PubMed · 2026-04-30
Brassinosteroids, a class of plant hormones, suppress root regeneration from cuttings by blocking auxin transport to wound sites. Reducing brassinosteroid activity accelerates root formation, and the finding holds across rapeseed, tobacco, and tomato.
Reduced brassinosteroid signaling promotes root regeneration from cuttings, while elevated signaling suppresses it, identifying brassinosteroids as a previously unreported negative regulator of this process.
Brassinosteroids activate a transcription factor (BZR1) that directly represses two auxin transporter genes (PIN1 and PIN3), cutting off auxin supply to wound sites and blocking root primordia formation.
The mechanism is conserved across three distinct plant families: rapeseed (Brassica napus), tobacco (Nicotiana benthamiana), and tomato (Solanum lycopersicum).
