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Certain tree species of Aquilaria and Gyrinops of family Thymelaeaceae are capable of producing
a valuable resin called agarwood as a result of a self-defense mechanism to protect the internal
tissue damage caused by pathogenic microorganisms entering via wounds occurred due to natural
or artificial causes. The aromatic properties of agarwood oil are extraordinary high and therefore it
is extensively used for incense, perfume and for traditional medicine in different parts of the
world. Among the microorganisms which are capable of causing agarwood formation inducement,
fungal species are believed to be the most influential agents. The ability of agarwood production
in Gyrinops walla, believed to be endemic to Sri Lanka was recently identified. Due to the legal
constraints of exporting agarwood and other products extracted from G. walla, Aquilaria crassna
was introduced to the country as a high income plantation crop by private sector companies.
However, studies were not conducted to identify the associated fungi in these species when grown
under the climatic and geological conditions of Sri Lanka, which could be potential inocula for
producing agarwood in artificial manner. Therefore the present study attempted to identify the
associated fungal species in various parts of G. walla and A. crassna grown in the wet zone in Sri
Lanka. For this reason, leaves, un-infected normal stem tissues and agarwood formed stem tissues
were extracted from G. walla and A. crassna trees growing in Neboda and Ingiriya region
respectively by non-destructive sampling. Those tissues were surface sterilised and separately
grown in Potato Dextrose Agar at room temperature for 7 days in the laboratory. The
morphological and genetic characteristics were then used for the identification of different fungal
species. Trichoderma harzianum, Botryosphaeria laricina, Aspergillus terreus, A. sojae, A. niger,
Fusarium sp, one unidentified Botryosphaeria sp and Sarcinomyces sp were identified in the
agarwood resinous tissues extracted from G. walla. B. laricina, A. terreus, one unidentified
Botryosphaeria sp and F. equiseti were identified from non-resinous stem tissue samples while T.
harzianum, Colletotrichum gloeosporioide sand A. terreus were identified from the leaves of G.
walla. B. laricina and one unidentified Aspergillus sp were identified from resinous tissue samples
of A. crassna while B. laricina and Diaparthe amygdale were identified from non-resinous tissues
and leaf samples respectively. The tests are currently underway to identify the most influential
fungal species among the above to form agarwood in artificial manner.
