Abstract
The CLAVATA pathway is a key regulator of stem cell function in the multicellular shoot tips of Arabidopsis, where it acts via the WUSCHEL transcription factor to modulate hormone homeostasis. Broad scale evolutionary comparisons have shown that CLAVATA is a conserved regulator of land plant stem cell function, but CLAVATA acts independently of WUSCHEL-like (WOX) proteins in bryophytes. The relationship between CLAVATA, hormone homeostasis and the evolution of land plant stem cell functions is unknown.
Here we show that in the moss, Physcomitrella (Physcomitrium patens), CLAVATA affects stem cell activity by modulating hormone homeostasis. CLAVATA pathway genes are expressed in the tip cells of filamentous tissues, regulating cell identity, filament branching, plant spread and auxin synthesis. The receptor-like kinase PpRPK2 plays the major role, and Pprpk2 mutants have abnormal responses to cytokinin, auxin, and auxin transport inhibition, and show reduced expression of PIN auxin transporters.
We propose a model whereby PpRPK2 modulates auxin gradients in filaments to determine stem cell identity and overall plant form. Our data indicate that CLAVATA-mediated auxin homeostasis is a fundamental property of plant stem cell function, likely exhibited by the last shared common ancestor of land plants.
Here we show that in the moss, Physcomitrella (Physcomitrium patens), CLAVATA affects stem cell activity by modulating hormone homeostasis. CLAVATA pathway genes are expressed in the tip cells of filamentous tissues, regulating cell identity, filament branching, plant spread and auxin synthesis. The receptor-like kinase PpRPK2 plays the major role, and Pprpk2 mutants have abnormal responses to cytokinin, auxin, and auxin transport inhibition, and show reduced expression of PIN auxin transporters.
We propose a model whereby PpRPK2 modulates auxin gradients in filaments to determine stem cell identity and overall plant form. Our data indicate that CLAVATA-mediated auxin homeostasis is a fundamental property of plant stem cell function, likely exhibited by the last shared common ancestor of land plants.
| Original language | English |
|---|---|
| Pages (from-to) | 149-163 |
| Number of pages | 15 |
| Journal | The New phytologist |
| Volume | 234 |
| Issue number | 1 |
| Early online date | 15 Jan 2022 |
| DOIs | |
| Publication status | Published - 1 Apr 2022 |
Bibliographical note
Funding Information:We thank the Gatsby Charitable Foundation and the Bristol Centre for Agricultural Innovation for funding Zoe Nemec‐Venza and Jill Harrison's work. We thank the ERDF for funding ‘Plants as a tool for sustainable global development’ (no. CZ.02.1.01/0.0/0.0/16_019/0000827), which supported hormone analyses. We thank Hana Martínková, Petra Amakorová and Kamila Wisnerová for their help with plant hormone analyses. We thank Joe Cammarata, Adrienne Roeder and Mike Scanlon for the gift of the mutant and useful discussions about our work. We thank Lucia Primavesi for technical support and training. The authors declare no conflicts of interest. Ppclv1a1brpk2
Funding Information:
We thank the Gatsby Charitable Foundation and the Bristol Centre for Agricultural Innovation for funding Zoe Nemec-Venza and Jill Harrison's work. We thank the ERDF for funding ?Plants as a tool for sustainable global development? (no. CZ.02.1.01/0.0/0.0/16_019/0000827), which supported hormone analyses. We thank Hana Mart?nkov?, Petra Amakorov? and Kamila Wisnerov? for their help with plant hormone analyses. We thank Joe Cammarata, Adrienne Roeder and Mike Scanlon for the gift of the Ppclv1a1brpk2 mutant and useful discussions about our work. We thank Lucia Primavesi for technical support and training. The authors declare no conflicts of interest.
Publisher Copyright:
© 2022 The Authors. New Phytologist © 2022 New Phytologist Foundation
Keywords
- CLAVATA
- CLV-WUS
- evo-devo
- moss filament identity
- physcomitrella
- plant stem cell