| Functional aspect | Key findings | Evidence type | Key sources with dates/URLs/DOIs |
|---|---|---|---|
| Identity / class | FEA2 in maize is the ortholog of Arabidopsis **CLAVATA2 (CLV2)** and is described as a **leucine-rich repeat receptor-like protein (LRR-RLP)** involved in CLAVATA/CLE meristem signaling. This matches the UniProt Q940E8 annotation for a CLAVATA2-like precursor protein in *Zea mays*. (pqac-00000000, pqac-00000027) | Primary genetics/mechanistic paper; review | Je et al., 2018, *eLife*, published Mar 2018, https://doi.org/10.7554/eLife.35673; Demesa-Arevalo et al., 2024, *Annual Review of Plant Biology*, first published Feb 29 2024, https://doi.org/10.1146/annurev-arplant-070523-035342 |
| Core molecular function | FEA2 functions as a **shared/co-receptor-like signaling component** in the maize CLV-WUS pathway, restricting stem-cell proliferation in shoot and inflorescence meristems. The evidence supports a signaling role rather than an enzymatic one; FEA2 helps transmit extracellular CLE-peptide information to intracellular downstream effectors that ultimately influence **ZmWUS** output. (pqac-00000000, pqac-00000002, pqac-00000024) | Genetic, biochemical, model synthesis, review | Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673; Fletcher, 2018, *Plants*, Oct 19 2018, https://doi.org/10.3390/plants7040087 |
| Ligands / peptide inputs | The strongest direct evidence shows FEA2 mediates responses to at least two CLE-family peptides: **ZmCLE7** (maize CLV3 ortholog) and **ZmFCP1** (ZmFON2-LIKE CLE PROTEIN1). fea2 mutants are resistant to both peptide treatments, supporting the conclusion that FEA2 is required for signaling from both inputs. (pqac-00000000, pqac-00000005, pqac-00000008) | Peptide-response assays, genetics | Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673 |
| Direct ligand binding vs co-receptor role | The study emphasizes that **CLV2/FEA2 does not itself directly bind CLV3/CLE peptides**, consistent with a co-receptor role. The proposed model is that FEA2 works with ligand-binding RLKs in different receptor complexes to relay distinct peptide signals. (pqac-00000027, pqac-00000028) | Mechanistic interpretation from primary paper | Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673 |
| Receptor complexes / interaction partners | FEA2 associates with **ZmCRN** and **CT2** in separate complexes. Co-immunoprecipitation showed ZmCRN pulls down FEA2, CT2 pulls down FEA2, and FEA2 can immunoprecipitate either partner; ZmCRN and CT2 do **not** appear to form one common three-way complex, implying distinct receptor assemblies. (pqac-00000003, pqac-00000004, pqac-00000025, pqac-00000026) | Biochemical interaction assays (Co-IP), BiFC, genetics | Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673 |
| Downstream effectors / branch specificity | FEA2 routes different CLE signals through different downstream components: **CT2** (heterotrimeric Gα, COMPACT PLANT2) primarily for **ZmCLE7**, and **ZmCRN** (CORYNE ortholog, pseudokinase) primarily for **ZmFCP1**. Additive phenotypes in **Zmcrn;ct2** double mutants and differential peptide resistance support two parallel downstream branches under a common FEA2 node. (pqac-00000002, pqac-00000004, pqac-00000005, pqac-00000024) | Genetics, peptide assays, biochemical interaction, model | Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673; Wu et al., 2018, *PLOS Genetics*, Apr 30 2018, https://doi.org/10.1371/journal.pgen.1007374 |
| Localization | Experimental evidence places the FEA2 signaling module at the **plasma membrane**. ZmCRN-mCherry was confirmed at the plasma membrane, co-localizing with FEA2/CT2-associated signaling; the authors further infer that FEA2 is on the plasma membrane even without ZmCRN because FEA2 still functions with CT2 in a **crn** background. (pqac-00000002, pqac-00000025, pqac-00000028, pqac-00000029) | Imaging, membrane-associated biochemical assays, inference from genetics | Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673 |
| Domain / structure inference | In the retrieved evidence, FEA2 is consistently described as an **LRR receptor-like protein** rather than a kinase, fitting a model of extracellular ligand perception with limited intracellular signaling capacity. The primary paper provides more explicit structural detail for partner **ZmCRN** (a transmembrane **pseudokinase**) than for FEA2, reinforcing the idea that FEA2 likely signals through associated proteins rather than intrinsic kinase activity. (pqac-00000027, pqac-00000029) | Annotation plus mechanistic inference | Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673 |
| Pathway position | FEA2 acts in the conserved **CLAVATA-WUSCHEL feedback system** that balances stem-cell maintenance and organ initiation. Recent reviews place maize FEA2 alongside TD1/CLV1, FEA3, ZmCLE7, and cytokinin-responsive control of **ZmWUS1**, showing FEA2 is part of a broader meristem signaling network rather than an isolated receptor. (pqac-00000011, pqac-00000012, pqac-00000017) | Review synthesis anchored in primary studies | Demesa-Arevalo et al., 2024, *Annual Review of Plant Biology*, Feb 29 2024, https://doi.org/10.1146/annurev-arplant-070523-035342; Chaudhry et al., 2024, *Plant Reproduction*, Oct 2024, https://doi.org/10.1007/s00497-024-00510-0 |
| Developmental roles / mutant phenotypes | Loss of FEA2 causes **enlarged shoot apical and ear inflorescence meristems** and **fasciated ears**, consistent with excess stem-cell proliferation. Reviews and primary studies also connect FEA2/CLV signaling to inflorescence architecture traits such as spikelet organization and kernel row number. (pqac-00000003, pqac-00000005, pqac-00000022) | Mutant phenotyping, review | Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673; Wu et al., 2018, *PLOS Genetics*, Apr 30 2018, https://doi.org/10.1371/journal.pgen.1007374 |
| Quantitative data | In the FEA2 signaling network, **Zmcrn** mutants had larger vegetative SAMs than normal siblings (**130.0 ± 4.1 µm vs 109.2 ± 4.6 µm; P < 0.0001**), and additional comparisons showed larger SAMs in **Zmcrn** and **fea2** single mutants (**166.3 ± 8.3 µm** and **176.1 ± 9.8 µm**) versus normal (**139.7 ± 4.8 µm**); the **Zmcrn;ct2** double mutant reached **191.8 ± 18.6 µm**. These data support FEA2-linked control of meristem size and parallel downstream pathways. (pqac-00000008, pqac-00000010) | Quantitative genetics / morphometrics | Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673 |
| Natural variation / agronomic trait association | Independent work cited in the retrieved evidence identifies **FEA2 as a locus controlling quantitative variation in maize kernel row number (KRN)**, making it one of the clearest CLV-pathway examples with agronomic relevance in maize. Related signaling components such as **ZmCRN** also show KRN-associated polymorphisms in the retrieved evidence. (pqac-00000009, pqac-00000008) | QTL/association context, review citation of primary study | Bommert et al., 2013, *Nature Genetics*, Feb 2013, https://doi.org/10.1038/ng.2534; Je et al., 2018, *eLife*, Mar 2018, https://doi.org/10.7554/eLife.35673 |
| Applications / real-world implementation | Reviews and follow-up studies present FEA2 as a **crop-improvement target** for tuning meristem size and yield-related traits. Chen & Gallavotti (2021) specifically note promising **field-trial results with fea2 weak alleles**, while broader maize G-protein engineering studies show that modulating the linked CT2 branch can improve spikelet density, kernel row number, and leaf angle—supporting practical meristem engineering strategies built around the FEA2 network. (pqac-00000014, pqac-00000022, pqac-00000023) | Review, field-translation context, transgenic trait engineering | Chen & Gallavotti, 2021, *Molecular Breeding*, Feb 2021, https://doi.org/10.1007/s11032-021-01212-5; Wu et al., 2018, *PLOS Genetics*, Apr 30 2018, https://doi.org/10.1371/journal.pgen.1007374 |


*Table: This table summarizes the strongest evidence-supported functional annotation points for maize FEA2, including mechanism, partners, localization, phenotypes, and agronomic relevance. It is designed as a compact reference for building a full research report on UniProt Q940E8.*