Age-associated growth control modifies leaf proximodistal symmetry and enabled leaf shape diversification
Xin-Min Li1, Hannah Jenke1, Sören Strauss1
1Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829 Cologne, Germany.
Current Biology : CB
|August 31, 2024
Summary
SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 9 (SPL9) regulates plant leaf shape by influencing proximodistal (PD) symmetry and marginal serrations. This age-dependent regulation impacts leaf complexity and diversification across species.
Area of Science:
- Developmental Biology
- Plant Morphology
- Evolutionary Genetics
Background:
- Biological shape diversity arises from organ symmetry modulation and patterned elaboration of repeated elements.
- Coordinated regulation of symmetry and patterning in organ development remains largely unclear.
- Plant leaves exhibit proximodistal (PD) axis asymmetries and marginal outgrowths, serving as a model for shape determination.
Purpose of the Study:
- To investigate the role of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 9 (SPL9) in regulating leaf symmetry and marginal patterning.
- To understand how age-dependent SPL9 expression influences leaf heteroblasty and shape diversity in Arabidopsis thaliana.
- To explore the conservation and species-specific mechanisms of heteroblastic growth reprogramming in related species.
Main Methods:
- Utilized genetics, quantitative shape analyses, and time-lapse imaging in Arabidopsis thaliana.
- Conducted comparative analyses with Cardamine hirsuta to study heteroblastic growth reprogramming.
- Investigated the interaction of SPL9 with homeobox genes controlling leaf complexity.
Main Results:
- Age-dependent SPL9 expression gradients decrease proximodistal (PD) symmetry in Arabidopsis thaliana leaves.
- SPL9 coordinately regulates the distribution and shape of marginal serrations, influencing overall leaf form.
- Heteroblastic growth in Cardamine hirsuta involves prolonged cell proliferation and delayed differentiation, similar to Arabidopsis.
Conclusions:
- Identified an age-dependent regulatory layer for organ PD growth that modulates leaf symmetry.
- SPL9 plays a crucial role in coordinating leaf symmetry and marginal patterning, contributing to leaf shape diversity.
- SPL9 facilitates species-specific gene actions that promote leaf complexity, highlighting its role in evolutionary diversification.
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