Low-copy nuclear markers in Isoëtes (Isoëtaceae) identified with transcriptomes

Abstract

Premise of the Study: Few genetic markers provide phylogenetic information in closely related species of Isoëtes (Isoëtaceae). We describe the development of primers for several putative low-copy nuclear markers to resolve the phylogeny of Isoëtes, particularly in the southeastern United States. Methods and Results: We identified regions of interest in Isoëtes transcriptomes based on low-copy genes in other plants. Primers were designed for these regions and tested with 16 taxa of Isoëtes and one species of Lycopodium. Parts of the pgiC, gapC, and IBR3 gene regions show phylogenetic signal within the North American and Mediterranean clades of Isoëtes. Conclusions: Transcriptome data prove useful for identification and primer design of low-copy genes. Three new markers show potential for inferring phylogenies in regional clades of Isoëtes, and possibly across the entire genus.