A note on bacterial symbiosis

Abstract Background Plant-endophyte symbioses often revolve around nitrogen metabolism, and involve varying degrees of intimacy. Although evidence for vertical inheritance of nitrogen-fixing endophytic bacteria is increasing, it is confined mostly to crop plants, and to date no such system has been reported for geophytes. Methods Bacterial endophytes associated with Oxalis, the most species-rich geophytic genus form the Cape Flora in southern Africa was studied. Culturable endophytes were isolated from surface-sterilized vegetative and reproductive plant organs for six host species at three locations. Colonies of microbes on various artificial media were morphotyped, enumerated and identified using sequence data. Filter exclusion experiments were conducted to determine if endophytes were vertically transmitted to seeds, determine if mucilage plays a role to actively attract microbes from the soil and to assess microbial richness isolated from the mucilage of Oxalis seedlings. Fluorescent microscopy was implemented in order to visualize endophytic bacteria in cryo-sectioned seeds. Results Evidence for a novel, vertically transmitted symbiosis was reported. Communities of nitrogen-fixing and plant growth-promoting Bacillus endophytes were found to associate with selected Oxalis hosts from nitrogen-deficient environments of the Cape. Bacillus endophytes were ubiquitous and diverse across species and plant bodies, and were prominent in seeds. Three common nitrogen-fixing Bacillus have known oxalotrophic properties and appear to be housed inside specialised cavities (containing oxalates) within the plant body and seeds. Conclusions The discovery of vertical transmission and potential benefits to both host and endophyte suggest a particularly tight mutualism in the Oxalis-endophyte system. This discovery suggests unexpected ways in which geophytes might avoid nitrogen deficiency, and suggest that such symbioses are more common than previously expected.

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First Description of Sulphur-Oxidizing Bacterial Symbiosis in a Cnidarian (Medusozoa) Living in Sulphidic Shallow-Water Environments

PLoS ONE ◽

10.1371/journal.pone.0127625 ◽

2015 ◽

Vol 10 (5) ◽

pp. e0127625 ◽

Cited By ~ 5

Author(s):

Sylvie Abouna ◽

Silvina Gonzalez-Rizzo ◽

Adrien Grimonprez ◽

Olivier Gros

Keyword(s):

Shallow Water ◽

Bacterial Symbiosis

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Calcium ions-effect on performance, growth and extracellular nature of microalgal-bacterial symbiosis system treating wastewater

Environmental Research ◽

10.1016/j.envres.2021.112228 ◽

2021 ◽

pp. 112228

Author(s):

Cong-Cong Tang ◽

Xin-Yi Zhang ◽

Rong Wang ◽

Tian-Yang Wang ◽

Zhang-Wei He ◽

...

Keyword(s):

Calcium Ions ◽

Bacterial Symbiosis

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Bacterial symbiosis in the fish gut and its role in health and metabolism

Symbiosis ◽

10.1007/s13199-016-0441-8 ◽

2016 ◽

Vol 72 (1) ◽

pp. 1-11 ◽

Cited By ~ 28

Author(s):

Goutam Banerjee ◽

Arun Kumar Ray

Keyword(s):

Bacterial Symbiosis ◽

Fish Gut

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Absence of a microbiome in the midgut trunk of six representative Crustacea

Journal of Crustacean Biology ◽

10.1093/jcbiol/ruz087 ◽

2019 ◽

Vol 40 (1) ◽

pp. 122-130

Author(s):

Gary G Martin ◽

Zain Natha ◽

Nicola Henderson ◽

Sabi Bang ◽

Hope Hendry ◽

...

Keyword(s):

Immune Responses ◽

Molecular Techniques ◽

Peritrophic Matrix ◽

Immune Functions ◽

Actual Surface ◽

Bacterial Symbiosis ◽

The Past ◽

Transmission Electron ◽

Accessory Molecules ◽

A Site

Abstract It has become a common expectation for an animal’s guts to be a site for bacterial symbiosis, which may play a role in influencing various aspects of physiology including digestion and immune responses. The presence of a microbiome in the digestive tracts of crustaceans has been demonstrated in the past using molecular techniques and has encouraged manipulations including probiotics to enhance growth rates in cultured species. We suggest, however, that bacteria are restricted to the lumen of the gut and separated from the epithelium by the peritrophic matrix, which prevents their establishment as a permanent component of the gut. The peritrophic matrix, found in most arthropods, is a chitinous sheet containing accessory molecules, and is continuously formed by delamination from the epithelium of the midgut such that the actual surface is constantly being cleaned. The lifted layer then surrounds ingested materials, including microbes, in an impenetrable wrapper compartmentalizing digestive and immune functions. The ectoperitrophic space, lying between the peritrophic matrix and the epithelium, was examined in six species representatives of six groups of crustaceans (Branchiopoda, Amphipoda, Copepoda, and Decapoda) for the presence of microbes using light and transmission electron microscopy as well as fluorescent probes for bacteria. The results suggest that a microbiome is lacking in several common groups of crustaceans.

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