A molecular timetable for apical bud formation and dormancy induction in poplar

Area of Science:

• Plant Biology
• Systems Biology
• Molecular Biology

Background:

• Perennial plants in temperate zones exhibit seasonal growth and dormancy cycles.
• Bud development in autumn initiates dormancy, a critical process for plant survival.

Purpose of the Study:

• To elucidate the molecular mechanisms governing apical bud development and dormancy in poplar (Populus tremula x Populus alba).
• To reconstruct the temporal sequence of events during bud development using a systems biology approach.

Main Methods:

• Combined transcript and metabolite profiling across a high-resolution time course from short-day induction to dormancy.
• Gene expression and metabolite dynamics analysis.
• Electron microscopy to determine the timing and location of cell proliferation arrest and storage compound accumulation.

Main Results:

• Bud development was dissected into distinct phases: bud formation, acclimation (dehydration/cold tolerance), and dormancy.
• Specific sets of regulatory genes and marker metabolites were identified for each developmental stage.
• Light, ethylene, and abscisic acid signaling pathways were found to consecutively regulate these processes.
• Ethylene signaling acts between light and abscisic acid signals, potentially triggered by low hexose levels.

Conclusions:

• The study provides a temporal framework and molecular reference for poplar bud dormancy.
• Identified conserved genes suggest shared molecular mechanisms for growth-to-dormancy transitions across different plant organs and species.
• This research lays the groundwork for future functional studies on plant dormancy.