Methyl jasmonate and crude extracts of Fusarium solani elicit agarwood compounds in shoot culture of Aquilaria malaccensis Lamk.

Ahmad Faizal,Rizkita Rachmi Esyanti,Nisaa Adn'Ain,Silmi Rahmani,Alda Wydia Prihartini Azar,Iriawati Iriawati,Maman Turjaman

doi:10.1016/j.heliyon.2021.e06725

Ahmad Faizal, Rizkita Rachmi Esyanti + Show 5 more

Open Access

https://doi.org/10.1016/j.heliyon.2021.e06725

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Abstract

Agarwood forms in the heartwood of trees in the family Thymelaeaceae in response to wounding, infection, or other stresses. Its formation is random and takes decades in natural populations, which are harvested for their aromatic compounds. This harvest has led to declining population, and many agarwood producing trees are considered endangered. Therefore, an alternative source would be desirable. We established an in vitro shoot culture method for one agarwood species, Aquillaria malaccensis. Agarwood production was elicited by introducing methyl jasmonate (MeJA) and crude extracts of Fusarium solani into the liquid culture medium. A high concentration of MeJA resulted in necrotic shoot tissue, while application of the crude extracts had no effect on growth of the shoots. Interestingly, gas chromatography-mass spectrometry (GC-MS) analysis of MeJA-treated shoots revealed the presence of several agarwood compounds, including sesquiterpenes and chromone derivative. In addition, GC-MS analysis of shoot-treated with the extracts revealed the presence of alkanes, aromatic compounds, and fatty acid derivatives. It may be that different elicitors induce the production of different compounds in A. malaccensis in vitro shoot cultures and could be used to manipulate the accumulation of different products in culture.

Highlights

Agarwood is a fragrant, resinous wood that forms in the heartwood of tress in the family Thymelaeaceae as a response to physical wounding, infection, or other stresses (Tan et al, 2019)
At the lowest concentration of methyl jasmonate (MeJA) (12.5 μM), there were no visible effect on shoots during the 3 weeks of treatment, but when MeJA concentration was 50–150 μM, we observed leaf senescence and shoot necrosis (Figure 1) and the shoots did not recover when the plants were transferred into fresh MS medium without MeJA
From analysis with gas chromatography-mass spectrometry (GC-MS), we detected several compounds associated with agarwood in the shoots, but these varied with respect to MeJA concentration and length of treatment (Figure 2)

Summary

Introduction

Resinous wood that forms in the heartwood of tress in the family Thymelaeaceae as a response to physical wounding, infection, or other stresses (Tan et al, 2019). The term applies to resin produced in the wood. The resin is only produced when the tissues of the tree are damaged. The physical damage caused by boring insects will be followed by microbial infection, including fungi. Fungi is believed to be the main microorganism which could induce plants defense mechanisms by entering through the wound. Agarwood compounds will be produced as a result of defense mechanism to the fungi as pathogens (Rasool and Mohamed, 2016)

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