Transgenic modification of gai or rgl1 causes dwarfing and alters gibberellins, root growth, and metabolite profiles in Populus
Transgenic modification of gai or rgl1 causes dwarfing and alters gibberellins, root growth, and metabolite profiles in Populus
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DOI：
10.1007/s00425-005-0213-9
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发表时间：
2006-07-01
期刊：
影响因子：
4.3
通讯作者：
Strauss, SH
中科院分区：
文献类型：
--
作者：
Busov, V;Meilan, R;Strauss, SH
在拟南芥和其他植物中，赤霉素 (GA) 调节的反应是由含有功能性 DELLA 结构域的 GAI、RGA 和 RGL1-3 等蛋白质介导的。通过转基因修饰，我们发现杨树中 GAI (gai) 和 RGL1 (rgl1) 的 DELLA-less 版本对表型具有深远的显性影响，在形态和代谢谱上产生多效性变化。芽变得矮小，可能是由于 GA 诱导的伸长受到组成型抑制，而根的生长在体外被促进了两到三倍。应用GA(3)抑制野生型杨树的不定根产生，但gai/rgl1杨树不受抑制的影响。表达gai和rgl1的植物叶片中生物活性GA(1)和GA(4)的浓度增加了12至64倍，而GA(1)的C-19前体(GA(53)、GA(44)和GA(19))减少了3至9倍，这与转基因植物中GA 20-氧化酶的反馈调节一致。转基因修饰引起了显着的代谢变化。在根中，代谢分析表明呼吸作用的增加是根生长增加的可能机制。在叶子中，我们发现代谢变化表明通过木质素生物合成途径的碳通量减少，并转向二次储存和防御代谢物的分配，包括各种酚、酚苷和酚酸缀合物。
In Arabidopsis and other plants, gibberellin (GA)-regulated responses are mediated by proteins including GAI, RGA and RGL1-3 that contain a functional DELLA domain. Through transgenic modification, we found that DELLA-less versions of GAI (gai) and RGL1 (rgl1) in a Populus tree have profound, dominant effects on phenotype, producing pleiotropic changes in morphology and metabolic profiles. Shoots were dwarfed, likely via constitutive repression of GA-induced elongation, whereas root growth was promoted two- to threefold in vitro. Applied GA(3) inhibited adventitious root production in wild-type poplar, but gai/rgl1 poplars were unaffected by the inhibition. The concentrations of bioactive GA(1) and GA(4) in leaves of gai- and rgl1-expressing plants increased 12- to 64-fold, while the C-19 precursors of GA(1) (GA(53), GA(44) and GA(19)) decreased three- to ninefold, consistent with feedback regulation of GA 20-oxidase in the transgenic plants. The transgenic modifications elicited significant metabolic changes. In roots, metabolic profiling suggested increased respiration as a possible mechanism of the increased root growth. In leaves, we found metabolite changes suggesting reduced carbon flux through the lignin biosynthetic pathway and a shift towards allocation of secondary storage and defense metabolites, including various phenols, phenolic glucosides, and phenolic acid conjugates.