Mechanism and function of root circumnutation

Early root growth is critical for plant establishment and survival. We have identified a molecular pathway required for helical root tip movement known as circumnutation. Here, we report a multiscale investigation of the regulation and function of this phenomenon. We identify key cell signaling events comprising interaction of the ethylene, cytokinin, and auxin hormone signaling pathways. We identify the gene Oryza sativa histidine kinase-1 (HK1) as well as the auxin influx carrier gene OsAUX1 as essential regulators of this process in rice. Robophysical modeling and growth challenge experiments indicate circumnutation is critical for seedling establishment in rocky soil, consistent with the long-standing hypothesis that root circumnutation facilitates growth past obstacles. Thus, the integration of robotics, physics, and biology has elucidated the functional importance of root circumnutation and uncovered the molecular mechanisms underlying its regulation.

Automated summary

Early root growth is crucial for plant establishment and survival. The molecular pathway required for helical root tip movement, known as circumnutation, has been identified. Key cell signaling events involving ethylene, cytokinin, and auxin hormone pathways are important for this process. The gene Oryza sativa histidine kinase-1 (HK1) and the auxin influx carrier gene OsAUX1 are essential regulators of circumnutation in rice. Robophysical modeling and growth challenge experiments demonstrate the importance of circumnutation for seedling establishment, especially in rocky soil. The integration of robotics, physics, and biology has revealed the functional significance and molecular mechanisms underlying the regulation of root circumnutation.