Light signaling-driven plant-microbiome interactions.

As sessile organisms, plants continuously perceive and adapt to dynamic light environments and complex microbial communities. Light serves not only as the energy source for photosynthesis, but also a key signal that regulates plant growth, development, and plant-microbe interactions. Through photoreceptor-mediated perception and downstream signaling networks, light modulates plant immunity and orchestrates beneficial microbial associations. This review summarizes how light signaling regulates plant-microbe interactions through three interconnected layers. First, photoreceptors and downstream factors directly modulate immune and hormonal defense pathways. Second, light regulates physical barriers, including cuticular wax deposition, cell wall lignification, and stomatal immunity. Third, light-driven reprogramming of carbon allocation and secondary metabolism reshapes rhizosphere chemistry and microbiome assembly. These findings highlight light signaling as a central coordinator of plant immunity, physical defense, and microbiome assembly, providing a basis for precisely manipulating plant-microbe interactions through light management to advance sustainable agriculture.