High Genetic Diversity and Insignificant Interspecific Differentiation in Opisthopappus Shih, an Endangered Cliff Genus Endemic to the Taihang Mountains of China

Abstract

Opisthopappus Shih is endemic to the Taihang Mountains, China. It grows in the crevice of cliffs and is in fragmented distribution. This genus consists of two species, namely, O. taihangensis (Ling) Shih and O. longilobus Shih, which are both endangered plants in China. This study adopted intersimple sequence repeat markers (ISSR) to analyze the genetic diversity and genetic structure from different levels (genus, species, and population) in this genus. A total of 253 loci were obtained from 27 primers, 230 of which were polymorphic loci with a proportion of polymorphic bands (PPB) of up to 90.91% at genus level. At species level, both O. taihangensis (PPB = 90.12%, H = 0.1842, and I = 0.289) and O. longilobus (PPB = 95.21%, H = 0.2226, and I = 0.3542) have high genetic diversity. Their respective genetic variation mostly existed within the population. And genetic variation in O. longilobus (84.95%) was higher than that in O. taihangensis (80.45%). A certain genetic differentiation among populations in O. taihangensis was found (G st = 0.2740, Φst = 0.196) and genetic differentiation in O. longilobus was very small (G st = 0.1034, Φst = 0.151). Gene flow in different degrees (N m = 1.325 and 4.336, resp.) and mating system can form the existing genetic structures of these two species. Furthermore, genetic differentiation coefficient (G st = 0.0453) between species and the clustering result based on the genetic distance showed that interspecific differentiation between O. taihangensis and O. longilobus was not significant and could occur lately.

Localized environmental heterogeneity drives the population differentiation of two endangered and endemic Opisthopappus Shih species

“…High genetic diversity in populations of organisms is a successful strategy that facilitates their adapting to various habitats and environmental conditions [41,42] toward increasing their effective colonization in new habitats [42][43][44]. In this study, high genetic diversity was observed in O. longilobus or O. taihangensis (Table 1), which was consistent with previous research by ISSR [36] and SRAP [38] markers. This was similar to other endemic and endangered species, such as Helianthemum songaricum [45], Sinowilsonia henryi [46], and Taihangia rupestris [47].…”

“…Between O. taihangensis and O. longilobus, several morphologica [30,34,35] and genetic variations [36][37][38][39][40] have been observed. Nevertheless, the interspecific hybridization of these two species have never been reported.…”

De novo Assembly and Transcriptome Characterization of Opisthopappus (Asteraceae) for Population Differentiation and Adaption

“…Additionally, with the rapid development of various molecular markers such as RFLP, RAPD, ISSR, simple sequence repeat (SSR), SR, AFLP and single nucleotide polymorphism (SNP), the genetic diversity analyses of Opisthopappus Shih populations were carried out to obtain more comprehensive information and data about genetic differentiation and variation. The results revealed abundant genetic diversity in populations but low level of genetic differentiation among populations and confirmed that the genetic difference of the species mainly existed within populations ( Guo et al, 2013 ). Meanwhile, the cluster analysis based on the genetic distance showed that O. longilobus populations were not monophyletic group, and the remaining populations of O. longilobus were gathered with O. taihangensis populations, which indicated that gene exchange or interspecific hybridization might occur between the two species ( Wang et al, 2015 ).…”

“…Population genetic analysis in Opisthopappus Shih have been carried out by using various molecular markers, such as RFLP, RAPD, ISSR, cpSSR, and SRAP ( Guo et al, 2013 ; Wang, 2013 ; Wang and Yan, 2013 ). However, no definitive conclusions were established to illustrate interspecific differences and confirm the taxonomy status between O. longilobus and O. taihangensis .…”

Genetic structure of Galium cracoviense (Rubiaceae): a naturally rare species with an extremely small distribution range

“…Direct comparison of our results with other studies is problematic, since genetic diversity depends on numerous factors such as life-history traits, geographic range, and even the type of molecular method used (Nybom 2004). Nevertheless, in the group of endemic taxa of rocky/mountainous habitats we find several examples of species characterized by high genetic variability, for example Aster pyrenaeus (Escaravage et al 2011), Astragalus albens (Neel 2008), Campanula sabatia (Federica et al 2012) or representatives of the genus Opisthopappus (Guo et al 2013). Further examples of species with high levels of genetic variability in the population are found in more widespread alpine species having topographically isolated populations inhabiting a harsh environment, such as Table 1 Fig .…”