The geographic and biological diversity of China has resulted in the differential adaptation of the eastern honeybee,Apis cerana,to these varied habitats.A.cerana were collected from 14 locations in China.Their genomes were sequenced,and nucleotide polymorphisms were identified at more than 9 million sites.Both STRUCTURE and principal component analysis placed the bees into seven groups.Phylogenomic analysis groups the honeybees into many of the same clusters with high bootstrap values(91%-100%).Populations from Tibet and South Yunnan are sister taxa and together represent the earliest diverging lineage included in this study.We propose that the evolutionary origin of A.cerana in China was in the southern region of Yunnan Province and expanded from there into the southeastern regions and into the north-eastern mountain regions.The Cold-Temperate West Sichuan Plateau and Tropical Diannan populations were compared to identify genes under adaptive selection in these two habitats.Pathway enrichment analysis showing genes under selection,including the Hippo signaling pathway,GABAergic pathway,and trehalose-phosphate synthase,indicates that most genes under selection pressure are involved in the process of signal transduction and energy metabolism.qRT-PCR analysis reveals that one gene under selection,the AcVIAAT gene,involved in the GABAergic pathway,is responding to cold temperature stress.Through homologous recombination,we show that the AcVIAAT gene is able to replace the CNAG_01904 gene in the fungus Cryptococcus neoformans and that it makes the fungus less sensitive to conditions of oxidative stress and variations in temperature.Our results contribute to our understanding of the evolutionary origin of A.cerana in China and the molecular basis of environmental adaptation.
adaptation Apis cerana evolution population signal induction stress
Peng Shi Jun Zhou Huali Song Yujuan Wu Lan Lan Xiangyou Tang Zhengang Ma Charles R.Vossbrinck Bettina Vossbrinck Zeyang Zhou Jinshan Xu
College of Life Sciences,Chongqing Normal University,Chongqing,China;Engineering Research Center of State Key Laboratory of Silkworm Genome Biology,Southwest University,Chongqing,China Department of Environmental Science,Connecticut Agricultural Experiment Station,New Haven,CT,USA Department of Math and Sciences,Gateway Community College,New Haven,CT,USA College of Life Sciences,Chongqing Normal University,Chongqing,China;Engineering Research Center of