Metabolomic Study of Chardonnay Grapevines Double Stressed with Esca-Associated Fungi and Drought

Abstract

Esca is a complex grapevine trunk disease associated with fungal infection of the xylem. However, the inconstancy of external symptoms and the ability of esca-associated fungi to inhabit grapevines without causing apparent disease suggests that abiotic factors might be involved in the disease. Water stress has been proposed to be one of the factors influencing esca symptom manifestation but the specific role played by water stress on esca development is unknown. We conducted a proton nuclear magnetic resonance spectroscopy-based metabolomic study aiming at unveiling drought-induced modifications in xylem sap composition that could contribute to esca-related infection progression. Vitis vinifera 'Chardonnay' plants were inoculated with Phaeomoniella chlamydospora or Phaeoacremonium minimum and exposed to water stress. Using this approach, 28 metabolites were identified in xylem sap. The results show that water stress induces a concentration increase of most metabolites in xylem sap. An average increase >100% was found for asparagine, isoleucine, leucine, methionine, phenylalanine, proline, tyrosine, valine, sarcosine, and trigonelline. The increase of these compounds seems to be also modulated by fungal infection. This study offers further support to the putative role of drought in esca expression, and opens new avenues of research by extending the current knowledge about metabolites possibly involved in esca disease.

Wood Metabolomic Responses of Wild and Cultivated Grapevine to Infection with Neofusicoccum parvum, a Trunk Disease Pathogen

“…Accumulation of alanine has been previously reported in Chardonnay leaves just before esca apoplexy [14]. Several amino acids (asparagine, isoleucine, leucine, methionine, phenylalanine, proline, tyrosine, and valine) were also found to increase in the xylem sap of Chardonnay undergoing both water stress and esca disease [39]. Alterations in amino acid contents thus seem to be a common feature of trunk diseases.…”

Clone-Dependent Expression of Esca Disease Revealed by Leaf Metabolite Analysis

“…For clone 76, C leaves accumulated a higher level of secondary metabolites (kaempferol, kaempferol-3- O -glucoside, isoquercitrin, quercetin, a quercetin glucoside and a probable quercetin derivative, epicatechin, and gentiobiose) whereas Ds+ leaves accumulated higher amounts of cis -4-hydroxycinnamate and amino acids, namely threonine, leucine, isoleucine, and valine. Accumulation of amino acids have been previously reported in ‘Chardonnay’ leaves just before apoplexy (Magnin-Robert et al, 2017) (alanine), and in the xylem sap of water-stressed Esca diseased ‘Chardonnay’ vines (asparagine, isoleucine, leucine, methionine, phenylalanine, proline, tyrosine, valine) (Lima et al, 2017b). Although changes in amino acid concentration seem a common feature associated to GTDs, no specific ones can be presently considered as markers of the foliar disease expression.…”

Ecophysiological impacts of Esca, a devastating grapevine trunk disease, on Vitis vinifera L.

“…Specifically, Esca pathogens involved in the development of wood necrosis show varying ability to utilize nutrients made available in injured tissues [6]. Higher nutrient availability in xylem sap could lead to increased fungal growth over time [27], and potentially affect sap transport in infected vines.…”