Programmed cell death might involve in progress of wounding induced agarwood formation in stems of Aquilaria sinensis.

Abstract

Agarwood, a non-timber fragrant wood, is derived from wounded Aquilaria trees (Thymelaeaceae) and is widely used in traditional medicine, incense and perfume. Agarwood-like substances and programmed cell death (PCD) can be induced by wounding signals in the suspension cells and aerial roots of Aquilaria sinensis. In this study, the dynamic process of wound-induced agarwood formation in stems of A. sinensis was observed, and the occurrence of PCD was synchronously detected using techniques such as 4',6-diamidino-2-phenylindole and dUTP nick-end labeling staining. The results showed that the wounding was a induce signal for agarwood resin formation, meanwhile might induce PCD. Interxylary phloem and xylem ray were the main sites of agarwood resin formation and PCD occurrence. There might be a relationship between the spatiotemporal pattern of PCD and agarwood resin formation: more severe PCD corresponded to a higher rate of resin formation but a shorter resin formation time; conversely, slower PCD progression corresponded to a lower rate of resin formation but a longer resin formation time. Our findings are the first to demonstrate that PCD might occur in the process of wound-induced agarwood formation at the tree level, and the spatiotemporal pattern is closely related to the formation of agarwood resin. This study provides valuable insight for further studies on the relationship between PCD and agarwood formation. HIGHLIGHTS: Programmed cell death (PCD) might occur in the process of wound-induced agarwood formation at the tree level. Interxylary phloem and xylem ray were the main sites of agarwood resin formation and PCD occurrence. Spatiotemporal pattern of PCD might have a strong impact on agarwood resin formation.