The union of fungi and financial aid bacteria financial aid vines to withstand the high temperatures and elevated CO2 associated with climate change
A study by the Biodiversity and Environment Institute BIOMA of the University of Navarra shows that symbiosis with fungi and bacteria improves the yield and quality of Cabernet Sauvignon under high temperatures and high CO₂.
09 | 10 | 2025
Climate change is seriously affecting Mediterranean viticulture, one of the most vulnerable in the world due to rising temperatures, heat waves and droughts. In this scenario, improving the resilience of young vines is a core topic to maintain grape productivity and quality.
A study conducted by María del Carmen Antolín, Daria Kozikova, Inmaculada Pascual and Nieves Goicoechea -researchers from the Plant Stress Physiologygroup of the BIOMA Institute-, together with Idoia Garmendia, from the University of Alicante, aimed goal evaluate whether the joint application of arbuscular mycorrhizal fungi and plant growth-promoting bacteria could increase the heat resistance of young Cabernet Sauvignon plants. In addition, it sought to test whether this combination helped maintain or improve their yield and fruit quality under simulated conditions of high temperature and CO₂, representative of the Mediterranean climate of the future.
"To conduct the study, we grew grafted Cabernet Sauvignon plants in thermal gradient greenhouses, simulating four scenarios: ambient temperature and CO₂, elevated temperature, elevated CO₂ and both factors combined," Daria Kozikova, a doctoral student at the BIOMA Institute, tells us. With these scenarios covered, half of the plants were inoculated with fungi and bacteria and half were not.
The findings showed promising results: under hot conditions and high CO₂, plants without mycorrhizae showed a sharp drop in yield (up to -75%) and loss of sugars and anthocyanins in the berries. In contrast, mycorrhizal plants maintained normal iron and copper levels, doubled yield and preserved grape quality (sugars, phenols and anthocyanins).
The symbiosis between arbuscular mycorrhizal fungi and plant growth-promoting bacteria improved photosynthetic efficiency, mineral nutrition (especially of micronutrients) and antioxidant capacity of the fruits. In addition, increased thermoresistance was observed: inoculated plants withstood heat waves better, with less physiological stress.
"We have clearly seen how co-inoculation of mycorrhizal fungi and bacteria is a promising strategy to increase the resilience of Mediterranean vineyards in the face of climate change," says Inmaculada Pascual, researcher at the BIOMA Institute. "The benefits were more noticeable when high CO₂ was combined with high temperatures," adds Inmaculada. The next step will be to transfer the research to the field and to other varieties to confirm these long-term effects.
→ Antolín, M.C., Kozikova, D., Garmendia, I., Pascual, I., & Goicoechea, N. (2025). Co-inoculation of arbuscular mycorrhizal fungi and plant growth-promoting bacteria improves thermotolerance and fruit quality of young Cabernet Sauvignon grapevines under elevated CO₂ and temperature. Plant and Soil. DOI: 10.1007/s11104-025-07893-7
