Revealing the ancient plant ethylene biosynthesis and ACC signaling pathway

2026-07-22

When ancestral plants colonized the land 450 million years ago, they needed to adapt to harsh environmental conditions when giving up their aquatic lifestyle. I hypothesize that during this water-to-land transition, the volatile plant hormone ethylene became an important growth regulator to face terrestrial stressors. In fact, modern-day crops use ethylene to regulate stress responses, and perhaps ethylene served this role in pioneering land plants to cope with the harsh conditions coinciding with this habitat transition. During my postdoc, I showed that ethylene signaling was functionally assembled in ancestral Charophyte green algae, prior to land colonization. Now I question why and how early land plants produced ethylene. While seed plants make ethylene using ACC as precursor, non-seed plants follow a different, yet unknown ethylene biosynthesis pathway, which I want to reveal using the liverwort Marchantia polymorpha, a model species representing early life on earth. I also question why non-seed plants make ACC, but not use it for ethylene synthesis. Recent studies revealed that ACC itself can act as a signaling molecule, independent from ethylene, by an unknown signaling pathway to regulate plant development. I also postulate that both the alternative ethylene biosynthesis and ACC signaling pathway might have an origin in ancient algae, prior to land colonization, and might be conserved in seed plants, possibly exerting important functions yet to be uncovered. Using functional genetics in representative species of algae and crops, ETHYLUTION will unravel the importance and role of ACC and ethylene that allowed plants to thrive on earth, perhaps one of the most impactful events in the evolutionary history of plants.

Belgium

2025-10-01