Study of the evolutionary relationship between Chaitophorus aphids and their primary endosymbiont Buchnera (Hemiptera: Aphididae: Chaitophorinae)
Author of the article:YANG Xue1, 2** JIANG Li-Yun1 CHEN Jing1*** QIAO Ge-Xia1, 2***
Author's Workplace：1. Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; 2. College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
Key Words：Aphids, Buchnera, symbiont, phylogeny, parallel evolution
Abstract： [Objectives] Aphids harbor various symbionts, all of which have a close endosymbiotic relationship with their hosts. For example, almost all aphids harbor an obligatory primary endosymbiont, Buchneraaphidicola. Due to this almost universal, obligate, endosymbiotic relationship, Buchnera is an ideal model for studying the evolution of mutualism. This study tested the parallelism hypothesis between aphids andBuchnera. [Methods] Species from the aphid genus Chaitophorus, which are monocious and holocyclic onPopulus and Salix, were chosen for study. We reconstructed the phylogenies of Chaitophorus and Buchnerabased on different kinds of molecular markers (i.e., mitochondrial and nuclear genes of aphids and genes derived from Buchnera), using both maximum likelihood and Bayesian methods. The phylogenetic congruence between aphids and Buchnera was tested with TreeMap, Jane and ParaFit. [Results] TreeMap and Jane analyses confirmed a significant pattern of cophylogeny between Chaitophorus and Buchnera. ParaFit analyses indicated that their overall correlation was extremely significant. [Conclusion] Our results provide strong evidence for the parallel evolution of Chaitophorus and Buchnera at the intraspecific, and interspecific, and taxonomic levels. In addition, the evolutionary relationships between Chaitophorus and Buchnera are not affected by host plants.