Identification of invasive grass species via DNA barcoding

Early intervention and mitigation of invasive grasses in Australia is often confounded by problems of species mis-identification. Field identifications can be erroneous through lack of taxonomic expertise or facilities to accurately distinguish invasive grasses from native varieties. Here we report the utility of DNA barcoding as a genetic method for assisting in the identification of high profile invasive grasses present in Eastern Australia. A total of 606 grass specimens, including four major invasive grass species [Nassella neesiana (Trin. & Rupr.) Barkworth (Chilean needle grass), Nassella trichotoma (Nees) Hack. ex Arechav. (serrated tussock), Eragrostis curvula (Schrad.) Nees (African love grass), and Hyparrhenia hirta (L.) Stapf (Coolatai grass)], and a variety of native species were sampled across a broad geographic area. Up to18 genetic markers (including 17 chloroplast markers and one nuclear marker) were screened for their efficiencies as potential DNA barcodes for identifications of weeds species. Preliminary results indicate that five genetic regions (ITS, matK, atpF, ndhK and petL) displayed some facility in separating particular species from others, but no single gene was suitable as a universal standalone DNA barcode region for accurate identification of all the surveyed species. Our future work will focus on these five genes to improve their PCR success rate across species, and to determine if multi-locus DNA barcodeprofiles can be used to distinguish all species in specific genera.