Reactive oxygen species and inhibition of plant pa-thogens during infection – the roles(s) of superoxide

Lorant Koraly (Budapest): Plants may exhibit resistance to the infection of certain pathogens. Although the genetics of plant disease resistance has been well characterized, we still do not know what factor(s) are actually responsible for inhibition/killing of plant pathogens? Reactive oxygen species (ROS, e.g. superoxide and hydrogen peroxide) are by-products of animal and plant metabolism capable of damaging/limiting both hosts and pathogens. The role of ROS as key players in plant resistance to pathogens has become a pivotal research topic, since ROS accumulation has been detected during several plant disease resistance events. Our research suggests that the early accumulation of ROS, especially superoxide, plays a crucial role during very efficient forms of plant disease resistance where usually no symptoms develop. Inhibition of plant ROS (superoxide) production by genetic means or heat increases susceptibility, while external application of ROS to plant tissues may increase resistance to certain viral, bacterial and fungal pathogens