Sizing up competition with strigolactones: the case of pea plants
Plants, often perceived as static and passive organisms, are in fact capable of movement, communication, and complex social interactions. The Mind(the)Plant laboratory, based at the Department of General Psychology at the University of Padua, investigates precisely these phenomena, with a particular focus on the ability of plants to perceive the presence of neighbors, perform articulated movements such as reaching for and grasping a support-behaviors typical of climbing species-and adapt their behavior based on context and environmental chemical cues.
In a recent study published in Plant Signaling & Behavior, Dr. Bianca Bonato, in collaboration with Professor Tom Bennett of the University of Leeds, explored the role of strigolactones (SLs)-a class of phytohormones secreted by plant roots-in modulating the motor behavior of Pisum sativum (the common pea plant) during support-grasping movements, both in individual and social settings.
Strigolactones are known to regulate root system growth and architecture and can be absorbed by neighboring plants, thereby conveying information about the identity and density of surrounding individuals. However, can these chemical signals also influence how plants move within a social context? To address this question, the study employed 3D kinematic analysis to observe the behavior of pea plants and their grasping movements toward a support, both in isolation and in the presence of conspecifics.
To this end, the researchers utilized wild-type pea plants (capable of both producing and perceiving SLs) as well as mutant genotypes with altered SL biosynthesis or perception: rms1-1, which perceives but does not produce SLs, and rms3-1, which produces SLs but is unable to perceive them. By combining wild-type plants with the different mutants in various pairings to simulate social conditions, the researchers were able to directly examine the effects of SL presence or absence on plant movement dynamics across different contexts.
The findings of this study are highly compelling. They demonstrate that both the presence and genotype of a neighboring plant specifically influence movement dynamics. Notably, mutants-regardless of the mutation type-were consistently unable to grasp the support. However, the rms1-1 mutant, which perceives but does not produce SLs, exhibited accelerated movement in the presence of a wild-type neighbor, suggesting a behavioral response to perceived chemical signals. In contrast, the rms3-1 mutant, which produces but cannot perceive SLs, showed a deceleration in social contexts, likely due to its inability to detect the presence of a potential competitor. Wild-type plants, by contrast, always succeeded in grasping the support but modulated their movement speed and trajectories strategically, depending on the genotype of the neighboring plant.
This study provides the first evidence that strigolactones function not merely as regulators of growth or markers of neighboring presence, but as social signals capable of influencing complex decision-making and competitive behaviors-manifesting even in the kinematic patterns of plant movement.
Link: https://www.tandfonline.com/doi/full/10.1080/15592324.2025.2506556?src=e...
Bonato, B., Bennett, T., Cannizzo, E., Avesani, S., Guerra, S., & Castiello, U. (2025). Sizing up competition with strigolactones: the case of pea plants. Plant Signaling & Behavior, 20(1).
https://doi.org/10.1080/15592324.2025.2506556
