Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-08-23T18:13:31Z No. of bitstreams: 1 2015 - Jakson Leite.pdf: 1055808 bytes, checksum: fa105f74410a81a1f30e45ae5e911c9d (MD5) / Made available in DSpace on 2017-08-23T18:13:31Z (GMT). No. of bitstreams: 1 2015 - Jakson Leite.pdf: 1055808 bytes, checksum: fa105f74410a81a1f30e45ae5e911c9d (MD5) Previous issue date: 2015-02-27 / CAPES / Cowpea [Vigna unguiculata (L.) Walp] is an important crop in northeastern Brazil with strategic advantages for production in semi-arid region, such its drought tolerance and good performance in low fertility soils. In addition, the nitrogen (N) fixed in symbiosis with rhizobia eliminates the demand for N fertilizers, with economic, social and environmental benefits. Little is known about the genetic diversity of bacteria associated to cowpea nodules in Brazilian semi-arid. The aim of the study was to characterize the bacterial diversity of Brazilian semi-arid soils associated with nodules of different cowpea cultivars by dependent and independent bacterial cultivation strategy. Initially a collection of 86 bacteria cowpea nodules isolated from semiarid soils was genetically characterized by partial 16S rRNA gene sequencing and symbiotic genes nifH and nodC. The sequences were compared with the NCBI database to identify isolates and phylogenetic relationships were built. In another study, we applied the independent cultivation method to evaluate bacterial communities associated with the nodules of two cowpea cultivars (BRS and BRS Acau? Pujante), in Ultisol with no history of cowpea cultivation. Nodules (N) were collected 35 days after germination, and soil samples (BS) from 0-20 cm deeper. DNA was extracted for analysis of bacterial communities with 454 pyrosequencing of the 16S ribosomal gene rRNA. The analysis of the diversity of the bacterial collection of the nodules 54 of the 86 isolates were Bradyrhizobium. Other (32) belong to Rhizobium (13) and Microvirga (1), Alfaproteobact?ria class; Burkholderia (8), and Ralstonia (1), Betaproteobacteria class; Acinetobacter (1), Cronobacter (3), Enterobacter (1), and Pantoea (1), Gamaproteobact?ria; and Leifsonia (3), phylum Actinobacteria. As Bradyrhizobium predominated, analyzes were performed with the almost full 16S rRNA, nifH and nodC and isolates were distributed in 5 lines: 16S rRNA type I (44 isolates), type II (6), Type III (1), Type IV ( 2) and type IV (1). Phylogenetic analysis of the 16S rRNA gene grouped the Type I strain in the large group Bradyrhizobium japonicum and close to the type strain of Bradyrhizobium yuanmingense. The analyses of the nifH and nodC gene separated the isolates in 5 symbiotic lines (I, II, III, IV and IV) and were congruent among them, which supports the theory of monophyletic in origin symbiotic gene Bradyhrizobium. The symbiotic lineages I and II are nearby and correspond to all isolates with 16S rRNA type I, being the dominant group associated with nodules. The partial 16S rRNA gene sequencing of bacterial communities showed high diversity in the three environments (BS, RS and N). The communities associated with the nodes were significantly different (p> 0.01) from the surrounding nodules (LS and RS). Phyla Actinobacteria, Bacteriodetes, Proteobacteria were plentiful for BS and RS. In nodes, the Proteobacteria and Bacteriodetes phyla predominated, Gammaproteobacteria being (58.8%) and Alphaproteobacteria (37.4%) in the phylum Proteobacteria and dominant Flavobacteriia (84.8%) and Sphingobacteriia (10.9%) in the phylum Bacteriodetes. For gender, Chryseobacterium, Entreobacter and Bradyrhizobium dominate in all nodes samples where Chryseobacterium prevailed in BRS Acau? and Enterobacter in BRS Pujante. / O feij?o-caupi [Vigna unguiculata (L.) Walp] ? uma das principais culturas no Nordeste do Brasil com vantagens estrat?gicas para produ??o no semi?rido, como toler?ncia a seca e bom desempenho em solos de baixa fertilidade. Al?m disso, fixa N em simbiose com riz?bios eliminando a demanda de fertilizantes nitrogenados, com benef?cios econ?micos, sociais e ambientais. Pouco se sabe sobre a diversidade gen?tica de bact?rias associadas aos n?dulos de feij?o-caupi no semi?rido. O objetivo do estudo foi caracterizar a diversidade de bact?rias de solos do semi?rido brasileiro associadas aos n?dulos de diferentes cultivares de feij?o-caupi com arbordagem que depende e independe de cultivo das bact?rias. Inicialmente uma cole??o de 86 bact?rias de n?dulos de feij?o-caupi isoladas de solos do semi?rido foi caracterizada geneticamente pelo sequenciamento parcial do gene 16S rRNA e dos genes simbi?ticos nifH e nodC. As sequ?ncias foram comparadas com as do banco de dados do NCBI para identificar os isolados e as rela??es filogen?ticas dos mesmos com as de esp?cies conhecidas. Em outro estudo, aplicou-se o m?todo independente de cultivo para avaliar comunidades de bact?rias associadas aos n?dulos de dois cultivares de feij?o-caupi (BRS Pujante e BRS Acau?), em Argissolo Amarelo sem hist?rico de uso com a lavoura. Os n?dulos (N) foram coletados 35 dias ap?s a germina??o e a amostragem do solo (BS) de 0-20 cm. O DNA das amostras foi extra?do para an?lises das comunidades bacterianas com 454 pirosequenciamento do gene ribossomal 16S rRNA. Na an?lise da diversidade da cole??o de n?dulos 54 dos 86 dos isolados foram de Bradyrhizobium. Os demais (32) pertencem aos g?neros Rhizobium (13) e Microvirga (1), classe Alfaproteobact?ria; Burkholderia (8) e Ralstonia (1), classe Betaproteobact?ria; Acinetobacter (1), Cronobacter (3), Enterobacter (1) e Pantoea (1), Gamaproteobact?ria; e Leifsonia (3), filo Actinobact?ria. Como Bradyrhizobium predominou, foram feitas an?lises com os genes 16S rRNA, nifH e nodC e os isolados distribu?ram-se em 5 linhagens: 16S rRNA tipo I (44 isolados), tipo II (6), tipo III (1), tipo IV (2) e tipo IV (1). A an?lise filogen?tica do gene 16S rRNA agrupou a linhagem tipo I no grande grupo Bradyrhizobium japonicum e pr?ximo da estirpe tipo de Bradyrhizobium yuanmingense. A an?lise dos genes nifH e nodC separou os isolados em 5 linhagens simbi?ticas (I, II, III, IV e IV) e as ?rvores foram congruentes, o que suporta a teoria da origem monofil?tica de genes simbi?ticos em Bradyhrizobium. As linhagens simbi?ticas I e II s?o pr?ximas e correspondem a todos os isolados com 16S rRNA tipo I, sendo o grupo dominante associado aos nodulos. O sequenciamento parcial do gene 16S rRNA das comunidades bacterianas mostrou alta diversidade nos tr?s ambientes (BS, RS e N). As comunidades associadas aos n?dulos foram significativamente diferentes (p> 0,01) das que cercam os n?dulos (LS e RS). Os filos Actinobacteria, Bacteriodetes, Proteobacteria foram abundantes para BS e RS. Em n?dulos, os filos Proteobacteria e Bacteriodetes predominaram, sendo Gammaproteobacteria (58,8%) e Alphaproteobacteria (37,4%) dominantes no filo Proteobacteria e Flavobacteriia (84,8%) e Sphingobacteriia (10,9%) no filo Bacteriodetes. Para g?nero, Chryseobacterium, Entreobacter e Bradyrhizobium dominam em todas as amostras de n?dulos, onde Chryseobacterium predominou em BRS Acau? e Enterobacter em BRS Pujante.