Genetic variation and population structure of clonal Zingiber zerumbet at a fine geographic scale: a comparison with two closely related selfing and outcrossing Zingiber species

Abstract

Background There has always been controversy over whether clonal plants have lower genetic diversity than plants that reproduce sexually. These conflicts could be attributed to the fact that few studies have taken into account the mating system of sexually reproducing plants and their phylogenetic distance. Moreover, most clonal plants in these previous studies regularly produce sexual progeny. Here, we describe a study examining the levels of genetic diversity and differentiation within and between local populations of fully clonal Zingiber zerumbet at a microgeographical scale and compare the results with data for the closely related selfing Z. corallinum and outcrossing Z. nudicarpum. Such studies could disentangle the phylogenetic and sexually reproducing effect on genetic variation of clonal plants, and thus contribute to an improved understanding in the clonally reproducing effects on genetic diversity and population structure. Results The results revealed that the level of local population genetic diversity of clonal Z. zerumbet was comparable to that of outcrossing Z. nudicarpum and significantly higher than that of selfing Z. corallinum. However, the level of microgeographic genetic diversity of clonal Z. zerumbet is comparable to that of selfing Z. corallinum and even slightly higher than that of outcrossing Z. nudicarpum. The genetic differentiation among local populations of clonal Z. zerumbet was significantly lower than that of selfing Z. corallinum, but higher than that of outcrossing Z. nudicarpum. A stronger spatial genetic structure appeared within local populations of Z. zerumbet compared with selfing Z. corallinum and outcrossing Z. nudicarpum. Conclusions Our study shows that fully clonal plants are able not only to maintain a high level of within-population genetic diversity like outcrossing plants, but can also maintain a high level of microgeographic genetic diversity like selfing plant species, probably due to the accumulation of somatic mutations and absence of a capacity for sexual reproduction. We suggest that conservation strategies for the genetic diversity of clonal and selfing plant species should be focused on the protection of all habitat types, especially fragments within ecosystems, while maintenance of large populations is a key to enhance the genetic diversity of outcrossing species.

Genetic Diversity and Population Structure of Rhododendron longipedicellatum, an Endangered Species

“…Some R. longipedicellatum plants occurring in the limestone habitat are attached to tree trunks, providing a stable yet polymorphic microenvironment that reduces the impact of natural and human-induced disturbance. Second, outcrossing plants tend to have higher genetic variation than selfing plants (Huang et al, 2021; Nybom, 2004). The cross-pollination reproductive system of R. longipedicellatum reported by Li, Liu, Li, Ma, et al (2018) may, therefore, also support the relatively high genetic diversity in this species.…”

“…The obvious homozygote deficiency or heterozygote excess may be associated with population regeneration in some plants (Stoeckel et al, 2010). In addition, the increased heterozygosity may be due to the small number of populations with few individual plants in each population or to the presence of a high allelic richness in the parent plants (Huang et al, 2021; Pudovkin et al, 1996).…”

“…The obvious homozygote deficiency or heterozygote excess may be associated with population regeneration in some plants ( Stoeckel et al, 2010). In addition, the increased heterozygosity may be due to the small number of populations with few individual plants in each population or to the presence of a high allelic richness in the parent plants (Huang et al, 2021;Pudovkin et al, 1996). The magnitude of gene flow between populations has a significant influence on the genetic structure of populations and is a key factor that predicts the effect of changes in the environment, such as human interference and population isolation (Wu et al, 2017).…”

What Makes a Good Plant Invader?

“…The genetic diversity of invasive populations can increase through multiple introductions and/or sexual reproduction along with recombination, especially if genetic variability is combined with phenotypic plasticity, facilitating adaptation and spread [49]. Clonal species may also gain significant amounts of genetic diversity via mutation [50]. Some inva-sive plants have even higher genetic diversity outside their native range [51].…”

Genetic Diversity and Chemicals Profile of Ginger (Zingiber officinale Roscoe) in Indonesia

“…Due to their restricted dispersal capabilities, plants that reproduce vegetatively always exhibit high levels of clonal clustering. Furthermore, clonal plants can be customized to adapt to various environmental circumstances [31]. It has long been recognized that habitats with differing conditions encourage the coexistence of locally adapted genotypes through diversifying selection, resulting in high levels of genetic variation [31].…”