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PubMedDate not supplied

New choke diseases and their molecular phylogenetic analysis in Agropyron ciliare var. minus and Agropyron tsukushiense var. transiens.

Choke diseases were surveyed in two closely related grass species, Agropyron ciliare var. minus and Agropyron tsukushiense var. transiens, in Shiga Prefecture, Japan. Perithecia and ascospores were not observed in either case. Stromata on A. ciliare var. minus enclosed and sterilized young inflorescences, as in the typical choke symptoms by Epichloë typhina. On the other hand stromata on A. tsukusiense var. transiens thinly covered mature spikes with white epiphyllous hyphae, as in stromata of Ephelis spp. The fungal isolates produced typical Neotyphodium-type conidia. Molecular phylogenetic analyses using the beta-tubulin gene (tubB) indicated that the two Agropyron species are infected with the species grouping into a novel single clade among Epichloë species and they are closely related to a haploid of hybrid Neotyphodium species. The host plant features may be the cause of the differences between stromata of A. ciliare var. minus and A. tsukushiense var.

Agropyron↗

PubMed2006

Growth of Agropyron elongatum in a simulated nickel contaminated soil with lime stabilization.

A greenhouse study was performed to evaluate the feasibility of using Agropyron elongatum and lime treatment for remediation of a simulated nickel (Ni) contaminated acidic soil. The acid soil was spiked with four levels of Ni, i.e., 0, 15, 50, and 100 mg Ni kg(-1) soil and the soil pH at each Ni level was adjusted to 4, 6 and 8 by liming with CaO. Addition of lime raised the soil pH and resulted in a decrease in concentrations of DTPA-extractable and water-soluble Ni in the soil, with a maximum reduction of 64 and 28 mg kg(-1), respectively at the highest level of Ni treatment as compared to the control without Ni treatment. In general, excessive Ni content in soil, especially at pH 4 inhibited the growth of Agropyron. Liming improved the growth condition and the highest dry weight yield of 12 g pot(-1) was obtained in soil spiked with 15 mg Ni kg(-1) at pH 6; and at the highest level of Ni, the dry weight yield increased from 0.48 to 5.96 g pot(-1) when the pH was increased from 4 to 6. However a further increase in pH to 8 did not improve plant yield because of the unavailability of nutrients at such a high pH. Nickel contents in plant were positively correlated to soil Ni contents at each respective pH level. Most of the Ni taken up by Agropyron was retained in the roots and the highest Ni uptake by plant was 3.9 mg pot(-1) in soil spiked with 100 mg Ni kg(-1) at pH 5.9, which was about 2.6% of total Ni added to the soil. This implies that Agropyron is not a hyperaccumulating species but is highly tolerant. Lime amendment together with the tolerant characteristic of Agropyron could provide a possible means to remediate Ni contaminated soils through phytostabilization.

Agropyron↗

PubMed2002

Water relations and leaf growth rate of three Agropyron genotypes under water stress.

The effects of water stress on leaf water relations and growth are reported for three perennial tussock grass genotypes under glasshouse conditions. Studies were performed in genotypes El Palmar INTA and Selección Anguil of Agropyron scabrifolium (Döell) Parodi, and El Vizcachero of A. elongatum (Host) Beauv. Agropyron scabrifolium El Palmar INTA is native to a region with warm-temperate and humid climate without a dry season, and an average annual precipitation of 900 mm. Agropyron scabrifolium Selección Anguil comes from a region with a sub-humid, dry to semiarid climate and a mean annual precipitation of 600 mm. Agropyron elongatum is a widespread forage in semiarid Argentina with well-known water stress resistance. A mild water stress treatment was imposed slowly; plants reached a minimum pre-dawn leaf water potential of about -1.83 MPa by day 21 after watering was withheld. In all genotypes, water stress led to a reduction of leaf growth. There was a tendency for a greater epicuticular wax accumulation on water-stressed plants of A. scabrifolium Selección Anguil and A. elongatum than on those of A. scabrifolium El Palmar INTA. This may have contributed to obtain greater turgor pressures and relative water contents in the first two than in the later genotype. In turn, this may have contributed to determine smaller leaf growth rate reductions in A. scabrifolium Selección Anguil and A. elongatum than in A. scabrifolium El Palmar INTA under water stress. This study demonstrated variation in water stress resistance between genotypes in A. scabrifolium, and between A. scabrifolium Selección Anguil and A. elongatum versus A. scabrifolium El Palmar INTA, which was related to their differential responses in water relations.

Agriculture↗

PubMed2004

[Evolution of partial promoter region of HMW glutenin genes from E and E1 genome of Agropyron elongatum].

The partial promoter regions of HMW glutenin subunit genes were cloned form the genomes E (in diploid Agropyron elongatum) and E1 (in tetraploid Agropyron elongatum) by PCR approach. There was only one nucleotide acid difference in the promoter sequences of x-type subunits between the two genomes; moreover, the promoter sequences of the two y-type subunits were completely identical. Although these promoter regions were very similar to each other, differences still existed in sequence size and the kind of nucleotide acid between the x-type and y-type subunits. It was speculated that the E1 genome in tetraploid Agropyron elongatum was probably originated from E genome in diploid species. The comparisons of these subunits with some of those from A, B, D and G genome of Triticeae demonstrated that the sequences of their partial promoter regions were conserved and shared a high homology more than 90%. The phylogenetic analysis based on the sequences in this region indicated that the y-type HMW glutenin subunits of Agropyron elongatum species were different from other subunits, whereas the x-type subunits of them were most closely related to that from the B genome.

Agropyron↗

PubMed2003

Root responses and nitrogen acquisition by Artemisia tridentata and Agropyron desertorum following small summer rainfall events.

Resources in the Great Basin of western North America often occur in pulses, and plant species must rapidly respond to temporary increases in water and nutrients during the growing season. A field study was conducted to evaluate below ground responses of Artemisia tridentata and Agropyron desertorum, common Great Basin shrub and grass species, respectively, to simulated 5-mm (typical summer rain) and 15-mm (large summer rain) summer rainfall events. The simulated rainfall was labeled with K(15)NO(3) so that timing of plant nitrogen uptake could be monitored. In addition, soil NH(4)(+) and NO(3)(-) concentrations and physiological uptake capacities for NO(3)(-) and NH(4)(+) were determined before and after the rainfall events. Root growth in the top 15 cm of soil was monitored using a minirhizotron system. Surprisingly, there was no difference in the amount of labeled N acquired in response to the two rainfall amounts by either species during the 7-day sample period. However, there were differences between species in the timing of labeled N uptake. The N label was detected in above ground tissue of Agropyron within 1 h of the simulated rainfall events, but not until 24 h after the rainfall in Artemisia. For both Agropyron and Artemisia, root uptake capacity was similarly affected by the 5-mm and 15-mm rainfall. There was, however, a greater increase in uptake capacity for NH(4)(+) than for NO(3)(-), and the 15-mm event resulted in a longer response. No root growth occurred in either species in response to either rainfall event during this 8-day period. The results of this study indicate that these species are capable of utilizing nitrogen pulses following even small summer rainfall events during the most stressful period of the summer and further emphasize the importance of small precipitation events in arid systems.

Absorption↗

PubMed2004

Intermediate fertile Triticum aestivum (+) Agropyron elongatum somatic hybrids are generated by low doses of UV irradiation.

We report the production and characterization of somatic hybrids between Triticum aestivum L. and Agropyron elongatum (Host) Nevishi (the synonym is Thinopyrum ponticum). Asymmetric protoplast fusion was performed between Agropyron elongatum protoplasts irradiated with a low UV dose and protoplasts of wheat taken from nonregenerable suspension cultures. More than 40 green plantlets were obtained from 15 regenerated clones and one of them produced seeds. The phenotypes of the hybrid plants and seeds were intermediate between wheat and Agropyron elongatum. All of the regenerated calli and plants were verified as intergeneric hybrids on the basis of morphological observation and analysis of isozyme, cytological, 5SrDNA spacer sequences and random amplified polymorphic DNA (RAPD). RFLP analysis of the mitochondrial genome revealed evidence of random segregation and recombination of mtDNA.

Agropyron↗

PubMed2006

Attempts to induce homoeologous pairing between wheat and Agropyron cristatum genomes.

Agropyron cristatum (2n = 4x = 28, PPPP) possesses potentially valuable traits that could be used in wheat (Triticum aestivum) improvement through interspecific hybridization. Homoeologous pairing between wheat chromosomes and P chromosomes added to wheat in a set of wheat - A. cristatum addition lines was assessed. First, the Ph-suppressing effect of P chromosomes (except 7P) was analyzed. It was concluded that this system is polygenic with no major gene, and consequently, has no prospect in the transfer of alien genes from wild relatives. In a second step, the potential of the deletion ph1b of the Ph1 gene for inducing P-ABD pairing was evaluated. Allosyndetic associations between P and ABD genomes are very rare. This very low level of pairing is likely due to divergence in the repeated sequences between Agropyron and wheat genomes. Development of translocation lines using ionizing radiation seems to be a more suitable technique than homoeologous recombination to exploit the A. cristatum genome in wheat improvement.

Agropyron↗

PubMed1995

Overexpression of mitochondrial genes in alloplasmic common wheat with a cytoplasm of wheatgrass (Agropyron trichophorum) showing depressed vigor and male sterility.

An alloplasmic hybrid (nucleus-cytoplasm hybrid) of common wheat (Triticum aestivum) with a cytoplasm of wheatgrass (Agropyron trichophorum) shows highly depressed vigor and complete male sterility. The presence of one short-arm telocentric homeologous group 1 chromosome (telosome) of the cytoplasm donor, however, restores normal vigor and male fertility of the hybrid. To study role(s) of the telosome on vigor/fertility restoration, mitochondrial genome organization and gene expression were compared among seedlings of the alloplasmic line showing depressed vigor, the corresponding restored line having a pair of the telosomes, and a euplasmic nuclear donor as control. No differences were detected in the mitochondrial genome structure between the depressed line and the restored line. Northern blot analysis using ten mitochondrial genes as probes showed no differences in transcript size and number between the depressed and restored lines, although clear differences were found in size of the major transcripts of two genes (cob and orf25) between the alloplasmic lines and the euplasmic control. Steady-state transcript levels were higher in the depressed line than in the other lines for all the mitochondrial genes analyzed including rrn18&5 when the same amount of mitochondrial RNA was loaded. The amount of rrn18&5 transcript in the total cellular RNA, however, did not differ among the lines. Run-on transcription analysis demonstrated markedly elevated transcriptional activities of all the mitochondrial genes analyzed in the depressed line based on unit amount of mitochondrial DNA, RNA and protein. The presence of Agropyron telosomes apparently normalized the level of mitochondrial transcription. These observations suggest either direct or indirect association of the observed mitochondrial gene overexpression with the depressed vigor and male sterility of the alloplasmic hybrid.

Amanitins↗

PubMed1980

Effects of an Agropyron chromosome on endosperm proteins in common wheat Triticum aestivum L.).

An Agropyron chromosome having a gene conferring blue color on the aleurone layer of the kernel endosperm causes a 15% increase in total grain protein content when it is added to the common wheat (2n=42) complement. In contrast, there is no effect of this chromosome on total protein content if it replaced part of a wheat chromosome. Endosperm protein components of isolines having blue aleurone due to the Agropyron chromosomes being added (2n=44) or translocated (2n=42) were compared to normal nonblue isoline counterparts. Gliadin proteins separated by aluminum lactate (pH 3.2) polyacrylamide gel electrophoresis (PAGE) in one or two dimensions showed greater staining intensity for the blue addition isolines (2n=44) than nonblue (2n=42) isolines. However the 42-chromosome blue isoline did not show increased protein staining over the nonblue isoline, but at least five protein differences were detected between the lines. SDS-PAGE showed that blue and nonblue differences were expressed primarily in the gliadins, but also in the glutenin, globulin, and albumin proteins.

Chromosomes↗

PubMed1999

A fertile amphiploid between diploid wheat (Triticum tauschii) and crested wheat grass (Agropyron cristatum).

Alloploidy, one of the most efficient evolutionary mechanisms in nature, has not been extensively exploited in plant breeding programmes. Many genomic combinations remain to be created by plant breeders, to be used directly as new crops or indirectly to widen the genetic basis of crops. The Triticeae tribe, to which wheat belongs, is among the botanical groups in which this strategy has been successfully explored. However, there remain valuable genomic combinations that have not been obtained at the diploid level. The Agropyron complex (wheat-grasses) has recently been the focus of attention for interspecific hybridization, but intergeneric hybrids or amphiploids with wheat have not been reported at the diploid level. Here we report synthesis of a tetraploid amphiploid between Triticum tauschii and Agropyron cristatum by crossing two tetraploid accessions. Using total genome in situ hybridization (GISH) staining on metaphase I pollen mother cells, data on allosyndetic and autosyndetic chromosome pairing have been obtained. These data support the view that the A. cristatum tetraploid parent used in the synthesis of the amphiploid has a segmental alloploidy nature.

Chromosome Mapping↗

PubMed2000

[Characterization of a wheat-Agropyron intermedium translocation line by sequential GISH and FISH].

The chromosome constitution on H96276-2, which is a stable line derived from a sterile wheat-Agropyron intermedium partial amphiploid Zhong 3 cross to common wheat Hui 75, was analyzed by sequential GISH and FISH. The results of GISH using genomic DNA of Agropyron intermedium as probe showed that H96276-2 possessed 20 pairs of wheat chromosomes and one pair of translocation chromosomes of wheat and Ag. intermedium. The translocated alien chromosome fragments located on the terminals of one pair of wheat chromosomes. Furthermore, reprobing of repeat sequence pSc119 was used to identify the wheat chromosomes involved in the translocation. It was determined that the alien fragments located in the terminals of the short arms of 2B chromosomes of wheat.

In Situ Hybridization, Fluorescence↗

PubMed2003

Asymmetric somatic hybridization between wheat (Triticum aestivum L.) and Agropyron elongatum (Host) Nevishi.

Suspension-derived protoplasts of Agropyron elongatum irradiated by ultra-violet light (UV) were fused with the suspension-derived protoplasts of Triticum astivum using PEG. Fertile intergeneric somatic hybrid plants were produced and various hybrid lines have been selected and propagated in successive generations. Their hybrid nature was confirmed by analysis of profiles of isozymes, RAPDs, and 5S rDNA spacer sequences, and via GISH analysis. By the procedure described, the phenotype and chromosome number of wheat could be maintained besides transfer of a few chromosomes and chromosomal fragments from the donor A. elongatum. The results above indicated that highly asymmetric fertile hybrid plants and hybrid progenies of wheat were produced via somatic hybridization.

Agropyron↗

PubMed2004

Two quality-associated HMW glutenin subunits in a somatic hybrid line between Triticum aestivum and Agropyron elongatum.

High-molecular-weight glutenin subunits (HMW-GSs) from hybrid line II-12 between wheat (Triticum aestivum L.) and Agropyron elongatum (Host) Nivski were characterized with SDS-PAGE. Out of these HMW-GSs, two subunits, h1Bx and h1By, had mobilities similar to the subunits 1Bx13 and 1By16 from common wheat 4072, which was used as control. Polyclonal antibodies (pAbs) of h1Bx and h1By were prepared, and Western blotting showed that the pAbs had strong affinities for h1Bx and h1By, separately. The specificity of h1Bx-pAb was further checked; it preferentially recognized subunits h1Bx and 1Bx13. HMW-GS gene coding sequences were amplified by genomic polymerase chain reaction from hybrid II-12. Two of the five amplicons, marked II2a and II31b, were sequenced. Their coding sequences are clustered to Glu-1Bx7 and Glu-1By9 of common wheat. Three discrepant regions in deduced amino acid sequences of II2a and 31b repeated one time more than Glu-1Bx7 and Glu-1By9. N-terminal sequences of h1Bx and h1By were determined, which were identical to the published sequences of 1Bx13 and 1By16 and in agreement with that deduced from II2a and II31b, respectively. These results indicated that the two novel genes separated from the hybrid wheat derived from the allelic variation of 1Bx7 and 1By9 of the parent wheat. There is an additional cysteine residue positioned at 271st amino acid of the mature peptide of II2a, which may be related to the high quality of the flour.

Agropyron↗

PubMed2005

LMW-GS genes in Agropyron elongatum and their potential value in wheat breeding.

To study the usefulness of low-molecular-weight glutenin subunits (LMW-GS) of Agropyron elongatum (Host) Nevski to wheat (Triticum aestivum L.) quality improvement, we characterized LMW-GS genes of A. elongatum. Nine LMW-GS genes of A. elongatum, which were named AeL1 to AeL9, were cloned by genomic PCR. After sequencing, we obtained complete open reading frames from AeL2 to AeL8 and partial genes of AeL1 and AeL9. All nine sequences are homoeologous to those of wheat and related grasses. Comparison of the deduced amino acid sequences with those of published LMW-GS suggests that the basic structures of all the subunits are very similar. However, except for AeL4 and AeL5, which contain the identical N-terminal sequence with LMW-m, other LMW-GS sequences separated from A. elongatum cannot be classified according to previous criteria for the three types: LMW-m (methionine), LMW-s (serine), and LMW-i (isoleucine), and then 12 groups. In addition, there are some characters in the LMW-GS sequences of A. elongatum: AeL2, AeL3, and AeL6 involve a Cys residue in the signal peptide respectively, which is absent in most of LMW-GS; AeL3, AeL6, AeL8, and AeL9 start their first Cys residues in the N-terminal repetitive domains, respectively; both AeL2 and AeL5 have nine Cys residues, with an extra Cys residue in the N-terminal repetitive domain and the repetitive and glutamine-rich domain; AeL2, AeL3, AeL6, and AeL9 comprise long repetitive domains. Phylogenetic analysis indicates that there is a relatively weak sequence identity between the LMW-GS genes from A. elongatum cloned in this study and those reported from other plants. Three LMW-GS sequences, AeL2, AeL3, and AeL6, are clustered to Glu-A3 from wheat than to those from other plants. The possible use of these genes in relation to the high quality of hybrid wheat is discussed.

Agropyron↗

PubMed2006

The introgression of chromosome 6P specifying for increased numbers of florets and kernels from Agropyron cristatum into wheat.

A wheat (Triticum aestivum L.) line 4844 with superior numbers of florets and grains per spike was derived from the cross between Fukohokomugi wheat and Agropyron cristatum (L.) Gaertn. In order to determine the genetic control of floret and kernel number per spike in this line, chromosome addition and substitution lines that were derived from line 4844 were characterized by means of in situ hybridization, microsatellite (SSR), and gliadin analyses. Genomic in situ hybridization analysis with biotinylated P genomic DNA of A. cristatum as a probe demonstrated that the increased number of florets and grains in a spike was associated with the introgression of an A. cristatum chromosome. Fluorescence in situ hybridization, using a repetitive sequence, pAs1, derived from Aegilops squarrosa L., indicated the replacement of chromosome 6D of wheat in the wheat-A. cristatum chromosome substitution lines. This was confirmed by microsatellite analyses with wheat SSR markers specific for chromosome 6D, suggesting that the A. cristatum chromosome was homoeologous to group 6 and was therefore designated as 6P. This conclvsion was further confirmed by amplification using EST-SSR markers and gliadin analysis. The increased number of florets and kernels within a spike of the wheat-A. cristatum hybrids thus was controlled by gene(s) located on A. cristatum chromosome 6P.

Agropyron↗

PubMed2004

Agropyron elongatum chromatin localization on the wheat chromosomes in an introgression line.

The introgressed small-chromosome segment of Agropyron elongatum (Host.) Neviski (Thinopyrum ponticum Podp.) in F5 line II-1-3 of somatic hybrid between common wheat (Triticum aestivum L.) and A. elongatum was localized by sequential fluorescence in situ hybridization (FISH), genomic in situ hybridization (GISH) and karyotype data. Karyotype analysis offered basic data of arm ratios and relative lengths of 21 pairs of chromosomes in parent wheat Jinan177 and hybrid II-1-3. Using special high repetitive sequences pSc119.2 and pAs1 for FISH, the entire B- and D-genome chromosomes were detected. The FISH pattern of hybrid II-1-3 was the same as that of parent wheat. GISH using whole genomic DNA from A. elongatum as probe determined the alien chromatin. Sequential GISH and FISH, in combination with some of the karyotype data, localized the small chromosome segments of A. elongatum on the specific sites of wheat chromosomes 2AL, 1BL, 5BS, 1DL, 2DL and 6DS. FISH with probe OPF-03(1296) from randomly amplified polymorphic DNA (RAPD) detected E-genome chromatin of A. elongatum, which existed in all of the small chromosome segments introgressed. Microsatellite primers characteristic for the chromosome arms above were used to check the localization and reveal the genetic identity. These methods are complementary and provide comprehensive information about the genomic constitution of the hybrid. The relationship between hybrid traits and alien chromatin was discussed.

Agropyron↗

PubMed2004

Genome sequences of Agropyron mosaic virus and Hordeum mosaic virus support reciprocal monophyly of the genera Potyvirus and Rymovirus in the family Potyviridae.

Assignment of mite-transmitted species to the genus Rymovirus (family Potyviridae) has changed several times, and the status of the genus has been questioned. To address this issue, complete genome sequences of the rymoviruses Agropyron mosaic virus (AgMV) and Hordeum mosaic virus (HoMV) were determined. AgMV (9540 nucleotides) and HoMV (9463 nucleotides) each encode a single polyprotein with proteinase cleavage sites demarcating protein products characteristic of monopartite species of the family Potyviridae. Of the described species of Potyviridae, AgMV and HoMV are most closely related to each other (68.5% nucleotide and 71.6% amino acid sequence identity) and equidistant (about 53% nucleotide and about 49% amino acid sequence identity) from a third rymovirus, Ryegrass mosaic virus (RGMV). Phylogenetic analyses by neighbor joining, maximum parsimony, and Bayesian inference each grouped the three Rymovirus species in an exclusive clade distinct from a clade containing 34 species of the genus Potyvirus. Because AgMV, HoMV, and RGMV share a reciprocal monophyletic relationship with species of the genus Potyvirus and are divergent in sequence and type of vector, the genus Rymovirus should be retained as a taxonomic unit within the family Potyviridae.

Agropyron↗

PubMed2004

Suitability of altai wildrye (Elymus angustus) and slender wheatgrass (Agropyron trachycaulum) for initial reclamation of saline composite tailings of oil sands.

The reclamation of freshly produced composite or consolidated tailings (CT) is a challenge for the Oil Sands Industry in the boreal forest of Western Canada. CT tailings materials are characterized by a relatively high salinity (dominated by sodium, sulphate and chloride) and a high pH (8-9). A greenhouse study was conducted to determine the germination, survival, injury and early plant growth of two grass species recommended for land reclamation, altai wildrye (Elymus angustus Trin) and slender wheatgrass (Agropyron trachycaulum Link Malte), growing in two different oil sand CT tailings (alum-CT and gypsum-CT), with and without peat amendment. Ion accumulation in the resulting plant tissues was determined. Our results showed that slender wheatgrass was most affected by the tailings at the germination stage, while for altai wildrye, the early growth stage was the most sensitive stage. Alum-CT had similar or less negative impact on plants than gypsum-CT. Amendment of CT with peat limited the reduction in germination and growth that was recorded in plants growing directly in CT. Based on these results, recommendations were made to improve reclamation strategies.

Agropyron↗