Phylogenetic Origin of Phyllolobium with a Further Implication for Diversification of Astragalus in China  

作　　者：Mingli Zhang Yun Kang Lihua Zhou Dietrich Podlech 

机构地区：[1]Laboratory of Evolution and Biodiversity Conservation in Add Region, Xinjiang Institute of Ecology and Geography, the Chinese Academy of Sciences, Urumqi 830011, China Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China [2]pharmacy School, Fudan University, Shanghai 200032, China [3]Department of Botany, California Academy of Sciences, San Francisco, CA 94118-4503, USA [4]Faculty of Biology, Munich University, Munich D-80336, Germany

出　　处：《Journal of Integrative Plant Biology》2009年第9期889-899,共11页植物学报（英文版）

基　　金：Supported by the Chinese Academy of Sciences (KSCX2-YW-2-069);National Natural Science Foundation of China (NSFC 30500035);Xinjiang Institute of Ecology and Geography, CAS, and China Scholarship Council (CSC) for supporting M.L. Zhang’s visit to the California Academy of Sciences

摘　　要：Astragalus is a species-rich genus occurring in the western arid habitats in China and its diversification and infrageneric relationships in this region remain unclear. In the present study, based on molecular data, we aim to （i） test whether Phyllolobium （previously treated as a subgenus Pogonophace in Astragalus） should be warranted; and （ii） date the origin of Phyllolobium and probable diversification of Astragalus sensu stricto （s.s.）. We sequenced five species from Phyllolobium first and collected all related sequences from the genus, Astragalus s.s and their close relatives （Oxytropis and Caragana etc.）. Our phylogenetic analyses suggested that all species of Phyllolobium comprise a monophyletic sister-group to genera of the subtribe Coluteinae. Molecular dating suggested that Phyllolobium and Astragalus s.s. originated around 8 and 10 million years ago. These two estimates are highly consistent with the intense uplifts of the Qinghai-Tibetan Plateau inferred from geological evidence. In addition, one section of Pogonophace （Sect. Robusti） was estimated to originate 2.5 million years ago and this section with a tendency for dry habitats seems to be evidence of Asian intensified aridity resulting from the intense uplift of the Qinghai-Tibetan Plateau.Astragalus is a species-rich genus occurring in the western arid habitats in China and its diversification and infrageneric relationships in this region remain unclear. In the present study, based on molecular data, we aim to （i） test whether Phyllolobium （previously treated as a subgenus Pogonophace in Astragalus） should be warranted; and （ii） date the origin of Phyllolobium and probable diversification of Astragalus sensu stricto （s.s.）. We sequenced five species from Phyllolobium first and collected all related sequences from the genus, Astragalus s.s and their close relatives （Oxytropis and Caragana etc.）. Our phylogenetic analyses suggested that all species of Phyllolobium comprise a monophyletic sister-group to genera of the subtribe Coluteinae. Molecular dating suggested that Phyllolobium and Astragalus s.s. originated around 8 and 10 million years ago. These two estimates are highly consistent with the intense uplifts of the Qinghai-Tibetan Plateau inferred from geological evidence. In addition, one section of Pogonophace （Sect. Robusti） was estimated to originate 2.5 million years ago and this section with a tendency for dry habitats seems to be evidence of Asian intensified aridity resulting from the intense uplift of the Qinghai-Tibetan Plateau.

关 键 词：ASTRAGALUS DATING distribution pattern DIVERSIFICATION Phyllolobium phylogeny Qinghai-Xizang （Tibet） Plateau Sino-Himalayan flora. 

分 类 号：S567.239[农业科学—中草药栽培] I207.22[农业科学—作物学]