Rhizobia and other legume nodule bacteria richness in brazilian Araucaria angustifolia forest

Abstract

The Araucaria Forest is a sub-type of the Atlantic Forest, dominated by Araucaria angustifolia, which is considered an endangered species. The understory has a high diversity of plant species, including several legumes. Many leguminous plants nodulate with rhizobia and fix atmospheric nitrogen, contributing to forest sustainability. This work aimed at bacteria isolation and phenotypic characterization from the root nodules of legumes occurring in Araucaria Forests, at Campos do Jordão State Park, Brazil. Nodule bacteria were isolated in YMA growth media and the obtained colonies were classified according to their growth characteristics (growth rate, color, extra cellular polysaccharide production and pH change of the medium). Data were analyzed by cluster and principal components analysis (PCA). From a total of eleven collected legume species, nine presented nodules, and this is the first report on nodulation of five of these legume species. Two hundred and twelve bacterial strains were isolated from the nodules, whose nodule shapes varied widely and there was a great phenotypic richness among isolates. This richness was found among legume species, individuals of the same species, different nodule shapes and even among isolates of the same nodule. These isolates could be classified into several groups, two up to six according to each legume, most of them different from the used growth standards Rhizobium tropici, Bradyrhizobium elkanii and Burkholderia sp. There is some evidence that these distinct groups may be related to the presence of Burkholderia spp. in the nodules of these legumes. Key words: N fixation, ombrophilous mixed forest, symbiotic bacteria, phenotypical characterization RIQUEZA DE RIZÓBIOS E DE OUTRAS BACTÉRIAS DE NÓDULOS DE LEGUMINOSAS EM FLORESTA DE Araucaria angustifolia

Characteristics of nodule bacteria from Mimosa spp grown in soils of the Brazilian semiarid region

“…The nodules of M. tenuiflora and M. paraibana were indeterminate, as has been described for those of other Mimosoideae legumes. Indeterminate nodules, with a wide range of size, formats and ramifications are usually attributed to species of Mimosoideae (Sprent et al, 2007), without influence of the microsymbionts (Lammel et al, 2007).However, some of the nodules grew more than usually reported (Patreze and Cordeiro, 2004), reaching more than 20 mm in their longest axis ( Figure 1). M. paraibana is one of the endemic species of caatinga that only recently was identified as capable of fixing nitrogen (Freitas et al, 2010) and the description of its nodules is being reported for the first time.…”

Relationships between microbial activity and soil physical and chemical properties in native and reforested Araucaria angustifolia forests in the state of São Paulo, Brazil

“…For the preservation of this forest, the presence of a high diversity of arbuscular mycorrhizal fungi (Moreira et al, 2009) and diazotrophic bacteria (Lammel et al, 2007), heterotrophic bacteria and archaebacteria (Maluche-Baretta, 2007;Bertini, 2010), and soil invertebrates (Merlim, 2005;Baretta et al, 2010) is fundamental. Conservation is therefore an urgent issue that must be addressed without delay, since the soil quality is fundamental, not only for food, timber, fiber, and fuel production, but also for the maintenance of biodiversity and environmental quality (Doran & Zeiss, 2000;Bastida et al, 2006;Kaschuk et al, 2010).…”

Floristic diversity, richness and distribution of Trentepohliales (Chlorophyta) in Neotropical ecosystems

“…(1 SMSP-Serra do Mar State Park; 2 INP-Itatiaia National Park; 3 CJR-Campos do Jordão Region; 4 SPFF-São Paulo forest fragments; 5 SCNP-Serra da Canastra National Park; 6 CVNP-Chapada dos Veadeiros National Park) exhibit a warm and wet climate without a dry season, seasonal semideciduous forest presents high temperatures but seasonal climate with a relatively severe dry season (generally from April to September) (Morellato et al 2000;Oliveira Filho and Fontes 2000). The mixed forest or Araucaria forest is characterized by the presence of the Brazilian pine (Araucaria angustifolia Kunze), a gymnosperm, and it is distributed along the subtropical, displaying a wet climate and low temperatures in the coldest months (Lammel et al 2007).…”