Nematology (2000) 2, p. 775 (Molinari)

Sergio Molinari (2000)
Molecular mechanism of resistance and virulence in the Meloidogyne-tomato interaction
Nematology 2 (7), 775-775
Presented at the 25th International Nematology Symposium, Herzliya, Israel, 2-7 April 2000
Abstract: The Meloidogyne-tomato interaction has been extensively studied in vivo and in vitro. Different (a)virulent populations of Meloidogyne spp. collected in fields or selected in glasshouse were inoculated on a number of resistant tomato cultivars. Changes in antioxidant enzyme activities of roots have been monitored from 24 h after juvenile inoculation either in pots or in cultures of excised roots. Catalase and ascorbate peroxidase activities were found to be lower in infested roots in every incompatible interaction tested in vivo and in vitro. Isoelectrofocusing separations of root catalase isozymes showed that specific isozymes were completely inactivated due to nematode infestation. Nematode-induced inhibition of such H₂O₂-degrading enzymes causes an increase of oxidative and peroxidative activity in root cells which ultimately leads to cell death. The consequent formation of a large necrotic area surrounding the juvenile is responsible for the arrest of nematode feeding and reproduction. Normally avirulent populations can be selected for virulence by repeated inoculations on resistant tomato cultivars. Near-isogenic populations were tested for difference in electrophoretical patterns of antioxidant isozymes. More marked catalase and peroxidase bands suggested a higher activity in virulent Meloidogyne females. Furthermore, evidence is emerging of a superoxide dismutase (SOD) isozyme specifically found in virulent females.
Database assignments for author(s): Sergio Molinari

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Meloidogyne (genus)	Tomato (Solanum lycopersicum)