<it>Rhizobium leguminosarum </it>bv. <it>trifolii rosR </it>is required for interaction with clover, biofilm formation and adaptation to the environment
<p>Abstract</p> <p>Background</p> <p><it>Rhizobium leguminosarum </it>bv. <it>trifolii </it>is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants <it>Trifolium </it>spp. Bacterial surface polysaccharide...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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BMC
2010-11-01
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| Series: | BMC Microbiology |
| Online Access: | http://www.biomedcentral.com/1471-2180/10/284 |
| _version_ | 1819058134688202752 |
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| author | Piersiak Tomasz Kutkowska Jolanta Janczarek Monika Skorupska Anna |
| author_facet | Piersiak Tomasz Kutkowska Jolanta Janczarek Monika Skorupska Anna |
| author_sort | Piersiak Tomasz |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p><it>Rhizobium leguminosarum </it>bv. <it>trifolii </it>is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants <it>Trifolium </it>spp. Bacterial surface polysaccharides are crucial for establishment of a successful symbiosis with legumes that form indeterminate-type nodules, such as <it>Trifolium</it>, <it>Pisum</it>, <it>Vicia</it>, and <it>Medicago </it>spp. and aid the bacterium in withstanding osmotic and other environmental stresses. Recently, the <it>R. leguminosarum </it>bv. <it>trifolii </it>RosR regulatory protein which controls exopolysaccharide production has been identified and characterized.</p> <p>Results</p> <p>In this work, we extend our earlier studies to the characterization of <it>rosR </it>mutants which exhibit pleiotropic phenotypes. The mutants produce three times less exopolysaccharide than the wild type, and the low-molecular-weight fraction in that polymer is greatly reduced. Mutation in <it>rosR </it>also results in quantitative alterations in the polysaccharide constituent of lipopolysaccharide. The <it>rosR </it>mutants are more sensitive to surface-active detergents, antibiotics of the beta-lactam group and some osmolytes, indicating changes in the bacterial membranes. In addition, the <it>rosR </it>mutants exhibit significant decrease in motility and form a biofilm on plastic surfaces, which differs significantly in depth, architecture, and bacterial viability from that of the wild type. The most striking effect of <it>rosR </it>mutation is the considerably decreased attachment and colonization of root hairs, indicating that the mutation affects the first stage of the invasion process. Infection threads initiate at a drastically reduced rate and frequently abort before they reach the base of root hairs. Although these mutants form nodules on clover, they are unable to fix nitrogen and are outcompeted by the wild type in mixed inoculations, demonstrating that functional <it>rosR </it>is important for competitive nodulation.</p> <p>Conclusions</p> <p>This report demonstrates the significant role RosR regulatory protein plays in bacterial stress adaptation and in the symbiotic relationship between clover and <it>R. leguminosarum </it>bv. <it>trifolii </it>24.2.</p> |
| first_indexed | 2024-12-21T13:50:23Z |
| format | Article |
| id | doaj.art-32473841c1404734b989562f94d0d8bb |
| institution | Directory Open Access Journal |
| issn | 1471-2180 |
| language | English |
| last_indexed | 2024-12-21T13:50:23Z |
| publishDate | 2010-11-01 |
| publisher | BMC |
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| series | BMC Microbiology |
| spelling | doaj.art-32473841c1404734b989562f94d0d8bb2022-12-21T19:01:42ZengBMCBMC Microbiology1471-21802010-11-0110128410.1186/1471-2180-10-284<it>Rhizobium leguminosarum </it>bv. <it>trifolii rosR </it>is required for interaction with clover, biofilm formation and adaptation to the environmentPiersiak TomaszKutkowska JolantaJanczarek MonikaSkorupska Anna<p>Abstract</p> <p>Background</p> <p><it>Rhizobium leguminosarum </it>bv. <it>trifolii </it>is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants <it>Trifolium </it>spp. Bacterial surface polysaccharides are crucial for establishment of a successful symbiosis with legumes that form indeterminate-type nodules, such as <it>Trifolium</it>, <it>Pisum</it>, <it>Vicia</it>, and <it>Medicago </it>spp. and aid the bacterium in withstanding osmotic and other environmental stresses. Recently, the <it>R. leguminosarum </it>bv. <it>trifolii </it>RosR regulatory protein which controls exopolysaccharide production has been identified and characterized.</p> <p>Results</p> <p>In this work, we extend our earlier studies to the characterization of <it>rosR </it>mutants which exhibit pleiotropic phenotypes. The mutants produce three times less exopolysaccharide than the wild type, and the low-molecular-weight fraction in that polymer is greatly reduced. Mutation in <it>rosR </it>also results in quantitative alterations in the polysaccharide constituent of lipopolysaccharide. The <it>rosR </it>mutants are more sensitive to surface-active detergents, antibiotics of the beta-lactam group and some osmolytes, indicating changes in the bacterial membranes. In addition, the <it>rosR </it>mutants exhibit significant decrease in motility and form a biofilm on plastic surfaces, which differs significantly in depth, architecture, and bacterial viability from that of the wild type. The most striking effect of <it>rosR </it>mutation is the considerably decreased attachment and colonization of root hairs, indicating that the mutation affects the first stage of the invasion process. Infection threads initiate at a drastically reduced rate and frequently abort before they reach the base of root hairs. Although these mutants form nodules on clover, they are unable to fix nitrogen and are outcompeted by the wild type in mixed inoculations, demonstrating that functional <it>rosR </it>is important for competitive nodulation.</p> <p>Conclusions</p> <p>This report demonstrates the significant role RosR regulatory protein plays in bacterial stress adaptation and in the symbiotic relationship between clover and <it>R. leguminosarum </it>bv. <it>trifolii </it>24.2.</p>http://www.biomedcentral.com/1471-2180/10/284 |
| spellingShingle | Piersiak Tomasz Kutkowska Jolanta Janczarek Monika Skorupska Anna <it>Rhizobium leguminosarum </it>bv. <it>trifolii rosR </it>is required for interaction with clover, biofilm formation and adaptation to the environment BMC Microbiology |
| title | <it>Rhizobium leguminosarum </it>bv. <it>trifolii rosR </it>is required for interaction with clover, biofilm formation and adaptation to the environment |
| title_full | <it>Rhizobium leguminosarum </it>bv. <it>trifolii rosR </it>is required for interaction with clover, biofilm formation and adaptation to the environment |
| title_fullStr | <it>Rhizobium leguminosarum </it>bv. <it>trifolii rosR </it>is required for interaction with clover, biofilm formation and adaptation to the environment |
| title_full_unstemmed | <it>Rhizobium leguminosarum </it>bv. <it>trifolii rosR </it>is required for interaction with clover, biofilm formation and adaptation to the environment |
| title_short | <it>Rhizobium leguminosarum </it>bv. <it>trifolii rosR </it>is required for interaction with clover, biofilm formation and adaptation to the environment |
| title_sort | it rhizobium leguminosarum it bv it trifolii rosr it is required for interaction with clover biofilm formation and adaptation to the environment |
| url | http://www.biomedcentral.com/1471-2180/10/284 |
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