Plant-parasitic nematodes secreted ROS regulatory factors

Abstract

Prevention of crop damage by plant-parasitic nematodes (PPNs) is a current important issue. Plant-derived reactive oxygen species (ROS) affect pathogens including PPNs directly and induce immune responses simultaneously. In resistant varieties of wheat and tomato, ROS production is increased at the infection site of nematodes as compared to susceptible cultivars. Intriguingly, PPNs are able counteract various oxidative stresses during parasitism. E.g., PPNs secrete peroxiredoxin to scavenge external ROS resulting in successful parasitism. Further examples are protein disulfide isomerase, glutathione peroxidase and transthyretin-like proteins with catalytic subunits that are produced by infecting nematodes. These nematode-derived enyzmes are supposed to fine tune the redox status at the pathogen-host interface. On the other hand, ROS production by respiratory burst oxidase homolog (RBOH) in the host plant was found to be essential for parasitism of cyst nematodes. Although several nematode effectors involved in ROS signaling have been identified, the complex interactions between PPNs and their hosts are far from being fully understood. Nematicides are used to control PPNs in agriculture, but due to environmental, user, and consumer safety more and more of these mostly highy toxic compounds are banned or withdrawn from the market. Therefore, there is an urgent demand for alternatives including specific agrochemicals and breeding of new crop varieties. The analysis of the role of ROS in nematode-host interactions may lead to insights facilitating the development of such approaches. In this review, we summarize current topics in this field of crop sciences.