Genes induced during early response to Meloidogyne incognita in roots of resistant and susceptible alfalfa cultivars

A cDNA library made to RNA from roots of Meloidogyne incognita (root-knot n ematode) susceptible alfalfa vv. Lahontan seedlings 72 h after root-knot ne matode inoculation was differentially screened with cDNA made from uninocul ated control and M. incognita infested (72 h) root RNA. Of the six cDNAs is olated, the deduced amino acid sequences of four showed significant homolog y to sequences present in the databank, while two were pioneer sequences. T he four cDNAs with matches to known sequences include those for glycine-ric h protein, the gluconeogenic pathway enzyme phosphoenolpyruvate carboxykina se, an isoflavone reductase-like protein, and metallothionein. We have foll owed the expression of these genes during the course of nematode infection in both the susceptible and resistant host and also in different plant orga ns. Based on these analyses, the genes induced early in nematode infection are related either to metabolic pathways or to stress/defense. (C) 2001 Els evier Science Ireland Ltd. All rights reserved.