Phylogeography of Buddleja crispa (Buddlejaceae) and its correlation with drainage system evolution in southwestern China.

PREMISE OF THE STUDY: Southwestern China is an area of active tectonism and erosion, yielding a dynamic, deeply eroded landscape that is hypothesized to have influenced the genetic structure of the resident populations of plants and animals. However, few studies have been conducted to examine the influence of changing river channels, particularly in the Yarlung Tsangpo area, on genetic distributions in plants. We here examine the population structure of Buddleja crispa, a dominant element of the dry, warm/hot river-valley communities, seeking to delimit the current population genetic structure and its relation to past changes in the courses of the major rivers in this area. • METHODS: Two chloroplast DNA fragments were used to estimate the genetic variation and phylogeographic structure of the populations, and to infer nested clades, of the species. • KEY RESULTS: We detected low intrapopulational haplotype diversity and higher overall population haplotype diversity (h(S) = 0.085, h(T) = 0.781). Molecular variance was mainly observed between groups (81.42%). Robust population genetic structure were detected by AMOVA (F(ST) = 0.967), coinciding with three nested clades (identified by NCPA) and five phylo-groups linked with paleo-drainage systems (identified by SAMOVA). No support for extensive spatial or demographical expansion was obtained. • CONCLUSIONS: A general pattern of genetic isolation by vicariance was inferred, and detected disjunct patterns strongly indicate that currently discontinuous drainage systems were historically linked. Most importantly, population subdivisions and genetic variation perfectly reflect the putative Paleo-Red-River drainage pattern, and Yarlung Tsangpo populations are closely related to Central Yunnan Plateau populations, indicating that they were previously connected by ancient river courses. Divergence times between these river systems estimated by molecular dating (in the Pleistocene) agree with previous findings.

The complete chloroplast genome of Ranunculus yunnanensis (Ranunculaceae).

Ranunculus yunnanensis Franch is endemic in Yunnan and Sichuan Provinces, southwestern China. Here, we report the complete chloroplast (cp) genome of R. yunnanensis. The chloroplast genome is 156,050 bp in length, with 111 encoded genes, including 78 protein-coding genes, 29 tRNA genes, and four rRNA genes. Maximum-likelihood phylogenetic reconstruction using the existing data of Ranunculus shows that R. yunnanensis is revealed at the basal position of the marsh buttercup clade. This result has improved a better understanding of the internal relationship of the Ranunculus.

The complete chloroplast genome of Beesia deltophylla (Ranunculaceae).

Beesia deltophylla is an endemic and rare species only distributed in Xizang, China. The chloroplast genome of B. deltophylla is 157,397 bp in length, with 112 encoded genes including 78 protein-coding genes, 30 tRNA genes and 4 rRNA genes. Phylogenetic reconstruction has confirmed the placement of B. deltophylla as sister to B. calthifolia. These two species formed a clade closely to a Japan endemic species Anemonopsis macrophylla.