Long-distance transport of phytohormones through the plant vascular system

• Plant vascular system plays an essential role in hormone distribution.
• Long-distance hormone transport provides a communication system between organs.
• No evidence for long-distance transport of brassinosteroids.
• Hormone translocation often involves multifunctional transporters.
• Most hormone transporters belong to two families: G-type ABC and NPF.

Phytohormones are a group of low abundance molecules that activate various metabolic and developmental processes in response to environmental and endogenous signals. Like animal hormones, plant hormones often have distinct source and target tissues, hence ensuring long-range communication at the whole-plant level. Plants rely on various hormone distribution mechanisms depending on the distance and the direction of the transport. Here, we highlight the recent findings on the long-distance movement of plant hormones within the vasculature, from the physiological role to the molecular mechanism of the transport.