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| (top) Before dehydration. (bottom) Rehydration after dehydration. (left column) A control plant. (right two columns) Two cle25 mutant plants. While normal plants can be revived after being subjected to dehydration, mutants lacking CLE25 cannot be. Additionally, control plants lost less water during dehydrations (images not shown). Credit: RIKEN |
Researchers at the RIKEN Center for Sustainable Resource Science (CSRS). Scientist of Japan have discovered a small plant hormone that helps to plants retain water concentration when water is completely loss/ water available trace amounts in the soil. Published in the journal Nature on April 4, the researchers study shows how the peptide harmone CLE25 moves from the roots to the leaves by signaling when water in trace concentration and helps to prevent water loss by closing pores in the leaf surface.
Mammalian peptide hormones propagate extracellular stimuli from sensing tissues to appropriate targets to achieve optimal growth maintenance. As meny of us knows In land plants, root-to-shoot signalling pathway is an important step to prevent water loss by transpiration ( loss of water from leaf) and to adapt to water-deficient conditions. The plant hormone abscisic acid (ABA) has a major role in the regulation of stomatal movement to prevent water loss. However, no mobile signalling molecules have yet been identified that can trigger abscisic acid accumulation in leaves of a plant.
Here researcher show that the CLAVATA3/EMBRYO-SURROUNDING REGION-RELATED 25 (CLE25) peptide transmits water-deficiency signals through vascular tissues in Arabidopsis, and affects the process of abscisic acid biosynthesis and stomatal control of transpiration in association with BARELY ANY MERISTEM (BAM) receptors present in leaves.
The CLE25 gene is expressed in vascular tissues and enhanced in roots in response to dehydration stress and draught conditions. The root-derived CLE25 peptide moves from the roots to the (shoot) leaves, where it induces stomatal closure by 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.
More information: Fuminori Takahashi et al, A small peptide modulates stomatal control via abscisic acid in long-distance signalling, Nature (2018) https://www.nature.com/articles/s41586-018-0009-2