No description available.

No description available.

No description available.

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No description available.

The effects of temperature on a 58-kDa phosphoprotein (PP58) have been examined in cell-free extracts of two alfalfa (Medicago sativa L.) cultivars, Apica and Trek. In the extracts prepared without the use of Triton X-100, PP58 is present in a 12,000 x g (P12), 28,000 x g (P28) and 100,000 x g (P100) pellets but is enriched in the P28 fraction. In these fractions PP58 is substantially and equally phosphorylated at both 4° and 24°C. When extracts are prepared in the presence Triton X-100, PP58 is present in the 28,000 x g supernatant (TXS fraction) is extensively dephosphorylated at 24°C but highly phosphorylated at 4°C. The phosphorylation of this protein increased sharply as temperature declined below 12°C, and was 15 times greater at 0° than at 24°C. The phosphorylation level doubled between 12° and 8°C and again between 8° and 4°C. Thus temperature effect is not mediated by Q10 effect. Interestingly, temperature-response curve of PP58 phosphorylation is similar to that of the reported cold-induced calcium influx (Plant Cell 7: 321-331). Labeling reactions carried out in the presence of [gamma-35S]thioATP indicated that low temperature inhibited the dephosphorylation reaction. These results were not mimicked at room temperature by the protein phosphatase 1 and 2A inhibitor okadaic acid. In reactions performed at 4°C, addition of calcium caused a 2-fold increase in the phosphorylation of PP58. A decrease in phosphorylation was observed when equimolar amounts of EGTA were added in the presence of MgCl 2 or MnCl2, but not in the presence of CaCl2, suggesting that this protein is phosphorylated by a calcium-dependent protein kinase. These results are consistent with the suggestion that PP58 and its putative kinase are membrane-localized whereas the putative PP58 phosphatase is a loosely-associated membrane peripheral protein lost to the supernatant during fractionation. We suggest that PP58 could be involved in low te

Alfalfa is an important forage crop in North America which can also escape cultivation and establish in unmanaged habitats. Genetically modified (GM) alfalfa has been approved for environmental release in Canada and the United States and the occurrence of alfalfa in unmanaged natural and semi-natural habitats may compromise the successful co-existence of GM and non-GM alfalfa. To-date, little information has been available on the nature and dynamics of roadside alfalfa populations and their ability to become feral. Such knowledge is necessary to design efficient trait confinement protocols and to enhance the co-existence of GM and non-GM alfalfa within agricultural regions. The overall aim of this work was to characterize roadside alfalfa populations and to establish their role in novel trait movement. A roadside survey revealed the widespread occurrence of feral alfalfa populations in southern Manitoba. We described the seedbanks of roadside alfalfa populations, seedling recruitment and adult reproductive success, indicating that alfalfa is capable of establishing self-perpetuating feral populations in unmanaged habitats. We also noted the successful establishment of alfalfa in a grass sward representing roadside vegetation. Roadside mowing can reduce (and perhaps prevent) seed production in roadside alfalfa; however, mowing failed to drive the populations to extinction in the short-term. Herbicide (2,4-D) applications controlled alfalfa plants but seeds in the seedbank may still contribute to new seedling recruitment. The roadside alfalfa populations we worked with exhibited high levels of genetic diversity, indicating an absence of past population bottlenecks or genetic drift. In addition, phenotypic characterization provided evidence that roadside alfalfa populations were experiencing selection pressure for adaptive traits including winter survivability, rhizome production and prostrate growth habit; all traits that favor persistence in unmanaged habitats. We also noted the occurrence of high (>60%) levels of outcrossing in feral alfalfa populations, establishing their role as sources and sinks for novel traits. Our findings indicate that alfalfa populations occurring in unmanaged habitats need to be considered in trait confinement protocols in order to reduce the adventitious presence (AP) of novel traits and to enhance the successful co-existence of GM and non-GM alfalfa.

Alfalfa is an important forage crop in North America which can also escape cultivation and establish in unmanaged habitats. Genetically modified (GM) alfalfa has been approved for environmental release in Canada and the United States and the occurrence of alfalfa in unmanaged natural and semi-natural habitats may compromise the successful co-existence of GM and non-GM alfalfa. To-date, little information has been available on the nature and dynamics of roadside alfalfa populations and their ability to become feral. Such knowledge is necessary to design efficient trait confinement protocols and to enhance the co-existence of GM and non-GM alfalfa within agricultural regions. The overall aim of this work was to characterize roadside alfalfa populations and to establish their role in novel trait movement. A roadside survey revealed the widespread occurrence of feral alfalfa populations in southern Manitoba. We described the seedbanks of roadside alfalfa populations, seedling recruitment and adult reproductive success, indicating that alfalfa is capable of establishing self-perpetuating feral populations in unmanaged habitats. We also noted the successful establishment of alfalfa in a grass sward representing roadside vegetation. Roadside mowing can reduce (and perhaps prevent) seed production in roadside alfalfa; however, mowing failed to drive the populations to extinction in the short-term. Herbicide (2,4-D) applications controlled alfalfa plants but seeds in the seedbank may still contribute to new seedling recruitment. The roadside alfalfa populations we worked with exhibited high levels of genetic diversity, indicating an absence of past population bottlenecks or genetic drift. In addition, phenotypic characterization provided evidence that roadside alfalfa populations were experiencing selection pressure for adaptive traits including winter survivability, rhizome production and prostrate growth habit; all traits that favor persistence in unmanaged habitats. We also noted the occurrence of high (>60%) levels of outcrossing in feral alfalfa populations, establishing their role as sources and sinks for novel traits. Our findings indicate that alfalfa populations occurring in unmanaged habitats need to be considered in trait confinement protocols in order to reduce the adventitious presence (AP) of novel traits and to enhance the successful co-existence of GM and non-GM alfalfa.

No description available.

Chopped alfalfa and chopped whole-plant corn were ensiled and the proteolytic changes which occurred during ensiling were investigated. Proteolysis was measured in terms of end-products of protein degradation and by protein isolation followed by electrophoresis. The effects of formic acid and ammonia, applied at the time of ensiling, on proteolytic changes were investigated. / Alfalfa treated with formic acid contained significantly reduced levels of NH$ sb3$-N and NPN compared to control silage; ammonia (NH$ sb3$)-treated alfalfa silage had significantly less NPN (P $<$ 0.05). After 90d of storage, formic acid-treated and NH$ sb3$-treated alfalfa silage contained lower levels of both branched and non-branched amino acids, sulfur containing, and basic amino acids compared to control silage; formic acid-treated and NH$ sb3$-treated corn silage contained lower levels of branched chain amino acids and sulfur containing amino acids after the same time period. Formic acid and ammonia were most effective in the reduction of proteolysis in alfalfa silage and corn silage, respectively. The protein ribulose 1,5-diphosphate carboxylase (RuDPCase) was depleted completely after 2d of fermentation in control silage. Conditions in NH$ sb3$-treated alfalfa silage stabilized RuDPCase during the first 24h of storage.