BradyrhizobiumandPseudomonasstrains obtained from coal-mining areas nodulate and promote the growth ofCalopogonium muconoidesplants used in the reclamation of degraded areas

Abstract

Aims: The objective of this work was to isolate and characterize indigenous rhizobia from coal-mining areas able to efficiently nodulate and fix nitrogen in association with Calopogonium mucunoides (calopo). Methods and Results: Isolation, authentication and morphological, biochemical and molecular characterization of the autochthonous rhizobia were performed and their symbiotic efficiency (SE) evaluated. Efficient rhizobial isolates suitable for the inoculation of calopo in coal-mining regions were obtained. A total of 30 isolates were obtained after nodulation authentication, of which five presented high SE with plant-growth promoting traits such as indole-3-acetic acid production, phosphate solubilization and biofilm formation. These isolates were identified as belonging to Bradyrhizobium, Pseudomonas and Rhizobium. Conclusions: Bradyrhizobium sp. A2-10 and Pseudomonas sp. A6-05 were able to promote calopo plant growth using soil obtained from coal-mining degraded areas, thus indicating their potential as inoculants aiming at land reclamation. Significance and Impact of the Study: To our knowledge, this is the first report of Pseudomonas nodule formation in calopo. Furthermore, the results demonstrated that autochthonous rhizobia obtained from degraded soils presented high SE in calopo and possess a wide range of plant-growth promoting traits. Ultimately, they may all contribute to an increased leguminous plant growth under stress conditions. The selected rhizobia strains may be used as inoculants and present a valuable role in the development of strategies aiming to recover coal-mining degraded areas. Bacterial inoculants would greatly reduce the use of often harmful nitrogen fertilizers vastly employed in revegetation programmes of degraded areas.the removal and deposition of soil, the mixing of other materials, and the removal of native vegetation from the impacted sites. An example of coal-mining pollution is seen in the Santa Catarina coal basin, located in southern Brazil, which has been classified as critical (Stahl et al. 2002). Soils from these areas are highly degraded, with Journal of Applied Microbiology 126, 523--533

The extreme plant‐growth‐promoting properties ofPantoea phytobeneficialisMSR2 revealed by functional and genomic analysis

“…This plant naturally associates with rhizobia, however, stress conditions greatly impact the nodulation process and C . mucunoides plant growth (González et al ., ).…”

“…Calopogonium mucunoides is a leguminous plant able to grow in acidic soils, thus facilitating the recovery of highly acidic soils associated with coal-mining activities. This plant naturally associates with rhizobia, however, stress conditions greatly impact the nodulation process and C. mucunoides plant growth (González et al, 2019).…”

Is the Application of Plant Probiotic Bacterial Consortia Always Beneficial for Plants? Exploring Synergies between Rhizobial and Non-Rhizobial Bacteria and Their Effects on Agro-Economically Valuable Crops

“…For instance, Hu et al [71] suggested that probiotic Pseudomonas communities may manage the functionality of the microbial communities associated with tomato via regulation of important plant-growth-promoting traits. Moreover, some authors have attributed the capacity to form nodules in legumes to some strains of this genus, as well as to some Paenibacillus and Enterobacteria strains [40,[72][73][74]. However, these studies must be taken very cautiously, as they showed no conclusive proof or correct controls.…”

Agronomic efficiency of an inoculant based on Bacillus amyloliquefaciens FZB45 for corn and soybean crops

“…Plant growth promoting bacteria (PGPB) can act through different mechanisms (direct and indirect) in increasing agricultural productivity, being characterized as an innovative technology for increasing sustainability in agricultural systems (González et al, 2019;Nascimento et al, 2020a). Notoriously, the role played by PGPB in agriculture is consolidated in the provision of nutrients such as nitrogen (N), resulting in the wide use of commercial products used for this purpose (Quintas-Nunes et al, 2022).…”