In the last decade, several studies demonstrated that plants have developed a tight
partnership with the edaphic microbial communities, mainly bacteria, fungi, and archaea.
Such microbiome accomplishes essential functions and ecological services
complementary to the functions encoded by the host plant, conferring adaptive
advantages to the plant, particularly during stressful conditions. The interaction between
microbial communities and their host plants in the natural ecosystem are complex and
the mechanisms regulating these mutualistic associations are not fully elucidated. Several
biotic and abiotic factors have been shown to be important during this process, including
the plant properties (species, age, stage, etc.), the soil type and agronomic practices, the
geo-climate conditions, and the biotic interaction.
In this context, the vineyard ecosystems represent a unique biogeography model to study
and disentangle microbial biodiversity patterns (compositional diversity and potential
functionality) across plants cultivated in different geographical regions. Here, I used the
rhizosphere and bulk soil of seven different rootstock-scion combinations (Vitis spp.) to
dissect the main factors driving the microbial communities’ recruitment in ten different
vineyards in Tuscany (Italy), distributed in the Pomino and Nipozzano estates of
Frescobaldi company. Among the factors investigated, I focused my attention on the
geographical area, soil type and rootstock-scion combination. By using high-throughput
sequencing of bacterial 16S rRNA gene and fungal ITS region, I show how both bacterial
and fungal communities associated with grapevine rhizosphere and bulk soils are mainly
affected by the geographical area and the soil. Nonetheless, I also revealed that the
rootstock-scion combination is an important driver in shaping the microbial community,
explaining a higher percentage of variability in comparison with the factors rootstock and
scion taken alone. Overall, the results obtained in my thesis offer a new perspective of research that aim to develop a deep understanding about the contribution of scionrootstock
combinations in the microbial community ecology of the plant holobiont.
Keywords: Plant-microbe interactions, edaphic microorganisms, Microbial ecology, Plant
Growth Promoting Bacteria, Rootstock-scion, Grapevine.
|Date of Award||Jul 2020|
|Original language||English (US)|
- Biological, Environmental Sciences and Engineering
|Supervisor||Daniele Daffonchio (Supervisor)|
- Vitis vinifera