| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Systematics |
2Royal Botanic Gardens, Kew, Richmond Surrey, TW9 3AB UK; 3Department of Botany, University of Dublin, Trinity College, Dublin 2, Ireland; 4Faculty of Education and Regional Sciences, Tottori University, Tottori 680-8551 Japan
Received for publication March 27, 2001. Accepted for publication July 31, 2001.
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
Key Words: AFLP • in situ hybridization • ITS • FISH • GISH • Miscanthus • Poaceae • polyploidy • trnL-F
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
; Bullard, Heath, and Nixon, 1995
; Bullard, Nixon, and Heath, 1997
). Research investigating the productivity and economic potential of Miscanthus has centered on taxa growing under the names M. sacchariflorus (Maxim.) Benth. et Hook. and M. xgiganteus Greef & Deuter ex Hodkinson & Renvoize (see discussion for further taxonomic details on M. xgiganteus). Miscanthus xgiganteus is also known as M. giganteus, M. sinensis Anderss. ‘Giganteus’, M. ‘Giganteus’, M. ogiformis Honda, and M. sacchariflorus var. brevibarbis (Honda) Adati. It is often confused with M. sacchariflorus, as this species is highly variable in morphology and chromosome number (see DISCUSSION).
Miscanthus xgiganteus was introduced to Denmark from Japan as an ornamental in 1935, and it is probable that rhizome-propagated clones used in agricultural field trials originated from this horticultural introduction. Little is known about the genetic origins of these clones and of other Miscanthus species such as M. sinensis and M. sacchariflorus, but such information is necessary for their successful utilization as a biomass resource (Renvoize, Hodkinson, and Chase, 1997
). Systematic studies of Miscanthus have been complicated by the high frequency of hybridization and polyploidy in these taxa (Bremer, 1934
). For example, published chromosome counts of M. sacchariflorus range from diploid (2n = 2x = 38) to pentaploid (2n = 5x = 95). Lafferty and Lelley (1994)
and others have indicated that many of these may be of hybrid origin (Adati and Shiotani, 1962
).
Miscanthus xgiganteus has been hypothesized to be an allotriploid hybrid (2n = 3x = 57), combining genomes from M. sinensis and M. sacchariflorus (Hirayoshi et al., 1957
; Linde-Laursen, 1993
), but experimental data to confirm this hypothesis are lacking. Hodkinson, Renvoize, and Chase (1997)
provided an historical outline of Miscanthus systematics and a morphological key to identify the species but felt that since morphology alone was insufficient to elucidate the complex hybrid origins of M. xgiganteus and its close relatives, a detailed molecular study was required.
The study reported here used amplified fragment length polymorphism (AFLP), DNA sequences from the nuclear internal transcribed spacer (nrITS) of 18S–5.8S–25S ribosomal DNA, and fluorescent in situ hybridization (FISH) including genomic in situ hybridization (GISH), to investigate the origin of M. xgiganteus. The AFLP technique is highly suited for the assessment of genetic variation within and between closely related species (Vos et al., 1995
; Reeves et al., 1998
; Mueller and Wolfenbarger, 1999
; Ridout and Donini, 1999
; Hodkinson et al., 2000
). Hodkinson, Chase, and Renvoize (in press)
used AFLP and intersimple sequence repeat (ISSR) polymerase chain reaction (PCR) to study infrageneric relationships within the genus Miscanthus and discovered that the closest relatives to M. xgiganteus were M. sinensis and M. sacchariflorus.
Sequencing of the nrITS region of 18S–5.8S–25S ribosomal DNA, nr(rDNA), has proven useful for phylogenetic reconstruction in other plants, including grasses (Baldwin et al., 1995
; Hsiao et al., 1999
), and were therefore applied in this study to investigate the origins of M. xgiganteus. Repeat units of nrDNA are typically homogenized by concerted evolution, so that only one predominant copy is present. For a review of concerted evolution, see Elder and Turner (1995)
. In a hybrid line that has undergone subsequent cycles of sexual reproduction, the process of concerted evolution may homogenize copy types but sometimes favors one parental type over the other (Wendel, Schnabel, and Seelanen, 1995a, b
; Cronn et al., 1996
). In the case of a sterile hybrid such as M. xgiganteus, concerted evolution could not have occurred by unequal crossing over, and two copy types, corresponding to the two parental species, could be detectable. However, some degree of concerted evolution may have occurred by gene conversion. DNA sequences were used in a similar way by Gaut and Doebley (1997)
to investigate the segmental allotetraploid origin of maize.
Nuclear DNA sequences, such as ITS, are also subject to recombination and, following a number of generations, individual repeats of the ITS sequence cannot only vary from each other but can also become highly heterogeneous themselves. The repeat units can therefore become a mosaic of nucleotides from both parental types such that the original types are not easily distinguished (Wendel and Doyle, 1998
). A well-documented example of recombination and concerted evolution is the case of tetraploid cotton, Gossypium L. (Wendel, Schnabel, and Seelanen, 1995a, b
), in which two divergent ITS sequences have been combined in the allotetraploid nucleus. A further study involving 5S rDNA in allopolyploid Gossypium (Cronn et al., 1996
) showed that concerted evolution had not homogenized this class of repeat. The 5S rDNA sequences are located near the centromere in Gossypium chromosomes (Hanson et al., 1996
) and so may be unable to undergo unequal crossing-over and thus concerted evolution (Leitch and Bennett, 1997
). Concerted evolution has not homogenized the ITS regions of a number of other polyploids even when numerous generations have passed. In a review of the use of ITS for phylogenetic reconstruction, Soltis and Soltis (1998)
reported that there were still two distinct copy types in polyploid Paeonia L. corresponding to the putative parental species, despite 
1 x 106 yr of evolution (Sang, Crawford, and Steussy, 1995
). Furthermore, they reported unpublished research by Koontz and coworkers showing that allotetraploid Tragopogon L. species of <80 yr had not experienced concerted evolution. All the studies of concerted evolution cited above involved fertile species. We are unaware of any studies that have examined concerted evolution and the fate of parental repetitive sequences such as nrDNA in sterile allopolyploids such as M. xgiganteus that can reproduce by vegetative propagation.
In our study the maternally inherited plastid trnL intron and the trnL-F intergenic spacer (hereafter trnL-F; Taberlet et al., 1991
) were sequenced to identify the maternal parent of M. xgiganteus. Plastid DNA regions have been used to discover the maternal parent of interspecific hybrids in other groups of grasses, such as Spartina Schreb. (Ferris, King, and Hewitt, 1997
). The chromosome number and ploidy of seven Miscanthus accessions were also assessed using standard cytological techniques to help interpret the results of these other studies. Fluorescent in situ hybridization (including GISH) was used to assess the degree of homology at the repetitive DNA level between the different parental species in M. xgiganteus. Such techniques have proved useful for studying genome origin and organization in other plants groups (e.g., Bennett, Kenton, and Bennett, 1992
; Leitch and Bennett, 1997
; Takahashi et al., 1997
). For example, Yang et al. (1999)
successfully used FISH to study genome structure and evolution in the allohexaploid wild oat, Avena fatua L.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
|
and precipitated using 100% ethanol for at least 48 h at –20°C. The DNA was then centrifuged to a pellet, washed with 70% ethanol, and purified via cesium chloride/ethidium bromide (1.55 g/mL) gradient centrifugation with subsequent dialysis. DNA was stored in TE buffer (10 mmol/L Tris-HCl, 1 mM EDTA, pH 8.0) at –80°C until use.
DNA sequencing and cloning of PCR products
Two DNA regions were sequenced. The first was the ITS region of nuclear 18S–5.8S–25S ribosomal DNA that was amplified by the PCR using primers described by White, Bruns, and Taylor (1990)
. The second was the spacer and intron regions of the plastid trnL-F region that were amplified using the primers "c" and "f" described by Taberlet et al. (1991)
. The thermal cycling for all PCRs comprised 30 cycles, each with 1 min denaturation at 97°C, 1 min annealing at 51°C, and an extension of 3 min at 72°C. A final extension of 7 min at 72°C was included. Amplified, double-stranded DNA fragments were purified using Promega Wizard PCR mini-columns (Promega, Madison, Wisconsin, USA) and sequenced using Taq Dye-Deoxy Terminator Cycle Sequencing Kits (Perkin Elmer Applied Biosystems, Foster City, California, USA) on an ABI 373 or 377 automated DNA sequencer (Perkin Elmer Applied Biosystems).
Sequence heterogeneity was found within ITS amplification products of M. xgiganteus. A cloning step was therefore required to obtain clean sequences for this region. Cloning was performed using Promega's pGem-T Easy Vector System (Promega), and then the ITS region was reamplified from the transformed bacterial colonies by using a small portion of a colony as the PCR template.
Amplified fragment length polymorphism
Amplified fragment length polymorphism is based on the selective amplification of restriction fragments from a digest of total DNA (see Vos et al. [1995]
or Ridout and Donini [1999]
for a full description of the method). Reactions were performed using standard protocols in the AFLP Plant Mapping Kit of ABI (Perkin Elmer Applied Biosystems). The DNA fragments were detected on an ABI 377 automated DNA sequencer with ABI GeneScan 2.02 and Genotyper version 1.1 software. Four primer pairs (see Table 2) were chosen for selective PCR based on a preliminary survey of 32 primer pairs. DNA fragments ranging from 50 to 500 base pairs (bp) from the AFLP analysis were scored. Neighbor joining (NJ) analysis was applied using Nei and Li genetic distances for restriction sites (Nei and Li, 1985
; PAUP 4.0: Swofford, 1999
). Internal support for groupings was assessed using the bootstrap procedure of Felsenstein (1985)
. Principal coordinates analysis (PCO) was performed with Le Progiciel R version 4.0d (Casgrain, 1999
) using Dice distances (Dice, 1945
).
|
and stored at –20°C until use.
Genomic probes
Total genomic DNA from M. sinensis and M. sacchariflorus was randomly sheared to 10 kb (kilobase) by vortexing for 5 min and then passing it 50 times through a hypodermic needle (Sterican, 1.1 x 40 mm; B. Braun, Melsungen, AG).
Ribosomal DNA probes
Nuclear 18S–5.8S–25S ribosomal DNA (18S–25S rDNA) sequences were probed using the clone pTa71. This 9 kb clone contains the 5.8S, 18S, and 25S rRNA genes, their internally transcribed spacers, and the nontranscribed intergenic spacer sequences isolated from wheat, Triticum aestivum (Gerlach and Bedbrook, 1979
), and recloned into pUC19.
Probe labelling and in situ hybridization
Probes (total genomic DNA and pTa71) were labelled with biotin-14-dATP by nick translation following the manufacturer's instructions (GIBCO BRL BioNick Labelling System, Life Technologies, Eggenstein, Gebührenfreie Bestellungen, Germany). In all GISH experiments, unlabelled blocking DNA (100–250 bp) from either M. sinensis or M. sacchariflorus was prepared by autoclaving total genomic DNA for 5 min at 105°C under 103 421 Pa. The appropriate blocking DNA was added to the genomic probe at a ratio of 1 : 100 (probe to block).
Genomic in situ hybridization was performed on M. xgiganteus using probes from either M. sinensis or M. sacchariflorus according to the method of Takahashi et al. (1997, 1999)
. Probe hybridization was detected using the fluorochrome fluorescein isothiocyanate (FITC). Chromosomes were counterstained with 4, 6-diamidino-2-phenylindole (DAPI), and propidium iodide.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
|
|
|
|
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
) is an illegitimate name under the rules of the International Code of Botanical Nomenclature (Greuter et al., 1994
) because a type was not specified nor a Latin description provided. The correct name is Miscanthus xgiganteus Greef & Deuter ex Hodkinson & Renvoize (Hodkinson and Renvoize, 2001
).
Another possible name is Miscanthus xogiformis Honda, which was described in 1939 and has since been treated as an allotriploid by Adati and Mitsuishi (1956)
, Hirayoshi, Nishikawa, and Hakura (1957)
, Hirayoshi et al. (1957)
, Adati (1958)
, and Nishikawa, Kubono, and Kamiya (1958)
. The ploidy level of this material is, however, unknown and the species is usually treated as a synonym of M. sacchariflorus. We feel that there is insufficient evidence to link this name with M. xgiganteus.
In the results obtained in the AFLP analysis (Figs. 1 and 2), M. xgiganteus is approximately equidistant from its two putative parents. Some unique genetic variation is found in the M. xgiganteus accessions, which probably results from the actual parental genotypes being different from those examined here. However, there is little evidence from AFLP analysis, a highly sensitive DNA fingerprinting technique (Pakniyat et al., 1997
; Reeves et al., 1998
; Mueller and Wolfenbarger, 1999
; Ridout and Donini, 1999
), that much variation exists within the M. xgiganteus collection held at The Royal Botanic Gardens, Kew, and the ADAS Arthur Rickwood Research Station. Based on AFLP analysis it was clear that some accessions (e.g., I.D. 23 and 204) were incorrectly named M. sacchariflorus because their AFLP profiles were indistinguishable from M. xgiganteus. Chromosome counts on a number of these plants showed that they were triploid. On morphological grounds, there are also no characters that separate them, as all these plants are large cane-like Miscanthus species with long spikelet callus hairs, no awn, and a spreading rhizome. Based on AFLP analysis the accession with I.D. 61 named M. sacchariflorus was clearly distinct from the other accessions initially named M. sacchariflorus (see above). The plant was smaller, and cytological analysis revealed that it was diploid (2n = 38). Many of the clones growing in Miscanthus collections and the European biomass trials under the name M. sacchariflorus are probably M. xgiganteus, but chromosome and/or AFLP data will be needed to confirm or refute this.
The following names were used in this study to represent the different taxa in the M. sacchariflorus complex: Miscanthus sacchariflorus, 2n = 2x = 38 (diploid); Miscanthus sacchariflorus x M. sinensis, 2n = 4x = 76 (allotetraploid). The allotetraploid (Miscanthus sacchariflorus x M. sinensis) is often known as M. sacchariflorus (including M. sacchariflorus var. brevibarbis (Honda) Adati) since it resembles M. sacchariflorus in its inflorescence and spikelet morphology (Adati and Shiotani, 1962
). This is unsuitable as it ignores the contribution of the M. sinensis genome.
Identifying the parental genomes in M. xgiganteus
The two different ITS sequences obtained by cloning M. xgiganteus PCR products closely match the PCR products from the two putative parents (Fig. 3). This is the expected result and supports the hypothesis that M. xgiganteus is an interspecific hybrid between the two species. In M. xgiganteus, concerted evolution has clearly not homogenized the repeat types. One copy type resembles that of M. sinensis and one M. sacchariflorus. These correspond to the putative parents of this hybrid taxon (Linde-Laursen, 1993
). This is precisely what would be expected from a sterile first generation, F1, hybrid in which concerted evolution has not operated to homogenize ITS copies.
Identifying the maternal genome donor in M. xgiganteus
Miscanthus xgiganteus shared a number of plastid nucleotide synapomorphies within the trnL-F intron and spacer regions with M. sacchariflorus, which were absent in M. sinensis. Among the species and accessions sequenced, Miscanthus sacchariflorus and M. xgiganteus uniquely share bases at four nucleotide positions. They also share a large deletion not found in any other species examined. This indicates that M. xgiganteus is the product of a hybridization in which either M. sacchariflorus or an allopolyploid with the plastid genome of M. sacchariflorus was the maternal parent (ovule donor). The entire trnL-F sequences for these two taxa are not identical, but this result can be explained as intraspecific variation (i.e., some other geographic race should match perfectly). Positions at which they differ are autapomorphies relative to the taxa studied here.
The DNA sequence and AFLP data therefore support the hypothesis that M. xgiganteus is an allotriploid with genomes from both M. sacchariflorus (the maternal lineage) and M. sinensis (Linde-Laursen, 1993
). It is unclear, however, which parent contributed two sets of chromosomes to the triploid.
Possible origins of M. xgiganteus
Linde-Laursen (1993)
examined chromosome pairing during meiosis and suggested that M. xgiganteus was an allotriploid with two genomes of high homology and one of lower homology to the rest. This contrasted with an autotriploid of M. sinensis named as M. sinensis ssp. condensatus T. Koyama (= M. condensatus Hackel), which had a high number of trivalents in pollen mother cells at metaphase I. Miscanthus xgiganteus has at least one genome each from M. sinensis and M. sacchariflorus because heterogeneity in ITS can be explained by the presence of only two copy types corresponding to either M. sinensis or M. sacchariflorus. Adati and Shiotani (1962)
indicated that many plants known as M. sacchariflorus may indeed be of a hybrid origin, with one genome from M. sinensis and one from an unidentified species. Adati and Shiotani (1962)
speculated that allotriploid forms of Miscanthus (which they named as varieties of M. sacchariflorus but which, according to our data, would be known as M. xgiganteus) were formed by the combination of a diploid M. sinensis and an allotetraploid Miscanthus species (produced from M. sinensis and an unidentified species). The unknown genome, on the basis of our evidence, would be from a diploid M. sacchariflorus (see Fig. 8).
|
), where M. xgiganteus is believed to have originated. Alternatively, the allotriploid may have originated from a hybrid between diploid M. sinensis and diploid M. sacchariflorus, in which one of the parental species produced an unreduced gamete (Fig. 8b). There is little evidence that supports either of these two possibilities. It is also possible that M. xgiganteus has formed more than once, so both hypotheses may be true. Allotriploid Miscanthus xgiganteus has been artificially synthesized by crossing a plant named M. sacchariflorus (presumably M. sinensis x M. sacchariflorus) with diploid M. sinensis (J. Clifton-Brown, University of Dublin, personal communication). If M. xgiganteus originated from a cross involving an allotetraploid and a diploid (hypothesis illustrated in Fig. 8a) then the allotetraploid would be expected to have rDNA from both M. sinensis and M. sacchariflorus. Whether or not a dominant ITS type has become established in an hypothesized allotetraploid parent is unknown, as we do not have such a hybrid in our collection (we are currently screening potential genotypes in the hope of finding such an allotetraploid). However, the fact that the ITS copy type of the diploid M. sacchariflorus in our collection has a close match to one of the ITS copy types of M. xgiganteus indicates that the M. sacchariflorus type has not been lost by recombination. If concerted evolution has taken place, it has done so in the direction of the M. sacchariflorus type.
FISH and GISH
Three hybridization sites of rDNA sequences were detected during FISH experiments involving M. xgiganteus and the ribosomal DNA probe pTa71 (Figs. 4 and 5), suggesting that two sites had come from one parent with the other parent donating just one site. However, despite the clear evidence presented here from the ITS, trnL-F sequence data and AFLP analysis that M. xgiganteus contains genomes from M. sacchariflorus and M. sinensis, we were unable to distinguish the different genomes using GISH (Figs. 6 and 7). Using either M. sinensis or M. sacchariflorus (data not shown) as a probe in the presence of 100 x blocking DNA from the other species resulted in dispersed labelling throughout all the chromosomes of M. xgiganteus with stronger hybridization at some centromeres and intercalary sites (Figs. 6 and 7). Therefore, the genomic origin of the different rDNA sites remains uncertain. The GISH predominantly detects repetitive DNA sequences, and, in our work, the parameters were set such that hybridization could only occur between sequences with >85% similarity. Thus, it seems that most repeats have undergone little sequence divergence because these different Miscanthus species evolved. Despite the conclusive evidence from the DNA sequences and AFLP data that identifies the parental species involved in the formation of M. xgiganteus, we were not able to discriminate between the different genomes using GISH.
The use of new approaches such as bacterial artificial chromosomes (BACs) to clone a genome specific class of repetitive DNA offer a potential way to not only identify how many chromosomes of each genome type are present in M. xgiganteus but also to visualize how the different genomes are organized with respect to each other. Such an approach has proven useful in Sorghum L. (Gomez et al., 1998
).
Conclusions
DNA sequences of ITS rDNA demonstrate that M. xgiganteus is almost certainly a hybrid produced from M. sinensis and M. sacchariflorus. The maternal genome donor on the basis of plastid DNA evidence was M. sacchariflorus. Two of the three genomes should be the same, but we were unable to resolve the parental origin of the chromosomes using GISH. The AFLPs indicate that M. xgiganteus is approximately equal genetic distance from both M. sinensis and M. sacchariflorus. An allotetraploid M. sinensis x M. sacchariflorus has yet to be identified in the material available for study. However, tetraploid M. sacchariflorus has been reported by other researchers and is reportedly the dominant type in parts of Japan (Adati and Shiotani, 1962
). Further work involving such a tetraploid would be highly desirable to evaluate the alternative hypotheses for the origin of M. xgiganteus (Fig. 8) and also further evaluate the process of concerted evolution in their tandemly repeated nrDNA. Two out of three genomes of M. xgiganteus should be from M. sinensis if it is a hybrid between an allotetraploid (M. sinensis x M. sacchariflorus) and a diploid M. sinensis (Fig. 8a). Further molecular cytogenetic techniques should resolve this problem.
|
FOOTNOTES |
|---|
5 Author for reprint requests (Trevor.Hodkinson{at}tcd.ie
).
|
LITERATURE CITED |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
Adati S. S. Mitsuishi 1956 Wild growing forage plants of the Far East, especially Japan, suitable for breeding purposes, part 1, Karyological study in Miscanthus (1). Bulletin of the Faculty of Agriculture Mie University 12: 1-10
Adati S. I. Shiotani 1962 The cytotaxonomy of the genus Miscanthus and its phylogenic status. Bulletin of the Faculty of Agriculture Mie University 25: 1-14
Baldwin B. G. M. J. Sanderson J. M. Porter M. F. Wojciechowski C. S. Cambell M. J. Donoghue 1995 The ITS region of nuclear ribosomal DNA: a valuable source of evidence on angiosperm phylogeny. Annals of the Missouri Botanical Garden 82: 247-277[CrossRef][ISI]
Bennett S. T. A. Y. Kenton M. D. Bennett 1992 Genomic in situ hybridization reveals the allopolyploid nature of Millium montianum (Gramineae). Chromosoma 101: 420-424[CrossRef][ISI]
Bremer G. 1934 De cytology van het suikerriet. VII. Een cytologisch onderzoek van een vijftigtal in 1929–1930 op Java geimporteerde rietsoorten. Archief Suikerindustrie Nederlands-Indië 1934: 141-166
Bullard M. J. M. C. Heath P. M. Nixon 1995 Shoot growth, radiation interception and dry matter production and partitioning during the establishment phase of Miscanthus sinensis ‘Giganteus' grown at two densities in the UK. Annals of Applied Biology 126: 94-102
Bullard M. J. P. M. Nixon M. C. Heath 1997 Quantifying the yield of Miscanthus xgiganteus in the UK. Aspects of Applied Biology 49: 199-206
Casgrain P. 1999 Le Progiciel release version 4.0di. Development release
Cronn R. C. X. Zhao A. H. Patterson J. F. Wendel 1996 Polymorphism and concerted evolution in a tandemly repeated gene family: 5S ribosomal DNA in diploid and allopolyploid cottons. Journal of Molecular Evolution 42: 685-705[CrossRef][ISI][Medline]
Dice I. R. 1945 Measures of the amount of ecological association between species. Ecology 26: 295-302
Doyle J. J. J. L. Doyle 1987 A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytochemical Bulletin of the Botanical Society of America 19: 11-15
Elder J. F. B. J. Turner 1995 Concerted evolution of repetitive DNA sequences in eukaryotes. Quarterly Review of Biology 70: 297-320[CrossRef][Medline]
Federov A. 1969 Chromosome numbers of flowering plants, 541. V.L. Komarov Botanical Institute, Leningrad, Russia
Felsenstein J. 1985 Confidence limits on phylogenies: an approach using the bootstrap. Evolution 39: 783-791[CrossRef][ISI]
Ferris C. R. A. King G. M. Hewitt 1997 Evidence for the maternal parentage in the hybrid origin of Spartina anglica. Molecular Ecology 6: 185-187[CrossRef]
Gaut B. S. J. F. Doebley 1997 DNA sequence evidence for the segmental allopolyploid origin of maize. Proceedings of the National Academy of Sciences, USA 94: 6809-6814
Gerlach W. L. J. R. Bedbrook 1979 Cloning and characterization of ribosomal RNA genes from wheat and barley. Nucleic Acids Research 7: 1869-1885
Gomez M. M. N. Islam-faridi M. Zwick D. G. Czeschin Jr. G. E. Hart R. A. Wing D. M. Stelly H. J. Price 1998 Tetraploid nature of Sorghum bicolor (L.). Journal of Heredity 89: 188-190
Greef J. M. M. Deuter 1993 Syntaxonomy of Miscanthus xgiganteus Greef et Deu. Angewandte Botanik 67: 87-90[ISI]
Greuter W. F. R. Barrie H. M. Burdet W. G. Chaloner V. Demoulin D. L. Hawksworth P. M. Jørgensen D. H. Nicolson P. C. Silva P. Trehane J. McNeill 1994 International code of botanical nomenclature (Tokyo Code) adopted by the Fifteenth International Botanical Congress, Yokohama, August–September 1993. Regnum Vegetabile 131
Hanson R. E. M. N. Islam-Faridi E. A. Percival C. F. Crane Y. Ji T. D. McKnight D. M. Stelly H. J. Price 1996 Distribution of 5S and 18S–28S rDNA loci in a tetraploid cotton (Gossypium hirsutum L.) and its putative diploid ancestors. Chromosoma 105: 55-61[ISI][Medline]
Heath M. C. M. J. Bullard J. B. Kilpatrick 1994 A comparison of the production and economics of biomass crops for use in agricultural or set-aside land. Aspects of Applied Biology 40: 505-515
Hirayoshi I. K. Nishikawa A. Hakura 1957 3x and 4x hybrids raised from the cross M. sinensis var. condensatus x M. sacchariflorus. Research Bulletin of the Faculty of Agriculture Gifu University 12: 82-88
Hirayoshi I. K. Nishikawa M. Kubono T. Murase 1957 Cyto-genetical studies on forage plants (IV): on the chromosome number of Ogi (Miscanthus sacchariflorus). Research Bulletin of the Faculty of Agriculture Gifu University 8: 8-13
Hodkinson T. R. M. W. Chase S. A. Renvoize In press Characterization of a genetic resource collection of Miscanthus (Saccharinae, Andropogoneae, Poaceae) using AFLP and ISSR PCR. Annals of Botany.
Hodkinson T. R. S. A. Renvoize 2001 Nomenclature of Miscanthus xgiganteus. Kew Bulletin. 56: 759–760 [CrossRef]
Hodkinson T. R. S. A. Renvoize M. W. Chase 1997 Systematics of Miscanthus. Aspects of Applied Biology 49: 189-198
Hodkinson T. R. S. A. Renvoize G. Ní Chonghaile C. Stapleton M. W. Chase 2000 A comparison of ITS Nuclear rDNA sequence data and AFLP markers for phylogenetic studies in Phyllostachys (Bambusoideae, Poaceae). Journal of Plant Research 113: 259-269[CrossRef][ISI]
Hsiao C. S. W. L. Jacobs N. J. Chatterton K. H. Asay 1999 A molecular phylogeny of the grass family (Poaceae) based on the sequences of nuclear ribosomal DNA (ITS). Australian Systematic Botany 11: 667-668[CrossRef][ISI]
Lafferty J. T. Lelly 1994 Cytogenetic studies of different Miscanthus species with potential for agricultural use. Plant Breeding 113: 246-249[CrossRef][ISI]
Leitch I. J. M. D. Bennett 1997 Polyploidy in angiosperms. Trends in Plant Science 2: 470-476[CrossRef][ISI]
Linde-Laursen I. B. 1993 Cytogenetic analysis of Miscanthus ‘Giganteus’, an interspecific hybrid. Hereditas 119: 297-300[CrossRef][ISI]
Mueller U. G. L. Wolfenbarger 1999 AFLP genotyping and fingerprinting. Trends in Ecology and Evolution 14: 389-394
Nei M. W. H. Li 1985 Mathematical model for studying genetic variation in terms of restriction nucleases. Proceedings of the National Academy of Sciences, USA 76: 5269-5273
Nishikawa K. M. Kubono M. Kamiya 1958 Morphological characters and chromosome conjunction in Miscanthus ogiformis. Japanese Journal of Breeding 8: 49
Pakniyat H. W. Powell E. Baird L. L. Handley D. Robinson C. M. Scrimgeor E. Nevo C. A. Hackett P. D. S. Caligari B. P. Forster 1997 AFLP variation in wild barley (Hordeum spontaneum C. Koch) with reference to salt tolerance and associated ecogeography. Genome 40: 332-341
Reeves G. D. Francis M. S. Davies H. J. Rogers T. R. Hodkinson 1998 Genome size is negatively correlated with altitude in natural populations of Dactylis glomerata. Annals of Botany 82: (Supplement A) 99-105
Renvoize S. A. T. R. Hodkinson M. W. Chase 1997 Miscanthus in Britain: a molecular based review of diversity in the living resources held in the UK and available in Europe. Research Development Ministry of Agriculture Fisheries and Food QA3580, London, UK
Ridout C. J. P. Donini 1999 Use of AFLP in cereals research. Trends in Plant Science 4: 76-79[CrossRef][ISI][Medline]
Sang T. D. J. Crawford T. F. Steussy 1995 Documentation of reticulate evolution in peonies (Paeonia) using internal transcribed spacer sequences of nuclear ribosomal DNA: implications for biogeography and concerted evolution. Proceedings of the National Academy of Sciences, USA 92: 6813-6817
Soltis D. E. P. S. Soltis 1998 Choosing an approach and an appropriate gene for phylogenetic analysis. In D. E. Soltis, P. S. Soltis, and J. F. Doyle [eds.], Molecular systematics of plants II: DNA sequencing, 1–42. Kluwer, Norwell, Massachusetts, USA
Swofford D. L. 1999 PAUP*: phylogenetic analysis using parsimony (and other methods), version 4.0. Sinauer, Sunderland Massachusetts, USA
Taberlet P. L. Gielly G. Pautou J. Bouvet 1991 Universal primers for amplification of three non-coding regions of chloroplast DNA. Plant Molecular Biology 17: 1105-1109[CrossRef][ISI][Medline]
Takahashi C. I. J. Leitch A. Ryan M. D. Bennett P. E. Brandham 1997 The use of genome in situ hybridization (GISH) to show transmission of recombinant chromosomes by a partially fertile bigeneric hybrid, Gasteria lutzii x Aloe aristata (Aloaceae), to its progeny. Chromosoma 105: 342-348[ISI][Medline]
Takahashi C. J. A. Marshal M. D. Bennett I. J. Leitch 1999 Genomic relationships between maize and its wild relatives. Genome 42: 1201-1207[Medline]
Vos P. R. R. Hogers M. Bleeker M. Reijans T. van de Lee M. Hornes A. Frijters J. Pot M. Kuiper M. Zabeau 1995 AFLP: a new technique for DNA fingerprinting. Nucleic Acids Research 23: 4407-4414
Wendel J. F. J. F. Doyle 1998 Phylogenetic incongruence: window into genome history and molecular evolution. In D. E. Soltis, P. S. Soltis, and J. F. Doyle [eds.], Molecular systematics of plants II: DNA sequencing, 265–296. Kluwer, Norwell, Massachusetts, USA
Wendel J. F. A. Schnabel T. Seelanen 1995a Bidirectional interlocus concerted evolution following allopolyploid speciation in cotton (Gossypium). Proceedings of the National Academy of Sciences, USA 92: 280-282
Wendel J. F. A. Schnabel T. Seelanen 1995b An unusual ribosomal DNA sequence from Gossypium gossypiodes reveals ancient, cryptic, intergenomic introgression. Molecular Phylogenetics and Evolution 4: 298-313[CrossRef][ISI][Medline]
White T. J. S. L. Bruns J. Taylor 1990 Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In M. Innis, D. Gelfand, J. Sninsky, and T. J. White [eds.], PCR protocols: a guide to methods and applications, 315–322. Academic Press, San Diego, California, USA
Yang Q. L. Hanson M. D. Bennett I. J. Leitch 1999 Genome structure and evolution in the allohexaploid weed Avena fatua L. (Poaceae). Genome 42: 512-518[Medline]
This article has been cited by other articles:
|
|
 |
|
  J. C. CAROLAN, I. L. I. HOOK, M. W. CHASE, J. W. KADEREIT, and T. R. HODKINSON Phylogenetics of Papaver and Related Genera Based on DNA Sequences from ITS Nuclear Ribosomal DNA and Plastid trnL Intron and trnL-F Intergenic Spacers Ann. Bot., July 1, 2006; 98(1): 141 - 155. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. T. KELLEHER, T. R. HODKINSON, G. C. DOUGLAS, and D. L. KELLY Species Distinction in Irish Populations of Quercus petraea and Q. robur: Morphological versus Molecular Analyses Ann. Bot., December 1, 2005; 96(7): 1237 - 1246. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. MARHOLD, J. LIHOVA, M. PERNY, and W. BLEEKER Comparative ITS and AFLP Analysis of Diploid Cardamine (Brassicaceae) Taxa from Closely Related Polyploid Complexes Ann. Bot., May 1, 2004; 93(5): 507 - 520. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. L. Nickrent, M. A. Garcia, M. P. Martin, and R. L. Mathiasen A phylogeny of all species of Arceuthobium (Viscaceae) using nuclear and chloroplast DNA sequences Am. J. Botany, January 1, 2004; 91(1): 125 - 138. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W.-L. Wu, B. A. Schaal, C.-Y. Hwang, M.-D. Hwang, Y.-C. Chiang, and T.-Y. Chiang Characterization and adaptive evolution of {alpha}-tubulin genes in the Miscanthus sinensis complex (Poaceae) Am. J. Botany, October 1, 2003; 90(10): 1513 - 1521. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. A. Simpson, C. A. Furness, T. R. Hodkinson, A. M. Muasya, and M. W. Chase Phylogenetic relationships in Cyperaceae subfamily Mapanioideae inferred from pollen and plastid DNA sequence data Am. J. Botany, July 1, 2003; 90(7): 1071 - 1086. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. L. Naidu, S. P. Moose, A. K. AL-Shoaibi, C. A. Raines, and S. P. Long Cold Tolerance of C4 photosynthesis in Miscanthus x giganteus: Adaptation in Amounts and Sequence of C4 Photosynthetic Enzymes Plant Physiology, July 1, 2003; 132(3): 1688 - 1697. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||
