Caracterização de rizóbios isolados de Jacatupé cultivado em solo salino no Estado de Pernanbuco, Brasil

Abstract

CHARACTERIZATION OF ISOLATED RHIZOBIA OF PACHYRHYZUS EROSUS CULTIVATED IN SALINE SOIL Of THE STATE OF PERNAMBUCO, BRAZILInvestigation on microbiological biodiversity in the saline soils involves searching for tolerant genotypes to this type of emvironmental stress. Genotypic data associated to morphologic, physiological and biochemical characteristics of bacteria provide important information regarding its identification and clusters. The objective of this work was to characterize indigenous rhizobial strains of saline soils in the Wasteland and Hinterland of Pernambuco State, using yam bean (Pachyrhizus erosus L. Urban) as plant-tramp. Assays had been performed in YMA media and the observed cultivation characteristics of twenty-four isolates had been: change of pH, time of growth, transparency, form, edge, production of exopolysaccharides of the colonies and resistance to salinity. DNA amplification by the PCR technique of the repetitive sequence BOX indicated a high level of genetic and fenotipic diversity between the thirteen indigenous isolates. Comparing cultivation and genetic characteristics of these isolates with

Exopolysaccharides produced by the symbiotic nitrogen-fixing bacteria of leguminosae

“…Besides, under normal cultivation conditions, there is great variability in the production of EPS by rhizobia strains, both quantitatively and qualitatively. The strains with high levels of EPS production tend to be more tolerant to acidic conditions and salinity than strains that produce low EPS levels (Cunningham & Munns, 1984;Eaglesham et al, 1987;Xavier et al, 1998;Freitas et al, 2007;Xavier et al, 2007). In the case of saline stress, the EPS surrounds the bacterial cells, decreasing the cell surface contact with the saline medium and increasing cell resistance to the osmotic effect (Elsheikh & Wood, 1990).…”

Plant growth-promoting rhizobacteria improved growth, nutrient, and hormone content of cabbage (Brassica oleracea) seedlings

“…Current efforts have been focused on the decreased use of chemical pesticides and inorganic fertilizers in agriculture, prompting the search for alternative ways to enhance soil fertility and crop production. Because the use of PGPR with the aim of improving nutrient availability for plants can be important for agriculture (Freitas et al, 2007), PGPRs have been recently used increasingly worldwide in sustainable agriculture as biological fertilizer (Yildirim et al, 2011a).…”

Phenotypic and molecular fingerprinting of fast growing rhizobia of field-grown pigeonpea from the eastern edge of the Brazilian Pantanal

“…Stocco et al (2008) observed similar results in an evaluation of the genetic diversity of common bean with both techniques. Both ARDRA and Box-PCR are feasible and inexpensive techniques that can be used to evaluate the fingerprinting of a diazotrophic bacterial collections (Zilli et al, 2004;Freitas et al, 2007;Stocco et al, 2008;Leite et al, 2009;Teixeira et al, 2010;Lima et al, 2012;Fernandes Jr. et al, 2013).…”

“…Evaluations of the diversity of rhizobial strains using phenotypic characterization combined with molecular fingerprinting have revealed the great diversity in strains isolated from different Brazilian regions from cowpea (Zilli et al, 2004;Leite et al, 2009;Florentino et al, 2010), yam bean (Freitas et al, 2007), and common bean (Stocco et al, 2008). In the Brazilian Pantanal, studies evaluating the diversity of nodule-forming bacteria with phenotypic and molecular methods remain scarce in spite of the great diversity of the plant cover in the region.…”