Molecular and cellular events during the interaction of phylloxera with grapevine roots

Abstract

Improved knowledge of phylloxera-grapevine interactions could contribute to new control strategies. Using potted vine and in vitro dual cultures, we see that root gall (nodosity) formation on Vitis vinifera is accompanied by accumulation of starch, free amino acids and amides, indicating formation of a nutrient sink. Steady state levels of a wide range of RNA transcripts remain unaltered, suggesting that if there is a molecular response to phylloxera attack, it is either transient or restricted to only a few cells. Lower reproductive rates of phylloxera on Ramsey (V.champini) correlate with a lack of starch accumulation in root galls. Feeding attempts on V. riparia and Börner result in rapid necrosis of root tissue. No feeding attempts have been observed on V. rotundifolia. Transgenic plants and ‘hairy roots’ expressing promoter-reporter gene constructs encoding, for example, GFP or GUS, are being used to examine phylloxera-root interactions in situ.