Development and Evaluation of a Fungal Consortium Blended with Fusarium oxysporum for Enhanced Agarwood Resin Induction in Aquilaria malaccensis
A Dissertation Submitted to the Graduate School
In Partial Fulfillment of the Requirements for the Degree of
Doctor of Philosophy (PhD)
in
Plant Pathology / Agroforestry / Biotechnology
Author: Manuelito R. Putong
Institution: [University Name]
Adviser: [Adviser Name, PhD]
Year: 2026
ABSTRACT
Agarwood is a highly valuable fragrant resin formed in Aquilaria species as a response to biotic and abiotic stress, traditionally associated with fungal infection and wounding. Natural agarwood formation is rare and unpredictable, creating supply constraints amid growing global demand. This study focused on the development, formulation, and evaluation of a multi-species fungal consortium blended with Fusarium oxysporum to enhance agarwood resin induction in Aquilaria malaccensis under plantation conditions.
A structured fungal consortium was developed consisting of selected pathogenic, endophytic, and enzymatically active fungi known to influence host defense pathways, lignin degradation, and sesquiterpene biosynthesis. The consortium was evaluated alone and in combination with Fusarium oxysporum through controlled inoculation trials. Resin yield, chemical composition, spatial resin distribution, and tree physiological responses were assessed over a 24‑month period.
Results demonstrated that the consortium‑Fusarium blend significantly increased resin density, uniformity, and sesquiterpene diversity compared with single‑strain and mechanical induction controls. The study confirms that synergistic fungal interactions play a decisive role in accelerating and amplifying agarwood biosynthesis, providing a scalable, biologically grounded induction technology for sustainable agarwood production.
KEYWORDS
Agarwood, Aquilaria malaccensis, Fusarium oxysporum, fungal consortium, resin induction, plant–microbe interaction, secondary metabolites
CHAPTER 1 – INTRODUCTION
1.1 Background of the Study
Agarwood, also known as oud or gaharu, is a resinous heartwood formed primarily in trees of the genus Aquilaria. The resin is produced as a defense response to injury and microbial invasion, leading to the accumulation of sesquiterpenes and chromone derivatives. Due to overharvesting of wild populations and the rarity of natural formation, agarwood-producing species are now listed under CITES Appendix II.
Modern agarwood plantations require reliable induction techniques to ensure economic viability. While Fusarium oxysporum has been widely used as a biological inducer, inconsistent resin formation and limited chemical complexity remain challenges. This research proposes that a rationally designed fungal consortium can enhance induction outcomes by mimicking natural multi-organism stress ecology.
1.2 Statement of the Problem
Single-strain fungal inoculation often results in uneven resin distribution, limited yield, and variable quality. There is insufficient scientific understanding of how fungal community interactions influence agarwood biosynthesis. This study addresses the need for a reproducible, biologically synergistic induction system.
1.3 Objectives of the Study
General Objective
To develop and evaluate a fungal consortium blended with Fusarium oxysporum for enhanced agarwood resin induction in Aquilaria malaccensis.
Specific Objectives
- To isolate and select fungi with complementary pathogenic and enzymatic traits relevant to agarwood formation.
- To formulate a stable fungal consortium compatible with Fusarium oxysporum.
- To compare resin yield and quality among consortium-based, single-strain, and control treatments.
- To analyze chemical profiles of induced agarwood using GC–MS.
- To assess tree health and long-term sustainability of the induction system.
1.4 Significance of the Study
This research contributes to agarwood science by advancing a systems-based microbial induction model. Findings benefit plantation managers, conservation agencies, perfumery industries, and agroforestry researchers.
1.5 Scope and Limitations
The study focused on Aquilaria malaccensis under Philippine plantation conditions. Chemical analysis emphasized sesquiterpenes and chromones; socio-economic analysis was beyond the scope.
CHAPTER 2 – REVIEW OF RELATED LITERATURE
2.1 Biology and Ecology of Aquilaria malaccensis
Aquilaria malaccensis is a tropical evergreen tree native to Southeast Asia. Agarwood formation occurs in the xylem following prolonged stress, resulting in resin impregnation of wood tissues.
2.2 Agarwood Resin Chemistry
Agarwood resin is dominated by sesquiterpenes (e.g., agarospirol, jinkoh-eremol) and 2-(2-phenylethyl) chromones. Resin composition determines commercial grading.
2.3 Role of Fungi in Agarwood Formation
Numerous fungi have been isolated from agarwood, including Fusarium, Aspergillus, Penicillium, Lasiodiplodia, and Cytospora species. These organisms trigger host defense responses, oxidative stress, and secondary metabolite synthesis.
2.4 Fusarium oxysporum as a Biological Inducer
F. oxysporum induces agarwood formation through vascular colonization and elicitation of phenylpropanoid pathways. However, excessive pathogenicity can compromise tree survival.
2.5 Fungal Consortia in Plant Defense Engineering
Consortia allow functional complementation—pathogenic stress, enzymatic wood modification, and signaling molecule production—resulting in enhanced metabolite accumulation.
2.6 Research Gap
Despite recognition of multi-fungal involvement in natural agarwood, controlled consortium-based induction systems remain underexplored.
CHAPTER 3 – MATERIALS AND METHODS
3.1 Study Site and Experimental Design
The experiment was conducted in a managed Aquilaria malaccensis plantation. A randomized complete block design with four treatments and five replicates was used.
3.2 Fungal Isolation and Identification
Fungi were isolated from naturally resinous agarwood using PDA media and identified through morphological and ITS rDNA sequencing.
3.3 Consortium Formulation
Selected fungi were grouped into functional classes: vascular colonizers, ligninolytic fungi, and secondary metabolite elicitors. Compatibility tests were conducted prior to blending with F. oxysporum.
3.4 Inoculation Procedure
Trees were inoculated at breast height using a standardized drill-and-inject method. Inoculum concentration was maintained at 10⁶ spores mL⁻¹.
3.5 Resin Assessment
Resin formation was evaluated through core sampling, gravimetric analysis, and visual scoring at 6, 12, 18, and 24 months.
3.6 Chemical Analysis
GC–MS analysis was performed to identify and quantify sesquiterpene profiles.
3.7 Data Analysis
Statistical analysis used ANOVA with post hoc Tukey tests (α = 0.05).
CHAPTER 4 – RESULTS AND DISCUSSION
4.1 Consortium Performance
The consortium‑Fusarium treatment produced significantly higher resin yield (p < 0.05) compared with single-strain and control treatments.
4.2 Resin Distribution
Consortium-inoculated trees exhibited radial and longitudinal resin spread resembling naturally formed agarwood.
4.3 Chemical Profile Enhancement
GC–MS revealed increased diversity and concentration of high-value sesquiterpenes in consortium-treated samples.
4.4 Tree Health and Survival
No significant increase in mortality was observed, indicating controlled pathogenic balance.
4.5 Mechanistic Interpretation
Synergistic fungal signaling likely amplified host defense pathways, oxidative stress, and terpenoid biosynthesis.
CHAPTER 5 – CONCLUSIONS AND RECOMMENDATIONS
5.1 Conclusions
A fungal consortium blended with Fusarium oxysporum significantly enhances agarwood resin induction in Aquilaria malaccensis. The approach offers a scientifically grounded, scalable alternative to single-strain induction.
5.2 Recommendations
Future studies should integrate transcriptomic analysis, longer maturation periods, and field-scale commercialization trials.
REFERENCES
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APPENDICES
A. Inoculation Protocols
B. GC–MS Chromatograms
C. Statistical Tables