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At least 127 records · Page 7Linked to original sources
PubMed2004

[Intraspecific structure and reproductive relationships between Elymus mutabilis and E. transbaicalensis (Poaceae) in southern Siberia from the viewpoint of taxonomical genetics].

The relationships between StH-genomic species Elymus mutabilis (Drob.) Tzvel. and E. transbaicalensis (Nevski) Tzvel. were examined using biosystematic and biochemical (SDS electrophoresis of endosperm proteins) methods. The results showed the following. (1) There is interspecific morphological discreteness that permits assigning most individuals from the wild to a definite species. However, self-fertile intermediate individuals of introgressive origin were found. (2) Both taxa exhibited marked specificity of electrophoretic characteristics of endosperm proteins. (3) The species form two separate recombination gene pools (RGPs). Thus, E. mutabilis and E. transbaicalensis should be regarded as two distinct species. Nevertheless, there is some genetic exchange and unidirectional gene flow between the RGPs, especially in secondary (successive) habitats where mixed populations are observed. Two RGPs form the single introgressive gene pool (IGP), which includes other StH-genomic species of Northern Eurasia.

Electrophoresis, Polyacrylamide Gel↗
PubMed2006

[PCR-RFLP analysis on Roegneria, Elymus, Hystrix and Kengyilia in Triticeae (Poaceae)].

PCR-RFLP of Plasmon on 23 species of Roegneria, Elymus, Hystrix and Kengyilia and 1 outgroup (Triticum aestivum L.) was carried out. The segments amplified with 3 cpDNA and 3 mtDNA universal primers were digested by 15 restriction endonucleases. Among 329 bands produced, 304 were polymorphic (92.4%). PCR-RFLP results showed that polymorphisms existed between the four genera and between the species in Roegneria, Elymus, Hystrix and Kengyilia, and genetic similarity coefficient was high. Roegneria grandis, R. aristiglumis, R. elytrigioides, R. alashanica and R. magnicaespes were grouped, while R. caucasica, R. ciliaris, R. amurensis and R. japonensis clustered together. Species of Kengyilia clustered independently. Five species of Elymus, 3 of Hystrix and Roegneria kamoji grouped together. The results suggested Kengyilia was a valid genus. As more cytological and molecular data are available, the taxonomic status of Roegneria, Elymus and Hystrix will be recognized.

DNA Primers↗
PubMed1997

Bamboozled again! Inadvertent isolation of fungal rDNA sequences from bamboos (Poaceae: Bambusoideae).

Polymerase chain reaction (PCR) amplification of the nuclear internal transcribed spacer (ITS) and 5.8S regions of rDNA from woody bamboos (Bambuseae) led to the recovery of fungal instead of bamboo sequences under a variety of PCR conditions and irrespective of whether the plant DNA was extracted from fresh leaves or silica gel-dried material. Phylogenetic analyses based on the 5.8S sequences indicated that the fungi were most likely basidiomycetes and that none was an ascomycete. A diverse assemblage of nonascomycetous fungi was isolated from different bamboos, and various fungi coexisted in the same host plant. There was no evidence that closely related fungi consistently associate with closely related host bamboos. Phylogenetic analysis based on 5.8S sequences showed that some fungi were in lineages near Volvariella, Lentinula, Peniophora, and Rhizoctonia, but the insufficiency of basidiomycete and zygomycete ITS sequences in sequence data bases precluded more precise fungal identifications. Bamboo ITS regions were amplified only when fresh leaves were surface sterilized before DNA extraction, suggesting that the fungal associates are epiphyllous rather than endophytic. This study highlights the possibility of inadvertent PCR amplification of contaminating DNAs in molecular phylogenetic studies, particularly when using "universal" amplification primers.

Base Sequence↗
PubMed1997

Molecular evolution and phylogenetic utility of the chloroplast rpl16 intron in Chusquea and the Bambusoideae (Poaceae).

Phylogenetic relationships within Chusquea, a diverse genus of neotropical woody bamboos, and among selected members of the Bambusoideae were explored using rpl16 intron sequence data from the chloroplast genome. Mechanisms of mutation, including slipped-strand mispairing, secondary structure, minute inversions, and base substitutions, were examined within the rpl16 intron, and their effects on sequence alignment and phylogenetic analysis were investigated. Thirty-five bamboo sequences were generated and two separate matrices were analyzed using maximum parsimony. In the first, 23 sequences from Chusquea, 1 of Neurolepis, and 3 outgroups were included. Neurolepis was supported as sister to Chusquea, Chusquea was strongly supported as a monophyletic lineage, and three species of Chusquea subg. Rettbergia were resolved as the most basal clade within the genus. In the second analysis, 15 sequences, 14 from across the subfamily and 1 outgroup, were included. A Bambusoideae clade was recovered with the Olyreae/Parianeae (herbaceous bamboos) and the Bambuseae (woody bamboos) each supported as monophyletic. Two clades corresponding to temperate and tropical woody bamboos were derived within the Bambuseae and the tropical taxa were further split into New World and Old World clades. The rpl16 intron in bamboos was found to be susceptible to frequent length mutations of multiple origins, nonindependent character evolution, and regions of high mutability, all of which created difficulties in alignment and phylogenetic analysis; nonetheless the rpl16 intron is phylogenetically informative at the inter- and intrageneric levels in bamboos.

Chloroplasts↗
PubMed2001

Molecular diversity and physical mapping of 5S rDNA in wild and cultivated oat grasses (Poaceae: Aveneae).

5S rDNA repeats studied in five genera of Aveneae have lengths between 285 and 329 bp (Avena sativa, Avena macrostachya, 26 species of Helictotrichon, Pseudarrhenatherum longifolium, Lagurus ovatus, and Trisetum spicatum). In only a single species (Helictotrichon aetolicum) an additional repeat of 456 bp occurs infrequently. Variation is largely due to insertions or deletions in the nontranscribed spacer as determined from sequences of 163 independent clones. The 5S gene of the Aveneae studied is conserved in length and sequence except for Helictotrichon bromoides and Helictotrichon marginatum in which duplications occur at two different sites. This new type of duplication and all duplications reported to date in 5S genes of angiosperms are shown to center on defined palindromic sequences. The "uncommon" 5S gene sequences detected in some Aveneae are not necessarily nonfunctional as pseudogenes because the essential features of the internal control region are maintained even after such duplication events. In each instance such gene sequences have spacers with unmodified structure, indicating that change in gene sequence is not necessarily coupled with change in adjacent spacers. The value of 5S spacer sequences for genomic identifications in Aveneae is exemplified in A. macrostachya (perennial), A. sativa (annual), and several diploid taxa of the genus Helictotrichon.

Avena↗
PubMed1996

The configuration of the seminal roots of Triticum aestivum L. (Poaceae).

The seminal root system of wheat (Triticum aestivum L.) is composed of the primary seminal root, the first pair of seminal roots, and the second pair of seminal roots, which are known to grow in different directions. The direction of root growth, which can be expressed by theta (the angle between the root and the plumb line) and phi (the angle between the root and a vertical plane including the primary seminal root), was studied with special attention to the latter. It was measured on seedlings grown in a small hemispherical soil-filled mesh basket. There were varietal differences in the phi of the first pair of roots (phi f) and in the phi of the second pair of roots (phi s). phi f and phi s were significantly correlated. The mean distance (MD), a measure to evaluate the efficiency of root spacing, was correlated with the difference between phi f and phi s. Neither experimentally applied low soil water potential nor the excision of the primary seminal root affected phi. When the grain was sown vertically with the tip of the embryo pointing downwards, it was found that the growth movement into a direction different from the plumb line and phi s was greatly modified. It is suggested that certain internal mechanisms, possibly involving gravitropic reactions, are operating to control the direction of root growth. The significance of root growth direction at the seedling stage is discussed.

Gravitropism↗
PubMed2002

Assessment of the C(4) phosphoenolpyruvate carboxylase gene diversity in grasses (Poaceae).

C(4) phosphoenolpyruvate carboxylase (PEPC) is a key enzyme in the C(4) photosynthetic pathway. To analyze the diversity of the corresponding gene in grasses, we designed PCR primers to specifically amplify C(4) PEPC cDNA fragments. Using RT-PCR, we generated partial PEPC cDNA sequences in several grasses displaying a C(4) photosynthetic pathway. All these sequences displayed a high homology (78-99%) with known grass C(4) PEPCs. PCR amplification did not occur in two grasses that display the C(3) photosynthetic pathway, and therefore we assumed that all generated sequences corresponded to C(4) PEPC transcripts. Based on one large cDNA segment, phylogenetic reconstruction enabled us to assess the relationships between 22 grass species belonging to the subfamilies Panicoideae, Arundinoideae and Chloridoideae. The phylogenetic relationships between species deduced from C(4) PEPC sequences were similar to those deduced from other molecular data. The sequence evolution of the C(4) PEPC isoform was faster than in the other PEPC isoforms. Finally, the utility of the C(4) PEPC gene phylogeny to study the evolution of C(4) photosynthesis in grasses is discussed.

Journal Article↗
PubMed2002

Comparative analysis of QTLs affecting domestication traits between two domesticated x wild pearl millet ( Pennisetum glaucum L., Poaceae) crosses.

Comparative mapping of Quantitative trait loci (QTLs) involved in domestication of adaptative syndrome traits of pearl millet was realized at the intra-specific level using two F(2) populations derived from domesticated ( Pennisetum glaucum ssp. glaucum) x wild ( Pennisetum glaucum ssp. monodii) crosses. The two domesticated parents analyzed differ in their geographical origins, agronomic characteristics and life cycles. In both populations, two regions of the genome were identified on linkage groups 6 and 7, that controlled most of the key morphological differences. The importance of these two linkage groups reveals their central role both in the developmental control of spikelet structure and in the domestication process of this crop. In contrast, QTLs involved in traits that are components of yield and measure differences in resource allocation (such as the shape of the spike, the number of spikes per plant and plant height) show a low level of correspondence among our two crosses. The results of the comparative mapping between cereals, although preliminary, reveal that genes involved in seed-shattering could correspond in maize, rice and sorghum. The evolutionary significance of our results, and especially the relationships between genome organization and cereal domestication, are discussed. The potential use of these results in pearl millet genetic-resources enhancement are presented.

Journal Article↗
PubMed2003

A linkage map of meadow fescue ( Festuca pratensis Huds.) and comparative mapping with other Poaceae species.

A genetic linkage map has been constructed for meadow fescue ( Festuca pratensis Huds.) (2n=2 x=14) using a full-sib family of a cross between a genotype from a Norwegian population (HF2) and a genotype from a Yugoslavian cultivar (B14). The two-way pseudo-testcross procedure has been used to develop separate maps for each parent, as well as a combined map. A total number of 550 loci have been mapped using homologous and heterologous RFLPs, AFLPs, isozymes and SSRs. The combined map consists of 466 markers, has a total length of 658.8 cM with an average marker density of 1.4 cM/marker. A high degree of orthology and colinearity was observed between meadow fescue and the Triticeae genome(s) for all linkage groups, and the individual linkage groups were designated 1F-7F in accordance with the orthologous Triticeae chromosomes. As expected, the meadow fescue linkage groups were highly orthologous and co-linear with Lolium, and with oat, maize and sorghum, generally in the same manner as the Triticeae chromosomes. It was shown that the evolutionary 4AL/5AL translocation, which characterises some of the Triticeae species, is not present in the meadow fescue genome. A putative insertion of a segment orthologous to Triticeae 2 at the top of 6F, similar to the rearrangement found in the wheat B and the rye R genome, was also observed. In addition, chromosome 4F is completely orthologous to rice chromosome 3 in contrast to the Triticeae where this rice chromosome is distributed over homoeologous group 4 and 5 chromosomes. The meadow fescue genome thus has a more ancestral configuration than any of the Triticeae genomes. The extended meadow fescue map reported here provides the opportunity for beneficial cross-species transfer of genetic knowledge, particularly from the complete genome sequence of rice.

Chromosome Mapping↗
PubMed2006

A perennial ryegrass CBF gene cluster is located in a region predicted by conserved synteny between Poaceae species.

CBF/DREB1 proteins are the most important regulators of the cold temperature signaling pathway in many plants. CBF genes are candidates for low-temperature tolerance QTL in wheat and barley. Ten novel putative CBF cDNAs of perennial ryegrass (Lolium perenne L.) have been isolated from cold-treated leaf tissue. Their primary structures contain some conserved motifs, characteristic of the gene class. Phylogenetic analysis revealed that LpCBF genes were attributable to the HvCBF3-, and HvCBF4-subgroups following the previously proposed classification of barley CBF genes. RT-PCR analysis revealed that the expression of LpCBF genes was rapidly induced in response to low temperature and that the expression pattern under the low-temperature conditions for a long period was different between the various LpCBF genes. Five of the ten LpCBF genes were assigned to the genetic linkage map using the p150/112 reference mapping population. LpCBFIb, LpCBFII, LpCBFIIIb and LpCBFIIIc were mapped on LG5 forming a cluster within 2.2 cM, while LpCBFVb was located on LG1. Based on comparative genetic studies, conserved synteny for CBF gene family was observed between the Triticeae cereals and perennial ryegrass. Information on the perennial ryegrass CBF genes at both the molecular and genetic level obtained in this study would be useful for the further study on the role of CBF genes and low-temperature tolerance in grasses.

Amino Acid Sequence↗
PubMed2002

Phylogenetics of Miscanthus, Saccharum and related genera (Saccharinae, Andropogoneae, Poaceae) based on DNA sequences from ITS nuclear ribosomal DNA and plastid trnLintron and trnL-F intergenic spacers.

DNA sequences were used to assess the monophyly and inter-relationships of Miscanthus, Saccharumand related genera in the Saccharum complex. Three DNA regions were sequenced, including the trnLintron and the trnL-F intergenic spacer of the plastid genome and the ITS region of nuclear ribosomal DNA (nrDNA). Because it was more variable, the ITS region proved most suitable for phylogenetic reconstruction at this level, and the results indicate that Miscanthus s.l. and Saccharum s.l. are polyphyletic. A set of species from Saccharum section Ripidium(clade a) do not group closely with any members of Saccharum s.l. A number of Miscanthus species from eastern or south-eastern Asia represent a monophyletic group with a basic chromosome number of 19 (clade b), but the other species from Africa and the Himalayas are clearly excluded. There is support for a monophyletic Saccharum s.s. clade including S. officinarumand S. spontaneum that is sister to Miscanthus s.s(clade c). There is no evidence to support the division of some Saccharum s.l. into the genera currently known as Erianthus and Narenga. Saccharum contortum( =Erianthus contortus), S. narenga (= Narenga porphyrocoma) and Erianthus rockii, group more closely with Miscanthus fuscus, a species from the Himalayas and also with the African Miscanthus s.l. species (= Miscanthidium, clade d).

Journal Article↗
PubMed2004

Indel patterns of the plastid DNA trnL- trnF region within the genus Poa (Poaceae).

The use of insertion/deletion (indel) patterns from sequences of the trnL intron and trnL-F intergenic spacer (IGS) in finding plastid genome types of the genus Poa L. was studied. New sequences for 23 taxa ( P. alpina, P. badensis, P. bulbosa, P. crassipes, P. molinerii, P. annua, P. chaixii, P. granitica, P. pratensis, P. sibirica, P. remota, P. botryoides, P. cenisia, P. compressa, P. laxa, P. margilicola, P. media, P. nemoralis, P. palustris, P. pannonica, P. pirinica, P. riphaea, and P. sejuncta) and 18 previously published sequences, which represent 11 of the 13 sections listed for Poa in Flora Europaea, were investigated. Collections were made primarily in central Europe. Indel patterns, despite sampling less than 0.7% of the plastid genome, produced four taxa groupings that were congruent with the major divisions obtained in intensive, previously published restriction-site studies. Insertion/deletion events in the trnL intron and trnL-trnF IGS were in nearly all cases unique to a single pattern group and thus provided almost no information about relationships among these groups. Indels did, however, provide a meaningful infrageneric classification criterion for Poa. They can serve as useful tools in studying relationships within this genus.

Base Sequence↗
PubMed2005

Genetic evaluation of in situ conserved and reintroduced populations of wild rice (Oryza rufipogon: Poaceae) in China.

We evaluated the genetic consequences and efficiency of conservation practices in Oryza rufipogon using microsatellite DNA markers. Spatial autocorrelation analysis from 12 microsatellite loci revealed that microsatellite alleles were exclusively distributed in patches within the population, indicating that large populations were unlikely to be homogeneous. An in situ conserved stand of O. rufipogon, which has been protected by a concrete wall from a large population, captured only 67.9% of the total genetic variation of the previous large population. The concrete wall was built to protect the wild rice, but it acted more as a physical barrier to gene exchanges between the two sides. An assignment test revealed only 11.1% putative seed exchanges across the wall. A reintroduced population was found to be genetically very diverse. About 76.3% of the total genetic variation detected in other populations was captured in this reintroduced population, and 24.8% of the total genetic variation in this population was not found in other populations. These results display two important findings for conservation of O. rufipogon. First, conserving one part of a large population of O. rufipogon will not preserve an adequate sample of the genetic variability, since populations are not homogeneous, and genotype distribution varies among localities. Second, a reintroduced population is not genetically depauperate, but it is too early to assess its long-term survival.

China↗
PubMed2005

Phylogenetic analysis of Bambusa (Poaceae: Bambusoideae) based on internal transcribed spacer sequences of nuclear ribosomal DNA.

Phylogenetic analyses of Bambusa species were performed using internal transcribed spacer sequences of nuclear ribosomal DNA. The 21 species sampled included members of Bambusa (sensu stricto), Dendrocalamopsis, Dendrocalamus, Guadua, Leleba, and Lingnania. Arundinaria gigantea was used as an outgroup. Using the maximum parsimony method with PAUP*, gaps were treated as missing states or new states. Parsimonious analysis revealed that Dendrocalamus latiflorus was closely related to the members of Dendrocalamopsis. Dendrocalamus membranaceus was a sister species to Dendrocalamus strictus. Three Dendrocalamus species were closely related to and nested in a polyphyletic Bambusa. Bambusa subaequalis was a sister species to B. multiplex, B. emeiensis to B. chungii, B. contracta to B. hainanensis, and B. flexuosa was a sister species to B. sinospinosa, B. tuldoides, B. surrecta, B. intermedia, and B. valida group, which raised doubts about the monophyly of the subgenera Bambusa (sensu stricto), Dendrocalamopsis, Leleba, and Lingnania under the genus Bambusa.

Bambusa↗
PubMed2006

A preliminary approach to the phylogeny of the genus Paspalum (Poaceae).

The present work intends to clarify the phylogenetic relationships among the species of Paspalum L. belonging to the informal groups Notata/Linearia and Dilatata, and to raise some preliminary hypotheses on the phylogeny of the genus as a whole. A combined dataset including morphological and molecular characters was used to analyze 28 species of Paspalum plus some representatives of related genera of the tribe Paniceae. Analyses were performed using both parsimony and maximum likelihood. The monophyly of Paspalum is not supported nor contradicted. The circumscription of informal groups of Paspalum is discussed, as well as the cladistic treatment of allopolyploid taxa, especially those comprising the Dilatata group. The relationships of members of the Dilatata with their putative progenitors is confirmed, but the monophyly of the group as a whole is not. A close relationship between P. dilatatum Poir. and P. lividum Trin. ex Schltdl. is shown. Our analysis is consistent with the monophyly of a group comprising Notata+Linearia, with a monophyletic Notata group nested within it. The delimitation of the core Notata is proposed by including P. conduplicatum Canto-Dorow, Valls and Longhi-Wagner, P. notatum Flüggé, P. minus E. Fourn., P. pumilum Nees and P. subciliatum Chase.

Databases, Genetic↗
PubMed2005

Genetic diversity among Paspalum L. species (Poaceae) belonging to the Notata and Linearia groups based on restriction fragment length polymorphism analyses.

A taxonomic study of Paspalum L. was carried out using a genetic diversity approach. Thirty accessions representing twenty one different species from the Notata and Linearia groups of Paspalum were studied using restriction fragment length polymorphism analysis of the amplified ITS ribosomal DNA (rDNA) and from the psbA-trnH of the chloroplast genome (cpDNA). The combined analysis of the internal transcribed spacer (ITS) and the chloroplast spacer region between the psbA and trnH genes identified genetic polymorphisms. A distance analysis of the molecular data generated a dendrogram which showed the relationships of the two informal groups of Paspalum studied here. Although the distribution of species in the dendrogram was found to be roughly in agreement with previous works based on morphological and cytological data, the results obtained reveal the current artificiality in Paspalum taxonomy. Based on molecular data, a new circumscription of the Notata and Linearia groups is proposed here in order to provide a more accurate delimitation of these groups and contribute to the taxonomy of Paspalum. This study, although preliminary, reveals the potential utility of such a molecular approach for clarifying the taxonomy of closely related taxa.

DNA, Chloroplast↗
PubMed1989

Interactive effects of aluminum, phosphorus and mycorrhizae on growth and nutrient uptake of Panicum virgatum L. (Poaceae).

The effects of Al on Panicum virgatum (switchgrass), a widespread perennial grass, were determined in relation to factors which might interact with Al in the soil. Plants were grown for 8 weeks in sand culture and were treated with 3 Al levels (0.5, 2.0, 5.0 mM), 2 P levels (0.065, 0.161 mM), 2 inoculum types (vesicular-arbuscular mycorrhizal (VAM) inoculum or VAM-free soil inoculum) and 2 inoculum sources (a high Al forest in NY or a low Al forest in Ohio) in a factorial design. Plant growth decreased with increasing Al and increased with increasing P, but the Al effect was less at high P than low P. VAM-inoculated plants outgrew non-VAM plants, especially at low and medium Al levels. Total P and Ca uptake decreased with increasing Al concentration, especially at low P levels. VAM inoculation did not result in increased P uptake at any Al level though VAM plants took up significantly more Ca than non-VAM plants at any Al level. VAM plants had lower tissue Al concentrations and took up less Al than non-VAM plants; Al uptake increased with increasing soil Al in non-VAM plants but not in VAM plants. Plants given inoculum from the high Al site had significantly lower tissue Al than plants given the low Al site inoculum, regardless of VAM status. We conclude that the presence of a VAM infection, moderate levels of soil P, and the source of the inoculum can reduce the effects of soluble Al. We discuss potential physiological and edaphic mechanisms by which Al may be immobilized and Ca availability increased in the presence of VAM fungi and other soil microflora.

Journal Article↗