Diazotrophic bacteria associated to sugarcane varieties cropped at Northeast Region of Brazil

Abstract

The objective of this work was to study the diversity of diazotrophic bacteria associated to 10 varieties of sugarcane cultivated in two states of the Northeast of Brazil and to identify the isolates by morphological and molecular methods. Diversity was studied by the application of traditional growth-depending microbiological methods: Gram-staining, comparison of colony morphology and growth on several culture media. Phylogenetic taxonomy was performed using 16S rRNA gene sequencing data. Almost all isolates obtained in semi-solid nitrogen free media were classified as Gram-negative and seven colony morphological groups were distinguished after growth on Potato medium. Among the 10 varieties evaluated, RB72454 resulted in higher number of isolates and diversity. The great majority of isolates from most of the genotypes tested showed similar characteristic to the genus Gluconacetobacter based on its peculiar colony morphology and growth characteristics in semi-solid media. Comparison of the 16S rRNA sequence of each isolate to the Genbank showed that they are closely related to Gluconacetobacter, Burkholderia, Kosakonia, Klebsiella and Stenotrophomonas.Key words: biological nitrogen fixation, ecology of diazotrophic bacteria, sugarcane Bactérias diazotróficas associadas a variedades de cana-de-açúcar cultivadas na região Nordeste do Brasil RESUMOO objetivo deste trabalho foi estudar a diversidade de bactérias diazotróficas associadas a 10 variedades de cana cultivadas em dois estados do Nordeste do Brasil e identificar os isolados por métodos morfológicos e moleculares. A diversidade foi estudada através da aplicação de métodos microbiológicos tradicionais dependentes de crescimento: coloração de Gram, comparação da morfologia de colónias e crescimento em vários meios de cultura. Taxonomia filogenética foi realizada utilizando dados de sequenciamento de gene 16S rRNA. Quase todos os isolados obtidos em meios semissólidos livres de nitrogênio foram classificados como Gram-negativos e sete grupos baseados na morfologia de colônias foram distinguidos após crescimento em meio batata. Entre as 10 variedades avaliadas, RB72454 resultou em maior diversidade e número de isolados. A grande maioria dos isolados dos genótipos testados apresentaram característica similar ao gênero Gluconacetobacter com base em seu peculiar crescimento em meios semissólidos e morfologia da colônia. A comparação da sequência do 16S rRNA de cada isolado com sequencias do GenBank mostrou que eles estão intimamente relacionados com Gluconacetobacter,

Microbial inoculants: reviewing the past, discussing the present and previewing an outstanding future for the use of beneficial bacteria in agriculture

“…Sugarcane is able to associate with a great diversity of diazotrophic plant growth-promoting bacteria, including species of the genera Azospirillum (Reis Junior et al 2000; Tejera et al 2005), Azotobacter (Tejera et al 2005), Burkholderia (Perin et al 2006; Antonio et al 2016; Silva et al 2016; Leite et al 2018a, b), Herbaspirillum (Baldani et al 1996; Reis Junior et al 2000), Pantoeae (Taulé et al 2012; Fischer et al 2012, Silva et al 2016), and the species Gluconacetobacter diazotrophicus (basonym Acetobacter diazotrophicus ) (Cavalcante and Döbereiner 1988; Munõz-Rojas and Caballero-Mellado 2003; Restrepo et al 2017), among others.…”

Application of Bryophyte Rhizoid-Associated Bacteria Increases Silicon Accumulation and Growth in Maize (Zea Mays L.) Seedlings

“…Several Kosakonia species isolated from soils and trees promote plant growth (Brady et al, 2013). Diazotrophic bacteria, K. pneumoniae and K. radicincitans were found to be associated sugarcane at Northeast Region of Brazil (Antonio et al, 2016). K. radicincitans improves fruit yield and quality of Solanum lycopersicum (Berger et al, 2017).…”