Nursery microbes shape grapevines for years

A study published Monday in the journal Environmental Microbiome found that microbes carried from the nursery to the vineyard can continue to shape young grapevines for years after planting, influencing both plant health and yield.

Researchers at the University of California, Riverside tracked the fungal and bacterial communities inside and around grafted Cabernet Sauvignon and Chardonnay vines over three years after they were planted in a commercial vineyard near Madera, Calif. The vines, grafted onto 1103P rootstock, came from two nurseries and were sampled across five plant compartments: the scion graft union, rootstock graft union, crown, roots and rhizosphere.

The team used amplicon-based sequencing to follow microbial succession as the vines moved from nursery conditions into the vineyard. They found that nursery-grown vines arrived with distinct endospheric microbiomes, and although those communities became more similar over time, they still remained significantly different after three years in the field.

The study also found that microbial turnover happened faster below ground than in trunk tissues. In roots and the rhizosphere, many of the original microbes disappeared more quickly after planting. By the end of the three-year period, about 15% of the initial microbes were still present in the vineyard vines.

The researchers said the fungal pathobiome inherited from the nurseries was also still detectable after three years and remained distinct from other microbial communities. That group included microbes linked to vascular diseases of trunks and roots. The vines in the study did not show clear disease symptoms or dieback during the trial, which the authors said may have been because they were not under enough stress during the study period.

Yield varied widely among clonal vines, even though they were grown under the same commercial conditions. Statistical models showed that a relatively small set of amplicon sequence variants, or ASVs, explained much of that variation. The top 10 high-impact ASVs accounted for 51% of yield variation in trunk tissues and 60% in belowground tissues.

Of the 19 yield-associated ASVs identified in the study, 16 came from the nurseries. The authors said that finding points to a long-lasting influence of nursery-derived microbes on vineyard performance, including both helpful and harmful organisms.

The work suggests that the nursery stage may be an important point for managing grapevine microbiomes before vines are planted in production fields. The authors said that approach could help improve resilience in young vineyards and may eventually support efforts to engineer beneficial microbial communities while limiting pathogens.

The study was supported by the California Department of Food and Agriculture and conducted with farming support from E&J Gallo Winery at an experimental block near Madera.