Auxin and cytokinin regulate growth dynamics underlying carpel initiation in Arabidopsis
Andrea Gómez-Felipe1, Stefan de Folter2, Daniel Kierzkowski1
1Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke St E, Montréal, QC H1X 2B2, Canada.
Journal of Experimental Botany
|December 12, 2025
Summary
Plant organ development relies on precise cellular coordination. This study reveals how auxin and cytokinin crosstalk guides Arabidopsis gynoecium initiation, shaping the female reproductive structure through differential growth.
Area of Science:
- Plant developmental biology
- Molecular and cellular biology
Background:
- Plant organ initiation requires precise spatial and temporal coordination of cellular behaviors.
- The gynoecium in Arabidopsis thaliana, the female reproductive structure, is crucial for fertilization and fruit formation.
- The interplay of phytohormones auxin and cytokinin in early carpel development is not fully understood.
Purpose of the Study:
- To investigate the role of auxin-cytokinin crosstalk in the cellular dynamics of Arabidopsis gynoecium initiation.
- To understand how hormone signaling influences growth patterns during carpel primordia development.
Main Methods:
- Confocal live imaging to observe cellular behaviors at high resolution.
- Hormone treatments (cytokinin) and hormone transport inhibition (auxin) to study their effects.
- Utilized hormone reporters to track signaling dynamics.
Main Results:
- Carpel primordia initiation is driven by differential growth between peripheral (fast-expanding) and central (slow-growing) regions.
- Ectopic cytokinin treatment enhances cell growth and division, increasing carpel primordia size.
- Inhibition of auxin transport reduces carpel primordia size, indicating opposing effects.
Conclusions:
- The interplay between auxin and cytokinin is essential for establishing the correct organ geometry during gynoecium initiation.
- Differential cell expansion and division, regulated by hormone crosstalk, drive the transformation of the floral meristem into carpels.
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