Abstract
Bacterial microbiota has a fundamental role in determining the fitness of a grapevine, the composition of grapes and the features of wines but, at present, little information is available. In this work, the bacterial microbiota that colonizes the different portions of a grapevine (bark, leaves and grapes) was explored in the vineyards of the Alpine region of Trentino, considering the impact of different environmental and agronomical variables. The six vineyards included in the work were identified considering different geographical positions, vine training systems and agronomical approaches, to explore the whole variability of the vine ecosystem. Moreover, the surface amount of copper was measured on grapes and leaves during the vegetative growth, to test its relation with microbiota development. Microbiological assays, performed using plate counts and Illumina MiSeq, started in May until October revealing an increase in the concentration of grape microbiota proportional to the ripening. Conversely, the peak of bacterial concentration onto leaves and bark occurred in August, probably due to the more favorable environmental conditions. In bark samples, the microbiota reached the 7 log UFC/cm2, while 6 log UFC/g were measured in grape samples. A remarkable biodiversity was observed, with 47 genera/species of bacteria present. The presence of the main microbial groups (Alphaproteobacteria, Desulfovibrionaceae, Clostriadiales, Oscillospira, Lachnospiraceae and Bacteroidales) was ubiquitous in vineyards, but differences in terms of relative abundance were observed according to the period, altitude of vineyard and training system. Bacteria having oenological implication (Lactobacillus, Pediococcus and Oenococcus) were detected only in grape samples collected in August. The data revealed a complex bacterial ecosystem inside the vineyard that, while maintaining common traits, evolves according to environmental and agronomical inputs. This study contributes to define the role of bacteria in the complex balance established in each vineyard between human actions and agricultural environment, known as terroir.
Inculcating Learners’ Listening Motivation in English Language Teaching: A Case Study of British Education and Training System
