Time-resolved oxidative signal convergence across the algae-embryophyte divide

Area of Science:

• Plant Biology
• Evolutionary Biology
• Molecular Biology

Background:

• The transition of plants to land presented significant environmental challenges, including rapid fluctuations in light and temperature.
• While key genetic components for stress responses are shared between land plants and their algal relatives (streptophytes), their coordinated function remains poorly understood.

Purpose of the Study:

• To investigate the kinetics of stress responses in streptophytes.
• To elucidate the gene regulatory networks underlying dynamic stress adaptation in early land plants and their relatives.

Main Methods:

• Utilized time-course stress profiling incorporating photophysiology, transcriptomics (2.7 Tbp data), and metabolite profiling (270 samples).
• Analyzed three streptophyte species with 600 million years of divergence.
• Employed co-expression analysis and Granger causal inference to predict gene regulatory networks.

Main Results:

• Identified a gene regulatory network that reveals ancient signal convergence points.
• Key convergence points include ethylene signaling components, osmosensors, and major kinase cascades.
• Demonstrated that these kinase hubs were integrated with diverse environmental inputs even before the terrestrial colonization by plants.

Conclusions:

• The study reveals the ancient origins of complex stress-response regulatory networks in streptophytes.
• These findings highlight the pre-adaptation of signaling pathways for environmental integration prior to the evolution of land plants.