Genetic structure of the endangered Leucomeris decora (Asteraceae) in China inferred from chloroplast and nuclear DNA markers

Abstract

The genetic variation and structure of Leucomeris decora, an endangered species in China were investigated. Analyses of three chloroplast DNA (cpDNA) regions (the rpl16 intron, trnQ-5 0 rps16 intergenic spacer and rpl32-trnL intergenic spacer) and one nuclear gene (GAPDH: encoding glyceraldehyde 3-phosphate dehydrogenase) were conducted on 11 L. decora populations. Low levels of cpDNA genetic diversity were found in this species and within populations, with the identification of 2 haplotypes in a total of 2,745 bp, while the level of genetic diversity revealed by the nuclear gene GAPDH was relatively high, indicating that random losses of genetic polymorphisms from populations may have occurred recently. High levels of genetic differentiation among populations for both markers were detected in L. decora, which could be a consequence of the limited gene flow caused by geographic isolation among populations. An analysis of molecular variance revealed at the nuclear locus suggested the presence of geographic structure within the haplotype distribution possibly due to geographical barriers among populations. The haplotype network and mismatch distribution analyses did not detect the signal for a recent population expansion in L. decora. L. decora may persist in situ during climatic oscillations. Based on the genetic diversity and uniqueness of the populations, conservation strategies are discussed for this endangered species.

Genetic Diversity and Population Structure of Rhododendron rex Subsp. rex Inferred from Microsatellite Markers and Chloroplast DNA Sequences

“…In addition, the complex topology of physical environmental condition in southwest China might cause geographical barriers between population migrations. This scenario was also found in the population demography of Leucomeris decora [86].…”

Diversity and conservation of plant species in dry valleys, southwest China

“…2). For instance, the present populations of L. decora are separated by geographic arrangement of Daxue mountains and Lancang River (Zhao and Gong 2012); in the case of M. delavayi, the haplotypes distribution pattern showed populations on the banks of Jinsha River harbored unique haplotypes (Fig. 2d), suggesting that Jinsha River acted as barriers to the dispersal of seeds and pollen.…”

“…2), which include (1) A. glaucifolium (Guan et al 2013), M. delavayi (Jia et al 2014), A. delavayi (Yang et al 2014) and T. gracilis (unpublished) becoming endangered due to the hydropower stations construction, (2) N. insignis (Gong et al 2011;Luan et al 2006), Leucomeris decora (Zhao and Gong 2012) and Cycas hongheensis (only two populations left) (unpublished) with decreasing populations because of human exploitation for woods or habitat destruction, (3) Psammosilene tunicoides facing overexploitation threats for herb medicines (Zhang et al 2011b), and Citrus hongheensis which is also an important wild germplasm resource (Table 1). We attempt to provide insights into genetic diversity and guidance on conservation managements for these species.…”

“…Our research used neutral markers to measure levels of genetic variation in the endemic species distributed in this region. Overall, low levels of genetic diversity within populations (Hs), as examined from cytoplasm DNA (cpDNA and mtDNA), were revealed, especially in the endangered species such as L. decora (only two cpDNA haplotypes) (Zhao and Gong 2012), A. glaucifolium (Guan et al 2013), N. insignis (Gong et al 2011), P. Tunicoides (Zhang et al 2011b). These genetic patterns may be mainly ascribed to the fragmented distribution and limited gene flow among populations.…”

“…First of all, within plant species, it is difficult to reach reciprocal monophyly for plastid DNA, because different populations often share haplotypes with high frequencies and the delimitation of populations is obscured in the phylogeny construction. For example, in the preliminary screening of numerous primers for cpDNA sequencing of L. decora, only two haplotypes were identified among individuals examined (Zhao and Gong 2012), i.e., most of the populations were fixed for one haplotype and had no unique combination of plastid genes. As a consequence, in comparison with animal mitochondrial genes, plastid genes are evolving slowly and plants will be less well represented as ESUs under this concept.…”