J Integr Plant Biol. ›› 2010, Vol. 52 ›› Issue (2): 244-251.DOI: 10.1111/j.1744-7909.2010.00888.x

• Research Articles • Previous Articles    

Downregulation of the Basic Peroxidase Isoenzyme from Zinnia elegans by Gibberellic Acid

María Josefa López Núñez-Flores1, Jorge Gutiérrez 2, Laura V. Gómez-Ros 1, Esther Novo Uzal2, Mariana Sottomayor3 and Alfonso Ros Barceló   

  1. 1* 1Department of Plant Biology, University of Murcia, E-30100, Murcia, Spain
  • Received:2009-08-27 Accepted:2009-09-11 Published:2010-02-01
  • About author: 2Department of Plant Biology, University of La Coruña, E-15071, La Coruña, Spain
    3IBMC, University of Porto, 4150 Porto, Portugal
    *Author for correspondence Tel: +34 868 884945; Fax: +34 868 883963; E-mail: rosbarce@um.es


Hypocotyl formation during the epigeal germination of seedlings is under strict hormonal regulation. In a 3 d old Zinnia elegans seedling system, gibberellic acid (GA3) exerts an opposite effect to that exerted by light on hypocotyl photomorphogenesis because GA3 promotes an etiolated-like growth with an inhibition of radial (secondary) growth. For this reason, the effect of GA3 on the basic peroxidase isoenzyme from Z. elegans (ZePrx), an enzyme involved in hypocotyl lignin biosynthesis, was studied. The results showed that GA3 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 GA3-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 GA3, with this effect matching the inhibitory effect of GA on the hypocotyl secondary growth.

López Núñez-Flores MJ, Gutiérrez J, Gómez-Ros LV, Novo Uzal E, Sottomayor M, Ros Barceló A (2010) Downregulation of the basic peroxidase isoenzyme from Zinnia elegans by gibberellic acid. J. Integr. Plant Biol. 52(2), 244–251.

Key words: gibberellins, peroxidase, secondary growth, Zinnia elegans.

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