Induced resistance in melon plants against Fusarium oxysporum f.sp. melonis caused by a nonpathogenic isolate of the same formae specialis.
Melon 'Charentais T' susceptible to Fusarium oxysporum f. sp. melonis (Fom) race 1.2 was pre-inoculated, as a resistance inducer agent, with a nonpathogenic isolate of Fom. The biocontrol agent was only effective when it was applied one or two days before a challenge inoculation with the pathogen. Simultaneous inoculation did not provide any durable protection. Melon cv 'Charentais Fom 1' carries a single dominant gene conferring resistance against Fom races 0 and 2, whereas 'Charentais Fom 2' carries a single dominant gene conferring resistance against races 0 and 1 but both genotypes are susceptible to Fom race 1.2. Co-inoculation with conidia of race 0 provided almost complete protection against the pathogenic race 1.2. It may be hypothesised that while in contact with the host, the non-pathogenic races of the melon Fusarium either possess or secrete an inducing factor causing a defence reaction in melons possessing a resistance gene and preventing the proliferation of the pathogenic race either by formation of a mechanical barrier or by the synthesis of fungistatic substances.
Chikh-Rouhou
H
H
Centro de Investigación y Tecnología Agroalimentaria de Aragón, Unidad de Tecnología en Producción vegetal, Unidad de Sanidad Vegetal, P.O.Box 727, ES-50080 Zaragoza, Spain.
Alvarez
M
M
González-Torres
R
R
D019662:Cucurbitaceae / Q000382:microbiology*; D005670:Fusarium / Q000145:classification / Q000254:growth & development / Q000302:isolation & purification / Q000472:pathogenicity*; D007113:Immunity, Innate; D010935:Plant Diseases / Q000382:microbiology*