| Functional aspect | Key points | Best supporting sources with year/venue and URL where available |
|---|---|---|
| Catalytic reaction | Arabidopsis thaliana RBOHD (UniProt Q9FIJ0; At5g47910) is a canonical plant NADPH oxidase/RBOH that transfers electrons from cytosolic NADPH to molecular oxygen, producing apoplastic superoxide (O2•−), which then dismutates to H2O2 for signaling and defense. RBOHD is identified as the major generator of pathogen-triggered ROS in Arabidopsis. (pqac-00000000, pqac-00000004, pqac-00000006) | Hasan 2019, review-like source/thesis (URL not available in snippet); Zhang et al. 2023, *Int J Mol Sci* https://doi.org/10.3390/ijms24043858; Torres 2024, *New Phytologist* https://doi.org/10.1111/nph.19502 |
| Electron transfer cofactors/domains | Defining RBOHD/RBOH architecture includes an extended cytosolic N-terminus with two EF-hand Ca2+-binding motifs and phosphorylation sites; a catalytic C-terminal core with FAD- and NADPH-binding domains; six transmembrane helices; and two heme groups coordinated by conserved His residues for electron transfer across the plasma membrane. These features align with the UniProt annotation and distinguish RBOHD from non-RBOH oxidoreductases such as FROs. (pqac-00000000, pqac-00000001, pqac-00000003, pqac-00000004, pqac-00000005) | Hu et al. 2020, *Cells* https://doi.org/10.3390/cells9020437; Zhang et al. 2023, *Int J Mol Sci* https://doi.org/10.3390/ijms24043858; Hasan 2019, review-like source/thesis (URL not available in snippet) |
| Activation inputs: Ca2+ and phosphoregulation | RBOHD is activated by direct Ca2+ binding to EF-hands and by phosphorylation. Residue-level sites supported in the available evidence: DORN1→S22/T24; BIK1→S39/S343/S347; RIPK→S343/S347; MAP4Ks→S347; CPK16→S133/S148/S163/S347; ALR1→S39; LKS4→S39 on AtRBOHC/D/F. Conserved phosphosites highlighted include S133, S163, S343, S347, and T912, with S39 moderately conserved and S148 weakly conserved. These modifications are linked to enzyme activation and ROS production. (pqac-00000012, pqac-00000013, pqac-00000015, pqac-00000016) | Krainiukova 2025, regulation review (journal not specified in snippet; URL not available); Torres 2024, *New Phytologist* https://doi.org/10.1111/nph.19502 |
| PRR-linked activation and signaling complexes | In PTI, PRR-BAK1 signaling activates BIK1, which phosphorylates RBOHD to trigger rapid ROS production. QSK1 is a PRR-RBOHD complex-associated LRR receptor kinase that downregulates FLS2 and EFR abundance and dampens PRR-triggered immunity. HopF2Pto exploits QSK1 to suppress this module. RBOHD therefore functions in a receptor-proximal signaling hub coupling PRRs to ROS and Ca2+ signaling. (pqac-00000010, pqac-00000006) | Goto et al. 2024, *Plant Cell* https://doi.org/10.1093/plcell/koae267; Torres 2024, *New Phytologist* https://doi.org/10.1111/nph.19502 |
| Negative regulation and turnover | RBOHD is tightly downregulated to prevent excessive ROS. PB1CP is a 2024-defined negative regulator that binds RBOHD, competes with BIK1 for RBOHD association, enhances dissociation of phosphorylated BIK1 from RBOHD after PAMP treatment, and relocalizes with RBOHD to small endomembrane compartments, consistent with promotion of endocytosis. Overexpression of PB1CP lowers RBOHD protein abundance. Expert commentary further states that PBL13 phosphorylates the RBOHD C-terminus, promoting PIRE-mediated ubiquitination and vacuolar degradation; deactivation also involves C-terminal nitrosylation. (pqac-00000008, pqac-00000009, pqac-00000014, pqac-00000017) | Goto et al. 2024, *New Phytologist* https://doi.org/10.1111/nph.19302; Torres 2024, *New Phytologist* https://doi.org/10.1111/nph.19502 |
| Post-transcriptional / translational control | Beyond post-translational regulation, RBOHD abundance is controlled post-transcriptionally. George et al. identified CBE1, an eIF4E1-binding protein associated with the 5′ mRNA cap/translation initiation machinery, as a negative regulator of RBOHD accumulation. Loss or knockdown of CBE1 and related decapping/translation-initiation regulators increases RBOHD protein levels, enhances elicitor-induced apoplastic ROS, and increases antibacterial immunity, supporting translational control of RBOHD output. (pqac-00000011) | George et al. 2023, *J Biol Chem* https://doi.org/10.1016/j.jbc.2023.105018 |
| Cellular localization | RBOHD is a plasma membrane-localized NADPH oxidase that produces ROS into the apoplast. Its activity and spatial control are tied to membrane microdomains and receptor complexes at the cell periphery. Upon PAMP treatment, PB1CP and RBOHD relocalize from the cell periphery to small endomembrane compartments, consistent with regulated endocytosis/turnover. (pqac-00000000, pqac-00000005, pqac-00000008) | Hasan 2019, review-like source/thesis (URL not available in snippet); Goto et al. 2024, *New Phytologist* https://doi.org/10.1111/nph.19302 |
| Key biological processes | Supported roles include pathogen-triggered immunity/PTI, fungal resistance, ROS-Ca2+ signal coupling, abiotic stress responses, wound/damage signaling, lignification, and ABA-/JA-related stomatal closure in broader RBOHD-focused regulation reviews/commentaries. In the supplied evidence, RBOHD is especially central to rapid PAMP-induced ROS production and downstream immune signaling. (pqac-00000002, pqac-00000006, pqac-00000008, pqac-00000010) | Torres 2024, *New Phytologist* https://doi.org/10.1111/nph.19502; Goto et al. 2024, *New Phytologist* https://doi.org/10.1111/nph.19302; Goto et al. 2024, *Plant Cell* https://doi.org/10.1093/plcell/koae267 |
| 2023–2024 advances | Notable recent advances in the supplied evidence are: (i) CBE1-mediated translational repression of RBOHD accumulation (2023); (ii) PB1CP as a negative regulator that removes phosphorylated BIK1 and promotes RBOHD endocytosis (2024); (iii) QSK1 as a PRR-RBOHD complex-associated regulator exploited by HopF2Pto (2024); and (iv) expert synthesis highlighting transient ROS burst control via PBL13/PIRE-mediated degradation, PB1CP action, and kinase layering (BIK1/RIPK/CRK2/SIK1). Direct quantitative fold-changes are not given in the available snippets, but the cited figures reportedly show enhanced ROS in pb1cp mutants, reduced ROS in PB1CP overexpressors, and reduced RBOHD protein abundance upon PB1CP overexpression. (pqac-00000008, pqac-00000010, pqac-00000011, pqac-00000014, pqac-00000018) | George et al. 2023, *J Biol Chem* https://doi.org/10.1016/j.jbc.2023.105018; Goto et al. 2024, *New Phytologist* https://doi.org/10.1111/nph.19302; Goto et al. 2024, *Plant Cell* https://doi.org/10.1093/plcell/koae267; Torres 2024, *New Phytologist* https://doi.org/10.1111/nph.19502 |


*Table: This table condenses the most relevant supported findings for Arabidopsis thaliana RBOHD, including catalytic function, domain architecture, residue-level regulation, localization, pathway context, and key 2023-2024 advances. It is useful as a citation-linked functional annotation snapshot restricted to claims supported by the provided evidence snippets.*