CHARACTERIZATION OF 2 PUTATIVE PATHOGENICITY GENES OF THE FUNGAL TOMATO PATHOGEN CLADOSPORIUM-FULVUM

The fungus Cladosporium fulvum is a biotrophic pathogen of tomato. On susceptible tomato plants, the fungus grows abundantly in the extracel lular spaces between the mesophyll cells. The mechanism by which C. fu lvum is able to establish and maintain basic compatibility on its one and only host species, the tomato, is unknown. The isolation and chara cterization of pathogenicity factors and the corresponding genes will provide insight into the mechanism by which C. fulvum colonizes its ho st. Two putative pathogenicity genes of C. fulvum encoding proteins, w hich occur abundantly in the extracellular space of infected tomato le aves, were isolated and characterized (ecp1 and ecp2). The DNA sequenc es of these ecp genes (encoding extracellular protein) do not share ho mology to any sequence present in the DNA databases. The ecp genes are highly expressed in planta but not in vitro, suggesting that they pla y a significant role in pathogenesis.