Diversidade e capacidade simbiótica de rizóbios isolados de nódulos de Mucuna-Cinza e Mucuna-Anã

Abstract

As espécies de mucuna são muito utilizadas como adubos verdes, e poucas informações estão disponíveis a respeito dos rizóbios nativos capazes de nodulá-las. O objetivo deste trabalho foi avaliar a diversidade e a capacidade simbiótica de isolados bacterianos de nódulos de mucuna-cinza (Mucuna pruriens (L.) DC.) e mucuna-anã (Mucuna deeringiana (Bort.) Merr.). As bactérias foram isoladas de nódulos de mucunas cinza e anã cultivadas em vasos com solos de um sistema de produção agroecológica. Foram isoladas 160 bactérias, sendo 80 de mucuna-anã e 80 de mucuna-cinza, que foram autenticadas e selecionadas para avaliação da capacidade simbiótica. A diversidade dos isolados foi avaliada por meio das características culturais em meio de cultura YMA e da técnica de análise de restrição do produto de PCR do gene 16S rDNA. A inoculação de cinco isolados em mucuna-cinza e dois em mucuna-anã apresentou elevada biomassa da parte aérea. A maioria dos isolados apresentou crescimento rápido e acidificou o meio de cultura. A análise de restrição demonstrou que as bactérias isoladas apresentam baixa similaridade com estirpes de referência, sugerindo a existência de isolados pertencentes a novos grupos, capazes de nodular as mucunas anã e cinza.

Prospecting of efficient rhizobia for peanut inoculation in a Planosol under different vegetation covers

“…This has also been observed for rhizobia isolates, inoculated in other legumes (Lima et al, 2012;Calheiros et al, 2013). Such variability in symbiotic system which has the ability of collections of rhizobia, is a result of high biodiversity of these microorganisms, associated with biotic and abiotic factors.…”

“…In recent years, prospecting of effective rhizobia for the inoculation of various legumes has been carried out in Brazilian soils, yielding promising results for calopo (Calheiros et al, 2013;Calheiros et al, 2015), velvet bean (Lima et al, 2012) and cowpea (Chagas Junior et al, 2010), among others. Nonetheless, few studies have evaluated the efficiency of peanut isolates (Hoffman et al, 2007;Torres Júnior et al, 2014;Sizenando et al, 2016).…”

Diversity of new root nodule bacteria from Erythrina velutina Willd., a native legume from the Caatinga dry forest (Northeastern Brazil)

“…The increased percentage of bacteria which are not able to re-nodulate the original host species is commonly found in studies of bacteria isolation from nodules of species in tropical climates (Lima et al, 2012). This incapacity may occur due to the loss of plasmids that carry the symbiotic genes during the successive cultivations in the process of isolation, purification and storage (Garcia de los Santos, 1996).…”

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).…”

“…The isolation and characterization of rhizobia from grain legumes such as soybean, cowpea, and common bean, have resulted in the identification of bacteria able to fix high amounts of N for use in improving crop nutrition and yield (Hungria et al, 2000;Martins et al, 2003). On the other hand, rhizobial isolation from other neglected crops, such as those used as green manure, is beginning in Brazil, and recent studies regarding the diversity and biotechnological applications of bacteria from green manure root nodules have shown great potential (Fernandes Jr. et al, 2010Lima et al, 2012).…”