genotype maintained higher levels of genetic diversity than the total samples within populations. Copies of homozygous genotypes at several loci resulting from clonal spread lead to decreased levels of genetic diversity within populations, indicating that clonal reproduction found in Cimicifuga affects population genetic structure. In general, more widely distributed species such as C. dahurica and C. japonica harbored higher levels of allozyme diversity than the other taxa examined. Although two varieties of C. heracleifolia are geographically and reproductively isolated, the genetic and clonal structure of var. bifida seems to resemble var. heracleifolia, indicating that the two varieties may have had a similar evolutionary history. However, the allozyme data strongly indicate that the two morphological types (Groups I and II) of C. simplex should be treated as separate species.

Korea Barcode of Life Database System (KBOL)

A major concern regarding the collection and storage of biodiversity information is the inefficiency of conventional taxonomic approaches in dealing with a large number of species. This inefficiency has increased the demand for automated, rapid, and reliable molecular identification systems and large-scale biological databases. DNA-based taxonomic approaches are now arguably a necessity in biodiversity studies. In particular, DNA barcoding using short DNA sequences provides an effective molecular tool for species identification. We constructed a large-scale database system that holds a collection of 5531 barcode sequences from 2429 Korean species. The Korea Barcode of Life database (KBOL, http://koreabarcode.org) is a web-based database system that is used for compiling a high volume of DNA barcode data and identifying unknown biological specimens. With the KBOL system, users can not only link DNA barcodes and biological information but can also undertake conservation activities, including environmental management, monitoring, and detecting significant organisms.