Rapid detection assay for the invasive vase tunicate, Ciona intestinalis, using loop-mediated isothermal amplification combined with lateral flow dipstick

Invasive tunicate species threaten the shellfish aquaculture industry not only in Prince Edward Island (PEI) but also nationally and worldwide. Rapid screening tools for water samples are crucial for the efficient management of aquatic invasive species. This project aims to develop a rapid detection assay capable of identifying larvae of the vase tunicate, Ciona intestinalis, in seawater. In this study, a loopmediated isothermal amplification (LAMP) method has been developed to detect the 18S ribosomal DNA extracted from C. intestinalis. This assay was performed in three steps: 1) a DNA extraction step using a direct lysis buffer, 2) an amplification step using a heating block, and 3) a detection step using a lateral flow dipstick. The sensitivity of the assay was estimated at one larva spiked in 100 L of seawater and the turnaround time of the assay was assessed at 80 min including the lysis step. Given the advantages of this assay such as rapid amplification, ease of use and detection, it could be implemented for monitoring bays and estuaries. In the future, rapid diagnostic assays will constitute a new generation of diagnostic platforms enabling the early detection of non-indigenous invasive species.