ddRAD Sequencing: A Novel Arsenal Added to the Biosecurity Toolbox to Trace the Origin of Brown Marmorated Stink Bug, Halyomorpha Halys (Hemiptera: Pentatomidae)

Abstract BackgroundBrown marmorated stink bug (BMSB), Halyomorpha halys (Hemiptera: Pentatomidae) is native to East Asia but has invaded many countries in the world. It is a polyphagous insect pest and causing significant economic losses to agriculture worldwide. Knowledge on the genetic diversity among BMSB populations is scarce but is essential to understand the patterns of colonization and invasion history of local populations. Efforts have been made to assess the genetic diversity of BMSB using partial mitochondrial DNA sequences but genetic divergence on mitochondria is not high enough to precisely identify and distinguish various BMSB populations. Therefore, in this study, we applied a ddRAD (double digest restriction-site associated DNA) sequencing approach to ascertain the genetic diversity of BMSB populations collected from 12 countries (2 native and 10 invaded) across four continents with the ultimate aim to trace the origin of BMSBs intercepted during border inspections and post-border surveillance.ResultA total of 1775 high confidence single nucleotide polymorphisms (SNPs) were identified from ddRAD sequencing data collected from 389 BMSB individuals. Principal component analysis (PCA) of the identified SNPs indicated the existence of two main distinct genetic clusters representing individuals sampled from regions where BMSB is native to, China and Japan, respectively, and one broad cluster comprised individuals sampled from countries which have been invaded by BMSB. The population genetic structure analysis further discriminated the genetic diversity among the BMSB populations at a higher resolution and distinguished them into five potential genetic clusters. ConclusionThe study revealed hidden genetic diversity among the studied BMSB populations across the continents. The BMSB populations from Japan were genetically distant from the other studied populations. Similarly, the BMSB populations from China were also separated from the Japanese and other populations. Further genetic structure analysis revealed the presence of at least three genetic clusters of BMSB in the invaded countries, possibly originating from multiple invasions. Furthermore, this study has produced novel set of SNP markers to enhance knowledge of genetic diversity among BMSB populations and demonstrate a great potential to trace the origin of BMSB individuals for future invasion events.