Paraburkholderia atlantica is the main rhizobial symbiont of Mimosa spp. in ultramafic soils in the Brazilian Cerrado biome

Abstract

were characterized for their nodulation capacity on M. pudica and common bean, and their tolerance to Ni in culture medium. Bacteria were also partially identified by their 16S rRNA gene sequences. In addition, recA, gyrB, nodC and nifH genes from five representative isolates were sequenced for phylogenetic studies. Results In situ detection indicated the exclusive presence of Paraburkholderia sp. within the nodules. This identification was confirmed for most of the isolates by the analysis of their 16S rRNA gene sequences. All isolates identified as Paraburkholderia sp. were able to effectively nodulate M. pudica, but those tested in common bean produced ineffective

Mimosaspecies endemic to acidic soils in central Brazil are nodulated by a high diversity ofParaburkholderiagenotypes, but widespread species are nodulated byParaburkholderia,CupriavidusorRhizobiumdepending on soil characteristics

“…Paraburkholderia caribensis was first reported to be a symbiont of Mimosa in Taiwan by Chen et al (2003a), but the (non-symbiotic) type strain MWAP64 T was isolated originally from soils in Martinique (Achouak et al 1999); since then, P. caribensis has been isolated from nodules of invasive Mimosa species in various locations in Asia, such as China (Liu et al 2020), but this is the first report of it as a symbiont of Mimosa in Brazil. Similarly, P. phenoliruptrix was originally isolated from a chemostat (Coenye et al 2004) and then revealed to be related to a symbiont of M. flocculosa in Brazil, as represented by Burkholderia strain BR3462 (Chen et al 2005a), which was later formally described as P. phenoliruptrix strain BR3459a (Cunha et al 2012), and which like BR3614 (this study), possesses P. phymatum -type nod and nif genes (Soares-Neto et al 2022). Thereafter, P. phenoliruptrix has been quite frequently isolated as a nodulating symbiont of native Mimosa and Calliandra species in Brazil, and with widely varying nod and nif genes (this study), but also of introduced species like Acacia decurrens (Zilli et al 2021; this study).…”

“…A significant difference between central Brazil and central Mexico is that soils are highly acidic in the former (dos Reis Junior et al 2010) and neutral-alkaline in the latter (Bontemps et al 2016). Low soil pH is a known factor in promoting the occurrence of acid-tolerant Paraburkholderia (Stopnisek et al 2014) as symbionts in both the main centers of Beta-rhizobial diversity, central Brazil and the CCR of South Africa (Garau et al 2009;Howieson et al 2013;Lemaire et al 2015Lemaire et al , 2016Pires et al 2018), especially when combined with low soil fertility (Elliott et al 2009;Pires et al 2018;Soares-Neto et al 2022).…”

“…was surveyed across their native range in several states of Brazil, encompassing various biomes. Rhizobial diversity is almost certainly at least partly related to soil characteristics (Elliott et al 2009;Bontemps et al 2016;Pires et al 2018;Soares-Neto et al 2022), given the solid biogeographical relationships between Mimosa diversity and its native environments. However, it is difficult to establish which factors other than co-evolution are involved in the selection of symbionts by many Mimosa spp.…”