Note: In many species, isoforms exist for each step, some targeted to distinct organelles (e.g., a mitochondrial MDH isoform for the “reverse” (formate → methanol) direction).
| Scenario | Observed effect | |----------|-----------------| | | Net CH₄ uptake of ≈ 0.04 nmol g⁻¹ h⁻¹ (measured by laser‑based CRDS). | | mmO1 knockout | CH₄ uptake drops > 90 %; leaf methanol levels rise 3‑fold. | | Over‑expression of MDH1 | ↑Methanol oxidation, lower leaf methanol, modest increase in serine pool (≈ 15 %). | | Drought stress (soil water potential = ‑1.5 MPa) | Up‑regulation of FDH1 (2.3‑fold); higher formate dehydrogenase activity correlates with improved recovery after re‑watering. | | Cyanobacterial symbionts | Transfer of methane‑oxidizing genes to the host plant via horizontal gene transfer (observed in Azolla ‑ Nostoc symbiosis). | pcsa00068