Title : TMK-mediated transcriptional auxin signaling in regulating plant development
Abstract:
Auxin plays diverse and profound roles in plants, regulating essentially all aspects of plant growth and development, but how auxin achieves the functional diversity and specificity is largely unknown.Multiple auxin signaling integrated totriggerdistinctive auxin responses according to its concentration, which is essential for differential growth such as apical hook development. We showed that high auxin at concave side of apical hook stimulates the C-terminus cleavage and cytosolic translocation of Trans-Membrane Kinase (TMK), which phosphorylates noncanonical IAAs. Surprisingly, in contrast to previous report that auxin degraded AUX/IAA proteins through TIR1/ AFB receptor to regulate gene expression, here we found that non-canonical IAAsproteins were stabilized by high auxin through TMKcleavage to negatively regulate gene expression and inhibit growth. This finding demonstrated a TIR independent transcriptional auxin signalingthat regulate growth inhibition in response to high auxin.
