Differential expression of antioxidant enzymes and PR-proteins in compatible and incompatible interactions of cowpea (Vigna unguiculata) and the root-knot nematode Meloidogyne incognita

This study aimed to evaluated the resistance and susceptibility of 10 cowpea cultivars to Meloidogyne incognita in field studies and to analyze the kinetics of the enzymes superoxide dismutase, catalase, peroxidase, chitinase, β-1,3-glucanases and cystein proteinase inhibitors in the root system of two contrasting cowpea cultivars after inoculation with M. incognita. The cultivars CE-31 and Frade Preto were highly resistant; CE-28, CE-01, CE-315, CE-237, were very resistant; CE-70 and CE-216 were moderately resistant, whereas Vita-3 and CE-109 were slightly resistant. In the roots of the highly resistant cultivar CE-31 the activity of the antioxidant enzyme superoxide dismutase increased and catalase decreased and those of the pathogenesis-related proteins chitinase, β-1,3-glucanase, peroxidase and cystein proteinase inhibitor increased in comparison with the root system of the slightly resistant CE-109, during the course of M. incognita infestation. Thus the changes in the activities of these enzymes might be related to the smaller final population of M. incognita in CE-31 and may contribute to the high resistance of this cowpea cultivar against infection and colonization by this nematode species.