Exopolysaccharide II Is Relevant for the Survival of <i>Sinorhizobium meliloti</i> under Water Deficiency and Salinity Stress
<i>Sinorhizobium meliloti</i> is a soil bacterium of great agricultural importance because of its ability to fix atmospheric nitrogen in symbiotic association with alfalfa (<i>Medicago sativa</i>) roots. We looked into the involvement of exopolysaccharides (EPS) in its surviv...
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MDPI AG
2020-10-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/25/21/4876 |
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| author | Emiliano Primo Pablo Bogino Sacha Cossovich Emiliano Foresto Fiorela Nievas Walter Giordano |
| author_facet | Emiliano Primo Pablo Bogino Sacha Cossovich Emiliano Foresto Fiorela Nievas Walter Giordano |
| author_sort | Emiliano Primo |
| collection | DOAJ |
| description | <i>Sinorhizobium meliloti</i> is a soil bacterium of great agricultural importance because of its ability to fix atmospheric nitrogen in symbiotic association with alfalfa (<i>Medicago sativa</i>) roots. We looked into the involvement of exopolysaccharides (EPS) in its survival when exposed to different environmental stressors, as well as in bacteria–bacteria and bacteria–substrate interactions. The strains used were wild-type Rm8530 and two strains that are defective in the biosynthesis of EPS II: wild-type Rm1021, which has a non-functional <i>expR</i> locus, and mutant Rm8530 <i>expA</i>. Under stress by water deficiency, Rm8530 remained viable and increased in number, whereas Rm1021 and Rm8530 <i>expA</i> did not. These differences could be due to Rm8530′s ability to produce EPS II. Survival experiments under saline stress showed that viability was reduced for Rm1021 but not for Rm8530 or Rm8530 <i>expA</i>, which suggests the existence of some regulating mechanism dependent on a functional <i>expR</i> that is absent in Rm1021. The results of salinity-induced stress assays regarding biofilm-forming capacity (BFC) and autoaggregation indicated the protective role of EPS II. As a whole, our observations demonstrate that EPS play major roles in rhizobacterial survival. |
| first_indexed | 2024-03-10T15:25:43Z |
| format | Article |
| id | doaj.art-7d1279abdba54951a73c3d93348660b9 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T15:25:43Z |
| publishDate | 2020-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-7d1279abdba54951a73c3d93348660b92023-11-20T18:06:25ZengMDPI AGMolecules1420-30492020-10-012521487610.3390/molecules25214876Exopolysaccharide II Is Relevant for the Survival of <i>Sinorhizobium meliloti</i> under Water Deficiency and Salinity StressEmiliano Primo0Pablo Bogino1Sacha Cossovich2Emiliano Foresto3Fiorela Nievas4Walter Giordano5Instituto de Biotecnología Ambiental y Salud (INBIAS), CONICET, Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Río Cuarto X5804BYA, Córdoba, ArgentinaInstituto de Biotecnología Ambiental y Salud (INBIAS), CONICET, Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Río Cuarto X5804BYA, Córdoba, ArgentinaInstituto de Biotecnología Ambiental y Salud (INBIAS), CONICET, Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Río Cuarto X5804BYA, Córdoba, ArgentinaInstituto de Biotecnología Ambiental y Salud (INBIAS), CONICET, Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Río Cuarto X5804BYA, Córdoba, ArgentinaInstituto de Biotecnología Ambiental y Salud (INBIAS), CONICET, Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Río Cuarto X5804BYA, Córdoba, ArgentinaInstituto de Biotecnología Ambiental y Salud (INBIAS), CONICET, Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Río Cuarto X5804BYA, Córdoba, Argentina<i>Sinorhizobium meliloti</i> is a soil bacterium of great agricultural importance because of its ability to fix atmospheric nitrogen in symbiotic association with alfalfa (<i>Medicago sativa</i>) roots. We looked into the involvement of exopolysaccharides (EPS) in its survival when exposed to different environmental stressors, as well as in bacteria–bacteria and bacteria–substrate interactions. The strains used were wild-type Rm8530 and two strains that are defective in the biosynthesis of EPS II: wild-type Rm1021, which has a non-functional <i>expR</i> locus, and mutant Rm8530 <i>expA</i>. Under stress by water deficiency, Rm8530 remained viable and increased in number, whereas Rm1021 and Rm8530 <i>expA</i> did not. These differences could be due to Rm8530′s ability to produce EPS II. Survival experiments under saline stress showed that viability was reduced for Rm1021 but not for Rm8530 or Rm8530 <i>expA</i>, which suggests the existence of some regulating mechanism dependent on a functional <i>expR</i> that is absent in Rm1021. The results of salinity-induced stress assays regarding biofilm-forming capacity (BFC) and autoaggregation indicated the protective role of EPS II. As a whole, our observations demonstrate that EPS play major roles in rhizobacterial survival.https://www.mdpi.com/1420-3049/25/21/4876<i>S. meliloti</i>exopolysaccharideswater deficiency stresssaline stressbiofilmautoaggregation |
| spellingShingle | Emiliano Primo Pablo Bogino Sacha Cossovich Emiliano Foresto Fiorela Nievas Walter Giordano Exopolysaccharide II Is Relevant for the Survival of <i>Sinorhizobium meliloti</i> under Water Deficiency and Salinity Stress Molecules <i>S. meliloti</i> exopolysaccharides water deficiency stress saline stress biofilm autoaggregation |
| title | Exopolysaccharide II Is Relevant for the Survival of <i>Sinorhizobium meliloti</i> under Water Deficiency and Salinity Stress |
| title_full | Exopolysaccharide II Is Relevant for the Survival of <i>Sinorhizobium meliloti</i> under Water Deficiency and Salinity Stress |
| title_fullStr | Exopolysaccharide II Is Relevant for the Survival of <i>Sinorhizobium meliloti</i> under Water Deficiency and Salinity Stress |
| title_full_unstemmed | Exopolysaccharide II Is Relevant for the Survival of <i>Sinorhizobium meliloti</i> under Water Deficiency and Salinity Stress |
| title_short | Exopolysaccharide II Is Relevant for the Survival of <i>Sinorhizobium meliloti</i> under Water Deficiency and Salinity Stress |
| title_sort | exopolysaccharide ii is relevant for the survival of i sinorhizobium meliloti i under water deficiency and salinity stress |
| topic | <i>S. meliloti</i> exopolysaccharides water deficiency stress saline stress biofilm autoaggregation |
| url | https://www.mdpi.com/1420-3049/25/21/4876 |
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