title: Trajectory and genomic determinants of fungal-pathogen speciation and host adaptation.
abstract: Much remains unknown regarding speciation. Host-pathogen interactions are a major driving force for diversification, but the genomic basis for speciation and host shifting remains unclear. The fungal genus Metarhizium contains species ranging from specialists with very narrow host ranges to generalists that attack a wide range of insects. By genomic analyses of seven species, we demonstrated that generalists evolved from specialists via transitional species with intermediate host ranges and that this shift paralleled insect evolution. We found that specialization was associated with retention of sexuality and rapid evolution of existing protein sequences whereas generalization was associated with protein-family expansion, loss of genome-defense mechanisms, genome restructuring, horizontal gene transfer, and positive selection that accelerated after reinforcement of reproductive isolation. These results advance understanding of speciation and genomic signatures that underlie pathogen adaptation to hosts.
authors.affiliation: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Xiao
authors.initials: X
authors.lastname: Hu
authors.affiliation: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Guohua
authors.initials: G
authors.lastname: Xiao
authors.affiliation: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Peng
authors.initials: P
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Shang
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and.
authors.forename: Yao
authors.initials: Y
authors.lastname: Su
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and.
authors.forename: Xingzhong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhan
authors.affiliation: Department of Entomology, University of Maryland, College Park, MD 20742.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: St Leger
authors.affiliation: Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; cswang@sibs.ac.cn.
authors.forename: Chengshu
authors.identifier: http://orcid.org/0000-0003-1477-1466
authors.initials: C
authors.lastname: Wang
mesh_terms: D000222:Adaptation, Physiological; D004251:DNA Transposable Elements; D023281:Genomics; D054884:Host-Pathogen Interactions; D052981:Metarhizium / Q000145:classification* / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D004251:DNA Transposable Elements
keywords: Metarhizium; genomic features; host specificity; speciation; transitional species