Transmission of Colletotrichum coccodes via tomato seeds

Anthracnose of tomato caused by Colletotrichum coccodes is a devastating disease of ripe fruits. This pathogen may also infect tomato roots, stems and leaves. In the present study, C. coccodes is shown to be capable of contaminating seeds collected from artificially inoculated tomato fruits. Seedlings germinating from these infected seeds exhibited disease symptoms and therefore may transmit the pathogen to the next crop. The proportion of infected seeds ranged between 20% and 63% in all C. coccodes isolates tested and correlated with the aggressiveness of the isolates to tomato fruits. Fungicidal treatment of the collected seeds reduced, but did not eliminate, seed infection. A transgenic C. coccodes isolate expressing green fluorescent protein was used to visualize the pathogen. Mycelium was observed both on surfaces of the seed coat and within 1% of the embryos.