Data from: Genetic diversity and population structure of Varronia curassavica: a medicinal polyploid species in a threatened ecosystem

Varronia curassavica is an important medicinal species associated with the restinga, one of the most threatened coastal ecosystems of the Atlantic Forest. These circumstances call for studies aimed at estimating effective population size and gene flow to improve conservation efforts. Hence, the present study aimed to characterize the genetic diversity, ploidy level and population structure of this species in different areas of restinga using microsatellites. Varronia curassavica was characterized as an autotetraploid, with high genetic variability, low divergence, and no significant fixation indices, indicating the absence of, or reduced, inbreeding and genetic drift in the study area. About 44 % of the alleles occurred at low frequency in adults of all populations and 41 % in the progenies evaluated. Gene flow was high, consistent with outcrossing species with high dispersal capacity (Nm = 4.87). The results showed no tendency toward isolation by distance. The estimated effective size indicates that the populations studied have the potential to ensure conservation of the species in the long term. The genetic variability and population structure of V. curassavica, as determined in this study, could form the foundation for activities directed toward the sustainable use of this resource and its conservation. Even though the restinga ecosystem has suffered dramatic reductions in area, this study provides evidence that this species is resilient to anthropogenic threats to its genetic integrity, since it is a polyploid with self-incompatibility mechanisms that contribute to maintaining high genetic diversity in an panmictic meta-population along the coast of Santa Catarina.

瓦罗尼亚属库拉索种（Varronia curassavica）是一种与海滨沙丘林（restinga）相关的重要药用物种，而海滨沙丘林是大西洋森林中受威胁最为严重的沿海生态系统之一。针对这一现状，亟需开展旨在评估有效种群大小与基因流的相关研究，以优化该物种的保护实践。为此，本研究借助微卫星标记（microsatellites），对海滨沙丘林不同分布区内该物种的遗传多样性、倍性水平及种群结构进行了系统表征。研究结果显示，瓦罗尼亚属库拉索种为同源四倍体（autotetraploid），具有较高的遗传变异度、较低的种群分化程度，且无显著的固定指数，表明研究区域内近交与遗传漂变的现象缺失或程度较低。约44%的等位基因在所有种群的成年个体中以低频形式存在，而在本次评估的子代群体中，这一比例为41%。该物种的基因流水平较高，这与具备高扩散能力的异交物种特征相符（Nm = 4.87），且未发现距离隔离效应的相关趋势。估算得到的有效种群大小表明，本次研究涉及的种群具备长期保障该物种存续的潜力。本研究解析得到的瓦罗尼亚属库拉索种遗传多样性与种群结构特征，可为该资源的可持续利用及保护相关工作奠定理论基础。尽管海滨沙丘林生态系统的面积已发生大幅缩减，本研究仍提供了证据表明，该物种对威胁其遗传完整性的人为干扰具有较强韧性——这是因为该物种为多倍体，且具备自交不亲和机制，有助于维持圣卡塔琳娜州沿岸泛交复合种群（panmictic meta-population）内的高水平遗传多样性。