Ecology and taxonomy of mimosas of Brazil: Diversity and interaction with hosts from different biomes

Autor: Bara?na, Alexandre Cardoso
Přispěvatelé: Reis, Veronica Massena, Zilli, Jerri ?dson, Soares, Lu?s Henrique de Barros, Coelho, Marcia Reed Rodrigues, Goi, Silvia Regina, Pinheiro, ?rika Fl?via Machado
Jazyk: portugalština
Rok vydání: 2017
Předmět:
Zdroj: Biblioteca Digital de Teses e Dissertações da UFRRJ
Universidade Federal Rural do Rio de Janeiro (UFRRJ)
instacron:UFRRJ
Popis: Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2021-03-26T08:47:15Z No. of bitstreams: 1 2017 - Alexandre Cardoso Bara?na.pdf: 3950672 bytes, checksum: 6cb9396c35bbe113bf4064e3a66d0f28 (MD5) Made available in DSpace on 2021-03-26T08:47:15Z (GMT). No. of bitstreams: 1 2017 - Alexandre Cardoso Bara?na.pdf: 3950672 bytes, checksum: 6cb9396c35bbe113bf4064e3a66d0f28 (MD5) Previous issue date: 2017-02-22 Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES, Brasil) Brazil is the main diversity center of mimosas in the world, with the Cerrado and Caatinga biomes concentrating about half of all the species described. Although these legumes establish symbiosis predominantly with Beta-rhizobia, members of the subclass Alpha-proteobacteria are also able to nodulate effectively. In Brazil, mimosas are predominantly nodulated by species of the genus Paraburkholderia, and to date, do not include the genus Cupriavidus and other alpha-rhizobia as native symbiotic partners. This thesis brings new biogeographic information about these interactions, and it is organized in two chapters: I. An ecological and taxonomic study of mimosas rhizobia of Amazon, Cerrado, Caatinga and Mata Atl?ntica biomes; and II. The description of a new species (Rhizobium altiplani) isolated from Mimosa pudica under an anthropic soil of Bras?lia within the Cerrado domain. The study was based on 724 bacteria derived from nodules of 16 invasive and endemic mimosas species collected from 25 study sites, where M. pudica constituted the main species studied. These isolates were characterized from phenotypic and genotypic attributes, where a dominance of Paraburkholderia species was demonstrated. However, for the first time, the presence of Cupriavidus nodulando mimosas species was observed spontaneously in three of the four biomes studied, while Rhizobium species were well represented in the Cerrado and Amazonian biomes. All collections were grouped from Box-PCR profiles or by comparing phenotypic characteristics profiles, and 188 bacteria were selected for submission to the Koch postulate using M. pudica as host plant. From this total, 106 rhizobia were able to form nodules with different size, color and leg-hemoglobin enzyme activity depending on the inoculated strains. Based on 16S rRNA gene sequences, 98 bacteria presented homologies with 16 alpha and beta-rhizobia species, consisting of P. tuberum, the main symbiont of mimosas in Brazil. The phylogenies of the 16S rRNA and recA genes showed that most of the isolates formed distinct clades for each species, being of low variability intraspecific, with the exception of the isolates of P. nodosa and P. diazotrophica species that showed differences among the populations of different localities. With respect to symbiotic genes (nifH and nodC), there was little evidence of horizontal gene transfer events, with most of the clusters similar to those observed in the conserved gene phylogenies. The strains of the genus Cupriavidus presented genes different from the type strains and similar to those found in Uruguay and Brazil, thus constituting a South American population. From this initial taxonomic study, five isolates belonging to the genus Rhizobium of the Federal District were distinct from any other type strain. This divergence was also confirmed by multilocus sequence analysis, genome comparison and phenotypic tests, and the isolation of a new species, Rhizobium altiplani, was confirmed. Finally, the R. altiplani type strain (BR 10423T) was transformed for expression of the GFP report gene and subjected to a cross inoculation experiment. The results showed that R. altiplani was able to nodulate Phaseolus vulgaris, Vigna unguiculata, Crotalaria juncea and Lupinus angustifolium and M. pudica, however, the effectiveness of nodulation occurred differently among host plants. O Brasil ? o principal centro de diversidade de mimosas no mundo e os Biomas Cerrados e Caatinga concentram cerca de metade das esp?cies descritas. Embora estas leguminosas estabele?am simbiose predominantemente com Beta-riz?bios, membros da subclasse Alfaproteobacteria tamb?m nodulam efetivamente. No Brasil, a principal nodula??o nas mimosas se d? por esp?cies do g?nero Paraburkholderia, e at? o momento, n?o incluem o g?nero Cupriavidus e outros alfa-riz?bios como parceiros simbi?ticos nativos. Essa tese traz novas informa??es biogeogr?ficas sobre estas intera??es, sendo dividida em dois cap?tulos: I - Um estudo ecol?gico e taxon?micos dos riz?bios de mimosas dos biomas Amaz?nia, Cerrado, Caatinga e Mata Atl?ntica; e II - A descri??o de nova esp?cie (Rhizobium altiplani) isolada de Mimosa pudica sob um solo antropizado de Bras?lia dentro do dom?nio Cerrado. O estudo foi baseado em 724 bact?rias provenientes de n?dulos de 16 esp?cies de mimosas invasivas e end?micas coletadas de 25 locais de estudos, onde M. pudica constituiu a principal esp?cie estudada. Estes isolados foram caracterizados a partir de atributos fenot?picos e genot?picos, sendo observada a domin?ncia de esp?cies de Paraburkholderia. Entretanto, pela primeira vez, foi constatada a presen?a de esp?cies de Cupriavidus nodulando mimosas, espontaneamente, em tr?s dos quatro biomas estudados, enquanto que esp?cies do g?nero Rhizobium foram bem representadas nos biomas Cerrado e Amaz?nia. Toda cole??o foi agrupada a partir de perfis de Box-PCR ou por meio da compara??o de perfis fenot?picos, sendo selecionadas 188 bact?rias para a submiss?o ao postulado de Koch utilizando M. pudica como planta hospedeira. Deste total, 106 riz?bios foram capazes de formar n?dulos com diferentes caracter?sticas de tamanho, colora??o e atividade da enzima leg-hemoglobina dependendo das estirpes inoculadas. Com base nas sequ?ncias do gene 16S rRNA, 98 bact?rias apresentaram homologias com 16 esp?cies de alfa e beta-riz?bios, consistindo P. tuberum o principal simbionte de mimosas do Brasil. As filogenias dos genes 16S rRNA e recA mostraram que a maioria dos isolados formaram clados distintos para cada esp?cie, sendo estes de baixa variabilidade intraespec?ficas, com exce??o dos isolados das esp?cies P. nodosa e P. diazotrophica que apresentaram diferen?as entre as popula??es de diferentes localidades. Quanto aos genes simbi?ticos (nifH e nodC) foram observadas poucas evid?ncias de eventos de transfer?ncia horizontal de genes, sendo a maior parte dos agrupamentos semelhantes aos observados nas filogenias dos genes conservados. As estirpes do g?nero Cupriavidus apresentaram genes distintos das estirpes tipo e semelhantes as do Uruguai e Brasil, constituindo assim uma popula??o Sul-americana. A partir deste estudo taxon?mico inicial, cinco isolados do g?nero Rhizobium do Distrito Federal mostraram-se distintos de qualquer outra estirpe tipo. Esta diverg?ncia tamb?m foi confirmada por meio de an?lises de sequ?ncias multilocus, compara??o de genoma e testes fenot?picos, sendo confirmado o isolamento de uma nova esp?cie, nomeada Rhizobium altiplani. Por fim, a estirpe tipo de R. altiplani (BR 10423T) foi transformada para a express?o do gene ?rep?rter? GFP e submetida a experimento de inocula??o cruzada. Os resultados mostraram que R. altiplani foi capaz de nodular Phaseolus vulgaris, Vigna unguiculata, Crotalaria juncea e Lupinus angustifolium e M. pudica, no entanto, a efetividade da nodula??o foi diferenciada entre as plantas hospedeiras.
Databáze: OpenAIRE
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