ITS Sequence Analysis of Invasive Plant Praxelis clematidea
Praxelis clematidea,native to South American,is a hugely invasive plant. In this paper,the nuclear ribosomal DNA internal transcribed spacer( ITS) variation of P.clematidea was examined. Twelve haplotypes were detected by analyzing 54 samples( 12 populations) in total from Hainan,Guangdong,and Fujian provinces,and that the same haplotype was found in all populations. An analysis of molecular variation(AMOVA) showed a low level of genectic variation and differentiation among populations,However,without a significant phylogeographical structure(NSTGST,p0.01). These data suggested that there may be frequent gene exchanges within P.clematidea populations for the high average gene among populations(Nm=1.18) and many invasive events. It is also implied that the prevention of P.clematidea invasion should be relied upon both timely quarantine and proper administration to reduce its damage to environment.