An international team of researchers, including the Institute of Molecular and Cellular Plant Biology (IBMCP, a joint centre of the Universitat Politècnica de València and the Spanish National Research Council), has discovered a new molecular mechanism that regulates the formation of vascular tissues in plants. The study reveals that a small molecule, thermospermine, can act as a biological switch to control the production of proteins key to xylem development. This tissue transports water and provides structural support to plants.
The research, published in the journal Science, shows that this regulation is only possible when ribosomes—the cellular structures responsible for protein synthesis—undergo a specific chemical modification in their RNA, catalysed by the OVAC enzyme. This finding offers a new perspective on how plants control their development at a molecular level.
"Although this is primarily basic research, understanding how vascular tissue formation is regulated could have long-term implications for agriculture and plant biotechnology. The mechanisms described could in the future contribute to strategies for adjusting xylem development and, consequently, influence key crop traits such as root or storage organ formation, water transport efficiency, or biomass and wood production," explains Miguel Ángel Blázquez, a researcher at the IBMCP and co-author of the study.
The work of the IBMCP team in this international research has enabled them to experimentally demonstrate that thermospermine activity depends on the chemical modification of the ribosome. To do this, they used a system for analysing translational efficiency in Arabidopsis protoplasts, a model plant widely used in research.
"Our experiments confirmed that thermospermine can only regulate the production of two key factors in vascular development—SACL and LHW—when the ribosomes have been previously methylated by the enzyme OVAC. The balance between these two proteins is fundamental, as it determines the fate of vascular cells: whether they differentiate into water-conducting vessels or storage cells," adds IBMCP researcher and co-author of the study, Alejandro Ferrando.
A new concept in plant molecular biology
The study introduces a new concept in plant molecular biology: the ribosome does not act solely as a "protein synthesis machine"; it can also function as a sensor that integrates metabolic signals and regulates the translation of specific genes.
This finding opens up new avenues for understanding how plants control key cellular development decisions at the translational level and how modifications to the ribosome can lead to functional specialisation.
The study was conducted by an international consortium led by the University of Cambridge and the University of Helsinki, with the participation of research centres in Europe, Asia, and the United States, including the IBMCP at the UPV and the CSIC.