Exploring the Potential of Four Novel Halotolerant Bacterial Strains as Plant-Growth-Promoting Rhizobacteria (PGPR) under Saline Conditions
Soil salinity, due to natural phenomena or human activities, alters the water potential, which in turn affects plant growth, negatively influencing their nutrient and water uptake. Plant-growth-promoting rhizobacteria (PGPR) can be used to counteract these negative effects, especially in glycophytes...
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| Format: | Article |
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MDPI AG
2023-03-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/13/7/4320 |
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| author | Gianmaria Oliva Luca Di Stasio Giovanni Vigliotta Francesco Guarino Angela Cicatelli Stefano Castiglione |
| author_facet | Gianmaria Oliva Luca Di Stasio Giovanni Vigliotta Francesco Guarino Angela Cicatelli Stefano Castiglione |
| author_sort | Gianmaria Oliva |
| collection | DOAJ |
| description | Soil salinity, due to natural phenomena or human activities, alters the water potential, which in turn affects plant growth, negatively influencing their nutrient and water uptake. Plant-growth-promoting rhizobacteria (PGPR) can be used to counteract these negative effects, especially in glycophytes. The aim of our study was to characterize physiologically, genetically, and biochemically the novel halotolerant/halophilic bacteria isolated in our previous work. We evaluated the plant-growth-promoting (PGP) features and NaCl regulation’s roles in them. In this regard, analysis based on 16S rDNA sequences confirmed that our isolates are distinct bacterial strains, probably belonging to new species, which we named <i>Bacillus</i> sp. M21 and M23 and <i>Halomonas</i> sp. QH23 and QH24. In literature, it is known that many species of <i>Halomonas</i> and <i>Bacillus</i> genera produce factors regulating plant development, such as indole-3-acetic acid (IAA), ammonium, and siderophores; and their efficiency in promoting plant growth and productivity was also demonstrated in vivo. We demonstrated that the newly isolated strains exhibit different PGP activities, highlighting how the latter are regulated by NaCl and in a strain-dependent manner. In particular, the main results showed that NaCl negatively affects the production of IAA in QH23, M21 and M23, whereas it promotes it in QH24, where it is strictly salt-dependent. Both <i>Halomonas</i> strains produce ammonium only in the presence of NaCl, directly correlated to its concentration. The opposite occurs in <i>Bacillus</i> strains, where salt reduces its production up to ten times. Overall, the results underline how halotolerance is a preferable, but not sufficient, condition for considering a PGPR potentially useful in applications aimed at improving the tolerance and productivity of crops in saline soils. |
| first_indexed | 2024-03-11T05:43:16Z |
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| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-11T05:43:16Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-d04322cdb1e747ea8be4e9370712a65d2023-11-17T16:18:40ZengMDPI AGApplied Sciences2076-34172023-03-01137432010.3390/app13074320Exploring the Potential of Four Novel Halotolerant Bacterial Strains as Plant-Growth-Promoting Rhizobacteria (PGPR) under Saline ConditionsGianmaria Oliva0Luca Di Stasio1Giovanni Vigliotta2Francesco Guarino3Angela Cicatelli4Stefano Castiglione5Department of Chemistry and Biology “A. Zambelli”, University of Salerno, 84084 Fisciano, SA, ItalyDepartment of Chemistry and Biology “A. Zambelli”, University of Salerno, 84084 Fisciano, SA, ItalyDepartment of Chemistry and Biology “A. Zambelli”, University of Salerno, 84084 Fisciano, SA, ItalyDepartment of Chemistry and Biology “A. Zambelli”, University of Salerno, 84084 Fisciano, SA, ItalyDepartment of Chemistry and Biology “A. Zambelli”, University of Salerno, 84084 Fisciano, SA, ItalyDepartment of Chemistry and Biology “A. Zambelli”, University of Salerno, 84084 Fisciano, SA, ItalySoil salinity, due to natural phenomena or human activities, alters the water potential, which in turn affects plant growth, negatively influencing their nutrient and water uptake. Plant-growth-promoting rhizobacteria (PGPR) can be used to counteract these negative effects, especially in glycophytes. The aim of our study was to characterize physiologically, genetically, and biochemically the novel halotolerant/halophilic bacteria isolated in our previous work. We evaluated the plant-growth-promoting (PGP) features and NaCl regulation’s roles in them. In this regard, analysis based on 16S rDNA sequences confirmed that our isolates are distinct bacterial strains, probably belonging to new species, which we named <i>Bacillus</i> sp. M21 and M23 and <i>Halomonas</i> sp. QH23 and QH24. In literature, it is known that many species of <i>Halomonas</i> and <i>Bacillus</i> genera produce factors regulating plant development, such as indole-3-acetic acid (IAA), ammonium, and siderophores; and their efficiency in promoting plant growth and productivity was also demonstrated in vivo. We demonstrated that the newly isolated strains exhibit different PGP activities, highlighting how the latter are regulated by NaCl and in a strain-dependent manner. In particular, the main results showed that NaCl negatively affects the production of IAA in QH23, M21 and M23, whereas it promotes it in QH24, where it is strictly salt-dependent. Both <i>Halomonas</i> strains produce ammonium only in the presence of NaCl, directly correlated to its concentration. The opposite occurs in <i>Bacillus</i> strains, where salt reduces its production up to ten times. Overall, the results underline how halotolerance is a preferable, but not sufficient, condition for considering a PGPR potentially useful in applications aimed at improving the tolerance and productivity of crops in saline soils.https://www.mdpi.com/2076-3417/13/7/4320salinityNaCl tolerancebacterial consortium<i>Halomonas</i><i>Bacillus</i> |
| spellingShingle | Gianmaria Oliva Luca Di Stasio Giovanni Vigliotta Francesco Guarino Angela Cicatelli Stefano Castiglione Exploring the Potential of Four Novel Halotolerant Bacterial Strains as Plant-Growth-Promoting Rhizobacteria (PGPR) under Saline Conditions Applied Sciences salinity NaCl tolerance bacterial consortium <i>Halomonas</i> <i>Bacillus</i> |
| title | Exploring the Potential of Four Novel Halotolerant Bacterial Strains as Plant-Growth-Promoting Rhizobacteria (PGPR) under Saline Conditions |
| title_full | Exploring the Potential of Four Novel Halotolerant Bacterial Strains as Plant-Growth-Promoting Rhizobacteria (PGPR) under Saline Conditions |
| title_fullStr | Exploring the Potential of Four Novel Halotolerant Bacterial Strains as Plant-Growth-Promoting Rhizobacteria (PGPR) under Saline Conditions |
| title_full_unstemmed | Exploring the Potential of Four Novel Halotolerant Bacterial Strains as Plant-Growth-Promoting Rhizobacteria (PGPR) under Saline Conditions |
| title_short | Exploring the Potential of Four Novel Halotolerant Bacterial Strains as Plant-Growth-Promoting Rhizobacteria (PGPR) under Saline Conditions |
| title_sort | exploring the potential of four novel halotolerant bacterial strains as plant growth promoting rhizobacteria pgpr under saline conditions |
| topic | salinity NaCl tolerance bacterial consortium <i>Halomonas</i> <i>Bacillus</i> |
| url | https://www.mdpi.com/2076-3417/13/7/4320 |
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