Planta

, Volume 213, Issue 1, pp 101–108 | Cite as

Amitrole treatment of etiolated barley seedlings leads to deregulation of tetrapyrrole synthesis and to reduced expression of Lhc and RbcS genes

  • N. La Rocca
  • N. Rascio
  • U. Oster
  • W. Rüdiger

Abstract.

The effect of amitrole, known as an inhibitor of carotenoid biosynthesis, upon tetrapyrrole biosynthesis and its regulation has been studied. Etiolated barley (Hordeum vulgare L.) seedlings, grown in 125 μM amitrole, accumulated high levels of 5-aminolevulinate, Mg-protoporphyrin, Mg-protoporphyrin monomethyl ester, and protochlorophyllide. The amitrole-treated seedlings did not form paracrystalline prolamellar bodies, and the induction of Lhc and RbcS gene expression was reduced by non-photooxidative, low-intensity light. None of these events was observed upon treatment of the seedlings with 100 μM norflurazon, another inhibitor of carotenoid biosynthesis. The effect of amitrole cannot be explained solely by interaction with a presumed feedback inhibition of 5-aminolevulinate synthesis since incubation with amitrole and 5-aminolevulinate indicated that deregulation also occurs at later steps of tetrapyrrole biosynthesis. A possible relationship between this deregulation and ultrastructural changes is discussed. In connection with previously published data, we discuss Mg-protoporphyrin and its monomethyl ester as possible candidates for a “plastid signal” that operates as a negative factor, reducing the expression of Lhc and RbcS genes in this higher plant.

Key words: Amitrole Etioplast structure Hordeum(tetrapyrrole biosynthesis) Magnesium Photoporphyrin Norflurazon Plastid signal 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • N. La Rocca
    • 1
  • N. Rascio
    • 1
  • U. Oster
    • 2
  • W. Rüdiger
    • 2
  1. 1. Dipartimento di Biologia, Universitá degli Studi di Padova, Via U. Bassi 58, 35131 Padova, ItalyIT
  2. 2. Botanisches Institut der Ludwig-Maximilians-Universität, Menzingerstr.67, 80638 München, GermanyDE

Personalised recommendations