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PubMed2004

Purification, properties and specificity of an endonuclease from Agropyron elongatum seedlings.

An endonuclease was isolated from 5 days old Agropyron elongatum 8x = Elytrigia turcica McGuire seedlings. The enzyme was purified by means of ammonium sulfate fractionation, DEAE-cellulose and Heparin Sepharose column. The final preparation, named nuclease A, gave a single band after silver staining had followed SDS-electrophoresis that was identified with nuclease activities. The enzyme also showed a single band after activity staining on gel polymerized in the presence of heat denatured DNA (ssDNA)/RNA. The Mr of native enzyme was 36 and the enzyme's moiety consisted of one polypeptide chain. Nuclease A activity was stimulated in the presence of Zn(2+) and was moderately reduced by NaCl yet strongly by spermine. The enzyme had pH optimum 5.5 and isoelectric point (pI) 4.7. It hydrolyzed the nucleic acids in the order ssDNA > dsDNA > or = RNA; hence it was classified as a plant nuclease type I (EC 3.1.30.2). Synthetic homopolyribonucleotides were hydrolyzed in the order polyU > polyI > or = polyA > polyG > polyC. Nuclease A nicked the supercoiled plasmid DNA while it was incapable of hydrolyzing dinucleoside monophosphates. With regard to nuclease A base linkage specificity towards a synthetic 5'-(32)P labeled deoxydecanucleotide [5'-(32)P]CCTGGCAGTT, the enzyme firstly exhibited a preference to Ap downward arrow G bond and then to Gp downward arrow T, Cp downward arrow A and Gp downward arrow G bonds while it was incapable of hydrolyzing the Cp downward arrow C bond. The substrate's products of nuclease A were oligonucleotides with the monoesterified phosphate at the 3' position. Nuclease A may perform a crucial function in the metabolism of nucleic acids during seedling growth and could be used as a biochemical tool for analysis of nucleic acids structure.

Agropyron↗
PubMed2004

Transfer of small chromosome fragments of Agropyron elongatum to wheat chromosome via asymmetric somatic hybridization.

The chromosome constitution of hybrids and chromatin patterns of Agropyron elongatum (Host)Neviski in F5 somatic hybrid lines II -1-3 and I-1-9 between Triticum aestivum L. and A. elongatum were analyzed. Based on the statistic data of pollen mother cells, F5 I-1-9 and II-1-3 had 20-21 bivalents with a frequency of 84.66% and 85.28%, of which, 89.83% and 89.57% were ring bivalents. The result indicated that both hybrid lines were basically stable in the chromosome constitution and behavior. RAPD analysis showed that the two hybrids contained biparental and integrated DNA. GISH (Genome in situ hybridization) revealed that in the form of small chromosome segments, A. elongatum chromatin was scattered on 4-6 wheat chromosomes near by the region of centromere and telomere in the two hybrid lines. SSR analysis indicated that A. elongatum DNA segments were distributed on the 2A, 5B, 6B and 2D wheat chromosomes in the hybrids, which was in accordance with the GISH results that small-segments intercalated poly-site.

Agropyron↗
PubMed2005

[Genome constitution of Agropyron elongatum 4x by biochemical and SSR markers].

We analyzed the electrophoritic patterns of 16 kinds of isozyme and three kinds of storage protein in Agropyron elongatum 2x and Ag. elongatum 4x by isoelectric focusing (IEF) and SDS-PAGE, respectively. The results showed three types of electrophoritic patterns. In the first type, the zymogram phenotypes are identical between Ag. elongatum 2x and Ag. elongatum 4x. Two kinds of isozyme belong to this type, which accounts for 10.5% of all the biochemical markers analyzed. In the second type, Ag. elongatum 4x showed a phenotype which is made up of combinations of the all of Ag. elongatum 2x bands and the specific bands. Ten kinds of isozyme and three kinds of storage protein fall into this class, which is the most part and accounts for 63.2% of all the markers analyzed. In the third type, Ag. elongatum 2x and Ag. elongatum 4x showed some identical bands and their own specific bands. Five kinds of isozyme were classified to this group,which accounts for 26.3% of all the markers analyzed. The results above suggested that Ag. elongatum 4x is a allotetraploid composed of one genome originated from Ag. elongatum 2x and another unknown genome which is apparently distinct from the St, J and N genomes of relative species. Otherwise, SSR primers were used to analyze the relation of Ag. elongatum 2x and Ag. elongatum 4x. The amplification results of most primers showed that Ag. elongatum 2x and Ag. elongatum 4x have some identical bands and Ag. elongatum 4x have some specific bands. This result validated the conclusion from biochemical marker analyses that Ag. elongatum 4x is a allotetraploid.

Agropyron↗
PubMed1996

Molecular cloning and nucleotide sequencing of the partial genomes of Agropyron and Hordeum mosaic viruses, two members of the Rymovirus genus in the taxonomic family Potyviridae.

Complementary DNAs encompassing the coat protein coding and adjacent regions of Agropyron mosaic virus (AgMV) and Hordeum mosaic virus (HoMV) were cloned and sequenced. Comparison with other sequenced potyviruses indicated that each clone contained the 3'-non-coding region (3'NCR), the coat protein (CP) gene and part of the nuclear inclusion protein (NIb) gene. Nucleotide and amino acid sequence comparisons of the 3'-terminal regions of these and other rymoviruses indicate that distinct groups exist. Ryegrass mosaic virus (RGMV) strains share sequence similarity with AgMV and HoMV. Wheat streak mosaic virus (WSMV) and brome streak mosaic virus (BrSMV) form a separate group, sharing limited sequence similarity with the other rymoviruses. It is proposed that subgroups occur within the Rymovirus genus, depending on the vector species involved in transmission and on sequences.

Amino Acid Sequence↗
PubMed1995

Effect of Herniaria hirsuta and Agropyron repens on calcium oxalate urolithiasis risk in rats.

The effects on the calcium oxalate urolithiasis urinary risk factors of Herniaria hirsuta L. (Carryophyllaceae) and Agropyron repens L. (Gramineae), in herb infusion form, combined with different diets (standard, high glucidic, high protein) have been studied using Wistar rats. From this study it is deduced that the possible effects of the A. repens infusion can not be assigned to any positive effects on the main urolithiasis risk factors. The tentative antilithiasic effects of the H. hirsuta infusion clearly depends on the diet. Thus, a clear increase in the citraturia was only detected when such infusion was administered with the high protein diet.

Animals↗
PubMed1982

Temperature Dependence of Photosynthesis in Agropyron smithii Rydb. : I. FACTORS AFFECTING NET CO(2) UPTAKE IN INTACT LEAVES AND CONTRIBUTION FROM RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE MEASURED IN VIVO AND IN VITRO.

As part of an extensive analysis of the factors regulating photosynthesis in Agropyron smithii Rydb., a C(3) grass, we have examined the response of leaf gas exchange and ribulose-1,5-bisphosphate (RuBP) carboxylase activity to temperature. Emphasis was placed on elucidating the specific processes which regulate the temperature response pattern. The inhibitory effects of above-optimal temperatures on net CO(2) uptake were fully reversible up to 40 degrees C. Below 40 degrees C, temperature inhibition was primarily due to O(2) inhibition of photosynthesis, which reached a maximum of 65% at 45 degrees C. The response of stomatal conductance to temperature did not appear to have a significant role in determining the overall temperature response of photosynthesis. The intracellular conductance to CO(2) increased over the entire experimental temperature range, having a Q(10) of 1.2 to 1.4. Increases in the apparent Michaelis constant (K(c)) for RuBP carboxylase were observed in both in vitro and in vivo assays. The Q(10) values for the maximum velocity (V(max)) of CO(2) fixation by RuBP carboxylase in vivo was lower (1.3-1.6) than those calculated from in vitro assays (1.8-2.2). The results suggest that temperature-dependent changes in enzyme capacity may have a role in above-optimum temperature limitations below 40 degrees C. At leaf temperatures above 40 degrees C, decreases in photosynthetic capacity were partially dependent on temperature-induced irreversible reductions in the quantum yield for CO(2) uptake.

Journal Article↗
PubMed1982

Temperature Dependence of Photosynthesis in Agropyron smithii Rydb. : II. CONTRIBUTION FROM ELECTRON TRANSPORT AND PHOTOPHOSPHORYLATION.

As part of an analysis of the factors regulating photosynthesis in Agropyron smithii Rydb., a C(3) grass, the response of electron transport and photophosphorylation to temperature in isolated chloroplast thylakoids has been examined. The response of the light reactions to temperature was found to depend strongly on the preincubation time especially at temperatures above 35 degrees C. Using methyl viologen as a noncyclic electron acceptor, coupled electron transport was found to be stable to 38 degrees C; however, uncoupled electron transport was inhibited above 38 degrees C. Photophosphorylation became unstable at lower temperatures, becoming progressively inhibited from 35 to 42 degrees C. The coupling ratio, ATP/2e(-), decreased continuously with temperature above 35 degrees C. Likewise, photosystem I electron transport was stable up to 48 degrees C, while cyclic photophosphorylation became inhibited above 35 degrees C. Net proton uptake was found to decrease with temperatures above 35 degrees C supporting the hypothesis that high temperature produces thermal uncoupling in these chloroplast thylakoids. Previously determined limitations of net photosynthesis in whole leaves in the temperature region from 35 to 40 degrees C may be due to thermal uncoupling that limits ATP and/or changes the stromal environment required for photosynthetic carbon reduction. Previously determined limitations to photosynthesis in whole leaves above 40 degrees C correlate with inhibition of photosynthetic electron transport at photosystem II along with the cessation of photophosphorylation.

Journal Article↗
PubMed1984

Temperature Dependence of Photosynthesis in Agropyron smithii Rydb. : III. Responses of Protoplasts and Intact Chloroplasts.

Protoplasts and intact chloroplasts isolated from Agropyron smithii Rybd. were utilized in an effort to determine the limiting factor(s) for photosynthesis at supraoptimal temperatures. Saturated CO(2)-dependent O(2) evolution had a temperature optimum of 35 degrees C for both protoplasts and intact chloroplasts. A sharp decline in activity was observed as assay temperature was increased above 35 degrees C, and at 45 degrees C only 20% of the maximal rate remained. The temperature optimum for 3-phosphoglycerate reduction by intact chloroplasts was 35 degrees C. Above this temperature, 3-phosphoglycerate reduction was more stable than CO(2)-dependent O(2) evolution. Reduction of nitrite in coupled intact chloroplasts had a temperature optimum of 40 degrees C with only slight variation in activity between 35 degrees C and 45 degrees C. Reduction of nitrite in uncoupled chloroplasts had a temperature optimum of 40 degrees C, but increasing the assay temperature to 45 degrees C resulted in a complete loss of activity. Reduction of p-benzoquinone by protoplasts and intact chloroplasts had a temperature optimum of 32 degrees C when measured in the presence of dibromothymoquinone. This photosystem II activity exhibited a strong inhibition of O(2) evolution as assay temperature increased above the optimum. It is concluded that, below the temperature optimum, ATP and reductant were not limiting photosynthesis in these systems or intact leaves. Above the temperature optimum, photosynthesis in these systems is limited in part by the phosphorylation potential of the stromal compartment and not by the available reductant.

Journal Article↗
PubMed2001

A fertile amphiploid between durum wheat (Triticum turgidum) and the x Agroticum amphiploid (Agropyron cristatum x T. tauschii).

Agropyron (Gaertn) is a genus of Triticeae which includes the crested wheatgrass complex, i.e. A. cristatum (L.) as representative species containing the P genome. This species is an important source for increase the genetic variability of both durum and bread wheat. Among the possible interesting features to be introgressed into wheat are resistance to wheat streak mosaic virus, rust diseases, and tolerance to drought, cold and moderate salinity. By crossing tetraploid wheat (Triticum turgidum conv durum, 2n = 4x = 28; AABB) with a fertile allotetraploid (2n = 4x = 28; DDPP) between diploid wheat (T. tauschii) and crested wheatgrass (A. cristatum L.), amphiploid plants were obtained. Fluorescence in situ hybridization (FISH) using both genomic DNA from A. cristatum and the repetitive probe pAs1, proved that the plants were true amphiploids with a chromosome number 2n = 8x = 56 and genomic constitution AABBDDPP. Using total genomic in situ hybridization (GISH) to study meiotic metaphase I, data on allosyndetic and autosyndetic chromosome pairing were obtained. The amphiploids were perennial like the male parent but their morphology was close to that of the wheat parent. They were resistant to wheat leaf rust and powdery mildew under field conditions.

Chimera↗
PubMed2000

[The genetic behavior of an Agropyron intermedium chromosome conferring BYDV resistance in wheat background].

Based on the chromosome origin identification of an Agropyron intermedium chromosome with BYDV resistance in Yi4212, a BYDV-resistant substitution line derived from the hybrids between 77-5433 and Zhong5, its ability compensating the lost wheat chromosomes and its transmission rate were investigated. The results indicated that the BYDV-resistant chromosomes originated from Zhong 5 could compensate the wheat chromosomes of homotologous group 2, 5 and 7. The chromosome conferring resistance to BYDV showed the intendance to substitute 2D rather than 2A, 2B wheat chromosomes in disomic substitution lines. In (77-5433/Zhong 5) selfing F2 population, 10 kinds of chromosome constitutions, including 9 expected and 1 unexpected kinds, and much chromosome number variation and little chromosome structure variation were observed. The transmission rate of the BYDV-resistant chromosome and the gametes carrying this chromosome were 56.3% and 33.0% respectively, both are lower than the expected ratio 75.0% and 50.0%. Some reasons were given to explain the related results, and chromosome in situ hybridization was an efficient and accurate way in studying the alien chromosome behavior in wheat background.

Chromosomes↗
PubMed2003

Comparison of growth performance of Lolium perenne L., Dactylis glomerata L. and Agropyron elongatum (Host.) P. Beauv. for erosion control in Turkey.

This study was carried out in plastic containers to compare growth performances of perennial ryegrass, orchardgrass and tall wheatgrass to be given priority in revegetation studies in Turkey. Three pre-germinated seeds of each grass species were planted separately into the soil in the black plastic containers. Seedlings were harvested 2, 4 and 6 months after planting pre-germinated seeds and measured for percentage of seedling emergence, rooting depth, height growth, leaf and tiller development and shoot and root weights. Germination percentage was 97.8% for perennial ryegrass, 64.1% for orchardgrass and 11.6% for tall wheatgrass and perennial ryegrass had the greatest whereas tall wheatgrass had the lowest seedling emergence. Two months old rooting depth was 25.66 cm for perennial ryegrass, 20.56 cm for orchardgrass and 30.10 cm for tall wheatgrass. At the end of the study, perennial ryegrass developed about 104 tillers per plant while they were 21.4 and 36.6 tillers per plant for orchardgrass and tall wheatgrass, respectively. Orchardgrass produced greater shoot and root biomasses than tall wheatgrass and similar to perennial ryegrass. All these meant that perennial ryegrass had a better growth performance than orchardgrass and tall wheatgrass to be used for erosion control.

Agropyron↗