Phylogeography of Rosa soulieana (Rosaceae) in the Hengduan Mountains: refugia and ‘melting’ pots in the Quaternary climate oscillations

Abstract

The Hengduan Mountains is the core of the Sino-Himalayan Floristic Region. Different views have been postulated from phylogeographic studies in understanding the historical biological events shaping presentday distributions and species diversities in this area. We analyzed the phylogeography of Rosa soulieana, a widely distributed rose species in dry and semi-dry valleys of the Hengduan Mountains of southwestern China using two cpDNA intergenic spacers. 9 cpDNA haplotypes were confirmed in 650 individuals from 39 populations, with the most dominant one existing in 36 populations. The relationship among the cpDNA haplotypes did not reflect the morphology-based intra-specific taxonomy of different varieties. There was very low cpDNA genetic diversity and relatively high population differentiation combined with lack of phylogeographic structure. The populations from Northwestern Yunnan, Southeastern Tibet and upper Yalongjiang River embraced most of the species genetic diversity, but with contribution of different historical effects. Northwestern Yunnan and upper Yalongjiang River appear to be the species refugia and centers of adaptive diversification, while Southeastern Tibet rather represents the species 'melting pot' in the Quaternary climate oscillations.

Yalongjiang River Has Had an Important Role in the Dispersal and Divergence of Rosa soulieana in the Hengduan Mountains of China

“…According to the genetic structure of R . soulieana based on AFLP genotypes in this study and the cpDNA haplotypes reported by Jian et al [ 16 ], it is preferable to collect and preserve the populations in southeastern Tibet, northwestern Yunnan and along the Yalongjiang River during wild rose germplasm collection. Furthermore, when choosing this wild rose as a plant for the ecosystem restoration of the dry and hot valleys in the Hengduan Mountains, it is better to choose propagation materials from the east of the Yalongjiang River for the revegetation of areas in the Mountain Warm Zones, and to choose propagation materials from the west of Yalongjiang River for the revegetation of areas in the Qinghai-Xizang Plateau Cold Climate Realm.…”

“…Nevertheless, morphological characteristics are not always able to detect taxonomic diversity [ 54 ]. Although 4 intraspecific varieties have been distinguished according to variable morphological characteristics, this intraspecific classification was not confirmed by detected cpDNA haplotype variation [ 16 ]. Based on the Bayesian analysis and NJ clustering, the genotypes of R .…”

“…Jian et al [ 16 ] postulated that northwestern Yunnan and Yalongjiang valley were the refuge and centers of adaptive divergence for R . soulieana during the Quaternary climate oscillations based on cpDNA phylogeography.…”

“…However, this morphology-based R . soulieana intraspecific classification was not supported by the cpDNA-based phylogeny [ 16 ], which can be due either to high morphological plasticity within the species or because of low resolution of the used molecular markers. Thus, genetically more variable markers are needed for robust conclusions.…”

Geological and Climatic Factors Affect the Population Genetic Connectivity in Mirabilis himalaica (Nyctaginaceae): Insight From Phylogeography and Dispersal Corridors in the Himalaya-Hengduan Biodiversity Hotspot

“…Over the last decade, a number of phylogeographic studies have investigated the link between organismic evolution of plant species and the geologic uplift associated with climate changes in the HHM and QTP (Qiu et al, 2011;Jian et al, 2015;Luo et al, 2016). For instance, phylogeographic studies on Primula tibetica related to the effects of Quaternary climatic oscillations in QTP (Ren et al, 2017a), Metrocoris sichuanensis concerned with geological effects in Sichuan Basin (Ye et al, 2018), and Allium section Sikkimensia linked with Hengduan Mountains massif uplift (Xie et al, 2019).…”