PubMed · 2026-05-21
Scientists mapped which proteins get chemically 'switched on' inside the tiny cells that open and close leaf pores (stomata). They found that when stomata are closed, proteins involved in internal cell-membrane traffic are unusually active, suggesting this membrane-sorting machinery helps regulate how tightly plants seal themselves against water loss.
Guard cells with closed stomata showed significantly higher phosphorylation (chemical activation) of proteins linked to endomembrane trafficking and vacuoles compared to both open stomata and whole leaf tissue.
The study generated a deep proteome profile of guard cell-enriched tissue that closely matched previously characterized guard cell protein inventories, validating the experimental approach.
The findings support a new hypothesis that phosphorylation of internal membrane-trafficking proteins is a key regulatory mechanism for stomatal movement, a pathway not previously well characterized.