Multi-genotype cross-protection against Pepino mosaic virus in tomato

The viral pathogen Pepino mosaic virus (PepMV) can cause serious problems in the crop tomato (Solanum lycopsericum). One strategy to control infections of this virus is the application of hygienic measures. Alternatively, tomato plants can be cross-protected by attenuated isolates of a PepMV genotype. After two weeks, these plants are cross-protected against virulent isolates of the same genotype. In this study, the effectivity of a multi-genotype cross-protection was assessed. In greenhouse experiments young tomato plants were inoculated with a mixture of attenuated isolates of the Peruvian (LP) and Chili-2 (CH2) genotype, named VX1 and VC1, respectively. Inoculated plants were challenged with virulent isolates of the EU and CH2 genotype. The mixture of attenuated isolates, named V10, prevented almost completely the appearance of viral symptoms like leaf and stem necrosis, stunting, loss of fruit quality and loss of yield, caused by the virulent isolates. In contrast, when only a single genotype (CH2) was used to cross-protect the plants, symptoms were not prevented after the challenge with the mixture of virulent isolates. This study offers perspectives for a large-scale application of a multi-genotype cross-protection against PepMV in tomato.