Molecular phylogeny and biogeography ofAstilbe(Saxifragaceae) in Asia and eastern North America

Abstract

Phylogenetic analyses were conducted for Astilbe (Saxifragaceae), an Asian/eastern North American disjunct genus, using sequences of nuclear ribosomal internal transcribed spacer (ITS) and plastid matK, trnL‐trnF and psbA‐trnH regions. The monophyly of Astilbe is well supported by both ITS and plastid sequences. Topological incongruence was detected between the plastid and the ITS trees, particularly concerning the placement of the single North American species, A. biternata, which may be most probably explained by its origin involving hybridization and/or allopolyploidy with plastid capture. In Astilbe, all species with hermaphroditic flowers constitute a well‐supported clade; dioecious species form a basal grade to the hermaphroditic clade. Astilbe was estimated to have split with Saxifragopsis from western North America at 20.69 Ma (95% HPD: 12.14–30.22 Ma) in the early Miocene. This intercontinental disjunction between Astilbe and Saxifragopsis most likely occurred via the Bering land bridge. The major clade of Astilbe (all species of the genus excluding A. platyphylla) was inferred to have a continental Asian origin. At least three subsequent migrations or dispersals were hypothesized to explain the expansion of Astilbe into North America, Japan and tropical Asian islands. The intercontinental disjunct lineage in Astilbe invokes a hybridization event either in eastern Asia or in North America. This disjunction in Astilbe may be explained by a Beringian migration around 3.54 Ma (95% high posterior density: 1.29–6.18 Ma) in the late Tertiary, although long‐distance dispersal from eastern Asia to North America is also likely. The biogeographical connection between continental Asia, Taiwan, the Philippines and other tropical Asian islands in Astilbe provides evidence for the close floristic affinity between temperate or alpine south‐western China and tropical Asia. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ●●, ●●–●●.

The Biogeographic South-North Divide of Polygonatum (Asparagaceae Tribe Polygonateae) within Eastern Asia and Its Recent Dispersals in the Northern Hemisphere

“…Astilbe Buch.-Ham. ex D.Don is a well-known genus of Saxifragaceae with an early divergence in nEA, which then migrated southwards into southern and tropical Asia [54]. It is also well supported that Phryma L. (Phrymaceae) diversified in nEA first and then migrated to sEA [55].…”

Evolutionary diversifications of plants on the Qinghai-Tibetan Plateau

“…The phylogenetic and biogeographic analyses of the genus (Kim et al, 2009; Zhu et al, 2013) support three major clades, a clade centered in the northern part of the Sino-Japanese region, a clade centered in the central and southern part of the Sino-Japanese region, and a clade of A. rivularis Buch.-Ham. ex D.Don primarily distributed in the Himalayan–Hengduan regions of the QTP extending to SE Asia.…”

A molecular phylogeny of Caraganeae (Leguminosae, Papilionoideae) reveals insights into new generic and infrageneric delimitations

“…The PCRs for ITS (primer pair: ITS4 and ITS5a) and psbA-trnH (primer pair: psbA and trnH) were performed according to Stanford et al (2000) and Hamilton (1999), respectively. The PCR primer pair for trnL-F was “c” and “f” as in Zhu et al (2013) and Taberlet et al (1991), and the thermal cycling program followed Soejima and Wen (2006). The barcoding region of the matK marker was amplified and sequenced with the primer pair Kim-3F/Kim-1R (CBOL Plant Working Group 2009; China Plant BOL Group 2011), and the amplification conditions were: 95°C (5min) for DNA pre-denaturation; 94°C (40s), 48°C (40s) and 72°C (100s) for 35 cycles; 72°C (10min) for final extension.…”