Department of Plant Biology, University of Murcia, E-30100, Murcia, Spain.
J Integr Plant Biol. 2010 Feb;52(2):244-51. doi: 10.1111/j.1744-7909.2010.00888.x.
Hypocotyl formation during the epigeal germination of seedlings is under strict hormonal regulation. In a 3 d old Zinnia elegans seedling system, gibberellic acid (GA(3)) exerts an opposite effect to that exerted by light on hypocotyl photomorphogenesis because GA(3) promotes an etiolated-like growth with an inhibition of radial (secondary) growth. For this reason, the effect of GA(3) on the basic peroxidase isoenzyme from Z. elegans (ZePrx), an enzyme involved in hypocotyl lignin biosynthesis, was studied. The results showed that GA(3) reduces ZePrx activity, similarly to the way in which it reduces seedling secondary growth. This hormonal response is supported by the analysis of the ZePrx promoter, which contains four types of GA(3)-responsive cis-elements: the W Box/O2S; the Pyr Box; the GARE; and the Amy Box. Taken together, these results suggest that ZePrx is directly regulated by GA(3), with this effect matching the inhibitory effect of GA on the hypocotyl secondary growth.
在幼苗的地上发芽过程中，下胚轴的形成受到严格的激素调控。在 3 天龄的百日草幼苗系统中，赤霉素（GA（3））对下胚轴光形态发生的作用与光相反，因为 GA（3）促进类似于黄化的生长，抑制径向（次生）生长。出于这个原因，研究了 GA（3）对参与下胚轴木质素生物合成的百日草基本过氧化物酶同工酶（ZePrx）的影响。结果表明，GA（3）降低了 ZePrx 的活性，这与它降低幼苗次生生长的方式相似。GA（3）反应元件的分析支持了这种激素反应，该元件包含四种类型的 GA（3）反应顺式元件：W 盒/O2S；嘧啶盒；GARE；和 Amy 盒。综上所述，这些结果表明 ZePrx 被 GA（3）直接调控，这种作用与 GA 对下胚轴次生生长的抑制作用相匹配。
