Kweon Heo

A footprint of past climate change on the diversity and population structure of Miscanthus sinensis

BACKGROUND AND AIMS Miscanthus is a perennial C4 grass that is a leading potential feedstock crop for the emerging bioenergy industry in North America, Europe and China. However, only a single, sterile genotype of M. × giganteus (M×g), a nothospecies derived from diploid M. sinensis (Msi) and tetraploid M. sacchariflorus (Msa), is currently available to farmers for biomass production. To facilitate breeding of Miscanthus, this study characterized genetic diversity and population structure of Msi in its native range of East Asia. METHODS A total of 767 accessions were studied, including 617 Msi from most of its native range in China, Japan and South Korea, and 77 ornamental cultivars and 43 naturalized individuals from the USA. Accessions were evaluated with 21 207 restriction site-associated DNA sequencing single nucleotide polymorphism (SNP) markers, 424 GoldenGate SNPs and ten plastid microsatellite markers. KEY RESULTS Six genetic clusters of Msi from geographically distinct regions in Asia were identified. Genetic data indicated that (1) south-eastern China was the origin of Msi populations found in temperate eastern Asia, which is consistent with this area probably having been a refugium during the last glacial maximum (LGM); (2) Msi migrated directly from south-eastern China to Japan before migrating to the same latitudes in China and Korea, which is consistent with the known sequence of warming post-LGM; (3) ornamental Msi cultivars were derived from the southern Japan population, and US naturalized populations were derived from a sub-set of the ornamental cultivars; and (4) many ornamental cultivars previously described as Msi have hybrid ancestry from Msa and Msi, whereas US naturalized populations of Msi do not. CONCLUSIONS Population structure of Msi was driven by patterns of warming since the LGM, and secondarily by geographical barriers. This study will facilitate germplasm conservation, association analyses and identification of potential heterotic groups for the improvement of Miscanthus as a bioenergy crop.

Genetic structure of Miscanthus sinensis and Miscanthus sacchariflorus in Japan indicates a gradient of bidirectional but asymmetric introgression

Summary Using high-density genetic markers, gene flow is identified from diploid Miscanthus sinensis to tetraploid M. sacchariflorus in Japan, in contrast to genetic isolation between these species in China.

Leaf anatomy and its implications for phylogenetic relationships in Taxaceae s. l.

The comparative study on leaf anatomy and stomata structures of six genera of Taxaceae s. l. was conducted. Leaf anatomical structures were very comparable to each other in tissue shape and their arrangements. Taxus, Austrotaxus, and Pseudotaxus have no foliar resin canal, whereas Amentotaxus, Cephalotaxus, and Torreya have a single resin canal located below the vascular bundle. Among them, Torreya was unique with thick-walled, almost round sclerenchymatous epidermal cells. In addition, Amentotaxus and Torreya were comprised of some fiber cells around the vascular bundle. Also, Amentotaxus resembled Cephalotaxusharringtonia and its var. nana because they have discontinuous fibrous hypodermis. However, C. fortunei lacked the same kind of cells. Stomata were arranged in two stomatal bands separated by a mid-vein. The most unique stomatal structure was of Taxus with papillose accessory cells forming stomatal apparatus and of Torreya with deeply seated stomata covered with a special filament structure. Some morphological and molecular studies have already been discussed for the alternative classification of taxad genera into different minor families. The present study is also similar to these hypotheses because each genus has their own individuality in anatomical structure and stomata morphology. In conclusion, these differences in leaf and stomata morphology neither strongly support the two tribes in Taxaceae nor fairly recognize the monogeneric family, Cephalotaxaceae. Rather, it might support an alternative classification of taxad genera in different minor families or a single family Taxaceae including Cephalotaxus. In this study, we would prefer the latter one because there is no clear reason to separate Cephalotaxus from the rest genera of Taxaceae. Therefore, Taxaceae should be redefined with broad circumscriptions including Cephalotaxus.

Antisense-overexpression of the MsCOMT gene induces changes in lignin and total phenol contents in transgenic tobacco plants.

Initially, we isolated the caffeic acid O-methyltransferase (COMT) gene from Miscanthus sinensis (accession number HM062766.1). Next, we produced transgenic tobacco plants with down-regulated COMT gene expression to study its control of total phenol and lignin content and to perform morphological analysis. These transgenic plants were found to have reduced PAL and ascorbate peroxidases expression, which are related to the phenylpropanoid pathway and antioxidant activity. The MsCOMT-down-regulated plants had decreased total lignin in the leaves and stem compared with control plants. Reduced flavonol concentrations were confirmed in MsCOMT-down-regulated transgenic plants. We also observed a morphological difference, with reduced plant cell number in transgenic plants harboring antisense MsCOMT. The transgenic tobacco plants with down-regulated COMT gene expression demonstrate that COMT plays a crucial role related to controlling lignin and phenol content in plants. Also, COMT activity may be related to flavonoid production in the plant lignin pathway.

Reproductive morphology ofMegaleranthis saniculifolia Ohwi (Ranunculaceae) and its systematic implications

To confirm the taxonomic treatment ofMegaleranthis saniculifolia Ohwi, an endemic genus and species in Korea, we compared its reproductive morphological characteristics with those ofTrollius and other genera within the Ranunculaceae. Although its external morphology might suggest thatMegaleranthis differs fromTrollius, Calathodes, and etc., we found no distinctly different features in this genus. Likewise, previous studies of their pollen structures, chromosome data, and petal morphology have indicated no differences betweenMegaleranthis andTrollius. In fact, related genera share similar characteristics, such as a tetrasporangia anther, glandular tapetum, simultaneous cytokinesis, an anatropous and bitegmic ovule, embryo sac formation of thePolygonum type, exarillate and copious albuminous seed, and several apocarps. Although the unique feature of having both tenuinucellate and crassinucellate ovules simultaneously may initially seem particular toMegaleranthis, it is present in other genera of the same family. Therefore, based on this evidence of reproductive morphology and other information, we suggest thatM. saniculifolia is closely related toTrollius, and should be included within that genus, i.e., asT. chosenensis Ohwi. Nevertheless, we have tentatively placedMegaleranthis within its own monotypic and endemic genus until definitive data become available.

Contrasting allelic distribution of CO/Hd1 homologues in Miscanthus sinensis from the East Asian mainland and the Japanese archipelago

Highlight Homologues of CONSTANS/Heading date 1 were cloned from Miscanthus sinensis and named MsiHd1. MsiHd1a in most Japanese accessions contained non-functional alleles, whereas Asian mainland accessions harboured only functional alleles.

Comparative leaf anatomy of native and cultivated Pinus (Pinaceae) in Korea: implication for the subgeneric classification

Comprehensive comparative anatomy of Pinus leaves was carried out. Some anatomical features were found to be quite useful and supported the classification of genus to subgenus and section level. The number of needles per fascicle, number of vascular bundles, position of resin ducts, shape of leaf in cross section, and distribution of stomata on the leaf surface showed remarkable variation between different species and facilitated the classification of Pinus into minor groups: subgenus, section, and subsection. The members of subgenus Pinus had two vascular bundles whereas members of subgenus Strobus had only one vascular bundle. The position of resin ducts was more consistent in subgenus Strobus than in subgenus Pinus. Interestingly, the species of subsection Strobus included in this study lacked stomata on the abaxial surface. The results indicate that the number of needles per fascicle and needle size are inversely related, and more importantly that a greater numbers of needles per fascicle lead to a more angular shape.

Characterization of Inorganic Components, Free Sugars, Amino Acids, and Fatty Acids in Angelica gigas Nakai

*Gangneung Science and Industry Promotion Agency, Gangneung 25451, Korea.**Bioherb Research Institute, Kangwon National University, Chuncheon 24341, Korea.***Department of Agricultural Life Science, Kangwon National University, Chuncheon 24341, Korea.****Department of Bioconvergence Science and Technology, Kangwon National University, Chuncheon 24341, Korea.ABSTRACTBackground : The major compounds of Angelica species are decursin, decursinol angelate, nodakenin, umbelliferone and β-sito-sterol, which act anti-inflammatories, reduce pains, protect the liver and enhance the immune system. This study investigated thechemical compositions, minerals, metals, sugars and overall amino acid composition in Angelica gigas Nakai.Methods and Results : Powder of Angelica roots smaller than 30 mesh were used. Physico-chemical analysis revealed the pres-ence of carbohydrates (62.0%), crude proteins (13.9%), moisture (11.4%), crude fats (7.3%) and ash (5.4%). Results showed thatpotassium was present in the highest amount (1,859 ppm), followed by magnesium (214.5 ppm), calcium (147.3 ppm) and sodium(6.0 ppm). Free sugar profiles showed the presence of sucrose (29.3 g/100 g). The total amino acids concentrations was 9,752㎎/100 g, the most common and dominant amino acids were arginine (2,181㎎/100 g), glutamic acid (1,212㎎/100 g) and asparticacid (834 ㎎/100 g). The total free amino acids contents was 1,476 ㎎/100 g, in which the most common amino acid were arginine(932 ㎎/100 g), glutamic acid (127㎎/100 g), and γ-aminobutyric acid (80.4㎎/100 g). The fatty acid composition of A. gigasshowed a higher concentration of unsaturated fatty acids such as linoleic acid (443.9㎎/100 g) and palmitic acid (181.3㎎/100 g)according to gas chromatography.Conclusions : These results showed that Angelica roots can be used in various fields of foods and medicines, and in the preparationof cosmetics.Key Words : Angelica gigas Nakai, Amino Acids, Fatty Acids, Free Sugar, General Component Analysis

Comparative wood anatomy of Taxaceae

Abstract. Comparative wood anatomy of Taxaceae s.l. was examined to elucidate the differences in wood features among genera. In total, 25 samples, comprising three varieties and seven species from five genera (Pseudotaxus was not included), were examined. Sliding microtome, wood maceration and scanning electron microscopy methods were used for the study. The growth rings are well developed and early and late wood are distinguishable in a cross-section. In general, there is remarkable uniformity in the characteristics of the five genera of Taxaceae, although some differences in quantitative traits were found. Wood of Taxaceae s.l. differs from that of most conifers by having helical thickening in the tracheid inner walls, with the exception of Austrotaxus spicata R.H.Compton. All genera are characterised by the absence of resin canals, predominantly uniseriate pits on the radial wall of the axial tracheids, and the presence of pits on the tangential walls of the axial tracheids. The rays are composed solely of parenchyma cells and are uniseriate (occasionally biseriate in Torreya nucifera (L.) Siebold et Zucc.), with a height of 1–22 cells. The genus Taxus shares more characteristics with Torreya than with Amentotaxus, Austrotaxus and Cephalotaxus. Correspondingly, Amentotaxus and Cephalotaxus resemble each other, marked by the presence of either diffuse or sparse axial parenchyma with nodulated transverse walls. Austrotaxus spicata is the sole species that lacks helical thickenings in the tracheid walls and has sparse axial parenchyma with smooth transverse walls. These two features, namely, the absence of helical thickenings and axial parenchyma with smooth transverse walls, are plesiomorphic and might be considered a more primitive character in wood anatomy. Among the other four genera, Amentotaxus appears to have an annular type of wall thickening that could be considered plesiomorphic to the spiral thickenings found in Taxus, Torreya and Cephalotaxus.

Establishment of Miscanthus sinensis with decreased lignin biosynthesis by Agrobacterium–mediated transformation using antisense COMT gene

This study was to determine a transformation system for Miscanthus sinensis, and to optimize factors and conditions required for expression of an antisense caffeic acid O-methyltransferase gene in the M. sinensis (MsCOMT-AS). Transformation of callus derived from seeds and immature inflorescences of M. sinensis was established by using Agrobacterium tumefaciens strain LBA4404 harboring a binary vector pMBP1. In order to establish the stable transformation system, several transformation factors such as explant type, strain, co-culture periods, acetosyringone concentration, and selective markers were assessed. In this study, seven putative transgenic plants were obtained from callus transformation and plantlet regeneration. Various tests including PCR analysis and RT-PCR were used to detect the transgenic insert. The transgenic plants were also characterized for their agronomic and morphological characteristics, expression of MsCOMT-AS gene, and variation in lignocellulosic content. Biomass related traits such as plant height, number of leaves, length of leaf, stem diameter, fresh weight, dry weight, and cell size of the control plants were superior to transgenic plants. Total lignin content of transgenic plants was lower than that of the control plant due to reduced caffeic acid O-methyltransferase (COMT) gene expression related to lignin production. Cellulose and hemicellulose content in transgenic plants were not increased. Variation in cellulose and hemicellulose content had no correlation with variation in lignin content of transgenic plants. In conclusion, transgenic M. sinensis was obtained with down-regulated COMT gene. Lignin synthesis was decreased what offers possibility of crop modification for facilitated biofuel production.