Utilização da genômica comparativa na busca por adaptações de leveduras do gênero Metschnikowia à vida em baixas temperaturas

• Ano de defesa: 2020
• Autor(a) principal: Heron Oliveira Hilário
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - DEPARTAMENTO DE BIOQUÍMICA E IMUNOLOGIA; Programa de Pós-Graduação em Bioinformatica; UFMG
• Palavras-chave em Português: genômica comparativa; levedura; Antártica; Metschnikowia; Bioinformática; Genômica; Regiões Antárticas
• Link de acesso: http://hdl.handle.net/1843/65272; https://orcid.org/0000-0002-2548-1053

The Metschnikowia genus comprises ascomycetous yeasts from diverse environments. Besides the flower-associated species there are also aquatic species, macroalgae associated and micro crustaceans’ parasites. M. bicuspidata, the most widespread, is found on almost every ocean and many temperate lakes. Despite being freeze tolerant, M. bicuspidata is not present in the Antarctic Ocean. M. australis, a closely related species, occupies its niche on these southern waters. Also freeze tolerant, M. australis performs better at low temperatures, as we show in this study. We have sequenced M. australis genome and investigated it together with M. bicuspidata and other 33 publicly available Metschnikowia genomes searching for freeze tolerance associated elements. All genomes were predicted and annotated using the same pipeline, and 1317 common single copy orthologous genes were used to reconstruct these yeasts phylogeny. We observed that M. australis has a smaller genome, with less predicted coding sequences and repetitive content in comparison to M. bicuspidata. We have also developed a homology-based network approach to visualize and identify orthologous genes shared among genomes, which shows paralogous expansions shared by M. australis and M. bicuspidata genomes and also exclusive to each organism, which may relate to adaptions do cold environments. 247 M. australis exclusive CDSs were analyzed by 3 Antifreeze protein classifiers to select the 16 most prominent candidates for in vivo detection. We found that 15 of those are expressed at 6 and 12˚C. Most have no similarity to any known gene, and future analyses will be done to identify their influence in freeze tolerance.