This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 150/1/494    most recent pp.109.138107v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Oracz, K. Articles by Bailly, C. Search for Related Content PubMed PubMed Citation Articles by Oracz, K. Articles by Bailly, C. Agricola Articles by Oracz, K. Articles by Bailly, C.

DEVELOPMENT AND HORMONE ACTION

The Mechanisms Involved in Seed Dormancy Alleviation by Hydrogen Cyanide Unravel the Role of Reactive Oxygen Species as Key Factors of Cellular Signaling during Germination^[C],[W]

UPMC Univ Paris 06, Unité de Recherche 5, Germination et Dormance des Semences, Site d'Ivry, F–75005 Paris, France (K.O., H.E.-M.-B., F.C., C.B.); Department of Plant Physiology, Warsaw University of Life Sciences, 02–776 Warsaw, Poland (K.O., R.B.); and Seed Conservation Department, Royal Botanic Gardens, Wakehurst Place, West Sussex RH17 6TN, United Kingdom (I.K.)

The physiological dormancy of sunflower (Helianthus annuus) embryos can be overcome during dry storage (after-ripening) or by applying exogenous ethylene or hydrogen cyanide (HCN) during imbibition. The aim of this work was to provide a comprehensive model, based on oxidative signaling by reactive oxygen species (ROS), for explaining the cellular mode of action of HCN in dormancy alleviation. Beneficial HCN effect on germination of dormant embryos is associated with a marked increase in hydrogen peroxide and superoxide anion generation in the embryonic axes. It is mimicked by the ROS-generating compounds methylviologen and menadione but suppressed by ROS scavengers. This increase results from an inhibition of catalase and superoxide dismutase activities and also involves activation of NADPH oxidase. However, it is not related to lipid reserve degradation or gluconeogenesis and not associated with marked changes in the cellular redox status controlled by the glutathione/glutathione disulfide couple. The expression of genes related to ROS production (NADPHox, POX, AO1, and AO2) and signaling (MAPK6, Ser/ThrPK, CaM, and PTP) is differentially affected by dormancy alleviation either during after-ripening or by HCN treatment, and the effect of cyanide on gene expression is likely to be mediated by ROS. It is also demonstrated that HCN and ROS both activate similarly ERF1, a component of the ethylene signaling pathway. We propose that ROS play a key role in the control of sunflower seed germination and are second messengers of cyanide in seed dormancy release.

^[C] Some figures in this article are displayed in color online but in black and white in the print edition.

^[W] The online version of this article contains Web-only data.

www.plantphysiol.org/cgi/doi/10.1104/pp.109.138107

^* Corresponding author; e-mail christophe.bailly{at}upmc.fr.

Received March 4, 2009; accepted March 26, 2009; published March 27, 2009.

This article has been cited by other articles:

				K. Muller, A. Linkies, R. A.M. Vreeburg, S. C. Fry, A. Krieger-Liszkay, and G. Leubner-Metzger In Vivo Cell Wall Loosening by Hydroxyl Radicals during Cress Seed Germination and Elongation Growth Plant Physiology, August 1, 2009; 150(4): 1855 - 1865. [Abstract] [Full Text] [PDF]