Here’s a detailed breakdown of Phomopsis sp. in the context of agarwood (Aquilaria spp.), including taxonomy and functional role:
1. Taxonomy of Phomopsis sp.
| Rank | Classification |
|---|
| Kingdom | Fungi |
| Phylum | Ascomycota |
| Class | Sordariomycetes |
| Order | Diaporthales |
| Family | Diaporthaceae |
| Genus | Phomopsis |
| Species | Various; often unidentified to species in agarwood studies (e.g., Phomopsis sp. isolated from Aquilaria) |
- Phomopsis species are endophytic or pathogenic fungi commonly associated with woody plants.
- They are known for producing enzymes and secondary metabolites that interact with plant tissues, sometimes causing cankers or necrosis.
2. Role of Phomopsis sp. in agarwood formation
- Resin induction
- Agarwood formation is primarily a defense response to stress, wounding, or microbial infection.
- Phomopsis sp. acts as a biological stressor: it infects Aquilaria xylem and cambium, triggering the tree’s defense mechanisms.
- This leads to accumulation of secondary metabolites, including sesquiterpenes and chromones, which form the resinous agarwood.
- Endophytic behavior
- Some Phomopsis strains live endophytically in Aquilaria without causing visible disease.
- These endophytes may prime the tree’s defense, leading to low-level resin production over time.
- Artificial inoculation
- In commercial agarwood production, Phomopsis sp. is frequently used in fungal inoculation protocols.
- Advantages:
- Induces resin faster than natural infection.
- Can influence chemical composition, affecting aroma profile.
- Risks:
- Over-infection can lead to xylem decay or tree death, so strain selection and inoculation method are crucial.
3. Comparison with other fungi
| Fungal Genus | Role in Agarwood |
|---|
| Cytospora | Aggressive pathogen, strong resin induction, higher risk of tree damage |
| Fusarium | Often used in combination inoculants, moderate induction |
| Phomopsis | Mild to moderate pathogen/endophyte, can enhance resin quality, often safer for controlled inoculation |
4. Summary
- Taxonomy: Phomopsis sp. → Ascomycete fungus, endophyte or pathogen.
- Functional role: Triggers defense response in Aquilaria, leading to resin (agarwood) formation.
- Practical application: Widely used in artificial inoculation protocols to produce high-quality agarwood while minimizing tree mortality.