Picking up on plant invasions

Posted on March 23, 2016


Environmental DNA (eDNA) is genetic material that can be obtained directly from environmental samples without any need to sample the source organisms. New technologies allow the presence of particular aquatic species to be inferred simply from eDNA extracted from water samples taken at a given site. This promises to be a very handy method of detecting rare species in need of conservation or alien species in the early stages of invasion. Mitochondrial genes have proved to be useful for identifying animal species through DNA barcoding, but the identification of suitable barcoding markers in plants has been much more challenging. However, a recent Canadian paper is the first to describe a successful eDNA-based method for surveying aquatic plants. The authors examined the DNA of ten invasive plant species and ten potentially sympatric aquatic plant species from various taxonomic groups. DNA was extracted from frozen leaf samples that were ground with liquid nitrogen, and three chloroplast DNA regions (matK, rbcL, trnH–psbA) were targeted. There were enough sequence differences in one of the DNA regions (mat K) to allow the researchers to develop primers for nine of the invasive species, namely water soldier (Stratiotes aloides), parrotfeather (Myriophyllum aquaticum), water hyacinth (Eichhornia crassipes), fanwort (Cabomba caroliniana), Brazilian waterweed (Egeria densa), European frogbit (Hydrocharis morsus-ranae), giant salvinia (Salvinia molesta), yellow floating heart (Nymphoides peltata) and water lettuce (Pistia stratiotes). The primers for all species except fanwort and frogbit were specific to the target species and successfully amplified the eDNA of the same species obtained from water samples. Once research has been carried out to develop methods suitable for field use, eDNA monitoring should become a valuable early warning tool for the detection of invasive plant species.

References:

Scriver, M. et al. 2015. Development of species-specific environmental DNA (eDNA) markers for invasive aquatic plants. Aquatic Botany 122, 27–31.
http://www.sciencedirect.com/science/article/pii/S0304377015000066
Various authors. 2015. Special issue: environmental DNA: a powerful new tool for biological conservation. Biological Conservation 183, 1-102. http://www.sciencedirect.com/science/journal/00063207/183

Various authors. 2015. Special issue: environmental DNA: a powerful new tool for biological conservation. Biological Conservation 183, 1-102. http://www.sciencedirect.com/science/journal/00063207/183

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