Organic volatile compounds as suitable markers of grapevine response to defense elicitors in the vineyard

Abstract

In greenhouse, emission of volatile organic compounds (VOC) by grapevine leaves has already been reported in response to the defence elicitor sulfated laminarin (PS3) [1]. In order to check that this response was not specific to PS3, experiments were conducted on Vitis cv Marselan plantlets with several other elicitors of different chemical structures: i.e. Bastid® (COS-OGA), chitosan, Redeli® (phosphonate), Romeo® (yeast extract) and Bion® (acibenzolar-S-methyl). Stir bar sorptive extraction (SBSE) was used as VOC sensor and volatiles compounds were analysed and identified by GC-MS. We confirmed that the observed increase in mono- and sesquiterpene emissions constitutes a common response of grapevine to elicitors in a time-dependent manner. Moreover, beta-ocimene and alpha-farnesene were systematically present within the emitted VOC “bouquet” [2]. Besides, stilbenes resveratrol and piceid were accumulated, but straight correlation with grapevine protection against downy mildew and those emissions terpenes and stilbenes could not be made. VOC emissions were then verified in two French vineyards in Burgundy and Bordeaux, respectively. VOC were analysed after Bastid® treatment of Vitis cvs Chardonnay and Cabernet franc at three phenological stages and using different collecting methods, i.e. passive or dynamic with either SBSE or Tenax sensors. As preliminary results, we observed that VOC emissions remain time-dependent and that terpenes, especially beta-ocimene, are also among the emitted volatiles. We found that the dynamic collect is more sensitive for VOC capture and is required in case of low level of emissions.
Overall these results suggest that VOC analysis could be a relevant method to further study vine response to defence elicitors in the vineyard.

References

[1] Chalal, M., J.B. Winkler, K. Gourrat, S. Trouvelot, M. Adrian, J.P. Schnitzler, F. Jamois and X. Daire, Sesquiterpene volatile organic compounds (VOCs) are markers of elicitation by sulfated laminarine in grapevine, Front Plant Sci, 6 (2015), 350.
[2] Lemaitre-Guillier, C., C. Dufresne, A. Chartier, S. Cluzet, J. Valls, L. Jacquens, A. Douillet, N. Aveline, M. Adrian and X. Daire, VOCs Are Relevant Biomarkers of Elicitor-Induced Defences in Grapevine, Molecules, 26(14) (2021).