Air channels create a directional light signal to regulate hypocotyl phototropism

Published in: SCIENCE, 23 Nov 2023, Vol 382, Issue 6673, pp. 935-940

Authors: GANESH M. NAWKAR, MARTINA, ANUPAMA GOYAL (TCGLS MEMBER), EMANUEL SCHMID-SIEGERT, JÉRÉMY FLEURY, ANTONIO MUCCIOLO, DAMIEN DE BELLIS, MARTINE TREVISAN, ANDREAS, AND CHRISTIAN FANKHAUSER

DOI: https://www.science.org/doi/10.1126/science.adh9384

Abstract: In plants, light direction is perceived by the phototropin photoreceptors, which trigger directional growth responses known as phototropism. The formation of a phototropin activation gradient across a photosensitive organ initiates this response. However, the optical tissue properties that functionally contribute to phototropism remain unclear. In this work, we show that intercellular air channels limit light transmittance through various organs in several species. Air channels enhance light scattering in Arabidopsis hypocotyls, thereby steepening the light gradient. This is required for an efficient phototropic response in Arabidopsis and Brassica. We identified an embryonically expressed ABC transporter required for the presence of air channels in seedlings and a structure surrounding them. Our work provides insights into intercellular air space development or maintenance and identifies a mechanism of directional light sensing in plants.