PT  - JOURNAL ARTICLE
AU  - Bihai Shi
AU  - Amelia Felipo-Benavent
AU  - Guillaume Cerutti
AU  - Carlos Galvan-Ampudia
AU  - Lucas Jilli
AU  - Geraldine Brunoud
AU  - Jérome Mutterer
AU  - Elody Vallet
AU  - Lali Sakvarelidze-Achard
AU  - Jean-Michel Davière
AU  - Alejandro Navarro-Galiano
AU  - Ankit Walia
AU  - Shani Lazary
AU  - Jonathan Legrand
AU  - Roy Weinstain
AU  - Alexander M. Jones
AU  - Salomé Prat
AU  - Patrick Achard
AU  - Teva Vernoux
TI  - A quantitative gibberellin signalling biosensor reveals a role for gibberellins in internode specification at the shoot apical meristem
AID  - 10.1101/2021.06.11.448154
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2021.06.11.448154
4099  - http://biorxiv.org/content/early/2022/06/15/2021.06.11.448154.short
4100  - http://biorxiv.org/content/early/2022/06/15/2021.06.11.448154.full
AB  - Growth at the shoot apical meristem (SAM) is essential for shoot architecture construction. The phytohormones gibberellins (GA) play a pivotal role in coordinating plant growth, but their role in the SAM remains mostly unknown. Here, we developed a ratiometric GA signalling biosensor by engineering one of the DELLA proteins, to suppress its master regulatory function in GA transcriptional responses while preserving its degradation upon GA sensing. We demonstrate that this novel degradation-based biosensor accurately reports on cellular changes in GA levels and perception during development. We used this biosensor to map GA signalling activity in the SAM. We show that high GA signalling is found primarily in cells located between organ primordia that are the precursors of internodes. By gain- and loss-of-function approaches, we further demonstrate that GAs regulate cell division plane orientation to establish the typical cellular organisation of internodes, thus contributing to internode specification in the SAM.Competing Interest StatementThe authors have declared no competing interest.