The Rhizobium Bacteroid State

Sutton, W.D.; Pankhurst, C. E.; Craig, A. S.

doi:10.1016/b978-0-12-364374-2.50014-8

Cited by 26 publications

(30 citation statements)

References 205 publications

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“…Rhizobia infect the roots of certain leguminous plants, forming nodules filled with differentiated bacterial cells (bacteroids) that fix nitrogen (98,200,238,245,319). As they develop, and depending on the bacterium-plant combination, bacteroids assume diverse shapes in a fairly linear set of stages: they may enlarge up to four to seven times their normal size, grow as distorted Y-shaped cells, branch repeatedly, or be pear shaped, swollen, rounded, or perfectly spherical (238,319).…”

Section: Bacteroids: Plant-microbe Symbiosismentioning

confidence: 99%

“…As they develop, and depending on the bacterium-plant combination, bacteroids assume diverse shapes in a fairly linear set of stages: they may enlarge up to four to seven times their normal size, grow as distorted Y-shaped cells, branch repeatedly, or be pear shaped, swollen, rounded, or perfectly spherical (238,319). In alfalfa, Rhizobium meliloti undergoes a stepwise differentiation into five types of bacteroids, progressing from rod-shaped cells to elongated rods to multiple pleomorphic forms (200,339).…”

Section: Bacteroids: Plant-microbe Symbiosismentioning

confidence: 99%

“…Different bacteria may exhibit the same morphology within nodules of a given host, and one bacterium may take on different, plant-specified morphologies in different hosts (200,319). For example, one set of bacteroids are rod shaped when hosted by Vigna mungo but grow as large cocci when hosted by Arachis hypogaea (319).…”

Section: Bacteroids: Plant-microbe Symbiosismentioning

confidence: 99%

“…First, the size, shape, ultrastructure, and number of bacteroids within nodules are determined in large part by the plant being infected (200,319). Different bacteria may exhibit the same morphology within nodules of a given host, and one bacterium may take on different, plant-specified morphologies in different hosts (200,319).…”

Section: Bacteroids: Plant-microbe Symbiosismentioning

confidence: 99%

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The Selective Value of Bacterial Shape

Young

2006

Microbiol Mol Biol Rev

848

777

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SUMMARY Why do bacteria have shape? Is morphology valuable or just a trivial secondary characteristic? Why should bacteria have one shape instead of another? Three broad considerations suggest that bacterial shapes are not accidental but are biologically important: cells adopt uniform morphologies from among a wide variety of possibilities, some cells modify their shape as conditions demand, and morphology can be tracked through evolutionary lineages. All of these imply that shape is a selectable feature that aids survival. The aim of this review is to spell out the physical, environmental, and biological forces that favor different bacterial morphologies and which, therefore, contribute to natural selection. Specifically, cell shape is driven by eight general considerations: nutrient access, cell division and segregation, attachment to surfaces, passive dispersal, active motility, polar differentiation, the need to escape predators, and the advantages of cellular differentiation. Bacteria respond to these forces by performing a type of calculus, integrating over a number of environmental and behavioral factors to produce a size and shape that are optimal for the circumstances in which they live. Just as we are beginning to answer how bacteria create their shapes, it seems reasonable and essential that we expand our efforts to understand why they do so.

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Section: Bacteroids: Plant-microbe Symbiosismentioning

confidence: 99%

Section: Bacteroids: Plant-microbe Symbiosismentioning

confidence: 99%

Section: Bacteroids: Plant-microbe Symbiosismentioning

confidence: 99%

Section: Bacteroids: Plant-microbe Symbiosismentioning

confidence: 99%

See 2 more Smart Citations

The Selective Value of Bacterial Shape

Young

2006

Microbiol Mol Biol Rev

848

777

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“…Bacteroids have been found to be distinctively different from free-living bacteria in morphology as well as in physiology (44). Several steps in bacteroid development, each of which is correlated with a specific histological region of the nodule, have been distinguished on the basis of differences in the ultrastructures of the bacteroids at each step (46).…”

mentioning

confidence: 99%

Genetic analysis of the Rhizobium meliloti bacA gene: functional interchangeability with the Escherichia coli sbmA gene and phenotypes of mutants

1997

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The Rhizobium meliloti bacA gene encodes a function that is essential for bacterial differentiation into bacteroids within plant cells in the symbiosis between R. meliloti and alfalfa. An Escherichia coli homolog of BacA, SbmA, is implicated in the uptake of microcin B17, microcin J25 (formerly microcin 25), and bleomycin. When expressed in E. coli with the lacZ promoter, the R. meliloti bacA gene was found to suppress all the known defects of E. coli sbmA mutants, namely, increased resistance to microcin B17, microcin J25, and bleomycin, demonstrating the functional similarity between the two proteins. The R. meliloti bacA386::TnphoA mutant, as well as a newly constructed bacA deletion mutant, was found to show increased resistance to bleomycin. However, it also showed increased resistance to certain aminoglycosides and increased sensitivity to ethanol and detergents, suggesting that the loss of bacA function causes some defect in membrane integrity. The E. coli sbmA gene suppressed all these bacA mutant phenotypes as well as the Fix ؊ phenotype when placed under control of the bacA promoter. Taken together, these results strongly suggest that the BacA and SbmA proteins are functionally similar and thus provide support for our previous hypothesis that BacA may be required for uptake of some compound that plays an important role in bacteroid development. However, the additional phenotypes of bacA mutants identified in this study suggest the alternative possibility that BacA may be needed for membrane integrity, which is likely to be critically important during the early stages of bacterial differentiation within plant cells.

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Genetic Aspects of Symbiotic Nitrogen Fixation

Long

1984

Gene Manipulation in Plant Improvement

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The Rhizobium Bacteroid State

Cited by 26 publications

References 205 publications

The Selective Value of Bacterial Shape

The Selective Value of Bacterial Shape

Genetic analysis of the Rhizobium meliloti bacA gene: functional interchangeability with the Escherichia coli sbmA gene and phenotypes of mutants

Genetic Aspects of Symbiotic Nitrogen Fixation

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