Interplay between low light and hormone-mediated signaling pathways in shade avoidance regulation in plants

Plants possess multiple protective mechanisms against abiotic stress which ensure their survival in limiting environments. Among those stressors, low light is an emerging cue for plants. Light is crucial to control the plant life as fuels photosynthesis which is strictly dependent to light intensity, duration and quality. In addition, plants are equipped with multiple photoreceptors (e.g. phytochromes, cryptochromes, and phototropin) that sense light and trigger light-mediated molecular/physiological responses. Fluctuations in light spectra and flux density, impact on plant performance at morphological, physiological, biochemical and molecular level, leading to severe alteration in plant growth and development. As sessile organisms, plants cannot escape light stress, thus, they have evolved specific mecanisms of adaptation to such conditions, including a complex network of phytohormones. In this review, we summarize the recent findings dealing with the regulation of plant response to low light, with a focus on the role(s) of phytohormones involved in such light-limited environments.