Data from: Genetic diversity and conservation status of Helianthus verticillatus, an endangered sunflower of the Southern United States

Evaluating species diversity and patterns of population genetic variation
is an essential aspect of conservation biology to determine appropriate
management strategies and preserve the biodiversity of native plants.
Habitat fragmentation and potential habitat loss are often an outcome of a
reduction in naturally occurring wildfires and controlled prescribed
burning, as seen in Helianthus verticillatus (whorled
sunflower). This endangered, wild relative of the common
sunflower, Helianthus annuus, is endemic to four locations in
Alabama, Georgia, and Tennessee, United States. Despite its endangered
status, there is no recovery plan for H. verticillatus, and
knowledge related to its basic plant biology and importance in ecosystem
services is mostly unknown. In this study, we utilized 14 microsatellite
loci to investigate fine-scale population structure and genetic diversity
of H. verticillatus individuals found on two sampling
sites within the Georgia population. Our results indicated moderate
genetic diversity and the presence of two distinct genetic clusters.
Analyses of molecular variance indicated that the majority of variance was
individually based, thus confirming high genetic differentiation and
limited gene flow between H. verticillatus collection
sites. The evidence of a population bottleneck in these sites suggests a
recent reduction in population size that could be explained by habitat
loss and population fragmentation. Also, high levels of linkage
disequilibrium were detected, putatively suggesting clonal reproduction
among these individuals. Our study provides a better understanding of
fine-scale genetic diversity and spatial distribution of H.
verticillatus populations in Georgia. Our results can underpin an
original recovery plan for H. verticillatus that could be
utilized for the conservation of this endangered species and to promote
its persistence in the wild.