ROS Signaling in Seed Dormancy Alleviation.

Reactive oxygen species have been suggested to play a signaling role in seed dormancy alleviation. When sunflower seeds become able to fully germinate during dry after-ripening, they accumulate high amount of hydrogen peroxide and exhibit a low detoxifying ability through catalase, resulting from the decrease in CATA1 transcript. ROS accumulation entails oxidative modification of soluble and storage proteins through carbonylation, which suggests that this process might play an important role in plant developmental processes.

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.

DspA/E, a type III effector essential for Erwinia amylovora pathogenicity and growth in planta, induces cell death in host apple and nonhost tobacco plants.

Erwinia amylovora is responsible for fire blight, a necrotic disease of apples and pears. E. amylovora relies on a type III secretion system (TTSS) to induce disease on hosts and hypersensitive response (HR) on nonhost plants.