Hydraulic flux–responsive hormone redistribution determines root branching

Mehra, Poonam and Pandey, Bipin K. and Melebari, Dalia and Banda, Jason and Leftley, Nicola and Couvreur, Valentin and Rowe, James and Anfang, Moran and De Gernier, Hugues and Morris, Emily and Sturrock, Craig J. and Mooney, Sacha J. and Swarup, Ranjan and Faulkner, Christine and Beeckman, Tom and Bhalerao, Rishikesh P. and Shani, Eilon and Jones, Alexander M. and Dodd, Ian C. and Sharp, Robert E. and Sadanandom, Ari and Draye, Xavier and Bennett, Malcolm J. (2022) Hydraulic flux–responsive hormone redistribution determines root branching. Science, 378 (6621). pp. 762-768. ISSN 0036-8075

Text (Poonam_add3771_Main_manuscript)
Poonam_add3771_Main_manuscript.pdf - Accepted Version
Available under License Creative Commons Attribution.
Download (1MB)

Abstract

Plant roots exhibit plasticity in their branching patterns to forage efficiently for heterogeneously distributed resources, such as soil water. The xerobranching response represses lateral root formation when roots lose contact with water. Here, we show that xerobranching is regulated by radial movement of the phloem-derived hormone abscisic acid, which disrupts intercellular communication between inner and outer cell layers through plasmodesmata. Closure of these intercellular pores disrupts the inward movement of the hormone signal auxin, blocking lateral root branching. Once root tips regain contact with moisture, the abscisic acid response rapidly attenuates. Our study reveals how roots adapt their branching pattern to heterogeneous soil water conditions by linking changes in hydraulic flux with dynamic hormone redistribution.