VIRUS AND FUNGAL RESISTANCE - FROM LABORATORY TO FIELD

Virus and fungal resistance traits are important targets in the genetic engineering of agricultural and horticultural crops. We have engineered resistance against potato virus X in important commercial potato cultivars. Four years of field trials with resistant potatoes have demonstrated the commercial feasibility of improving potato cultivars by selectively adding new traits while preserving intrinsic properties. In our pursuit for a broad resistance against fungi we have focused on the exploitation of genes encoding antifungal proteins. We present results demonstrating the antifungal effect of some of these proteins in vitro, as well as the synergy between specific chitinases and beta-1,3-glucanases. We also report high level resistance against Fusarium oxysporum in transgenic tomato plants expressing a specific combination of genes encoding these enzymes.