Molecular phylogeography and population evolution analysis of Citrus ichangensis (Rutaceae)

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• 作者：Xiaoming Yang ; Hang Li ; Huiwen Yu ; Lijun Chai ; Qiang Xu…
• 关键词：Citrus ; Ichang papeda ; Phylogeography ; Genetic diversity ; Population structure ; Evolution
• 刊名：Tree Genetics & Genomes
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：13
• 期：1
• 全文大小：
• 刊物主题：Forestry; Plant Genetics & Genomics; Plant Breeding/Biotechnology; Tree Biology; Biotechnology;
• 出版者：Springer Berlin Heidelberg
• ISSN：1614-2950
• 卷排序：13

文摘

Ichang papeda (Citrus ichangensis), a wild and endemic perennial plant in Rutaceae, is characterized by the existence of wild and natural populations in southwestern and middle-west China. We analyzed a total of 231 individuals across 16 natural populations using chloroplast SSR markers, nuclear SSR markers, and single-copy nuclear genes. Standard population genetic analyses as well as Bayesian and maximum likelihood models were used to clarify the genetic diversity, population differentiation, barriers to gene flow, bottleneck events, isolation by distance, history migration, demographic history among populations, and phylogeny evolution. The chloroplast and nuclear genome analyses revealed a low level of genetic diversity in C. ichangensis. Clear signals of recent bottlenecks and strong patterns of isolation by distance were detected among different subpopulations, indicating a low extent of historical gene flow for this species and that genetic drift would occur after population differentiation. Bayesian clustering analyses revealed a clear pattern of genetic structure, with one cluster spanning the potential refugia in Wuling Mountains and Ta-pa Mountains, and other two clusters covering a more limited distribution range. The demographic history also supported the scenario that two isolated clusters originated in parallel from the genetic diversity center. Taxonomically, Ichang papeda may be a member of subgenus Citrus. Owing to the complicated topography, the mountainous regions and the Yangtze River have provided long-term stable habitats for C. ichangensis and acted as main barriers for its expansion, which might facilitate the process of speciation. Statistical population models and genetic data indicated strong genetic structure in C. ichangensis, which might result from the restricted gene flow, genetic drift, and population bottlenecks.