title: Microevolutionary analyses of Pythium insidiosum isolates of Brazil and Thailand based on exo-1,3-β-glucanase gene.
abstract: Pythium insidiosum is an important oomycete due to its ability to infect humans and animals. It causes pythiosis, a disease of difficult treatment that occurs more frequently in humans in Thailand and in horses in Brazil. Since cell-wall components are frequently related to host shifts, we decided here to use sequences from the exo-1,3-β-glucanase gene (exo1), which encodes an immunodominant protein putatively involved in cell wall remodeling, to investigate the microevolutionary relationships of Brazilian and Thai isolates of P. insidiosum. After neutrality ratification, the phylogenetic analyses performed through Maximum parsimony (MP), Neighbor-joining (NJ), Maximum likelihood (ML), and Bayesian analysis (BA) strongly supported Thai isolates being paraphyletic in relation to those from Brazil. The structure recovered by these analyses, as well as by Spatial Analysis of Molecular Variance (SAMOVA), suggests the subdivision of P. insidiosum into three clades or population groups, which are able to explain almost 81% of the variation encountered for exo1. Moreover, the two identified Thai clades were almost as strongly differentiated between each other, as they were from the Brazilian clade, suggesting an ancient Asian subdivision. The derived positioning in the phylogenetic tree, linked to the lower diversity values and the recent expansion signs detected for the Brazilian clade, further support this clade as derived in relation to the Asian populations. Thus, although some patterns presented here are compatible with those recovered with different molecular markers, exo1 was revealed to be a good marker for studying evolution in Pythium, providing robust and strongly supported results with regard to the patterns of origin and diversification of P. insidiosum.
authors.affiliation: Laboratório de Pesquisas Micológicas, Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Programa de Pós-graduação em Farmacologia (PPGF), Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil.
authors.forename: Tatiana Corrêa
authors.initials: TC
authors.lastname: Ribeiro
authors.affiliation: Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Programa de Pós-graduação em Medicina Veterinária (PPGMV), UFSM, Santa Maria, RS, Brazil.
authors.forename: Carla
authors.initials: C
authors.lastname: Weiblen
authors.affiliation: Laboratório de Pesquisas Micológicas, Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Programa de Pós-graduação em Farmacologia (PPGF), Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil.
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: de Azevedo
authors.affiliation: Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Programa de Pós-graduação em Medicina Veterinária (PPGMV), UFSM, Santa Maria, RS, Brazil.
authors.forename: Sônia
authors.initials: S
authors.lastname: de Avila Botton
authors.affiliation: Instituto de Ciências Biológicas (ICB), Universidade Federal do Rio Grande (FURG), Rio Grande, RS, Brazil.
authors.forename: Lizandra Jaqueline
authors.initials: LJ
authors.lastname: Robe
authors.affiliation: Departamento de Microbiologia e Parasitologia, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas, RS, Brazil.
authors.forename: Daniela Isabel Brayer
authors.initials: DI
authors.lastname: Pereira
authors.affiliation: Laboratório de Parasitologia Humana e Biologia Molecular, UFSM, Santa Maria, RS, Brazil.
authors.forename: Danieli Urach
authors.initials: DU
authors.lastname: Monteiro
authors.affiliation: Laboratório de Parasitologia Humana e Biologia Molecular, UFSM, Santa Maria, RS, Brazil.
authors.forename: Douglas Miotto
authors.initials: DM
authors.lastname: Lorensetti
authors.affiliation: Laboratório de Pesquisas Micológicas, Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Programa de Pós-graduação em Farmacologia (PPGF), Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil. Electronic address: janio.santurio@gmail.com.
authors.forename: Janio Morais
authors.initials: JM
authors.lastname: Santurio
mesh_terms: D001938:Brazil; D019143:Evolution, Molecular; D014644:Genetic Variation; D043326:Glucan 1,3-beta-Glucosidase / Q000235:genetics*; D010802:Phylogeny; D011775:Pythium / Q000201:enzymology / Q000235:genetics*; D013785:Thailand
chemical_list: D043326:Glucan 1,3-beta-Glucosidase
keywords: Evolution; Exo-1,3-β-glucanase; Oomycete; Phylogenetic; Phylogeography