Aquatic invasive species displace and outcompete native species, alter ecosystem function, interfere with recreational activity, and negatively impact the economy. Climate change and globalization will facilitate increases in the distribution and abundance of aquatic invasive species through warmer waters, milder winters, and increased shipping to new, suitable habitats. Hydrilla verticillata is one of the most prevalent and invasive aquatic plants across the United States. Prevention and early detection are essential for controlling the spread of Hydrilla, but its rapid growth and reproduction from fragments, tubers, turions, and seeds pose a serious challenge in identifying its presence early on. Therefore, rapid and reliable detection is critical in identifying Hydrilla to inform management strategies and policies to protect native aquatic ecosystems. We present a novel approach to detect the presence of Hydrilla using loop-mediated isothermal amplification (LAMP) of environmental DNA (eDNA) in aquatic ecosystems. LAMP colorimetric assays change color based on DNA concentration and have the potential to provide on-site, rapid, and reliable detection of Hydrilla and other aquatic invasive species.
Results/Conclusions
Serial dilutions of artificial and genomic Hydrilla DNA can be adequately quantified using Taqman-based quantitative Polymerase Chain Reaction (qPCR). While single-stranded artificial Hydrilla DNA cannot be amplified using LAMP, the serial dilution of genomic DNA employed in qPCR resulted in visible concentration-depended color changes from red to yellow along a series of LAMP reactions. As determined through Principal Component Analysis (PCA), absorption spectra of these color changes where most variable between wavelengths of 520-750 nm, and the Principal Components of spectra obtained from the employed DNA concentrations could be used in regression analysis much like in qPCR. Consequently, our approach will soon likely have the ability to accurately detect and possibly inform on the concentration of Hydrilla DNA in natural water bodies. Improvement of this novel technique will be a gateway for substantially cheaper, rapid, reliable, on-site detection of invasive species in susceptible aquatic ecosystems.