Evolutionary adaptation makes Posidonia photosynthesis more efficient

How can Posidonia oceanica thrive at depths of up to 50 metres, where light is extremely limited? A study published in Nature Communications has identified the evolutionary mechanism that enables this seagrass to use the scarce light available on the seabed with remarkable efficiency.

The research shows that, during evolution, Posidonia oceanica reshaped the structure of its Photosystem I, developing a larger light-harvesting system than that of terrestrial plants while accelerating energy transfer towards the photosynthetic reaction centre. This adaptation allows the plant to maintain highly efficient photosynthesis even under very low-light conditions.

The study is the result of a collaboration between the Politecnico di Milano, the Anton Dohrn Zoological Station, the University of Verona and the National Research Council of Italy (CNR) within the European Research Council (ERC) Advanced Grant "GrInSun". Researchers Mattia Russo, Margherita Maiuri and Giulio Cerullo from the Politecnico di Milano used Two-Dimensional Electronic Spectroscopy (2DES) to observe energy transfer within the photosystem on the femtosecond timescale, providing key insights into the mechanisms that make Posidonia oceanica photosynthesis so efficient.

Beyond advancing our understanding of marine plant evolution, these findings open new opportunities for developing crops capable of using available light more efficiently, with potential benefits for agricultural productivity and sustainability.