Local light signalling at the leaf tip drives remote differential petiole growth through auxin-gibberellin dynamics

Arabidopsis plants transfer information from the leaf tip to the petiole base to induce adaptive upward leaf movement upon neighbour detection through Far-Red light enrichment in the leaf tip. To determine how a distally derived signal can specifically regulate growth in the abaxial petiole we analysed the transcriptome in the leaf tip and abaxial-adaxially split petiole sections during the first hours of far-red enrichment. Wild-type Arabidopsis plants were exposed to white light control or white light + Far-Red for five hours. Samples were taken at timepoints ranging from 40 - 300 minutes after the start of treatment. The harvested samples were the leaf tip, abaxial petiole base and adaxial petiole base. There were 4 biological replicates, each consisting of material from selected leaves of 13 plants.