Agarwood induction in cell suspension culture of Aquilaria malaccensis Lam.
Most species of Aquilaria in the Thymelaeaceae family produce agarwood or ‘gaharu’. In Malaysia, the primary producer of agarwood is Aquilaria malaccensis, a tree species locally known as ‘karas’. Agarwood is one of the precious woods on earth and prized for its rich and wonderful fragrance. This st...
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| Format: | Thesis |
| Language: | English |
| Published: |
2013
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/39628/1/FH%202013%209%20IR.pdf |
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| Summary: | Most species of Aquilaria in the Thymelaeaceae family produce agarwood or ‘gaharu’. In Malaysia, the primary producer of agarwood is Aquilaria malaccensis, a tree species locally known as ‘karas’. Agarwood is one of the precious woods on earth and prized for its rich and wonderful fragrance. This study aimed at inducing agarwood production in cell suspension culture of Aquilaria malaccensis, by investigating the optimal growth medium, optimal inocula size and finding suitable elicitors. To establish cell suspension culture, callus was first induced from nursery-derived leaf explants incubated on basic Murashige and Skoog (MS) solid medium containing 1.5% sucrose, at pH 5.7. Different auxin types including 1-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), and indole-3-butyric acid (IBA), were tested at various concentrations (0.55, 1.1 and 1.65 μM). Compact type callus was induced by 1.1 μM NAA with highest biomass dry weight (DW) of 17.3 mg. This auxin concentration was then combined with either 6-benzylaminopurine (BAP) or kinetin, at 0.55, 1.1, 2.2 and 3.3 μM, to induce growth of friable callus. The 1.1μM NAA + 2.2μM BAP combination produced friable callus with the highest biomass (93.3mg DW). Microscopic observations revealed the arrangement of the friable callus as loosely packed with relatively large cells. However, for the compact callus, the cells were small and densely packed. Further investigation on effects of elicitor in agarwood production were studied using cell suspension culture with initial an inocula of 4% (fresh weight, FW) of callus. The culture was challenged with fungal elicitor prepared from two species of fungi, Trichoderma and Lasiodiplodia. Fungal elicitor in the form of mycelial crude extract was added to the medium to a final
concentration of 2, 4, 6, 8, and 10 mg/L, respectively. A light scent of agarwood was detected from the culture after it had been challenged for 20 days with 8mg/L Trichoderma extract. To increase scent intensity, cell suspension cultures were initiated from 4%, 8%, 16% and 32% (FW) of calli and elicited with 8 and 16 mg/L Trichoderma extract, respectively. The combination of 16% of inocula and 8 mg/L Trichoderma extract produced the most intense fragrance comparable to agarwood scent. Several important agarwood compounds were detected using GC-MS including 8-epi-.gama.-eudesmol, á-guaiene, alloaromadendrene oxide-1 and chromone,5-hydroxy-6,7,8-trimethoxy-2,3-dimethyl. Trichoderma appeared to be a suitable elicitor for agarwood production. In conclusion, the presence of these compounds was evidence that agarwood had been induced in the fungal inoculated cell suspension culture. |
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