RT Journal Article
SR Electronic
T1 Gibberellins promote polar auxin transport to regulate stem cell fate decisions in cambium
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.07.15.500224
DO 10.1101/2022.07.15.500224
A1 Riikka Mäkilä
A1 Brecht Wybouw
A1 Ondrej Smetana
A1 Leo Vainio
A1 Anna Solé-Gil
A1 Munan Lyu
A1 Lingling Ye
A1 Xin Wang
A1 Riccardo Siligato
A1 Mark Kubo Jenness
A1 Angus S. Murphy
A1 Ari Pekka Mähönen
YR 2022
UL http://biorxiv.org/content/early/2022/07/16/2022.07.15.500224.abstract
AB Vascular cambium contains bifacial stem cells, which produce secondary xylem to one side and secondary phloem to the other. However, how these fate decisions are regulated is unknown. Here, we show that the positioning of an auxin signalling maximum within the cambium determines the fate of stem cell daughters. The position is modulated by gibberellin-regulated, PIN1-dependent polar auxin transport. Gibberellin treatment broadens auxin maximum from the xylem side of the cambium towards the phloem. As a result, xylem-side stem cell daughter preferentially differentiates into xylem, while phloem-side daughter retains stem cell identity. Occasionally, this broadening leads to direct specification of both daughters as xylem, and consequently, adjacent phloem-identity cell reverts to being stem cell. Conversely, reduced gibberellin levels favour specification of phloem-side stem cell daughter as phloem. Together, our data provide a mechanism by which gibberellin regulates the ratio of xylem and phloem production.Competing Interest StatementThe authors have declared no competing interest.