New preprint on Seed Microbiota
Very happy that we were invited to participate in this very nice piece of work directed by the group of Natalia González Benítez and Carmen Molina from the Rey Juan Carlos University in Madrid. The best thing is that this work is supposed the be just the beginning of a fruitful collaboration between our labs.
González Benítez N. et al. 2026 SSRN
Synopsis
Arsenic contamination represents one of the most critical anthropogenic stressors compromising organism resilience in the current context of Global Change. However, some plant species can complete their life cycle in soils highly contaminated with this metalloid. Studies on plant–soil microbiome symbiosis have largely emphasized horizontal microbiome transmission (from soil to roots), while underestimating the role of vertically transmitted seed borne microbiomes. This work examines the seed endophytic bacterium Acinetobacter radioresistens MC 14, originally isolated from arsenic hyper-resistant plants such as Jasione montana and known for its arsenic tolerance and plant-growth-promoting traits. The study investigates its capacity to modulate plant phenotypic traits and enhance adaptation under arsenic stress. To this end, we evaluated the physiological responses of Arabidopsis thaliana exposed to increasing As(III) concentrations following inoculation with MC 14, which apoplastically colonizes non native roots and establishes a non-invasive facultative symbiosis that improves plant survival under arsenic stress. A. radioresistens MC 14 improves plant fitness and ecological success, with optimal inoculum levels maximizing the benefits of the interaction while minimizing symbiotic costs. Moreover, A. radioresistens MC 14 mitigates arsenic induced phytohormonal imbalances in roots during early development. This bacterium–plant association promotes root growth and reduces As(III) triggered oxidative stress by activating cellular recovery mechanisms. As a result, plants produce more roots, flowers, and leaves even under toxic conditions. Overall, these findings indicate that plants exert selective pressure on their seed microbiome, driving co-evolution and maintaining beneficial microbial reservoirs across generations, ultimately enhancing plant performance in stressful environments.
