Differential responses in vitroof rice cultivars to Italian lineages of the blast pathogen Pyricularia grisea (Cooke) Sacc. 1. Oxidative burst

• Published in: Journal of plant physiology Vol. 160; no. 9; pp. 1033 - 1040
• Main Authors: Rożkowicz, Anna, Picco, Anna M., Rodolfi, Marinella, Pinamonti, Silvano, Forlani, Giuseppe
• Format: Journal Article
• Language: English
• Published: Elsevier GmbH 2003
• Subjects: blast pathogen; fungal elicitor; oxidative burst; reactive oxygen species; rice, Oryza sativa L; blast pathogen; oxidative burst; fungal elicitor; reactive oxygen species; rice, Oryza sativa L
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1078/0176-1617-00941

Suspension cultured cells of six rice cultivars differing in their sensitivity to blast were treated with mycelial wall hydrolysates prepared from seven isolates belonging to different Pyricularia grisea lineages. Soon after elicitor addition, rice cells produced significant amounts of superoxide anion, which was rapidly converted into diffusible peroxide. Maximal effects were achieved at 50 mg L −1 elicitor. In all cases, a 7 to 13-fold increase in the basal rate of reactive oxygen species production was found. Neither differential effects among strains nor clear relationships between lineage and the resulting oxidative burst were evident. Interestingly, a good correlation was found between basal (and elicited) levels of peroxide generation and the overall tolerance of rice cultivars to the pathogen. About two days after elicitation, cell death occurred proportional to the amount of hydrogen peroxide released. Peroxide was required to trigger loss of cell viability, but the latter was not due to a direct toxic effect, suggesting the induction of programmed cell death. Results represent the first data aimed to develop in vitro tests for pathogenicity prediction of Italian blast lineages toward rice cultivars.