“Fusarium oxysporum Induction Enhancement” as part of Agarwood R&D protocol series (FOIFA vs. chemical vs. combined approach)
Purpose:
To support both host tree metabolism and Fusarium oxysporum fungal colonization during agarwood inoculation, enhancing resin biosynthesis and sustained host vitality.
1. Mechanistic Basis
A. Role of Magnesium Chloride (MgCl₂):
- Supplies magnesium (Mg²⁺) — a central ion in chlorophyll and enzyme activation.
- Supports host photosynthesis, carbohydrate translocation, and cell wall stability.
- Enhances osmotic balance in infected tissues, reducing cellular stress after inoculation.
- Facilitates phenolic compound synthesis, which are precursors to agarwood resin.
B. Role of Sugar (Sucrose or Glucose):
- Acts as an energy substrate for both the tree and the inoculated fungus.
- Promotes fungal sporulation and colonization at the infection site.
- Supports secondary metabolite synthesis (sesquiterpenes and chromones) by providing carbon skeletons.
- Serves as an osmoprotectant, mitigating oxidative stress post-inoculation.
2. Functional Synergy
When combined, MgCl₂ + sugar creates a biocompatible microenvironment at the inoculation site:
- The tree remains metabolically active (nutrient-supported recovery).
- The fungus receives carbon and minerals for colonization.
- Localized biochemical stress triggers resin formation, a defensive response.
3. Example Formulation (for R&D Testing)
For experimental use only — field calibration and pH adjustment required.
| Component | Concentration | Function |
|---|---|---|
| MgCl₂·6H₂O | 0.1–0.2 M (approx. 2–4 g per 100 mL) | Osmotic regulator, enzyme activator |
| Sucrose or Glucose | 2–5% (w/v) | Carbon source for host + fungus |
| Sterile Water | q.s. to 100 mL | Solvent |
| Optional Additive: Yeast extract (0.1%) | Enhances fungal nutrient uptake | |
| pH range: 5.5–6.5 | Optimum for Fusarium oxysporum and host compatibility |
4. Application Notes
- Inject or infuse 5–10 mL per inoculation point, depending on trunk diameter.
- Use sterile technique to avoid contaminant fungi.
- Reapply every 3–4 months in R&D trials to sustain resin induction.
- Monitor color change, resin odor, and fungal mycelium activity at the wound site.
5. Scientific Rationale
The Mg²⁺ ions activate key defense enzymes (PAL, PPO), while sugar provides the metabolic fuel.
Together, they accelerate secondary metabolite accumulation, leading to denser and more aromatic agarwood resin.