Bikinin

Bikini is a strong activator of Brassinosteroid (BR) signaling [1] and an inhibitor of glycogen synthase kinase 3 proteins (GSK3) [2].
BRs are a group of polyhydroxylated steroid hormones implicated in multiple developmental processes, including stem elongation, leaf expansion, vascular development, seed germination, and resistance to biotic and abiotic stresses. Genetic defects in biosynthesis or perception of BRs resulted in dwarfism, dark-green and curled leaves, reduced seed germination and fertility, and de-etiolation in the dark. [1]
Bikinin is the first nonsteroidal molecule to modulate the BR signaling cascade downstream of the BRI1 receptor. Bikinin directly targeted BIN2 and activated BR-dependent gene expression. Application of bikini partially restored the phenotype of the bri1 loss-of-function mutant and the bin2 gain-of-function mutant to wild-type. Bikinin clearly rescued the dwarfism of the hypocotyls and the petioles of the bin2 gain-of-function mutant. Bikinin are fully rescuing the BR-related phenotypes of this mutation while having no effect on the auxin-related phenotypes. [1]
Bikinin treatment also induced tracheary element differentiation in Nicotiana benthamiana leaf disks, this leaf-disk culture system may be applicable to different plant species. [2]
References:
[1]. De Rybel B, Audenaert D, Vert G et al. Chemical inhibition of a subset of Arabidopsis thaliana GSK3-like kinases activates brassinosteroid signaling. Chem Biol. 2009 Jun 26;16(6):594-604.
[2]. Kondo Y, Fujita T, Sugiyama M, Fukuda H. A Novel System for Xylem Cell Differentiation in Arabidopsis thaliana. Mol Plant. 2014 Dec 13. pii: S1674-2052(14)00026-4.