Expression of an oxalate oxidase gene in tomato and severity of disease caused by Botrytis cinerea and Sclerotinia sclerotiorum

A cDNA clone of wheat oxalate oxidase (OxO) under the control of the constitutive CAMV 35S promotor was expressed in tomato plants by Agrobacterium-mediated transformation. Twenty-six transgenic tomato lines were obtained and analysed. PCR experiments confirmed the incorporation of the OxO gene in all tested tomato lines. The transgenic tomato plants expressed a 124-kDa protein showing OxO activity, and were able to convert different oxalic acid (OA) concentrations in vitro. In a detached leaf assay, most of the transgenic lines showed reduced disease symptoms compared with controls, following inoculation with Botrytis cinerea. In addition, leaves of the line T15 showed a marked reduction in symptoms compared with the control following inoculation with Sclerotinia sclerotiorum.