Phylogeography of Quercus glauca (Fagaceae), a dominant tree of East Asian subtropical evergreen forests, based on three chloroplast DNA interspace sequences

Abstract

Historical geoclimatic events have shaped the distribution patterns and intraspecific divergence of plants. Numerous phylogeographical studies in China have focused on the Qinghai-Tibetan Plateau and surrounding areas due to the complex topography and high species diversity, but the impact of Neogene events and Quaternary climatic change on the flora of subtropical China remains poorly understood. Quercus glauca, a widespread tree of East Asian subtropical evergreen forests, has rich fossil records dating back to the Neogene, and it provides a good model to explore the impact of paleogeoclimate changes on East Asian subtropical forests. We used three chloroplast DNA (cpDNA) intergenic spacer regions and ecological niche modeling (ENM) to analyze the divergence pattern and demographic history of Q. glauca in China and Japan. A total of 33 haplotypes were detected. The phylogenetic analysis revealed two major haplotype lineages (Southwest China vs. Southeast China and East China Sea). The limited dispersal ability of seeds and complex topography resulted in the high total, inter-and intrapopulation haplotype diversity. The fossil-constrained BEAST analysis revealed a lineage diversification in the late Miocene-Pliocene. The formation of complex topography changes since Miocene in east Himalaya and adjacent area might be the key factor that triggered the intraspecific divergence of Q. glauca. Haplotype spatial distribution, ENM, mismatch distribution, and neutrality tests suggest that Q. glauca in Southeast China experiences expansion, and the current distribution in region III might be shaped by southward expansion from regions I and II after last glacial maximum (LGM). Regions I and II were the potential glacial refugia of Q. glauca.

Divergence maintained by climatic selection despite recurrent gene flow: a case study of Castanopsis carlesii (Fagaceae)

“…; Xu et al . ). This global cooling and associated environmental changes probably seriously affected the distribution of C. carlesii and allowed the differentiation of two lineages into distinct eastern and western lineages (similarly to the distribution contraction observed during the LGM).…”

Warm–cold colonization: response of oaks to uplift of the Himalaya–Hengduan Mountains

“…Heterobalanus was a response to the HHM uplift. A phylogeographic study of the warm evergreen oaks, Quercus glauca, revealed that two major haplotype lineages (southwest China versus southeast China and East China Sea) were separated by the topographic barrier of the Himalayan uplift in the Miocene which allowed the two lineages to diverge (Xu et al 2015), providing evidence that the colonization event was caused by the Himalayan uplift.…”

Differential Quaternary dynamics of evergreen broadleaved forests in subtropical China revealed by phylogeography of Lindera aggregata (Lauraceae)

“…Thus, various studies have focused on species that are ecologically minor components of EBLF or failed to cover geographical key areas such as those adjacent to the current southern EBLF boundary (Li, Yan, & Ge, 2012;Tian et al, 2018;Wang et al, 2015); their results may therefore not be representative for the biome as a whole. On the other hand, most studies of major or widely distributed EBLF species have to date only used cytoplasmatic markers (Sun, Hu, Huang, & Vargas-Mendoza, 2014;Tian et al, 2015;Xu et al, 2015;Fan et al, 2016; but see Shi et al, 2014); their results do hence not provide any insights into important processes such as pollen-mediated gene flow and secondary admixture. As a result, we still ignore many aspects of past population and range dynamics in subtropical China that could provide valuable insights into the past evolution of the EBLF biome.…”