Jack of all trades: crosstalk between FERONIA signaling and hormone pathways

Abstract

The receptor kinase FERONIA (FER) is a multifaceted regulator of plant growth, development, reproduction, and stress responses. FER is functionally connected to many plant hormones in diverse biological processes. This review summarizes the current understanding of the interplay between FER and phytohormones, with a focus on abscisic acid, ethylene, jasmonic acid, auxin, and brassinosteroid. The mutual regulation between FER and plant hormones happens at multiple levels including ligands, receptors, and downstream signaling components. Plant hormones can regulate the expression of genes encoding FER and its ligands RAPID ALKALINIZATION FACTORs (RALFs) as well as the abundance and kinase activity of FER proteins. On the other hand, FER can regulate hormone biosynthesis, transport, perception, and downstream signaling components such as transcription factors. Evidence of the crosstalk between FER and phytohormones is also emerging in crop species. Despite the rapid progress made in this field, more mechanistic studies are still needed to gain a comprehensive understanding of the FER-phytohormone crosstalk. Future research prospects and potential approaches are also discussed in this review.

Keywords: Abscisic acid; FERONIA receptor kinase; auxin; brassinosteroid; ethylene; jasmonic acid; peptide ligand; plant growth and stress responses; plant hormones.

Fig. 1.

The crosstalk between FER and ABA and JA pathways. (A) The crosstalk between FER and ABA. In the presence of ABA, ABA-bound PYR/PYL/RCARs form a complex with ABI2 and suppress its phosphatase activity, leading to the activation of SnRK2s and downstream responses including transcriptional responses mediated by transcription factor ABI5. FER can activate ABI2 through the FER–GEF1/4/10–ROP11 module to inhibit ABA signaling. ABI2 can dephosphorylate FER as a negative feedback mechanism. In addition, FER can directly phosphorylate and destabilize ABI5 to inhibit ABA signaling. RALF1–FER binding triggers phosphorylation of GRP7, which promotes GRP7-mediated alternative splicing of ABA-related mRNAs, leading to negative regulation of ABA signaling. FER phosphorylates CARK1 and activates CARK1-mediated phosphorylation of ABA receptors PYR/PYL/RCARs to promote their monomerization, which enhances ABA binding and signaling. (B) The crosstalk between FER and JA. FER phosphorylates and destabilizes MYC2, a master transcription factor that promotes JA signaling. RALF23 inhibits FER function to stabilize MYC2. Parasitic nematodes can secrete RALF mimics to activate FER-mediated MYC2 degradation, which promotes parasitism. Created in BioRender. Tang, J. (2025) https://BioRender.com/w89v501.

Fig. 2.

The crosstalk between FER and auxin and BR pathways. (A) The crosstalk between FER and auxin. FER activates ROP2 through GEFs to promote NADPH oxidase-mediated ROS production and possibly NO production. ROS and NO are critical for oxidation of auxin receptors TIR1 and AFB2, which is important for their translocation from cytoplasm to nucleus. TIR1 and AFB2 are F-box proteins that form a complex with Cul1, Rbx2, and SKP1 to ubiquitinate and destabilize transcriptional repressors Aux/IAAs, leading to the activation of auxin-responsive genes. RALF1 treatment increases the expression of the auxin biosynthesis genes YUCs in a FER-dependent manner. RALF1–FER binding triggers phosphorylation of AHA2 and inhibits its activity. AHA2 is also phosphorylated and activated by TMKs, a family of receptor-like kinases that sense extracellular auxin together with ABP1/ABLs. In addition, FER is needed for proper cellular trafficking of the auxin transporter PIN2. (B) The crosstalk between FER and BR. In the presence of BR, BR perception by receptor BRI1 and co-receptor BAK1 leads to inhibition of BIN2 and activation of master transcription factors BES1/BZR1. In tomato, BZR1 binds to the promoters of FER genes and promotes FER expression, leading to enhanced FER function. In Arabidopsis, RALF23 expression is reduced by BL treatment or in a gain-of-function bes1-D mutant. BES1-binding sites are identified in the promoter of the RALF23 gene but whether BES1 directly regulate RALF23 expression is not known. Created in BioRender. Tang, J. (2025) https://BioRender.com/u17o471.