Clone Configuration and Spatial Genetic Structure of Two Halophila ovalis Populations With Contrasting Internode Lengths

Abstract

Fine-scale spatial genetic structure (SGS) is predominantly determined by gene flow. While sexually reproducing plants can disperse their genes through pollen and seed grains, clonal plants can additionally disperse genes through clonal growth. Plants' clonal reproduction strategy, however, often varies within and between species. Still, the effect of differential clonal reproduction strategy on fine-scale SGS remains somewhat unclear. Halophila ovalis is a fast-growing clonal seagrass, whose internode length (which defines a species' clonal reproduction strategy) varies among populations. Using eight polymorphic microsatellites, here we compare the genetic diversity, clonal structure and fine-scale SGS of two H. ovalis populations with contrasting internode lengths (Yingluo vs. Xialongwei populations). We found moderate to high genotypic and allelic richness and heterozygosities in both populations. Compared to Xialongwei population, genetic and genotypic diversity was significantly lower in Yingluo population. Although their internode length was relatively short, clones of Yingluo population spread farther than those of Xialongwei population. Sexual-to-vegetative dispersal variance ratios were 34.6 and 445.5 in Yingluo and Xialongwei populations, respectively. In both populations, clonal growth significantly intensified the SGS, especially in short distance classes. The SGS at small distance classes were weaker in Yingluo than Xialongwei, in part, due to more intermingled distribution of genets and more extensive clonal expansion in the former population. Our results indicate that vegetative dispersal variance/distance, rather than internode length, plays a crucial role in shaping the fine-scale genetic structure.

Genomics-Based Phylogenetic and Population Genetic Analysis of Global Samples Confirms Halophila johnsonii Eiseman as Halophila ovalis (R.Br.) Hook.f.

“…These findings indicate that H. ovalis is a species that has high turnover meadows that are maintained through sexual reproduction. Preliminary findings pertaining to genetic diversity in H. johnsonii are in stark contrast to the inferences made for H. ovalis by Xu et al (2019). The availability of microsatellite markers allows further testing of the reproductive biology of H. johnsonii and this study will be the first to use high resolution co-dominant markers to assess genetic diversity in the species.…”

“…Microsatellites, the markers of choice for seagrass clonality research (e.g., Arnaud-Haond et al, 2005;McMahon et al, 2014McMahon et al, , 2017 were later developed for H. ovalis (Xu et al, 2010). A subsequent study using these markers found high genetic diversity in two monospecific H. ovalis populations in the Hepu Dugong National Nature Reserve of Guangxi, China and that a small number of genets consisted of multiple ramets (Xu et al, 2019). One of the main findings was that clonal diversity was high and clones were small compared to other seagrass species (e.g., Arnaud-Haond et al, 2012;Bricker et al, 2018).…”

Genetic Diversity and Population Structure Analysis of Anatolian Kara Grapevine (Vitis vinifera L.) Germplasm Using Simple Sequence Repeats

“…Therefore, these clones, which are morphologically very similar, are very difficult to distinguish by visual observation [74]. On the other hand, SSR markers have frequently been used in clone analysis of different plant species in recent years, as they are highly informative about the level of heterozygosity between and within grapevine cultivars [75][76][77][78].…”