Root-knot and cyst nematode parasitism genes: the molecular basis of plant parasitism.

Roundworms of the Nematoda comprise one of the largest animal phyla on Earth (1). They inhabit diverse terrestrial and aquatic niches through adaptations of a spectrum of trophic groups, including parasites that threaten human, animal and crop plant health. The most well-known nematode, Caenorhabditis elegans, is a native soil-dwelling microbivore that has emerged as a premier model for animal biology and genomics (2). While studies of C. elegans provide a blueprint of fundamental nematode biology, recent advances in molecular genetics of parasitic nematodes indicate specific divergence in adaptations of nematodes for obligate parasitism of an array of plant and animal host species (3-8). Identifications of the molecular tools enabling a particular mode of parasitism by nematodes are providing some intriguing discoveries about the nature of parasite evolution. ROOT-KNOT AND CYST NEMATODE PARASITISM GENES: THE MOLECULAR BASIS OF PLANT PARASITISM