Population Genetic Variation and Structure of the Invasive Weed Mikania micrantha in Southern China: Consequences of Rapid Range Expansion

Abstract

Invasive plants such as Mikania micrantha provide valuable opportunities for studying population genetic consequences of rapid range expansion. Twenty-eight populations of M. micrantha throughout its introduced range in southern China were examined by using intersimple sequence repeat markers. Population genetic parameters were estimated by Bayesian approaches as well as conventional methods. Bottleneck signature, multilocus linkage disequilibrium, character compatibility, and cluster analyses were conducted to assay the factors that may act to shape population variability. High levels of genetic variation and differentiation were detected in the introduced populations of M. micrantha. All populations experienced severe bottlenecks. Most of them demonstrated significant linkage disequilibrium and matrix compatibility. Populations were mainly clustered into 2 groups, and those from different regions intermingled in the unweighted pair group method with arithmetic mean (UPGMA) dendrogram. No geographical signature was found in the pattern of population genetic variation. This research indicates that during M. micrantha invasion, multiple introductions mitigated the loss of genetic variation associated with bottlenecks. Nonetheless, bottlenecks enhanced the population differentiation. Human-mediated long-distance dispersal events of seeds or propagules explain the lack of geographic structure in genetic variation. Although asexual reproduction is the predominant mating mode in M. micrantha, it has little effect on the population genetic composition.

Clonal structure and reduced diversity of the invasive alien plant Erigeron annuus in Lithuania

“…The use of a two-marker system is especially important for polyploids such as E. annuus (triploid) because part of the genotype diversity in polyploid species may be masked by the dominant character of particular RAPD, AFLP or ISSR markers [30]. Only a coincidence of results between two or more marker systems can eliminate arguments about the suitability of such markers for invasive plant studies [10,27,35]. In our study, there was a significant correlation (r=0.91, P<0.05) between genetic distances among populations established using RAPD and ISSR data.…”

“…The difficulty of evaluating statistical data for polyploids and plants with restricted outcrossing is a common problem affecting all dominant molecular marker-based analyses, including RAPD and ISSR [10,27]. As E. annuus is a triploid apomictic plant species, genotypes with multiple dominant alleles (+ + +, + + −) cannot be distinguished from genotypes possessing only one dominant (+ − −) allele.…”

Development of expressed sequence tag-simple sequence repeat markers for genetic characterization and population structure analysis of Praxelis clematidea (Asteraceae)

“…Compared with other noxious invasive species of the Asteraceae, such as Mikania micrantha Kunth (I = 0.2518, H = 0.2404, andP = 85.65%;Wang et al, 2007) and Chromolaena odorata (L.) R.M. King & H. Rob.…”

“…Several types of molecular markers have been used to analyze the genetic variation of invasive species, including inter-simple sequence repeats (ISSRs; Chapman et al, 2004;Li et al, 2014;Wang et al, 2007Wang et al, , 2015 and random amplified polymorphic DNA (RAPD; Li et al, 2006;Li et al, 2011). Expressed sequence tag-simple sequence repeats (EST-SSRs), which involve ESTs and SSR-enriched genomic libraries, have also become an important resource for population genetic studies (Ellis and Burke, 2007;Yan et al, 2011).…”

The complete chloroplast genome sequence of Mikania micrantha (Asteraceae), a noxious invasive weed to South China

“…It not only kills other plants by blocking the light, twinning, smothering and preventing forest tree regeneration ), but also competes for water and nutrients with coexisting natives (Wang et al 2004). Currently, studies on M. micrantha focus in investigation of basic features such as the biological characteristics (Hu & But 1994), photosynthetic activity (Wen et al 2000), allelopathy (Shao et al 2003), and genetic variation (Wang et al 2008). However, its characteristics of chloroplast genome remain unresolved.…”