Sucrose-responsive osmoregulation of plant cell size by a long non-coding RNA

• Published in: Molecular plant
• Main Authors: Hajný, Jakub, Trávníčková, Tereza, Špundová, Martina, Roenspies, Michelle, Karim Rony, R. M. Imtiaz, Sacharowski, Sebastian, Krzyszton, Michal, Zalabák, David, Hardtke, Christian S., Pečinka, Aleš, Puchta, Holger, Swiezewski, Szymon, van Norman, Jaimie M., Novák, Ondřej
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 30.09.2024
• ISSN: 1674-2052; 1752-9867; 1752-9867
• DOI: 10.1016/j.molp.2024.09.011

In plants, sugars are the key source of energy and metabolic building blocks. The systemic transport of sugars is essential for plant growth and morphogenesis. Plants evolved intricate molecular networks to effectively distribute sugars. The dynamic distribution of these osmotically active compounds is a handy tool for regulating cell turgor pressure, an instructive force in developmental biology. Here, we set out to investigate the molecular mechanism behind the dual role of a receptor-like kinase CANAR. We functionally characterized a long non-coding RNA, CARMA, as a negative regulator of CANAR. Sugar-responsive CARMA specifically fine-tunes CANAR expression in the phloem, the route of sugar transport. Based on our genetics, molecular, microscopy, and biophysical data, we propose that by controlling sugar phloem transport from shoot to root, the CARMA-CANAR module allows cells to flexibly adapt to the external osmolality by appropriate water uptake and thus adjust the size of vascular cell types during organ growth and development. We identify a nexus of plant vascular tissue formation with cell internal pressure monitoring and reveal a novel functional aspect of long non-coding RNAs in developmental biology. The CARMA-CANAR module acts as a novel osmoregulatory system controlling cell size in the root stele in response to external osmolality. CANAR activity regulates the shoot-to-root phloem transport of sugars, which influences internal pressure via cellular water uptake and, thus, resultant cell size.