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

Abstract

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.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.

Overexpression of ZePrx in Nicotiana tabacum Affects Lignin Biosynthesis Without Altering Redox Homeostasis

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Lignin biosynthesis in wheat (Triticum aestivum L.): its response to waterlogging and association with hormonal levels

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More or Less: Recent Advances in Lignin Accumulation and Regulation in Horticultural Crops

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