Fungal inoculation induces agarwood in young Aquilaria malaccensis trees in the nursery

Abstract

Fungi are often used to induce agarwood in Aquilaria trees. This study was conducted to evaluate the effect of several fungi on agarwood formation over time in young Aquilaria malaccensis (Lam.) trees. Typical changes in the length and light intensity of the resulting discoloration were observed after three and six month periods following inoculation. Wood samples were observed microscopically and classified into several light intensity groups. The discoloration length was measured longitudinally. The duration after inoculation affected the mean of discoloration length: the 6-month old sample (1.70 cm) had a wider discoloration zone when compared to the 3-month old sample (1.17 cm). When measuring the discoloration intensity, a positive relationship with time was perceived. Digital images, captured using a camera-equipped microscope, revealed that wood samples collected after six months appeared to be 1.8-times darker than after three months. We concluded that time, not the species of any of the tested fungi, had significant effect on discoloration length and intensity. Gas chromatography/mass spectrometry (GCMS) analysis of the 6-month old sample yielded some important agarwood compounds such as benzylacetone, anisylacetone, guaiene and palustrol. This demonstrates that the tested fungi have the ability to induce agarwood formation in nursery A. malaccensis trees.

Keywords

Artificial inoculation / discoloration zone / fungi / guaiene / palustrol

References

[1] Barden A, Anak NA, Mulliken T, Song M. Heart of the matter: Agarwood use and trade and CITES implementation for Aquilaria malaccencis, 2000

[2] Bhuiyan MNI, Begum J, Bhuiyan MNH. Analysis of essential oil of eaglewood tree (Aquilaria agallocha Roxb.) by gas chromatography mass spectrometry. Bangladesh Journal Pharmacology, 2009, 4: 24-28.

[3] Chang YS, Nor Azah MA, Abdul Rashid AM. Inducement of gaharu and potentials of gaharu oils. Tapping the wealth from karas (Aquilaria malaccensis) tree. Malayan Forest Records, 2011, 50: 48-62.

[4] Chen HQ, Yang Y, Jian X, Wei JH, Zhang Z, Chen HJ. Comparison of compositions and antimicrobial activities of essential oils from chemically stimulated agarwood, wild agarwood and healthy Aquilaria sinensis (Lour.) Gilg trees. Molecules, 2011, 16: 4884-4896.

[5] CITES. Appendix II of Convention on International Trade in Endangered Species of Wild Fauna and Flora, 2010

[6] Jong PL. Effects of mechanical wounding and infection patterns of Fusarium solani on gaharu formation in Aquilaria malaccensis Lam, 2012

[7] Kakino M, Tazawa S, Maruyama H, Tsuruma K, Araki Y, Shimazawa M, Hara H. Laxative effects of agarwood on low-fiber diet-induced constipation in rats. BMC Complementary Alternative Medicine, 2010, 10: 68-75.

[8] Lin F, Mei WL, Wu J, Dai HF. GC-MS analysis of volatile constituents from Chinese eaglewood produced by artificial methods. Journal Chinese Medicinal Materials, 2010, 33: 222-225.

[9] Naef R. The volatile and semi-volatile constituents of agarwood, the infected heartwood of Aquilaria species. Flavour Fragrance Journal, 2011, 26: 73-87.

[10] Ng LT, Chang YS, Kadir AA. A review on agar (gaharu) producing Aquilaria species. Journal of Tropical Forest Products, 1997, 2: 272-285.

[11] Nobuchi T, Siripatanadilok SA. Nobuchi T, Mohd Hamami S. The formation of wood in tropical forest trees. Cytological observations of Aquilaria crassna wood associated with the formation of aloeswood. 2008, Malaysia: UPM Press, 147 160

[12] Okudera Y, Ito M. Production of agarwood fragrant constituents in Aquilaria calli and cell suspension cultures. Plant Biotechnology, 2009, 26: 307-315.

[13] Pojanagaroon S, Kaewrak C. Jatisatienr A, Paratasilpin T, Elliott S, Anusarnsunthorn V, Wedge D, Craker LE, Gardner ZE. Mechanical methods to stimulate aloes wood formation in Aquilaria crassna Pierre Ex H. LEC. (Kristsana) trees. III WOCMAP Congress on medicinal and aromatic plants — Volume 2: Conservation, cultivation and sustainable use of medicinal and aromatic plants. 2005, Chiang Mai, Thailand: ISHS Acta Horticulturae 676, 161 166

[14] Tamuli P, Boruah P, Nath SC, Leclercq P. Essential oil of eaglewood tree: a product of pathogenesis. Journal Essential Oil Research, 2005, 17: 601-604.

[15] Wong MT, Siah CH, Faridah QZ, Mohamed R. Characterization of wound-responsive genes in Aquilaria malaccensis. Journal Plant Biochemistry Biotechnology, 2012

[16] Zhang Z, Yang Y, Meng H, Sui CH, Wei JH, Chen HQ. Advances in studies on mechanism of agarwood formation in Aquilaria sinensis and its hypothesis of agarwood formation induced by defense response. Chinese Traditional Herbal Drugs, 2010, 41: 156-160.

[17] Zhang XL, Liu YY, Wei JH, Yun Y, Zhang Z, Huang JQ, Chen HQ, Liu YJ. Production of high quality agarwood in Aquilaria sinensis trees via whole-tree agarwood induction technology. Chinese Chemical Letters, 2012, 23: 727-730.