Oak seedling microbiome assembly under climate warming and drought.

Despite that climate change is currently one of the most pervasive challenges, its effects on the plant-associated microbiome is still poorly studied. The aim of this study was to evaluate the impact of the independent and combinatory effect of climate warming and drought on the microbiome assembly of oak from seed to seedling. In a multifactorial experimental set up, acorns were subjected to different temperatures (15 °C, 20 °C, and 25 °C) and soil moisture levels (drought (15%) and control (60%)) from germination until the seedling stage, after which the bacterial and fungal communities associated to the rhizosphere and phyllosphere were characterized by amplicon sequencing and qPCR. The results showed a stronger effect of temperature on fungal than on bacterial diversity and the effect was more pronounced in the phyllosphere. Under drought condition, temperature had a significantly negative effect on phyllosphere fungal diversity. In the rhizosphere, temperature had a significant effect on the fungal community composition which was primarily caused by species turnover. Regardless of temperature, Actinobacteriota was significantly enriched in drought, a group of bacteria known to increase plant drought tolerance. This study provides new insights into the effect of climate change on the plant microbiome in natural ecosystems.

The potential of e-nose aroma profiling for identifying the geographical origin of licorice (Glycyrrhiza glabra L.) roots.

Licorice roots cultivated commercially in distinct geographical areas such as China, Iran, Italy (Abruzzo, Basilicata, Calabria and Sicily) and Turkey were classified using an artificial olfactive system (e-nose) based on metal oxide semiconductor sensors (MOS). The resultant instrumental data were processed using a multivariate statistical analysis method in order to classify the raw samples according to its origin. The e-nose odourprintings were obtained by a canonical discriminant analysis carried out with the aim of relating the specific data-sets corresponding to whole licorice roots aroma with the e-nose reference dataset. E-nose results were compared to those obtained by SPME/GC-MS. The HS-SPME/GC/MS analysis was used as a control system to check for the actual existence of differences in the chemical composition of sample headspace. These results imply the possibility to use an electronic nose as a tool for a quick, effective and non-destructive authentication of licorice roots.

Non-destructive flavour evaluation of red onion (Allium cepa L.) ecotypes: an electronic-nose-based approach.

This work reports preliminary results on the potential of a metal oxide sensor (MOS)-based electronic nose, as a non-destructive method to discriminate three "Tropea Red Onion" PGI ecotypes (TrT, TrMC and TrA) from each other and the common red onion (RO), which is usually used to counterfeit. The signals from the sensor array were processed using a canonical discriminant function analysis (DFA) pattern recognition technique. The DFA on onion samples showed a clear separation among the four onion groups with an overall correct classification rate (CR) of 97.5%. Onion flavour is closely linked to pungency and thus to the pyruvic acid content. The e-nose analysis results are in good agreement with pyruvic acid analysis. This work demonstrated that artificial olfactory systems have potential for use as an innovative, rapid and specific non-destructive technique, and may provide a method to protect food products against counterfeiting.

Essential oil chemical composition and antifungal effects on Sclerotium cepivorum of Thymus capitatus wild populations from Calabria, southern Italy

The paper reports the qualitative and quantitative composition and its antifungal activities of Thymus capitatus (L.) Hoffmanns. & Link, Lamiaceae, essential oils isolated by hydrodistillation from the aerial parts of plants collected in Calabria, Southern Italy. The essential oils of 22 samples were analysed by GC-Flame ionization detection and GC/MS. A total of sixty five compounds were identified. Phenols were present in highest percentage (average: 79,03%). Carvacrol was the main component (81,52%-78,40%) in all samples, confirming that T. capitatus is a carvacrol chemotype, according to literature data for this species. This essential oil was also characterized by high level of biogenetic precursor of the phenols: p-cimene (4,98%), γ-terpinene (3,13%) and by β-cariophyllene, were the most abundant sesquiterpene hydrocarbons. Antifungal activity against Sclerotium cepivorum Berk., a soil born fungus, was tested. At the concentration of 250 ppm there was no development of fungal mycelium. To our knowledge, studies have never been conducted on Calabria wild populations of T. capitatus essential oil nor were conducted studies on parasitic fungi of specific interest for crops such as Sclerotium cepivorum.