SECRETS OF THE SWAMP: UNCOVERING THE GENETIC DIVERSITY OF A FEDERALLY THREATENED PLANT, SWAMP PINK (HELONIAS BULLATA L.)

Helonias bullata L. (swamp pink) is a monotypic plant genus belonging to the Melanthiaceae family. Helonias is listed as federally threatened plant species and is a long-lived perennial evergreen herb that occurs in wetlands and bog subtypes in the eastern United States. While these habitats are already increasingly rare, development and urbanization has fractured and extirpated many Helonias occurrences, leading to a mosaic of small, isolated populations throughout its range. Due to the limited number of individuals within many of these populations, Helonias faces the perilous threat of genetic diversity loss which can lead to population instability and collapse. This research focused on developing an in-depth genetic diversity analysis of the extant Helonias populations in North Carolina, as well as identifying the occurrence of genetic drift within smaller populations. Currently, there is very limited genetic data available for Helonias; only two sites in North Carolina have previously been assessed. Leaf samples from 15 Element Occurrences across the state were collected and DNA extracted using an advanced CTAB approach. MIG-seq, a next-generation sequencing method, was used to construct reduced-representation libraries for Helonias. After sequencing, single nucleotide polymorphisms (SNPs) within the genome of each individual sampled were identified. In total, 279 individuals were genotyped using multiplexed inter-simple sequence repeat (ISSR) genotyping by sequencing. These data were used to calculate genetic diversity values for each population, observed through nucleotide diversity, heterozygosity, and F-statistics. Genetic analyses indicated that all sampled populations in North Carolina possessed low genetic diversity and elevated levels of inbreeding. However, all populations within North Carolina were also observed to have a level of gene flow and genetic connectivity regardless of geographic distance. The results of this research will help inform future management decisions such as augmentations, reintroductions, habitat conservation, and population delineation.<p></p>