Long-Term Impact of Chemical and Alternative Fungicides Applied to Grapevine cv Nebbiolo on Berry Transcriptome

Stefano Ghignone,Gabriela Quiroga,Valentina Fiorilli,Raffaella Balestrini,Giorgio Gambino,Irene Romano

doi:10.3390/ijms21176067

Abstract

Viticulture is one of the horticultural systems in which antifungal treatments can be extremely frequent, with substantial economic and environmental costs. New products, such as biofungicides, resistance inducers and biostimulants, may represent alternative crop protection strategies respectful of the environmental sustainability and food safety. Here, the main purpose was to evaluate the systemic molecular modifications induced by biocontrol products as laminarin, resistance inducers (i.e., fosetyl-Al and potassium phosphonate), electrolyzed water and a standard chemical fungicide (i.e., metiram), on the transcriptomic profile of ‘Nebbiolo’ grape berries at harvest. In addition to a validation of the sequencing data through real-time polymerase chain reaction (PCR), for the first-time the expression of some candidate genes in different cell-types of berry skin (i.e., epidermal and hypodermal layers) was evaluated using the laser microdissection approach. Results showed that several considered antifungal treatments do not strongly affect the berry transcriptome profile at the end of season. Although some treatments do not activate long lasting molecular defense priming features in berry, some compounds appear to be more active in long-term responses. In addition, genes differentially expressed in the two-cell type populations forming the berry skin were found, suggesting a different function for the two-cell type populations.

Highlights

Grapevine is one of the most important cultivated fruit crops worldwide, whose fruits are consumed fresh or dried as table grapes or used to produce beverage and nutraceutical products
I.e., fosetyl-Al (Fos-Al), potassium phosphonate (K-Pho), laminarin (Lam), electrolyzed water (EOW) and metiram (Met), were applied in 2017 in a vineyard of ‘Nebbiolo’ following the scheme reported in Table S1 and previously described [22]
The antifungal compounds were used in combination with sulphur and copper since the experiment was conducted in a commercial vineyard and it was necessary to follow the legal rules for antifungal treatments

Summary

Introduction

Grapevine is one of the most important cultivated fruit crops worldwide, whose fruits are consumed fresh or dried as table grapes or used to produce beverage (e.g., juice as well as wines and spirits after fermentation) and nutraceutical products. There is the need to identify new molecules/formulates or to improve the use of those already available, in a context of a more environmentally friendly viticulture The effectiveness of these products, such as biofungicides, resistance inducers and biostimulants, applied alone or included in protection approaches in combination with routinely used fungicides, may lead to the development of alternative crop protection strategies respectful of the environmental sustainability and food safety [16]. Berry transcriptomic profiles have been already studied with the aim to identify the candidate genes associated with phenotypic plasticity [6] and to developmental processes such as ripening [28] in ‘Nebbiolo’ grape [10], few information are present on the changes associated to the application of biocontrol products. The expression of some candidate genes in different cell-types of berry skin was evaluated using the laser microdissection approach

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Results

Conclusion