Douro study finds soil exerts the strongest pull on grapevine root microbiomes

Researchers in Portugal have found that soil conditions and grapevine rootstock both shape the bacterial communities living around vine roots in the Douro Demarcated Region, offering new evidence that the microbiome of a vineyard is closely tied to place and plant material at a time when climate change is putting pressure on wine regions.

The study, published June 11 in Microbial Ecology, examined four vineyards in the Douro, one of the world’s best known winemaking areas. The authors analyzed rhizosphere bacteria, the microorganisms that live in the soil immediately surrounding roots, using 16S metabarcoding on soil samples collected from July 2022 through January 2024.

According to the researchers, the strongest influence on those bacterial communities came from soil physicochemical properties. Organic matter content and pH stood out as major factors, helping determine both the composition of the microbiome and the diversity and richness of bacterial populations in each vineyard.

The study also found that rootstock genotype played a secondary but still important role. The authors reported that the 1103-P rootstock was associated with a higher abundance of copiotrophic bacteria than R110. In their interpretation, 1103-P appeared to recruit a more versatile and exploratory microbiome, while R110 tended to attract a more specialized community focused on efficient resource use.

The work supports what the researchers described as an ecological hierarchy in vineyard soils. In that framework, environmental conditions act first as the main filter for microbial life, while the host plant then exerts an additional layer of selection. The result, they wrote, is a highly specific microbial community for each vineyard scenario.

The research was carried out by João Prada, Leandro Pereira-Dias, João A. Santos and Conceição Santos, with affiliations including the University of Trás-os-Montes and Alto Douro and the University of Porto. The authors said their findings help establish a baseline for future precision viticulture strategies, including possible bio-inoculants aimed at improving grapevine adaptation to climate change.

That could matter beyond soil science. For wine producers facing hotter and less predictable growing conditions, a better understanding of how each parcel’s soil profile and rootstock influence microbial communities may help move vineyard management away from broad, uniform practices and toward site-specific decisions. In time, that could support more targeted inoculation strategies intended to improve resilience and sustainability in grape production.

The paper places those findings in the context of mounting climate risk for the Douro wine sector. The authors noted that climatic shifts are expected in the region and said understanding how environmental and genetic traits modulate the rhizobiome is important for managing vineyards under changing conditions.

The study was funded in part through a Ph.D. scholarship from Portugal’s Foundation for Science and Technology and through the VineProtect project under PRIMA and the European Union. The authors declared no competing interests.