Cytospora rhizophorae is a fungal species belonging to the genus Cytospora, which is known to include many plant pathogenic fungi. Here’s a detailed overview:
Taxonomy
- Kingdom: Fungi
- Phylum: Ascomycota
- Class: Sordariomycetes
- Order: Diaporthales
- Family: Valsaceae
- Genus: Cytospora
- Species: Cytospora rhizophorae
Host and Habitat
- Primarily associated with mangrove species, especially Rhizophora spp. (hence the name rhizophorae).
- Found in tropical coastal areas, where it colonizes stems, branches, and roots of mangrove trees.
1. Natural role in agarwood formation
- Agarwood resin (the fragrant, dark heartwood) is primarily produced in response to stress or injury, which can be mechanical (wounds) or biological (pathogen/fungal infection).
- Cytospora rhizophorae can infect the xylem and cambium of Aquilaria trees, causing localized cell death and tissue stress.
- The tree responds to this infection by producing secondary metabolites, mainly sesquiterpenes and chromones, which accumulate as resin around the infected site.
- Therefore, in agarwood, C. rhizophorae acts as a biological trigger for resin production, though uncontrolled infection can also harm tree health.
2. Mechanism of resin induction
- Fungal invasion – The fungus enters through wounds or weak spots in the tree.
- Host response – Aquilaria recognizes the infection and activates its defense pathways, producing resin as a protective barrier.
- Resin accumulation – Over months to years, the infected xylem accumulates dark, aromatic resin—the part harvested as agarwood.
- Resin composition – Research shows that fungal infection, including Cytospora spp., can influence the specific sesquiterpene profile, affecting fragrance quality.
3. Practical relevance
- In agarwood cultivation, fungi like Cytospora rhizophorae are sometimes used in artificial inoculation techniquesto stimulate resin formation in a controlled manner.
- Controlled inoculation ensures:
- Faster resin production than natural formation.
- Higher-quality resin if the infection is localized and managed.
- However, over-aggressive infection can lead to tree mortality, so selection of fungal strains and inoculation technique is critical.
4. Summary
- Cytospora rhizophorae is not the resin itself, but a biological agent that triggers agarwood formation.
- It plays a resin induction role by stressing the tree, activating defense mechanisms, and stimulating aromatic compound accumulation in the wood.
- Its use is relevant in sustainable and artificial agarwood production systems, as part of fungal inoculation protocols.