Gindro K., Alonso-Villaverde V., Voinesco F., Spring J.-L., Viret O.
Revue suisse de viticulture arboriculture horticulture 42(6), 352-357, 2010
Leaves of different Vitis vinifera L. cultivars, susceptible (Chasselas) or resistant to downy mildew (Solaris and 2091), as well as the immune Muscadinia rotundifolia were inoculated with Plasmopara viticola. Samples were examined by microscopy for their ability to synthesize toxic compounds towards downy mildew at infection sites (stilbenic phytoalexins). In the susceptible Chasselas, P. viticola completes its life cycle with the production of functional haustoria as the cultivar produces mainly the non toxic piceide. The development of downy mildew is different in each of the other three resistant grape cultivars. In Solaris and 2091, the development is stopped after the formation of haustoria and is correlated to the synthesis of respectively ?-viniferin and pterostilbene. In M. rotundifolia, downy mildew development stops immediately after germ tube penetration (without functional haustoria formation). Stilbenes are here produced exactly at the infection sites. Their concentration is at least 20 times higher than in the three other cultivars. The relevant role of stilbenes in mildew resistance of Vitis spp. is discussed.
|Download full text (PDF, 356 kb)|
Key words: downy mildew, epifluorescence microscopy, grapevine, leaf, stilbenes, stomata, resistance, ultrastructure
Adress: Research Station Agroscope Changins-Wädenswil ACW, 1260 Nyon