Phototropin connects blue light perception to starch metabolism in green algae

Yizhong Yuan; Anthony A. Iannetta; Minjae Kim; Patric W. Sadecki; Marius Arend; Angeliki Tsichla; M. Águila Ruiz‐Sola; Georgios Kepesidis; Denis Falconet; Emmanuel Thévenon; Marianne Tardif; Sabine Brugière; Yohann Couté; Jean-Philippe Kleman; Irina A. Sizova; Marion Schilling; Juliette Jouhet; Peter Hegemann; Yonghua Li‐Beisson; Zoran Nikoloski; Olivier Bastien; Leslie M. Hicks; Dimitris Petroutsos

doi:10.1038/s41467-025-57809-3

Plant BiologyNature CommunicationsMar 14, 2025

Peer-reviewed journal article

Phototropin connects blue light perception to starch metabolism in green algae

Yizhong Yuan iD, Anthony A. Iannetta iD, Minjae Kim iD, Patric W. Sadecki iD, Marius Arend iD, Angeliki Tsichla iD, M. Águila Ruiz‐Sola iD, Georgios Kepesidis iD, Denis Falconet iD, Emmanuel Thévenon, Marianne Tardif iD, Sabine Brugière iD, Yohann Couté iD, Jean-Philippe Kleman iD, Irina A. Sizova iD, Marion Schilling iD, Juliette Jouhet iD, Peter Hegemann iD, Yonghua Li‐Beisson iD, Zoran Nikoloski iD, Olivier Bastien iD, Leslie M. Hicks iD, Dimitris Petroutsos iD

Abstract

In photosynthetic organisms light acts as an environmental signal to control their development and physiology, and as energy source to drive the conversion of CO2 into carbohydrates used for growth or storage. The main storage carbohydrate in green algae is starch, which accumulates during the day and is broken down at night to meet cellular energy demands. The signalling role of light quality in the regulation of starch accumulation remains unexplored. Here, we identify PHOTOTROPIN-MEDIATED SIGNALLING KINASE 1 (PMSK1) as a key regulator of starch metabolism in Chlamydomonas reinhardtii. In its phosphorylated form (PMSK1-P), it activates GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAP1), promoting starch biosynthesis. We show that blue light, perceived by PHOTOTROPIN, induces PMSK1 dephosphorylation that in turn represses GAP1 mRNA levels and reduces starch accumulation. These findings reveal a novel blue light-mediated signaling pathway that advances our understanding of photoreceptor-controlled carbon metabolism in microalgae. One-Sentence SummaryBlue light perception by PHOTOTROPIN triggers kinase-mediated signaling to inhibit starch accumulation in the green alga Chlamydomonas.

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