The application of ozonated water rearranges the Vitis vinifera L. leaf and berry transcriptomes eliciting defence and antioxidant responses

Abstract

Ozonated water has become an innovative, environmentally friendly tool for controlling the development of fungal diseases in the vineyard or during grape postharvest conservation. However, little information is currently available on the effects of ozonated water sprayings on the grapevine physiology and metabolism. Using the microvine model, we studied the transcriptomic response of leaf and fruit organs to this treatment. The response to ozone was observed to be organ and developmental stage-dependent, with a decrease of the number of DEGs (differentially expressed genes) in the fruit from the onset of ripening to later stages. The most highly up-regulated gene families were heat-shock proteins and chaperones. Other up-regulated genes were involved in oxidative stress homeostasis such as those of the ascorbate–glutathione cycle and glutathione S-transferases. In contrast, genes related to cell wall development and secondary metabolites (carotenoids, terpenoids, phenylpropanoids / flavonoids) were generally down-regulated after ozone treatment, mainly in the early stage of fruit ripening. This down-regulation may indicate a possible carbon competition favouring the re-establishment and maintenance of the redox homeostasis rather than the synthesis of secondary metabolites at the beginning of ripening, the most ozone responsive developmental stage.

Ozone and Bioactive Compounds in Grapes and Wine

“…Specifically, it is well known that plants produce isoprene, terpenes, and C6 in response to the oxidative stress after O 3 exposition [ 37 , 38 ]. This was again confirmed by Campayo et al [ 73 ], who observed an increase of the total free terpenoids in wine made starting from ozonated vine, mainly due to the accumulation of farnesol and nerolidol. When treatments were repeated during the growing season, citronellol and nerolidol increased.…”

“…As stated by many researches, O 3 treatment ranging from 0.1 mg/L/day or higher allows to prolong table grape shelf-life, inhibiting the growth of grey mold [ 71 , 72 ]. Furthermore, O 3 was reported to boost the phenolic and aromatic compound biosynthesis, since O 3 induces in living tissues different defense mechanisms at the genetic, transcriptional, and biochemical level [ 73 ].…”

“…As already discussed, O 3 has been widely used not only as sanitizing agent and for increasing the shelf-life of harvested grapes, but also as an exogenous elicitor to enrich grapes of secondary metabolites, significant factors for grape quality and human health. Hence, at berry level, the oxidative stress modifies the accumulation of different compounds to defend the cells from possible oxidative damages [ 73 ]. Most of the studies available in the literature focused on the elicitor effect on grape metabolism, confirming the aptitude of O 3 in increasing the bioactive compound presence.…”

“…Recently, ozonated water was applied to control grapevine diseases, and the effect on grapes and wine quality ( Vitis vinifera L. cv. Bobal) was studied by Campayo et al [ 33 , 73 , 81 ]. These authors tested two different applications (i.e., a single treatment with ozonated water during the ripening period, and three treatments with ozonated water performed between fruit set-up to harvest), evaluating their effect on grapes, and during winemaking.…”

Transcripts switched off at the stop of phloem unloading highlight the energy efficiency of sugar import in the ripening V. vinifera fruit

“…Following density sorting, endeavours were made to identify genes expressed or repressed at the late stages of ripening, which may be used as indicators of maturity for oenological scope 8 , 21 . Individual berries from vines that underwent heat stress, leafroll virus infection or received ozonated water applications were re-synchronised based on their primary metabolites content 22 – 25 . This brief survey shows that the awareness of berry heterogeneity is a rising topic, although usual samples aiming to represent the whole diversity at the experimental plot still predominate 7 , 26 .…”