Inoculation of Pseudomonas mutant strains can improve growth of soybean and corn plants in soils under salt stress
Section snippets
. Introduction
Currently, soybean and corn crops stand out for being the ones with the greatest territorial expansion and causing the main losses of biodiversity in tropical regions (Phalan et al., 2013). In Argentina, soybean and corn are the two main crops and the largest source of foreign exchange with 17.2 and 9.1 million planted hectares, respectively (Ministry of Agriculture, Livestock, Fishing, 2019). For these reasons, Argentina is the world's third-largest producer of soybean and is positioned among
Microorganisms, chemical, and culture media
Microorganisms used in this work were: P. putida KT2440, wild-type strain, derived from P. putida mt-2 strain (Regenhardt et al., 2002); and the mus-20, mus-42, and EU206 mutants (Martínez-Gil et al., 2013). The four strains were kindly provided by the Department of Environmental Protection, Zaidín Experimental Station, CSIC, Granada, Spain.
Luria-Bertani (LB) medium, used for maintaining the strains and studying the microbial growth, contained (g L−1): NaCl, 5.0; yeast extract, 5.0; casein
Characterization of PGPR traits
In this study, the ability to solubilize phosphates and synthesize indolic compounds and siderophores by the P. putida KT2440 strain and the mus-20, mus-42, and EU206 mutants was assessed (Table 2).
In this study, the presence of phosphate solubilization halos was not visualized for any of the evaluated strains, after 24 h of incubation. However, small halo zones were observed after 72 h. These results indicate that P. putida KT2440 and its mutants would have ability to solubilize P in the PKV
. Discussion
The use of highly saline soils, unsuitable for agriculture, represents a promising solution to improve food production and reduce the exploitation of native forests. In this context, the incorporation of PGPRs can be a useful tool to achieve this goal. Therefore, in the current study, different mutants of P. putida with non-biofilm producing and EPS overproducing phenotypes were tested for their ability to produce indolic compounds, synthesize siderophores, and solubilize phosphate. Besides,
Conclusions
Taken together, these findings suggest that the inoculation with P. putida KT2440 and its mutants could be suitable for improving plant growth promotion in soybean and corn crops, even under saline conditions, as an alternative to chemical fertilizers. Comparing the plant growth promotion effects of the three mutants, the EU206 strain appears to be the most efficient PGPR by significantly increasing seed germination, shoot and root lengths, and fresh and dry weights of plants regarding the
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
Authors acknowledge financial support of PICT 2017-2285 and PICT 2018-3552 grants from Fondo para la Investigación Científica y Tecnológica (FONCyT) and PIP 908-15 grant from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). The authors would like to show their gratitude to Dr. Fabián E. López for his assistance during the planning and development of this research work. The authors also acknowledge Eng. M. Carolina Caram di Santo and Biochem. Pharma. Ana M. Zenoff for their
References (76)
A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding
Anal. Biochem.
(1976)- et al.
Phytotoxicity of hexachlorocyclohexane: effect on germination and early growth of different plant species
Chemosphere
(2010) - et al.
Effect of biofilm forming plant growth promoting rhizobacteria on salinity tolerance in barley
Ann. Agric. Sci.
(2016) - et al.
An AM fungus and a PGPR intensify the adverse effects of salinity on the stability of rhizosphere soil aggregates of Lactuca sativa
Soil Biol. Biochem.
(2010) - et al.
Induction of antioxidant enzymes is involved in the greater effectiveness of a PGPR versus AM fungi with respect to increasing the tolerance of lettuce to severe salt stress
Environ. Exp. Bot.
(2009) - et al.
Alginate-perlite encapsulated Pseudomonas putida A (ATCC 12633) cells: preparation, characterization and potential use as plant inoculants
J. Biotechnol.
(2018) - et al.
Interplay between extracellular matrix components of Pseudomonas putida biofilms
Res. Microbiol.
(2013) - et al.
Plant hormones and seed germination
Environ. Exp. Bot.
(2014) - et al.
Bioremediation of lindane-contaminated soils by combining of bioaugmentation and biostimulation: effective scaling-up from microcosms to mesocosms
J. Environ. Manag.
(2020) - et al.
Siderophore production by Pseudomonas aeruginosa FP6, a biocontrol strain for Rhizoctonia solani and Colletotrichum gloeosporioides causing diseases in chilli
Agric. Nat. Resour.
(2016)
Universal chemical assay for the detection and determination of siderophores
Anal. Biochem.
Exopolysaccharide-producing plant growth-promoting rhizobacteria under salinity condition
Pedosphere
Comparative effectiveness of Pseudomonas and Serratia sp. containing ACC-deaminase for improving growth and yield of wheat (Triticum aestivum L.) under salt-stressed conditions
Arch. Microbiol.
Effectiveness of exopolysaccharides and biofilm forming plant growth promoting rhizobacteria on salinity tolerance of faba bean (Vicia faba L.)
Afr. J. Microbiol. Res.
Biofilm formation is determinant in tomato rhizosphere colonization by Bacillus velezensis FZB42
Environ. Sci. Pollut. Res.
Multifaceted plant-associated microbes and their mechanisms diminish the concept of direct and indirect PGPRs
Smart engineering of genetic resources for enhanced salinity tolerance in crop plants
Crit. Rev. Plant Sci.
Plant growth-promoting rhizobacteria: context, mechanisms of action, and roadmap to commercialization of biostimulants for sustainable agriculture
Front. Plant Sci.
Response of maize (Zea mays L.) to seed priming with NaCl and salinity stress
Spanish J. Agric. Res.
Efficient rhizosphere colonization by Pseudomonas fluorescens f113 mutants unable to form biofilms on abiotic surfaces
Environ. Microbiol.
Mucoid mutants of the biocontrol strain Pseudomonas fluorescens CHA0 show increased ability in biofilm formation on mycorrhizal and nonmycorrhizal carrot roots
Mol. Plant Microbe Interact.
Desarrollo de un método para evaluar el daño ocasionado por aves en cultivos comerciales de soja recién emergida
Idesia (Arica)
Pseudomonas PS01 isolated from maize rhizosphere alters root system architecture and promotes plant growth
Microorganisms
Evaluation of salinity tolerance indices in seedling of maize (Zea mays L.)
Revista Fac. Agron. Univ. Nac. La Plata
Microflora of the Soybean Rhizosphere in Conditions of High Salinity: Isolation and Study of Pseudomonas Putida Strains Benefits against Saline Stress
Plant growth promotion by Pseudomonas putida KT2440 under saline stress: role of eptA
Appl. Microbiol. Biotechnol.
Effect of phosphate-solubilizing Pseudomonas putida on the growth of maize and its survival in the rhizosphere
Indones. J. Crop Sci.
High incidence of plant growth-stimulating bacteria associated with the rhizosphere of wheat grown on salinated soil in Uzbekistan
Environ. Microbiol.
Genetic analysis of functions involved in adhesion of Pseudomonas putida to seeds
J. Bacteriol.
Root colonization by Pseudomonas putida: love at first sight
Microbiology
Cell density- dependent gene contributes to efficient seed colonization by Pseudomonas putida KT2440
Appl. Environ. Microbiol.
Fatty acid-mediated signalling between two Pseudomonas species
Environ. Microbiol. Rep.
Comparison of five bacterial strains producing siderophores with ability to chelate iron under alkaline conditions
AMB Express
Passing the baton between laps: adhesion and cohesion in Pseudomonas putida biofilms
Mol. Microbiol.
A critical examination of the specificity of the Salkowski reagent for indolic compounds produced by phytopathogenic bacteria
Appl. Environ. Microbiol.
Plant root growth, architecture and function
Plant Soil
Differential biofilm formation and motility associated with lipopolysaccharide/exopolysaccharide-coupled biosynthetic genes in Stenotrophomonas maltophilia
J. Bacteriol.
Cited by (18)
Role of beneficial soil microbes in alleviating climatic stresses in plants
2022, Microbiome Under Changing Climate: Implications and SolutionsBacillus sp., fertilization forms, and salt stress on soybean production
2024, Revista Brasileira de Engenharia Agricola e Ambiental
- 1
These authors contributed equally to this work.