PHYLLOXERA - GRAPE INTERACTION: A HISTOCHEMICAL APPROACH ON NODOSITIES

Phylloxera (Daktulosphaira vitifoliae) induce galls (nodosities) on young grape vine roots. Histological and histochemical methods were applied to study the gall’s morphology and enzyme activation (peroxidase, leucine aminopeptidase and acidic phosphatase). Susceptible V. vinifera cv. Cabernet Sauvignon was compared with the resistant rootstock 5BB (V. berlandieri x V. riparia). Aseptic dual culture conditions were applied to exclude environmental effects and secondary fungal or bacterial soil borne antagonists. The gall induction phase was analysed before visible signs of possible resistance responses were detected. Increased metabolically activity has been assessed in nodosities compared to uninfected roots. Peroxidase, acidic phosphatase and leucine aminopeptidase activity was highest at the incision. Starch granules were incorporated in a gradient increasing towards the periphery of the gall.