ROS production and protein oxidation as a novel mechanism for seed dormancy alleviation.
At harvest, sunflower (Helianthus annuus L.) seeds are dormant and unable to germinate at temperatures below 15 degrees C. Seed storage in the dry state, known as after-ripening, is associated with an alleviation of embryonic dormancy allowing subsequent germination at suboptimal temperatures. To identify the process by which dormancy is broken during after-ripening, we focused on the role of reactive oxygen species (ROS) in this phenomenon. After-ripening entailed a progressive accumulation of ROS, namely superoxide anions and hydrogen peroxide, in cells of embryonic axes. This accumulation, which was investigated at the cellular level by electron microscopy, occurred concomitantly with lipid peroxidation and oxidation (carbonylation) of specific embryo proteins. Incubation of dormant seeds for 3 h in the presence of hydrogen cyanide (a compound that breaks dormancy) or methylviologen (a ROS-generating compound) also released dormancy and caused the oxidation of a specific set of embryo proteins. From these observations, we propose a novel mechanism for seed dormancy alleviation. This mechanism involves ROS production and targeted changes in protein carbonylation patterns.
Oracz
Krystyna
K
Department of Plant Physiology, Warsaw Agricultural University, Nowoursynowska 159, 02-776 Warsaw, Poland.
El-Maarouf Bouteau
Hayat
H
Farrant
Jill M
JM
Cooper
Keren
K
Belghazi
Maya
M
Job
Claudette
C
Job
Dominique
D
Corbineau
Françoise
F
Bailly
Christophe
C
D020869:Gene Expression Profiling; D018525:Germination / Q000502:physiology*; D006368:Helianthus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D006856:Hydrogen Cyanide / Q000494:pharmacology; D010084:Oxidation-Reduction; D010269:Paraquat / Q000494:pharmacology; D010940:Plant Proteins / Q000378:metabolism*; D050050:Protein Carbonylation / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012639:Seeds / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013997:Time Factors; D014867:Water
D010940:Plant Proteins; D017382:Reactive Oxygen Species; D014867:Water; D006856:Hydrogen Cyanide; D010269:Paraquat