Seeds are central to agriculture and human nutrition, yet the mechanisms that led to their evolutionary success remain only partially understood. An international collaboration led by Enrico Magnani’s group at the Institut Jean-Pierre Bourgin (INRAE, Versailles), with the participation of the Centro de Biotecnología y Genómica de Plantas (CBGP), sheds light on a crucial developmental process: the elimination of the nucellus, a maternal tissue that must be cleared to allow seed growth.

The researchers demonstrate that this process begins with a biochemical change in the cell wall. Specifically, they show that pectins-complex polysaccharides that give structure to plant cell walls-undergo de‑methylesterification followed by degradation. This sequence weakens the cell wall and precedes the activation of a cell death program, ultimately leading to the disappearance of nucellus cells.

Importantly, these processes are coordinated by the transcription factor TRANSPARENT TESTA 16 (TT16), identified as a key regulator of nucellus elimination. When this regulatory pathway is disrupted, or when pectin modification is experimentally blocked, the nucellus persists, demonstrating that cell wall remodeling is not merely a consequence but a driving force of tissue elimination.

This work highlights the strength of international collaboration between CBGP and IJPB-INRAE, combining expertise in plant development, cell wall biology and transcriptomics. Beyond advancing our understanding of seed biology, the findings suggest that evolutionary changes in pectin composition may have been instrumental in the emergence of seeds-one of the most transformative innovations in plant evolution.

In the longer term, this research could also have practical implications. Since nucellus elimination influences seed size and resource allocation, understanding its regulation may open new avenues for crop improvement and yield enhancement.