Abstract
Myriophyllum heterophyllum is an aquatic macrophyte that is invasive to the northeastern United States and several western European countries. Spreading by vegetative clonal propagation, especially fragmentation, extensive resources are devoted to limit its growth and spread; however, genetic assessments are not typically included in management strategies. Reduction in genetic (clonal) diversity should accompany biomass reduction, yet without genetic assessment the efficacy of plant removal remains unclear. This paper is the first to describe a microsatellite marker library and its use in characterization of the genetic diversity of Myriophyllum heterophyllum.
Eighty-seven tissue samples were collected across the invasive distribution of Myriophyllum heterophyllum in Maine, USA. DNA was extracted and PCR amplification was employed to screen 13 of the microsatellites published in Wu et al. 2013. Sequencing of the amplified loci was performed to characterize repeat motifs and confirm primer binding sites. Fragment sizing of PCR amplicons was employed to determine microsatellite lengths across the 87 samples.
Eight of the 13 tested markers amplified with seven of those eight found to be variable. Polyploidy was evident from allelic diversity within individuals, although precise ploidy could not be determined. Expected heterozygosity ranged from 0.12 to 0.89 across variable markers.
This seven-marker library was effective in characterizing the genetic diversity of both newly discovered (<5 years) and older (>50 years) infestations and is expected to be suitable for assessment of genetic diversity in populations within the native range of M. heterophyllum. The marker library also shows promise for use in several other Myriophyllum species.