Original title: Sugar metabolism drives shoot branching by repressing BRC1 through miR319 -targeted TCP4 in Rosa
Léo Gouaille, Julie Mallet, Julie Legrix, Alexis Porcher +9 · September 2026
Plants need sugar to grow new branches, but scientists did not fully know how sugar triggers this growth. Researchers studied rose buds to map this process. They found that active sugar breakdown suppresses a tiny regulatory molecule called RhmiR319. When sugar levels drop and metabolism slows down, RhmiR319 builds up. This buildup turns off two target genes, RhTCP4a and RhTCP4b. Normally, these TCP4 proteins act as growth helpers. They directly attach to the control region of RhBRC1, a gene that stops buds from sprouting, and shut it down. By blocking this growth brake, active sugar processing allows buds to branch out. Tests in rose and Arabidopsis showed this same chain reaction controls branching, revealing how plants turn available energy into new shoots.
Imagine deciding how many branches to build on a treehouse based on how much snack mix you have. The problem is you cannot see the snack mix directly; you only get a note that says "snacks low" or "snacks high." If the note says "snacks high," you send out a builder who puts up many branches, but if the note says "low," a guard stops the builder. Here, the note is the microRNA miR319, which is sent only when sugar metabolism is low. When sugar is high, the note is not sent, so the builder (TCP4) is free to start branching.
Understanding how sugar controls branching could help farmers and horticulturists breed plants with desired shapes, like more flowers or better fruit yields. This knowledge may allow new strategies to manage plant growth without relying on chemicals.
The study only examines two species (rose and Arabidopsis) and focuses on one miRNA. Other miRNAs and pathways might also be involved. The exact conservation across all plants and environments needs further testing.
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Sugar metabolism drives shoot branching by repressing BRC1 through miR319 -targeted TCP4 in Rosa — Léo Gouaille, Julie Mallet, Julie Legrix et al. — bioRxiv — doi:10.64898/2026.09.09.750302
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.