外來入侵植物貓腥草(Praxelis clematidea)之分子鑑定

Abstract

Praxelis (Praxelis clematidea (Griseb.) R. M. King & H. Rob) is an annual Compositae plant and native to South America, became an invasive plant in Taiwan in recent decades. As the morphological characteristics is similar, Praxelis has been easily misidentified with Ageratum (Ageratum houstonianum Mill.) and Goat weed (A. conyzoides L.) before blossom. DNA-based molecular markers have been used to detect the genetic diversity of invaded alien species. Novel methods for the identification of the invasive plant Praxelis, Ageratum and Goat weed at the early stage of plant development have established in this study, based on direct sequencing of the internal transcribes spacer (ITS) region of 18S-26S ribosomal DNA (rDNA), PCR-restriction fragment length polymorphism (RFLP), allelic-specific PCR and inter-simple sequence repeat (ISSR) markers. The 5.8S rRNA-ITS regions of Praxelis, Ageratum and Goat weed were 644, 646 and 646 bp, respectively. The PCR product on the 5.8S rRNA-ITS of Praxelis, Ageratum and Goat weed were digested with the restriction endonuclease Fok I、Not I、Sml I and Stu I. Each fragment gave unique electrophoretic profiles. Among one hundred ISSR UBC primers, only #822, 844, 857 and 868 primers can significantly distinguish Praxelis, Ageratum and Goat weed by 2-8 different polymorphic markers. The specific primers of AS-PCR were designed from the 5.8S rRNA-ITS nucleotide polymorphism to differentiate Praxelis, Ageratum and Goat weed, via multiplex PCR to produce unique 353 bp, 485 bp and 485 bp single bands, respectively. AS-PCR and ISSR markers may assist the effective management in invasion plant Praxelis and maintain the balance of biodiversity in agricultural ecosystems.