Dwarfism Research Today is a free monthly online journal that collates and summarizes the latest research about Dwarfism, including details on genetics, diet, mental and motor development. | ||||||||
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Decreased shoot stature and grain {alpha}-amylase activity following ectopic expression of a gibberellin 2-oxidase gene in transgenic wheat.Appleford NE, Wilkinson MD, Ma Q, Evans DJ, Stone MC, Pearce SP, Powers SJ, Thomas SG, Jones HD, Phillips AL, Hedden P, Lenton JR Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom. Ectopic expression of a gibberellin 2-oxidase gene (PcGA2ox1) decreased the content of bioactive gibberellins (GAs) in transgenic wheat, producing a range of dwarf plants with different degrees of severity. In at least one case, a single transformation event gave rise to T(1) plants with different degrees of dwarfism, the phenotypes being stably inherited over at least four generations. The dwarf phenotype, which included dark-green leaves, increased tillering and, in severe cases, a prostrate growth habit, was replicated by the application of a GA biosynthesis inhibitor to the wild type. Ear rachis length, grain set, and grain size were also decreased in the wheat transformants, compared with an azygous (null) line. The extent of post-germination alpha-amylase production in grains reflected the severity of the shoot phenotype of the transformants and both developmental processes were restored to normal by the application of gibberellic acid (GA(3)). Expression of two GA biosynthesis genes (TaGA20ox1 and TaGA3ox2) was up-regulated, and that of two alpha-amylase gene families (alpha-Amy1 and alpha-Amy2) down regulated, in scutella of semi-dwarf lines, compared with controls. The marked decline in transcript abundance of both alpha-amylase gene families in aleurone was associated with a decreased content of bioactive GAs in grains of the semi-dwarf lines. Published 5 November 2007 in J Exp Bot, 58(12): 3213-26.
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