NEMATODE-INDUCED PLANT GENE-EXPRESSION AND RELATED CONTROL STRATEGIES

Sedentary endoparasitic nematodes such as Meloidogyne spp. establish an intimate and complex relationship to the host plant. Very little is understood of the molecular and cellular mechanisms involved in establishment and maintenance of a feeding site, or in host resistance to nematode attack. It is known that many plant genes in both susceptible and resistant hosts are either induced or altered in their expression during nematode infection. For example, genes encoding proteins such as chitinases and glucanases may be induced during a defense response. In addition, the expression of other genes, such as those encoding structural proteins or constitutive enzymes may be enhanced to accommodate the increased cellular metabolism occurring during nematode infection. Identification of host genes altered in their expression patterns may lead to identification of DNA sequences directing expression in nematode infection sites. We have isolated one such sequence. The availability of promoters capable of directing expression of a foreign gene in the infection site will allow the development of molecular-based nematode control strategies.