Phytogeography and Diversity of Prairie cordgrass (Spartina pectinata Link) in U.S. based on Chloroplast DNA Sequences

Prairie cordgrass (Spartina pectinata Link) is a native warm-season (C4) perennial grass whose high tolerant ability to abiotic stresses makes it attractive as a biofuel feedstock on marginal land. Prairie cordgrass is a polyploid species comprised of three known cytotypes, tetra- (2n = 4x=40), hexa- (2n = 6x =60), and octoploids (2n = 8x =80), with basic number of x=10. In previous studies, a wide geographic distribution of cytotypes throughout U.S. was observed. In order to gain insight into differentiation of cytotypes, ten chloroplast DNA loci were sequenced from prairie cordgrass samples collected across USA. Comparative genomic analysis of chloroplast DNA is an informative tool for intraspecific phylogeographic studies. In this study, related haplotypes were geographically clustered. Based on the phylogeny tree, five haplotypes were formed. Two haplotypes were mostly distributed in octoploids in the West North Central regions. Other three haplotypes widely distributed in both tetra and octoploids in Central and East Northern regions of U.S.