The genetics of plant-nematode parasitic systems

Abstract

The genetic basis of plant-nematode interactions is discussed with special emphasis on potato-Globodera rostochiensis/pallida, barley/oat-Heterodera avenae, soybean-H, glycines and tomato-Meloidogyne incognita parasitic systems. The basis of physiological specialization and its role in breaking down cultivar resistance is explored. There are numerous reports on the inheritance of resistance as compared to a few on the inheritance of virulence. These reports indicate certain general characteristics of the host-parasite genes. The genes for resistance and virulence are conditional in the sense that the expression of one is dependent on the presence of the other in the association. Therefore, host-parasite genes, often exhibit a gene-for-gene interaction, the basis of which is discussed and illustrated. Also, the genetics of the complex parasitic systems is briefly mentioned. Fungal and nematode parasitic systems are compared throughout the review.