ROS production and protein oxidation as a novel mechanism for seed dormancy alleviation

Abstract

SummaryAt harvest, sunflower (Helianthus annuus L.) seeds are dormant and unable to germinate at temperatures below 15°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.

Burning vegetation produces cyanohydrins that liberate cyanide and stimulate seed germination

“…The mode of action of cyanide in stimulating seed germination remains unclear but is thought to involve reactive oxygen species 32,39 . It has also been proposed that cyanide acts at an initial step in dormancy alleviation and nitrogen oxide is required at a later step 33 .…”

Chitooligosaccharide Prolongs Vase Life of Cut Roses by Decreasing Reactive Oxygen Species

“…, H 2 O 2 contents Superoxide anion content was determined according to the method developed by Elstner and Heupel (Oracz et al, 2007). One gram of outermost whorl petals was ground with liquid nitrogen.…”

Unraveling the Tapestry of Networks Involving Reactive Oxygen Species in Plants

“…There is new information on the fate of oxidized proteins from investigations that link protein oxidation and autophagy (Bassham, 2007;Xiong et al, 2007aXiong et al, , 2007b and describe the role of protein oxidation in seed dormancy (Oracz et al, 2007). It was found that protein oxidation is followed by controlled degradation and recycling and that these processes are essential for cellular viability, signaling, development, and recovery from oxidative stress.…”