Auxin Response Factors Mediate Arabidopsis Organ Asymmetry via Modulation of KANADI Activity

摘要: Members of the KANADI gene family in Arabidopsis thaliana regulate abaxial identity and laminar growth lateral organs. Promoter APETALA3-mediated ectopic expression restricts petal expansion was used a genetic screen for factors involved KANADI-mediated signaling. Through this screen, mutations ETTIN (ETT; also known as Auxin Response Factor3 [ARF3]) were isolated second site suppressors found to ameliorate activity throughout plant well. Mutant phenotypes ett are restricted flowers; however, double mutants with closely related ARF4 exhibit transformation tissues into adaxial ones all aerial parts, resembling KANADI. Accordingly, common RNA domain both ARFs be on side Truncated, negatively acting products strong alleles map an ARF-specific, N-terminal ETT. Such strongly enhance tissue loss only when ARF activities compromised. As is not required either ETT or transcription, their overexpression cannot rescue kanadi mutants, cooperative implied. proteins pivotal mediating auxin responses; thus, we present model linking transient local gradients gradual partitioning organs along abaxial/adaxial axis.