A Journey into Lettuce Chronobiology: From Domestication and Clock Diversity to Applying Circadian Resonance

Summary

This thesis uncovered how biological clocks have driven crop domestication and can boost agricultural productivity, using lettuce as a study case. Using the world's largest lettuce collection (445 varieties), we discovered that cultivated lettuce has a unique ~26.5-hour internal clock, longer than the typical 24-hour rhythm. We identified the mechanisms behind this slower clock and found a key gene that controls both the clock change and bolting, a highly undesired trait in lettuce cultivation. Moreover, we serendipitously discovered that wild lettuce tells time in a fundamentally different way than what is reported for higher plants, challenging basic assumptions about plant biology. Finally, we proved this knowledge has real-world applications. When we grew lettuce under 27-hour light cycles matching their slower internal clocks, plants produced 30% more biomass without quality loss. This "circadian farming" approach has enormous potential for controlled environment agriculture systems like vertical farms. Our research demonstrates how understanding plant timing mechanisms can simultaneously advance fundamental science and create practical solutions for crop cultivation.