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Microbial metabarcoding is the standard approach to assess communities’ diversity. However reports are often limited to simple OTU abundances for each phylum, giving rather one-dimensional views of microbial assemblages, overlooking other accessible aspects. The first is masked by databases incompleteness; OTU picking involves clustering at 97% (near-species) sequence identity, but different OTUs regularly end up under a same taxon name. When expressing diversity as number of obtained taxonomical names, a large portion of the real diversity lying within the data remains underestimated. Using the 16S sequencing results of an environmental transect across a gradient of 17 coastal habitats we first extracted the number of OTUs hidden under the same name. Further, we observed which was the deepest rank yielded by annotation, revealing for which microbial groups are we missing most knowledge. Data were then used to infer an evolutionary aspect: what is, in each phylum the success of the present time individuals (abundances for each OTU) in relation to their prior evolutionary success in differentiation (number of OTUs). This information reveals whether the past speciation/diversification force is matched by the present competitiveness in reproduction/persistence. The final layer explored is functional diversity, i.e. abundances of groups involved in specific environmental processes.

Research was carried out in two vineyards planted with the variety 'Merlot' in order to evaluate the effect of soil compost addition on soil organic matter and grapevine production and quality. The vineyards were established in Valnogaredo and Zovon, on the Euganean Hills, Italy. Two treatments were compared: application of 5 t/ha of compost versus no compost application. Soil and microbial analyses were performed. SPAD values and leaf chlorophyll content were measured during the growing season. Quantitative and qualitative parameters of vine production were evaluated. The soil of the two vineyards was calcareous and gravelly, with clay texture and alkaline pH. Organic matter content increased after the compost treatment, whereas the other investigated parameters did not change significantly. The organic C content increased in Valnogaredo but not in Zovon. The humification index and microbial biomass increased in both vineyards. In 2007 and 2008 SPAD values in the leaves were higher for the compost treated vines compared with those untreated and strong correlations were found with leaf chlorophyll contents. At harvest, in Valnogaredo in 2007 and 2008, in Zovon in 2008 and 2009, an increase in the yield/vine of bunch and berry weight and volume and qualitative parameters were observed in plants treated with compost. In conclusion, compost application, depending on soil characteristics, can increase soil organic matter and microbial biomass but can also affect vine productivity.

This work aimed to study the effects in tomato (Solanum lycopersicum L.) of foliar applications of a novel calcium-based biostimulant (SOB01) using an omics approach involving transcriptomics and physiological profiling. A calcium-chloride fertilizer (SOB02) was used as a product reference standard. Plants were grown under well-watered (WW) and water stress (WS) conditions in a growth chamber. We firstly compared the transcriptome profile of treated and untreated tomato plants using the software RStudio. Totally, 968 and 1,657 differentially expressed genes (DEGs) (adj-p-value < 0.1 and |log2(fold change)| ≥ 1) were identified after SOB01 and SOB02 leaf treatments, respectively. Expression patterns of 9 DEGs involved in nutrient metabolism and osmotic stress tolerance were validated by real-time quantitative reverse transcription PCR (RT-qPCR) analysis. Principal component analysis (PCA) on RT-qPCR results highlighted that the gene expression profiles after SOB01 treatment in different water regimes were clustering together, suggesting that the expression pattern of the analyzed genes in well water and water stress plants was similar in the presence of SOB01 treatment. Physiological analyses demonstrated that the biostimulant application increased the photosynthetic rate and the chlorophyll content under water deficiency compared to the standard fertilizer and led to a higher yield in terms of fruit dry matter and a reduction in the number of cracked fruits. In conclusion, transcriptome and physiological profiling provided comprehensive information on the biostimulant effects highlighting that SOB01 applications improved the ability of the tomato plants to mitigate the negative effects of water stress.