Conservation Strategies for Aquilaria sinensis: Insights from DNA Barcoding and ISSR Markers

The evergreen tree species Aquilaria sinensis holds significant economic importance due to its specific medicinal values and increasing market demand. However, the unrestricted illegal exploitation of its wild population poses a threat to its survival. This study aims to contribute to the conservation efforts of A. sinensis by constructing a library database of DNA barcodes, including two chloroplast genes (psbA-trnH and matK) and two nuclear genes (ITS and ITS2). Additionally, the genetic diversity and structure were estimated using inter-simple sequence repeats (ISSR) markers. Four barcodes of 57 collections gained 194 sequences, and 1371 polymorphic bands (98.63%) were observed using DNA ISSR fingerprinting. The Nei's gene diversity (H) of A. sinensis at the species level is 0.2132, while the Shannon information index (I) is 0.3128. The analysis of molecular variance revealed a large significant proportion of total genetic variations and differentiation among populations (Gst = 0.4219), despite a relatively gene flow (Nm = 0.6853) among populations, which were divided into two groups by cluster analysis. There was a close genetic relationship among populations with distances of 0.0845 to 0.5555. This study provides evidence of the efficacy and dependability of establishing a DNA barcode database and using ISSR markers to assess the extent of genetic diversity A. sinensis. Preserving the genetic resources through the conservation of existing populations offers a valuable proposition. The effective utilization of these resources will be further deliberated in subsequent breeding endeavors, with the potential to breed agarwood commercial lines.