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Gene expression analysis associated with agarwood formation in Aquilaria malaccensis

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Aquilaria malaccensis produces exorbitant aromatic wood known as agarwood. The fragrant wood is primarily utilized for its aroma as a retainer of perfume and medicinal values, making it a high-value product suitably called liquid gold. Only infected trees produce agarwood which are exploited for agarwood oil extraction resulting in indiscriminate cutting of trees and its inclusion in Appendix II of the CITES. The current research aims to understand the changes in gene expression during agarwood deposition in A. malaccensis under natural condition. Expression of 25 genes involved in terpenoids biosynthesis was assessed by semi-quantitative PCR followed by qRT-PCR using RNA obtained from infected and non-infected wood. Seven housekeeping genes were also screened of which, GAPDH served as the best potential internal reference gene. Our results showed that, nine of 25 primer pairs tested can differentiate gene expression of agarwood and healthy wood. The genes involved in sesquiterpenoid biosynthesis pathway were up regulated up to 41.59 fold in agarwood as compared to healthy wood which suggests the involvement of these genes in agarwood formation. Sesquiterpene biosynthesis genes were found to be express more in naturally infected Aquilaria plants as compared to artificially induced plants.

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We acknowledge Department of Biotechnology (DBT), Govt. of India, for the Research Grant (Grant no-BT/PR6346/GBD/27/405/2012).

Author information

MRI: Conducted field work and performed semi quantitative PCR, qRT-PCR, analysis and manuscript writing. SB: Designed and planned the work, refining of the manuscript and bringing the financial support. BSB: Provided guidance in qRT-PCR work and infrastructure support for the work.

Correspondence to Sofia Banu.

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Supplementary Fig. 1 PCR efficiency of the sesquiterpene biosynthesis genes (A-F) and defense response genes (G-I) (TIFF 206 kb)

Supplementary Fig. 2 Expression profile for seven housekeeping genes (A) TUA (B) ELF (C) 26sRNA (D) GAPDH (E) UBQ (F) 18sRNA (G) RIB among 24 A. malaccensis wood cDNA samples (TIFF 279 kb)

Supplementary Fig. 3 (A) Mechanical wounding of A. malaccensis plant using an electric drill machine (B) Deposition of agarwood resin around drilled area after 6 months of wounding (JPEG 98 kb)

Supplementary Fig. 4 Semi quantitative PCR analysis of sesquiterpene biosynthesis genes (A-F) and defense response genes (G-I) with labeled cDNA samples of infected (**), non-infected (*), artificially induced (***) and seedling (IS1) of A. malaccensis.Sample coding: Gn20, Gn21, Gn22 non-infected plants and G1, G2, G11 infected plants from Hoollongapar Gibbon Sanctuary; Nn20, Nn21, Nn22 non-infected plants and N1, N3, N4 from Naharani; BN1, BN2, BN3 non infected plants and BT1, BT2, BT3 infected plants from Batiporia and BF1, BF2, BF3 plants from Biotech Farm that were artificially induced and IS1, IS2, IS3 plantlets under 3 years of age (TIFF 5668 kb)

Supplementary material 5 (DOC 49 kb)

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Islam, M.R., Bhau, B.S. & Banu, S. Gene expression analysis associated with agarwood formation in Aquilaria malaccensis. Plant Physiol. Rep. (2020). https://doi.org/10.1007/s40502-020-00505-9

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  • Aquilaria malaccensis
  • Agarwood
  • Sesquiterpenes
  • Semi-quantitative
  • Real-time