Candidatus Glomeribacter gigasporarum
editCandidatus Glomeribacter gigasporarum is a gram-negative β-proteobacteria. [1] The bacterium is rod-shaped, and has a obligate endosymbiotic relationship with the arbuscular-mycorrhizal fungi Gigaspora margarita. [2] 16S rRNA Sequencing has revealed that the bacteria is a member of Burkholderia. [1][2] Candidatus Glomeribacter gigasporarum is unculturable as of yet, but can stay alive in culture for up to 4 weeks. [3] The candidate bacteria is listed as "the smallest beta-proteobacterium" by Jargeat et. al. with a genome size of 1.4 Mb with a chromosome length of 750-kb and a plasmid length of 600- to 650-kb. [3]. The genome size was determined using gel-electrophoresis[3].
Symbiotic Relationship
editThe relationship between Candidatus Glomeribacter gigasporarum and the fungi Gigaspora margarita is obligate endosymbiotic. This occurs when either the symbiote or the host cannot live without the other. In this case the bacteria cannot live without the fungi. In certain studies, it has been found that over multiple generations of cloning certain spores of Gigaspora margarita contain no bacteria[4]. It was also found that these spores that lacked the bacteria had several different physiological changes in spore diameter, nuclear diameter and wall thickness[4]. The fungi root system did not grow as abundant and changes in cell structure occurred in the fungi without bacterial[4]. The fungi were able to grow and complete their life cycle supporting that they can live without the symbiotic bacteria inside of them[4]. Since Candidatus Glomeribacter gigasporarum has only been found inside the fungi, it is the current idea that it cannot live by itself without the fungi.
References
edit- ^ a b Bianciotto, Valeria; Lumini, Erica; Bonfante, Paola; Vandamme, Peter (2003). "'Candidatus Glomeribacter gigasporarum' gen. nov., sp. nov., an endosymbiont of arbuscular mycorrhizal fungi". International Journal of Systematic and Evolutionary Microbiology,. 53 (1): 121–124. doi:10.1099/ijs.0.02382-0. ISSN 1466-5026.
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: CS1 maint: extra punctuation (link) - ^ a b Bianciotto, V.; Bandi, C.; Minerdi, D.; Sironi, M.; Tichy, H. V.; Bonfante, P. (1996-08-01). "An obligately endosymbiotic mycorrhizal fungus itself harbors obligately intracellular bacteria". Applied and Environmental Microbiology. 62 (8): 3005–3010. ISSN 0099-2240. PMID 8702293.
- ^ a b c Jargeat, P.; Cosseau, C.; Ola'h, B.; Jauneau, A.; Bonfante, P.; Batut, J.; Bécard, G. (2004-10). "Isolation, free-living capacities, and genome structure of "Candidatus Glomeribacter gigasporarum," the endocellular bacterium of the mycorrhizal fungus Gigaspora margarita". Journal of Bacteriology. 186 (20): 6876–6884. doi:10.1128/JB.186.20.6876-6884.2004. ISSN 0021-9193. PMID 15466041.
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(help) - ^ a b c d Lumini, Erica; Bianciotto, Valeria; Jargeat, Patricia; Novero, Mara; Salvioli, Alessandra; Faccio, Antonella; Bécard, Guillaume; Bonfante, Paola (2007). "Presymbiotic growth and sporal morphology are affected in the arbuscular mycorrhizal fungus Gigaspora margarita cured of its endobacteria". Cellular Microbiology. 9 (7): 1716–1729. doi:10.1111/j.1462-5822.2007.00907.x. ISSN 1462-5822.