Decreased shoot stature and grain α-amylase activity following ectopic expression of a gibberellin 2-oxidase gene in transgenic wheat
Decreased shoot stature and grain α-amylase activity following ectopic expression of a gibberellin 2-oxidase gene in transgenic wheat
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DOI：
10.1093/jxb/erm166
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发表时间：
2007-10-01
影响因子：
6.9
通讯作者：
Lenton, John R.
中科院分区：
文献类型：
--
作者：
Appleford, Nigel E. J.;Wilkinson, Mark D.;Lenton, John R.
异位表达的赤霉素2氧化酶基因（PcGA2ox1）降低了转基因小麦中生物活性赤霉素（GAs）的含量，产生了一系列不同程度的矮化植株。在至少一个案例中，一个单一的转化事件产生了具有不同程度侏儒症的T-1植株，这种表型至少稳定地遗传了四代。矮化表型包括深绿色叶片，分蘖增加，在严重的情况下，匍匐生长习惯，通过在野生型中应用GA生物合成抑制剂可以复制。与偶交（零）系相比，小麦转化系的穗轴长度、籽粒密度和籽粒大小也有所减少。籽粒萌发后α -淀粉酶的产生程度反映了转化子茎型的严重程度，施用赤霉素酸（GA3）使这两个发育过程恢复正常。与对照相比，半矮系鳞茎中2个GA生物合成基因TaGA20ox1和TaGA3ox2的表达上调，2个α -淀粉酶基因家族α - amy1和α - amy2的表达下调。糊粉中α -淀粉酶基因家族转录丰度的显著下降与半矮秆系籽粒中生物活性气体含量的下降有关。
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 (GA3). 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.