Report of two distinct ribotypes in ITS sequences of Phalaris arundinacea (Poaceae) in western Canada and Alaska

Abstract

Phalaris arundinacea L. (reed canary grass) is a widely occurring grass throughout the Northern Hemisphere. In North America, it is thought to consist of introduced agricultural forms from Europe as well as native populations. During a survey of Phalaris arundinacea in western Canada, we discovered two distinct ribotypes in the sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal DNA: one full length (ITS-long) and one with a seven base pair deletion (ITS-short). In addition, ITS-long plants have fixed heterozygosity indicating possible polyploidy. Phylogenetic analysis reveals that ITS-short is a unique ribotype that characterises an intraspecific clade. We designed an efficient PCR-based assay that allows sizing of a 238/245 base pair fragment in a capillary sequencer. This approach provides a novel marker that could be useful in future surveys of Phalaris arundinacea.