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Oliveira J.T.A.,Federal University of Ceara | Andrade N.C.,Federal University of Ceara | Martins-Miranda A.S.,ADAGRI | Soares A.A.,Federal University of Ceara | And 4 more authors.
Plant Physiology and Biochemistry | Year: 2012

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. © 2011 Elsevier Masson SAS. Source

Eloy Y.R.G.,Federal University of Ceara | Eloy Y.R.G.,University of Fortaleza | Vasconcelos I.M.,Federal University of Ceara | Barreto A.L.H.,Brazilian Agricultural Research Corporation EMBRAPA Meio Norte | And 2 more authors.
Fungal Biology | Year: 2015

Plant-fungus interactions usually generate H2O2 in the infected plant tissue. H2O2 has a direct antimicrobial effect and is involved in the cross-linking of cell walls, signaling, induction of gene expression, hypersensitive cell death and induced systemic acquired resistance. This has raised the hypothesis that H2O2 manipulation by pharmacological compounds could alter the lifestyle of Colletotrichum gloeosporioides during interaction with the BR-3-Tracuateua cowpea genotype. The primary leaves of cowpea were excised, infiltrated with salicylic acid (SA), glucose oxidase+glucose (GO/G), catalase (CAT) or diphenyliodonium chloride (DPI), followed by spore inoculation on the adaxial leaf surface. SA or GO/G-treated plantlets showed increased H2O2 accumulation and lipid peroxidation. The fungus used a subcuticular, intramural necrotrophic strategy, and developed secondary hyphae associated with the quick spread and rapid killing of host cells. However, CAT or DPI-treated leaves exhibited decreased H2O2 concentration and lipid peroxidation and the fungus developed intracellular hemibiotrophic infection with vesicles, in addition to primary and secondary hyphal formation. These results suggest that H2O2 plays an important role in the cowpea (C. gloeosporioides) pathosystem given that it affected fungal lifestyle during interaction. © 2015 The British Mycological Society. Source

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