Molecular Mechanisms of Root Gravitropic Responses and Nutrient Uptake

Gravitropism of plant roots is one of the important factors determining the spatial pattern of root growth and thus may have a great effect on nutrient uptake. An understanding of the molecular mechanisms of root gravitropic response and subsequent root growth changes related to nutrient uptake would facilitate the genetic improvement of nutrient efficiency in plants. This review summarizes the molecular mechanisms of root gravitropic responses in terms of root gravity sensing, signal transduction and auxin asymmetrical distribution. It discusses the physiological basis of root gravitropic responses to nutrient stresses, especially phosphorus deficiency, and its relation to uptake of nutrients, especially phosphorus. Included are problems and perspectives for future research.