Dynamic Phytomeric Growth Contributes to Local Adaptation in Barley

Area of Science:

• Plant biology
• Crop genetics
• Evolutionary biology

Background:

• Vascular plants exhibit segmented body axes with nodes and internodes.
• Node initiation and internode elongation are crucial for plant fitness and crop yield.
• The spatiotemporal coordination of these developmental events remains poorly understood.

Purpose of the Study:

• To investigate the coordination of node initiation and internode elongation in barley (Hordeum vulgare L.).
• To understand the impact of domestication on these developmental processes.
• To explore the genetic basis and evolutionary trajectories of plant architecture in barley.

Main Methods:

• Comparative analysis of domesticated barley subpopulations.
• Genetic and functional analyses of key developmental genes.
• Investigation of spatiotemporal gradients in node and internode development.

Main Results:

• Domestication extended the apical meristematic phase, promoting node initiation but limiting internode elongation.
• Internode elongation exhibits a proximal-distal gradient in both vegetative and reproductive phases.
• Flowering-time genes have been repurposed to regulate internode elongation timing and duration.

Conclusions:

• Barley's plant architecture is shaped by domestication, influencing node and internode development.
• Node initiation and internode elongation display distinct geographical gradients.
• Plant architecture can be viewed as dynamic phytomeric units shaped by adaptive evolution.