Microorganisms associated with Vitis vinifera (grapevine) can affect its growth, health and grape quality. The aim of this study was to unravel the biodiversity of the bacterial rhizosphere microbiota of grapevine in an integrated pest management vineyard located in Piedmont, Italy. Comparison between the microbial community structure in the bulk and rhizosphere soil (variable: space) were performed. Moreover, the possible shifts of the bulk and rhizosphere soil microbiota according to two phenological stages such as flowering and early fruit development (variable: time) were characterized. The grapevine microbiota was identified using metagenomics and next-generation sequencing. Biodiversity was higher in the rhizosphere than in the bulk soil, independent of the phenological stage. Actinobacteria were the dominant class with frequencies ≥ 50% in all the soil samples, followed by Proteobacteria, Gemmatimonadetes, and Bacteroidetes. While Actinobacteria and Proteobacteria are well-known as being dominant in soil, this is the first time the presence of Gemmatimonadetes has been observed in vineyard soils. Gaiella was the dominant genus of Actinobacteria in all the samples. Finally, the microbiota associated with grapevine differed from the bulk soil microbiota and these variations were independent of the phenological stage of the plant.

A major aldehydic end product of the peroxidation of arachidonic acid, 4–hydroxy–2,3–nonenal (HNE), has recently been considered for its potential involvement in a variety of cell functions. Here we report on the differential regulation of rat hepatocyte protein kinase C (PKC) isoforms by concentrations of HNE actually detectable in specific biological fluids or tissues. PKC βI and, to a much greater extent, PKC βII activities were markedly increased by 0.1 μmol/L HNE (final concentration in cell medium) whereas they were unaffected or even inhibited by 1 to 10 μmol/L HNE. On the contrary, the calcium independent PKC δ activity was inhibited by 0.1 μmol/L and increased by 1 and 10 μmol/L. Further, we show here that HNE–induced stimulation of PKC βI and βII activities, both in cytosolic and in membrane fractions, is paralleled by a marked stimulation of the anterograde transport of a lysosomal enzyme within the central vacuolar system. In fact, the treatment with 0.1 μmol/L HNE accelerated the PKC–dependent transport of lysosomal procathepsin D from the trans–Golgi network to the endosomal–lysosomal compartment and, in addition, increased the exocytosis of mature cathepsin D (CD) from these compartments. On the other hand, hepatocyte cotreatment with a selective inhibitor of classic PKCs prevented the aldehyde–induced activation of CD transport. These results support the possible involvement of HNE in the PKC–dependent regulation of the traffic of secretory glycoproteins, and point to remarkable implications of this aldehyde in the pathophysiology of various exocytic processes including hepatocyte lipoprotein secretion.