dc.contributor.author |
Jooste, Michelle
|
|
dc.contributor.author |
Roets, Francois
|
|
dc.contributor.author |
Midgley, Guy F.
|
|
dc.contributor.author |
Oberlander, Kenneth C.
|
|
dc.contributor.author |
Dreyer, Leanne Laurette
|
|
dc.date.accessioned |
2020-01-27T07:40:48Z |
|
dc.date.available |
2020-01-27T07:40:48Z |
|
dc.date.issued |
2019-10-23 |
|
dc.description |
Additional file 1: Figure S1. Seedling germination and development
of recalcitrant Cape Oxalis, where foliar leaf development and growth is
followed by delayed radicle growth. O. clavifolia Sond. (a) and O. glabra
Thunb. (b) one (i), three (ii), five (iii) and 10 (iv) days after germination. All
seedlings oriented with radicle pointing to bottom of figure. CT =
cotyledons, FL = foliar leaf, RD = radicle. |
en_ZA |
dc.description |
Additional file 2: Figure S2. Phylogenetic consensus tree constructed
with universal 16S region sequences for endophytic bacteria isolated
from Cape Oxalis (boldface font) and representative GenBank BLAST
results. Colour boxes indicate the most likely species identifications of
Oxalis isolates. B. megaterium and B. aryabhattai that had unresolved
relationships based on the consensus tree. |
en_ZA |
dc.description |
Additional file 3: Figure S3. Original red-and-green confocal staining
images of cross sections of sterilized Oxalis seeds indicating bacteria
(bright green rods) inside cavities. (i-ii) O. hirta, (iii) O. pes-caprae. |
en_ZA |
dc.description |
Additional file 4: Table S1. Properties of bacterial endophytes isolated
from Oxalis host plants, as described in literature [57–67]. |
en_ZA |
dc.description |
Additional file 5: Table S2. A key to all species names relating to Fig. 2. |
en_ZA |
dc.description.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. |
en_ZA |
dc.description.department |
Plant Production and Soil Science |
en_ZA |
dc.description.librarian |
am2020 |
en_ZA |
dc.description.sponsorship |
The National Research Foundation for the Scarce Skills Doctoral
Scholarship (awarded to M.J.) and National Research Foundation Blue Skies
Research Grant (awarded to L.L.D.). |
en_ZA |
dc.description.uri |
https://bmcplantbiol.biomedcentral.com |
en_ZA |
dc.identifier.citation |
Jooste, M., Roets, F., Midgley, G.F. et al. 2019, 'Nitrogen-fixing bacteria and Oxalis –
evidence for a vertically inherited bacterial
symbiosis', BMC Plant Biology, vol. 19, art. 441, pp. 1-10. |
en_ZA |
dc.identifier.issn |
1471-2229 |
|
dc.identifier.issn |
1471-2229 (online) |
|
dc.identifier.other |
10.1186/s12870-019-2049-7 |
|
dc.identifier.uri |
http://hdl.handle.net/2263/72925 |
|
dc.language.iso |
en |
en_ZA |
dc.publisher |
BioMed Central |
en_ZA |
dc.rights |
© The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License. |
en_ZA |
dc.subject |
Bacillus |
en_ZA |
dc.subject |
Endophytic bacteria |
en_ZA |
dc.subject |
Geophytes |
en_ZA |
dc.subject |
Nitrogen fixation |
en_ZA |
dc.subject |
Oxalotrophic bacteria |
en_ZA |
dc.subject |
Oxalis |
en_ZA |
dc.subject |
Vertical |
en_ZA |
dc.subject |
Bacterial endophytes |
en_ZA |
dc.title |
Nitrogen-fixing bacteria and Oxalis – evidence for a vertically inherited bacterial symbiosis |
en_ZA |
dc.type |
Article |
en_ZA |