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Poster: Molecular & Cellular Plant-Microbe Interactions: Proteomics/Metabolomics/Genomics


A metabolomic approach to investigate the putative role of drought stress in Esca disease of grapevine
M. LIMA (1), A. Machado (1), W. Gubler (1) (1) University of California Davis, U.S.A.

Esca is a destructive disease of grapevine known to be associated with several xylem inhabiting fungi, namely Phaeomoniella chlamysdospora (Pch) and Phaeoacremonium alephilum (Pal). However, the disease mechanism(s) remains unclear. These fungi seem capable of living for several years as endophytes without apparently causing the disease. It is unknown why these fungi become pathogenic, but symptom appearance has been associated with abiotic factors, particularly water stress. We hypothesize that changes induced by drought on the components of xylem sap contribute to symptom appearance. H1-Nuclear Magnetic Resonance spectroscopy coupled with multivariate statistical techniques was used to investigate the interaction of drought stress and Esca-associated pathogen infection. Young, greenhouse-grown, Vitis vinifera cv. Chardonnay cuttings were inoculated with Pch or Pal six weeks before inducing drought stress. Xylem sap was collected thirteen weeks after inoculation. Drought stress induced major changes in several compound classes, e.g. amino acids, carbohydrates and aromatic compounds. The modulation of these metabolic changes by fungal inoculation is being considered. This “omic” approach allowed to gain better insight into the biotic-abiotic interaction, and suggested candidates that could be tested in the control of esca-associated fungi, thus leading Science closer to Practice.