The luxurious vegetation at Sanya, the most southern location in China on the island of Hainan, provided a perfect environment for the 'Auxin 2016' meeting in October. As we review here, participants from all around the world discussed the latest advances in auxin transport, metabolism and signaling pathways, highlighting howauxin acts during plant development and in response to the environment in combination with other hormones. The meeting also provided a rich perspective on the evolution of the role of auxin, from algae to higher plants.