Dynamic analysis of gene expression and determination of chemicals in agarwood in Aquilaria sinensis

Agarwood is the resinous heartwood of Aquilaria species. However, low yields and high costs of existing stimulation methods have led to the need for new techniques to produce agarwood rapidly and effectively. We developed a biological agarwood-inducing technique (Agar-Bit) that produces high yields and quality within 6 months. To better understand agarwood formation by Agar-Bit, dynamic gene expressions of key synthetases pathways of sesquiterpenes and chalcone- related enzymes at different times were determined after both Agar-Bit and the traditional burning chisel drilling (BCD) stimulation on Aquilaria sinensis trees. The qRT-PCR results show that some characteristic synthase genes were expressed at greatly different levels and times compared with the controls. For the Agar-Bit technology, main changes were after the 3rd or 5th month, while BCD expression clearly changed at the 5th month. Essential oils and total chromone contents were simultaneously determined. In the Agar-Bit group, both were higher and similar to natural levels. The Agar-Bit methodology is a new option for producing agarwood as demonstrated by genetic and chemical aspects. The differences in gene expression within 6 months for both groups indicates that the mechanisms of the two methods are different. These findings provide information on genetic variation during the process of agarwood formation.