Gene

Meristem

Guard cell

Mutant

Transpiration

Photosynthesis

Chemistry

Shoot

Peptide

Arabidopsis

Abscisic acid

Biochemistry

Botany

Biology

Cell biology

Nature

Mammalian peptide hormones propagate extracellular stimuli from sensing tissues to appropriate targets to achieve optimal growth maintenance                  1                . In land plants, root-to-shoot signalling is important to prevent water loss by transpiration and to adapt to water-deficient conditions2, 3. The phytohormone abscisic acid has a role in the regulation of stomatal movement to prevent water loss                  4                . However, no mobile signalling molecules have yet been identified that can trigger abscisic acid accumulation in leaves. Here we show that the CLAVATA3/EMBRYO-SURROUNDING REGION-RELATED 25 (CLE25) peptide transmits water-deficiency signals through vascular tissues in Arabidopsis, and affects abscisic acid biosynthesis and stomatal control of transpiration in association with BARELY ANY MERISTEM (BAM) receptors in leaves. The CLE25 gene is expressed in vascular tissues and enhanced in roots in response to dehydration stress. The root-derived CLE25 peptide moves from the roots to the leaves, where it induces stomatal closure by modulating abscisic acid accumulation and thereby enhances resistance to dehydration stress. BAM receptors are required for the CLE25 peptide-induced dehydration stress response in leaves, and the CLE25–BAM module therefore probably functions as one of the signalling molecules for long-distance signalling in the dehydration response. In an Arabidopsis model, the CLE25 peptide acts as a root-to-shoot signalling molecule that modulates abscisic acid expression to close stomata and enhance resistance to dehydration.

A small peptide modulates stomatal control via abscisic acid in long-distance signalling