Grapes aminoacidic profile: impact of abiotic factors in a climate change scenario

Abstract

Amino acids play a crucial role in determining grape and wine quality [1]. Recently, research has suggested their metabolism is key to plant abiotic stress tolerance [2]. Therefore, the study of amino acid accumulation in grape berries and its response to environmental factors is of both scientific and economic importance. This study investigates the influence of increased temperature, reduced rainfall and the combination of both effects on the content and amino acidic profile of grapes cv. Monastrell from a goblet-trained conventional managed and rainfed vineyard located in Jumilla, (Murcia, southeastern Spain). For this purpose, open top chambers and rainout shelters simulated warming (~2-7 ºC, W) and rainfall reduction (~30%, RR).  A combination of both treatments (W+RR) was also used. Vines without top chambers or rainout shelters were considered as control (C). The experiment was established in February of 2023, and all vines were manually harvested at 28-09-2023. The aminoacidic identification and quantification were performed by HPLC analysis [3]. Total free (FAN), yeast-assimilable (YAN) and aromatic precursor (PAN) nitrogen content were calculated according to Valdés et al. [3]. The results were subjected to one-way (C vs W vs, RR vs C+W-RR) and two-way ANOVA (W, R and W*R effect) and Tukey’s test for comparison of means. No changes in the amino acid profile were found, and high proline and arginine levels, specially in W treatments, were observed, as previously was reported [4]. In fact, these compounds were the predominant amino acids in all treatments. Their concentrations reached 116.85, 96.26, 33.19, and 24.52 mgN/L, as well as 76.27, 55.77, 16.57, and 8.3 mgN/L in W-RR, W, C, and RR, respectively, accounting for about 50 % and 25 % of the total FAN. The concentrations of the remaining identified and quantified amino acids were far below of these two and lower than 2 mgN/L in all cases. FAN, YAN, PAN and Ammonia contents followed the WRR > W > C > RR trend, with significant differences observed between the first two treatments and the rest in all cases. The analysis of the combined effects of increase of temperature and rainfall reduction indicated a significant effect of these environmental factors on the contents of the parameters analyzed. W caused the highest percentage of differences between samples (more than 80% in all cases). However, probably due to the low rainfall during the season, the RR treatment resulted in minimal differences.

Acknowledgements

Project PID2021-124382OB-I00 funded by the Agencia Estatal de Investigación (MICINN/AEI/ ERDF, EU).

References

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[2] Le Guan, B., Wu, B., Hilbert, G., Li, S., Gomès, E., Delrot, S., Dai, Z. (2017). Food Res. Int., 98, 2–9.

[3] Valdés, M. E., Talaverano, M. I., Moreno, D., Prieto, M. H., Mancha, L. A., Uriarte, D., Vilanova, M. (2019). Food Chem., 292, 24–31.

[4] Torres, N., Hilbert, G., Luquin, J., Goicoechea, N., and Antolín, M. C. (2017). J. Food Composit. Analys., 62, 51-62.