New research across Europe reveals significant variation in bacteria living on Arabidopsis thaliana plants. This large-scale study found that drought conditions strongly influence which bacteria colonise plants. The findings show complex relationships between climate, plant genetics, and microbial communities.
The study identified two distinct bacterial communities on A. thaliana: one prevalent in Northern Europe, the other in Southern Europe. Drought severity emerged as the strongest predictor of which bacterial community a plant harboured. Both plant genetics and drought directly influenced bacterial composition, with 10% of core bacteria affected by drought and 20% by host genetic factors associated with drought tolerance.
Researchers found the microbes by collecting A. thaliana samples from 267 locations across Europe between February and May 2018. They sequenced the V3-V4 region of the 16S ribosomal RNA to identify bacterial species present on the plants. DNA extraction and sequencing were also performed to analyse plant genetics. Advanced statistical techniques, including random forest modelling and mixed-effects models, were used to analyse relationships between bacterial communities, plant genetics, and various climate factors, particularly drought-related metrics.
This continental-scale study expands on previous smaller-scale research, providing a comprehensive view of plant-microbe interactions across diverse environments. The findings highlight drought’s significant role in shaping these interactions, suggesting that water availability affects which microbes colonise and thrive on plants. Understanding these relationships could have important implications for agriculture and conservation as climate change alters precipitation patterns.
Drought not only plays a major selective role in A. thaliana populations”, but it is also known to affect the ability of plants to withstand pathogen attack. An important question will be whether different background microbiomes in plants that are more likely to experience drought in the wild will help or hamper defense against pathogens.
Karasov, T.L., Neumann, M., Leventhal, L. et al., 2024. Continental-scale associations of Arabidopsis thaliana phyllosphere members with host genotype and drought. Nature Microbiology. Available at: https://doi.org/10.1038/s41564-024-01773-z (OA)
