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Lynn S. Dahleen Muthusamy Manoharan 《In vitro cellular & developmental biology. Plant》2007,43(6):493-506
Barley, an important member of the cereals, has been successfully transformed through various methods such as particle bombardment,
Agrobacterium tumefaciens, DNA uptake, and electroporation. Initially, the transformation in barley concentrated on developing protocols using marker
genes such as gus, bar, and hpt. Immature embryos and callus derived from immature embryos were targeted for transformation. Subsequently, genes of agronomic
and malting importance have been deployed in barley. Particle bombardment appears to be the preferred choice for barley transformation
in the majority of the reports, although Agrobacterium-mediated transformation is being used more often. The current review focuses on the challenges encountered in barley transformation
such as somaclonal variation, development of transformation systems for commercial cultivars, gene expression, stability and
inheritance, and gene flow. Newer markers such as the green fluorescent protein (gfp), firefly luciferase, and phosphomannose isomerase were found to be useful in the selection of transgenic plants. Tissue-specific
promoters such as those for B1-hordein and D-hordein genes, and spike-specific promoters, are increasingly used to drive gene
expression. The review also describes recent research on gene-tagging through transformation, insertion of disease resistance,
and abiotic stress resistance genes, transformation with genes for improved malting quality, nutrient content, feed quality,
and the production of feed enzymes and pharmaceutical compounds. 相似文献
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Size selectivity of aqueous pores in stomatous cuticles of <Emphasis Type="Italic">Vicia faba</Emphasis> leaves 总被引:1,自引:0,他引:1
Size selectivity of aqueous pores in Vicia leaf cuticles was investigated by measuring the penetration of calcium salts into the abaxial surface of detached leaves. Molecular weights of salts ranged from 111 g mol–1 to 755 g mol–1. Penetration in light at 20°C and 100% humidity was a first order process and rate constants of penetration ranged from 0.39 h–1 (CaCl2) to 0.058 h–1 (Ca-lactobionate). Penetration was a first order process in the dark as well, but the rate constants were smaller by a factor of 1.82. Plotting logarithmatised rate constants versus anhydrous molecular weights resulted in straight lines both in light and in the dark. The slopes per hour were very similar and the average slope was –1.2×10–3 mol g–1. Hence, size selectivity was not affected by stomatal opening, and in light or darkness permeability of Vicia cuticles decreased by a factor of 2.9 when molecular weight increased from 100 g mol–1 to 500 g mol–1. Silver nitrate was preferentially precipitated as silver chloride in guard cells, glandular trichomes and at the base of trichomes. It was concluded that these precipitates mark the location of aqueous pores in Vicia leaf cuticles. The size selectivity of aqueous pores in Vicia leaf cuticles is small compared to that observed in poplar leaf cuticles, in which permeability decreased by a factor of 7–13 for the same range of molecular weights. It is also much smaller than size selectivity of the lipophilic pathway in cuticles. These findings suggest that active ingredients of pesticides, growth regulators and chemical inducers with high molecular weights penetrate leaves at higher rates when formulated as ions. 相似文献
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Islam MR Jimenez T Pelham C Rodova M Puri S Magenheimer BS Maser RL Widmann C Calvet JP 《The Journal of biological chemistry》2010,285(50):38818-38831