Acute ozone exposure predispose Phaseolus vulgaris beans to botrytis cinerea

Abstract

The impact of ozone in predisposingPhaseolus vulgaris toBotrytis cinerea has been investigated. One day after 8 h exposures to 0, 120, 180 and 270 μg ozone m−3, primary and trifoliate leaves of four bean cultivars were detached and inoculated with conidia suspended in water or in an inorganic phosphate (Pi) solution. Visible ozone injury increased with increasing ozone concentrations in all cultivars. Primary leaves were more sensitive than trifoliate leaves. Conidia suspended in Pi solution caused lesions on healthy leaves, whereas conidia in water did not. Ozone-injured leaves of all cultivars showed lesions byB. cinerea after inoculations in water. The number of lesions was significantly correlated with ozone injury for primary leaves. After Pi inoculations, the number of lesions on the ozone-sensitive cultivars also increased with increasing ozone concentrations. However, the ozone-tolerant cultivar Groffy showed first a decrease in the Pistimulated infection at the lowest ozone dosages. The trifoliate leaves of all cultivars were less predisposed to the fungus than the primary leaves. The results indicate that realistic concentrations of ozone enhance the predisposition of bean leaves toB. cinerea. The rate of enhancement depends on the level of ozone-induced injury which was influenced by cultivar, leaf and ozone concentrations.