Mimosa caesalpiniifolia Benth. adapts to rhizobia populations with differential taxonomy and symbiotic effectiveness outside of its location of origin

Abstract

Mimosa caesalpiniifolia Benth. is a legume native to the semi-arid region of Brazil, in the Northeast. Its successful adaptation to other locations, such as the Atlantic Forest in the Southeast region, may be related to its ability to establish symbiosis with nitrogen-fixing bacteria, especially β-rhizobia of the genus Paraburkholderia. The objective of this work was to determine whether M. caesalpiniifolia adapted to bacterial symbionts in locals where it was introduced. Bacteria were recovered from nodules of M. caesapiniifolia and characterized at the genetic level by BOX-PCR, and sequencing of the 16S rRNA, recA, nifH, and nodC genes. Their symbiotic effectiveness was assessed under axenic conditions. M. caesalpiniifolia nodulated mainly with P. sabiae and a few strains of Rhizobium in the Southeast. On the other hand, the symbionts found in the Northeast were, predominantly, P. diazotrophica. Regardless of its origin, P. diazotrophica promoted a superior accumulation of plant biomass than other bacterial species. The results presented here demonstrate the ability of M. caesalpiniifolia to adapt to bacterial populations outside its location of origin, and indicate that, in this case, the symbiotic effectiveness was associated to the taxonomical classification of the strains.

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).…”

“…In their study, the authors observed the influence of the soil where the bacteria were obtained rather than the biochar management, showing the importance of the soil chemical characteristics in the diversity of cowpea rhizobia. Although, the soil properties are influenced by the agricultural land use, and rhizobial diversity has been highlighted in studies investigating the impact of agriculture on the population of this group of microorganisms, which are important for natural and/or agricultural systems (Leite et al 2009;Yan et al 2014;Vuong et al 2017).…”

“…Probably, due to this reason, these studies reported the predominance of bacteria with phenotypic characteristics associated to low symbiotic efficiency and the inability to renodulate the original host. The influence of different land uses on rhizobia diversity has been highlighted in several studies investigating the impact of agriculture on these important microorganisms in natural and/or agricultural systems (Leite et al 2009;Yan et al 2014;Vuong et al 2017). Even though, these evaluations were not conducted to Brazilian semiarid region.…”