| Study (year) | System/organism | What was done (application) | Key quantitative results | Relevance to pqqB/PQQ pathway | URL/DOI | Citation ID |
|---|---|---|---|---|---|---|
| Chen et al. (2024) | 76 soil phosphate-solubilizing bacterial isolates; highlighted strain *Burkholderia cepacia* 51-Y1415 | Genome-guided screening of PSB using pqq gene clusters as markers for agricultural phosphate-solubilizer discovery | 76 genomes analyzed; 73 strains experimentally assessed; P release examples included 96.32 ± 27.05 µg mL⁻¹ and 92.03 µg mL⁻¹ for strong solubilizers; medium pH for strong strains ~4.2–5.2; qPCR presence threshold Ct < 30 (pqac-00000021, pqac-00000023) | Positions the pqq cluster as an actionable screening target for PSB; supports applied importance of core pathway genes including pqqB, though pqqC was emphasized as the strongest marker (pqac-00000021, pqac-00000023) | https://doi.org/10.1186/s13568-024-01745-w | (pqac-00000021, pqac-00000023) |
| Chen et al. (2024) | *Burkholderia cepacia* 51-Y1415 | Time-course linkage of pqqABCDE expression to phosphate release and organic-acid output for candidate biofertilizer selection | 144-h cultivation; P release vs gene abundance correlations: pqqA 0.946*, pqqB 0.902*, pqqC 0.940*, pqqD 0.897*, pqqE 0.872; P release vs 2-keto-D-gluconic acid 0.903*; pqqA–E vs 2-keto-D-gluconic acid 0.988**–0.995** (pqac-00000022, pqac-00000025) | Directly ties pqqB abundance to functional output in an application setting; supports using pqq genes as practical predictors of PQQ-dependent GDH-driven phosphate solubilization (pqac-00000022, pqac-00000025) | https://doi.org/10.1186/s13568-024-01745-w | (pqac-00000022, pqac-00000025) |
| Anzuay et al. (2024) | Gram-negative plant-associated phosphate-solubilizing bacteria; mixed cultures and peanut rhizosphere samples | Developed pqqE-based molecular traceability approach for monitoring beneficial PSB in environmental samples | pqqE amplification detected in all Gram-negative PSB analyzed; tested across pure cultures, mixed cultures, inoculated and uninoculated rhizosphere DNA preparations (pqac-00000026) | Relevant because pqqA–E are typically organized together; pqqB is part of the same core biosynthetic module whose presence underpins PQQ-dependent phosphate solubilization (pqac-00000007, pqac-00000020, pqac-00000026) | https://doi.org/10.1007/s00294-024-01296-4 | (pqac-00000007, pqac-00000020, pqac-00000026) |
| Pan & Cai (2023) | Review of phosphate-solubilizing bacteria in agriculture | Synthesized physiological and molecular mechanisms by which PSB mobilize soil phosphorus for crop use | Global soil total phosphorus cited as 400–1000 mg/kg, but only 1.00–2.50% plant-available (from review synthesis) (paper metadata) | Frames the applied importance of PQQ biosynthesis genes, including pqqB, because PQQ-dependent GDH/gluconic acid production is a major acidolysis mechanism in PSB (paper metadata; supported in 2024 mechanistic summaries) | https://doi.org/10.3390/microorganisms11122904 | (pqac-00000006, pqac-00000008) |
| Pang et al. (2024) | Review of phosphate-solubilizing microorganisms in soil-plant systems | Summarized current implementations of PSMs for improving plant phosphorus uptake and sustainability | Review emphasizes PSM-mediated activation of insoluble P via organic acids and highlights PQQ synthesis genes as major molecular drivers; no single pqqB-specific metric reported in retrieved excerpt (pqac-00000006) | Supports real-world relevance of the PQQ pathway for agricultural bioinoculants; pqqB belongs to the six-core-gene biosynthetic framework discussed for PQQ production (pqac-00000006) | https://doi.org/10.3389/fmicb.2024.1383813 | (pqac-00000006) |
| Gorniak et al. (2024) | *Pseudomonas alloputida* KT2440 | Transcriptome-level study of lanthanide effects on PQQ-dependent alcohol dehydrogenase physiology | Light lanthanides (La, Ce, Nd) improved growth, whereas heavy lanthanides imposed fitness costs; transcriptome-wide effects examined in strain KT2440 during growth on 2-phenylethanol (paper metadata) | Demonstrates a modern biotechnology context in which endogenous PQQ supply is operationally important because PedE/PedH are PQQ-dependent enzymes; thus pqqB remains relevant as an upstream biosynthetic gene even though it was not the direct focus (paper metadata) | https://doi.org/10.1128/msphere.00685-24 | (pqac-00000019) |
| Pause et al. (2024) | *Pseudomonas putida* KT2440 in a bioelectrochemical system | Tested glucose uptake routes under anaerobic electro-fermentation to improve oxidative bioprocessing | About half of secreted acetate originated from inoculation biomass and half from substrate; deletion of individual sugar uptake routes did not significantly alter secreted acetate concentrations among strains (paper metadata) | Relevant because PQQ-dependent periplasmic oxidation is part of KT2440 carbon processing architecture; performance of such systems depends indirectly on intact PQQ biosynthesis, to which pqqB contributes (paper metadata) | https://doi.org/10.1111/1751-7915.14375 | (pqac-00000019) |
| Liang et al. (2024) | *Hyphomicrobium denitrificans* H4-45 mutant AE-9 | Strain improvement for industrial PQQ production using UV-LiCl mutagenesis, ALE, and fermentation optimization | Nearly 400 generations of mutagenesis/ALE; mutant PQQ titer increased 80.4%; cell density increased 14.9%; final PQQ reached 307 mg/L with productivity 4.26 mg/L/h in a 3.7-L bioreactor (paper metadata) | Although not pqqB-specific, this is a direct real-world implementation of the PQQ biosynthetic pathway as a production platform, underscoring the industrial value of understanding genes such as pqqB (paper metadata) | https://doi.org/10.1007/s00253-024-13053-1 | (pqac-00000006, pqac-00000008) |


*Table: This table summarizes recent application-oriented studies and reviews relevant to PQQ biosynthesis genes, including quantitative results where available. It highlights how pqq genes, including pqqB, are being used as markers or enabling components in phosphate-solubilization, environmental tracing, and biotechnology contexts.*