FERONIA mediates root nutating growth.

Root nutation indicates the behavior that roots grow in a waving and skewing way due to unequal growth rates on different sides. Although a few developmental and environmental factors have been reported, genetic pathways mediating this process are obscure. We report here that the Arabidopsis CrRLK1L family member FERONIA (FER) is critical for root nutation. Functional loss ofFERresulted in enhanced root waviness on tilted plates or roots forming anti-clockwise coils on horizontal plates. Suppressing polar auxin transport, either by pharmacological treatment or by introducing mutations atPIN-FORMED2(PIN2) orAUXIN RESISTANT1(AUX1), suppressed the asymmetric root growth (ARG) infer-4, a null mutant ofFER, indicating that FER suppression of ARG depends on polar auxin transport. We further showed by pharmacological treatments that dynamic microtubule organization and Ca(2+)signaling are both critical for FER-mediated ARG. Results presented here demonstrate a key role of FER in mediating root nutating growth, through PIN2- and AUX1-mediated auxin transport, through dynamic microtubule organization, and through Ca(2+)signaling.