INSTITUTO DE FISIOLOGIA VEGETAL
Unidad Ejecutora - UE
A survey on occurrence of Cladosporium fulvum identifies race 0 and race 2 in tomato growing areas of Argentina.
ROCIO MEDINA; SILVINA M. Y. LÓPEZ; MARIO E. E. FRANCO; CRISTINA ROLLAN; LIA RONCO; MARIO SAPARRAT; PIERRE DE WIT; PEDRO A. BALATTI
AMER PHYTOPATHOLOGICAL SOC
The presence of Cladosporium fulvum (syn Passalora fulva), causal agent of tomato leaf mold, was confirmed in the two main greenhouse-production areas of tomato in Argentina. Using both morphological characters and ITS sequencing, we confirmed the presence of physiological races of this pathogen. A diagnostic multiplex PCR was also developed, using primers derived from C. fulvum Avr genes. Twenty isolates of Cladosporium spp. were obtained as monospore cultures and twelve were identified as C. fulvum. By this method we showed that of these 12 isolates, five were race 0 (carrying functional Avr2, Avr4, Avr4E and Avr9 genes) and seven were race 2 (lacking the Avr2 gene). Race identity was confirmed by testing their virulence on a set of tomato differentials carrying different Cf resistance genes. All Avr genes could be amplified in single or multiplex PCR using DNA isolated from in vitro grown monospore cultures, but only three Avr could be amplified when genomic DNA was isolated from C. fulvum-infected necrotic leaf tissue.