Fluctuating Light Interacts with Time of Day and Leaf Development Stage to Reprogram Gene Expression

Area of Science:

• Plant Physiology
• Molecular Biology
• Plant Biochemistry

Background:

• Plants require flexible adjustment between light energy utilization and photoprotection due to variable natural light.
• Long-term acclimation to light intensity is crucial for plant performance but responses to fluctuating light (FL) are understudied.
• Previous studies focused on constant light intensity, neglecting dynamic light changes.

Purpose of the Study:

• To investigate long-term gene expression responses to fluctuating light (FL) in Arabidopsis leaves.
• To determine if FL responses differ between young and mature leaves.
• To examine variations in FL responses between morning and end-of-day time points.

Main Methods:

• Transcriptome profiling of Arabidopsis thaliana leaves under fluctuating light conditions.
• Comparative analysis of gene expression in young versus mature leaves.
• Examination of temporal gene expression changes at different times of day.

Main Results:

• Fluctuating light induced global reprogramming of gene expression, affecting photoprotection, photosynthesis, photorespiration, and metabolism.
• Gene expression changes under FL varied significantly between young and mature leaves, and between morning and evening.
• Circadian clock and light signaling pathways coordinate acclimatory responses, with limited overlap in gene regulation across conditions.

Conclusions:

• Plant acclimation to fluctuating light involves complex, dynamic gene expression adjustments influenced by leaf development and time of day.
• FL acclimation mechanisms are coordinated by the circadian clock and light signaling, impacting various metabolic and protective pathways.
• Evidence suggests potential crosstalk between FL acclimation and systemic acquired resistance pathways in young leaves.