Suppression of Plant Defences by Nematodes
Biotrophic plant parasites rely on a single feeding site for all the nutrients required throughout their life cycle and these feeding structures therefore have to be kept alive for a period of up to six weeks. However, plants have well developed systems for detection of biotrophic pathogens and destruction of the pathogen or the plant tissues on which they depend. The mechanisms used by plant nematodes to protect themselves from direct attack by their hosts are relatively well characterised and show many parallels to the systems employed by animal parasitic nematodes to protect themselves from the immune responses of their hosts. In both cases housekeeping antioxidant proteins become changed in their expression patterns so that they are present at the host-parasite interface where they can detoxify host derived active oxygen species in a fine example of convergent evolution. However, the systems by which plant nematodes protect their biotrophic feeding structures are less well characterised. The available evidence to date suggests parallels with other plant pathogenic micro-organisms.