Enhancing plant defense: carbon dots for efficient spray-induced gene silencing 

Evaluation of the fertility management practices in wine grape varieties production. Wine grape represents one of the most important productions in Greece with major impact to the socioeconomic characteristics of the country. The objective of this study is to evaluate, with the support of Geospatial Technologies, the potential effects of an innovative foliar fertilizer system, which is composed of three parts: a mineral fertilizer in a micronized formulation, a biostimulant as an enhancing factor of the process and, an amino acid compound (SANOVITA concept). The study was established at a collaborative, private vineyard, in the area of Trilofos-Thessaloniki, at the region of Northern Greece.

L’essai a été effectué dans un vignoble du cépage Nero d’Avola greffé sur 1103 Paulsen dans un terroir de la D.O.C Alcamo en Sicile. Le système de conduite des vignes était à espalier, la taille à cordon coursonné et l’irrigation à goutte a goutte. On a été confrontés trois types de traitements: A) vignes non irriguées; B) vignes irriguées quand le

Soil is a reservoir of microorganisms playing important roles in biogeochemical cycles and interacting with plants whether in the rhizosphere or in the root endosphere. The composition of the microbial communities thus impacts the plant health. Rhizodeposits (such as sugar, organic and amino acids, secondary metabolites, dead root cells …) are released by the roots and influence the communities of rhizospheric microorganisms, acting as signaling compounds or carbon sources for microbes. The composition of root exudates varies depending on several factors including genotypes. As most of the cultivated grapevines worldwide are grafted plants, the aim of this study was to explore the influence of rootstock and scion genotypes on the microbial communities of the rhizosphere and the root endosphere. The work was conducted in the GreffAdapt plot (55 rootstocks x 5 scions), in which the 275 combinations have been planted into 3 blocks designed according to the soil resistivity. Samples of roots and rhizosphere of 10 scion x rootstock combinations were first collected in May among the blocks 2 and 3. The quantities of bacteria, fungi and archaea have been assessed in the rhizosphere by quantitative PCR, and by cultivable methods for bacteria and fungi. The communities of bacteria, fungi and arbuscular mycorrhizal fungi (AMF) was analyzed by Illumina sequencing of 16S rRNA gene, ITS and 28S rRNA gene, respectively. The level of mycorrhization was also evaluated using black ink coloration of newly formed roots harvested in October. The level of bacteria, fungi and archaea was dependent on rootstock and scion genotypes. A block effect was observed, suggesting that the soil characteristics strongly influenced the microorganisms from the rhizosphere and root endosphere. High-throughput sequencing of the different target genes showed different communities of bacteria, fungi and AMF associated with the scion x rootstock combinations. Finally, all the combinations were naturally mycorrhized. The root mycorrhization intensity was influenced by the rootstock genotype, but not by the scion one. Altogether, these results suggest that both rootstock and scion genotypes influence the rhizosphere and root endophytic microbiomes. It would be interesting to analyze the biochemical composition of the rhizodeposition of these genotypes for a better understanding of the processes involved in the modulation of these microbiomes. Moreover, crossing our data with the plant agronomic characteristics could provide insights into their roles on plant fitness.

The studies developed by INRA and UV, in Angers, concern wine-growing areas and their optimized management, both from an agro-viticultural and oenological point of view. Previous work (Morlat, 1989) made it possible to give a scientific dimension to the concept of viticultural terroir and demonstrated the considerable influence of this production factor on the quality and typicity of wines (Asselin et al, 1992 ) . A methodology for the integrated characterization of terroirs, based on the “Basic Terroir Natural Unit” (considered as the smallest spatial unit of territory usable in practice, and in which the response of the vine is homogeneous), has been development (Riou et al , 1995).

The UV-C light enhances oxidative processes in wine. Increasing the dose of UV-C can lead to olfactoric, gustatoric and colour changes in wine. These changes are triggered by a series of photochemical reactions such as degradation of esters, the formation of odour-active substances such as 2 aminoacetophenone through the photooxidation of amino acids. Ultimately, these reactions can lead to a reduced wine quality.