Auxin promotes hypocotyl elongation by enhancing BZR1 nuclear accumulation in <i>Arabidopsis</i>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36598987.
- Also identified by DOI 10.1126/sciadv.ade2493 and PMC identifier 9812374.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Auxin and brassinosteroids (BRs) are two major growth-promoting phytohormones that shape hypocotyl elongation; however, the cross-talk between auxin and BR in this process is not fully understood. In this study, we found that auxin-induced hypocotyl elongation is dependent on brassinazole-resistant 1 (BZR1), a core BR signaling component. Auxin promotes BZR1 nuclear accumulation in hypocotyl cells, a process dependent on mitogen-activated protein kinase 3 (MPK3) and MPK6, which are both activated by auxin and whose encoding genes are highly expressed in hypocotyls. We determined that MPK3/MPK6 phosphorylate and reduce the protein stability of general regulatory factor 4 (GRF4), a member of the 14-3-3 family of proteins that retain BZR1 in the cytoplasm. In summary, this study reveals the molecular mechanism by which auxin promotes hypocotyl elongation by enhancing BZR1 nuclear accumulation via MPK3/MPK6-regulated GRF4 protein stability.