Soil characteristics determine the rhizobia in association with different species of Mimosa in central Brazil

Abstract

Background and aims To evaluate the influence of soil type on the symbiosis between Mimosa spp. and rhizobia. Methods A greenhouse experiment was carried out with trap plants using seeds of six species of Mimosa and soils from three different locations in central Brazil: Posse, Brasília and Cavalcante. Plant dry biomass and number of nodules were measured after four months. Symbiotic bacteria were isolated from nodules and their molecular identification was performed. Three housekeeping genes (16S rRNA, recA and gyrB) plus the nodC and nifH symbiotic genes were used to determine the identity of the symbionts and to reconstruct the phylogenetic relationships among the isolated nitrogen-fixing bacteria. Results Rhizobia from the Betaproteobacterial genus Paraburkholderia (former Burkholderia) and the Alphaproteobacterial genus Rhizobium were isolated from different species of Mimosa. As in previous studies, the phylogenies of their symbiosis-essential genes, nodC and nifH, were broadly congruent with their core housekeeping genes (16S rRNA, recA and gyrB), which suggests limited or no horizontal gene transfer. Edaphic factors such as pH and fertility influenced the occurrence of these unrelated rhizobial types in the nodules on these Mimosa spp.

Microvirgasp. symbiovar mediterranense nodulatesLupinus cosentiniigrown wild in Morocco

“…Although European, African and American species of Lupinus are generally considered to be nodulated by slowgrowing rhizobia affiliated to different Bradyrhizobium lineages (see Andrews and Andrews 2017 The ability of Microvirga to nodulate lupines may be related to the soil physicochemical properties where they grow. It is known that biotic, for example, the composition and diversity of the microbial community, and abiotic factors, such as salinity, pH, altitude, nutrient availability, etc., play an important role in the interactions between the two partners (Thrall et al 2011;Lemaire et al 2015Lemaire et al , 2016Wang et al 2017;de Castro-Pires et al 2018). The Microvirga LUP strains were isolated form L. cosentinii grown in alkaline soils (pH 7Á5) of the Maamora forest, which is in line with previous results on Microvirga strains recovered from L. micranthus and L. luteus growing in Tunisian alkalinized soils (Msaddak et al 2017a(Msaddak et al , 2017bRejili et al 2019) and suggests that the soil pH is a key factor for determination of the biogeography of the Microvirga species.…”

“…; de Castro‐Pires et al . ). The Microvirga LUP strains were isolated form L. cosentinii grown in alkaline soils (pH 7·5) of the Maamora forest, which is in line with previous results on Microvirga strains recovered from L. micranthus and L. luteus growing in Tunisian alkalinized soils (Msaddak et al .…”

The Root Nodule Microbiome of Cultivated and Wild Halophytic Legumes Showed Similar Diversity but Distinct Community Structure in Yellow River Delta Saline Soils

“…In addition, Naamala et al observed that species of Bradyrhizobium were the major rhizobia detected in G. max [23]. Undoubtedly, fewer rhizobia were characterized in our study, which we speculate could be attributable to the influence of saline soil [24]. This assumption tends to be supported by the result of a previous study that reported rhizobial distribution was affected by environment and soil characteristics [22].…”

Molecular, Physiological, and Symbiotic Characterization of Cowpea Rhizobia from Soils Under Different Agricultural Systems in the Semiarid Region of Brazil

“…In addition to cowpea, Mimosa spp. rhizobia are also influenced by soil conditions in Brazil (Pires et al 2018;de Oliveira et al 2019).…”