[permaculture] Fwd: Intracellular colonization of roots of Arabidopsis and crop plants by Gluconacetobacter diazotrophicus - Springer

Lawrence London lfljvenaura at gmail.com
Thu Aug 1 01:07:36 EDT 2013

Intracellular colonization of roots of *Arabidopsis* and crop plants
by *Gluconacetobacter

   - Edward C. Cocking<http://link.springer.com/search?facet-author=%22Edward+C.+Cocking%22>,

   - Philip J. Stone<http://link.springer.com/search?facet-author=%22Philip+J.+Stone%22>,

   - Michael R.



We have investigated the interaction of *Gluconacetobacter diazotrophicus*,
a non-nodulating endophytic nitrogen-fixing bacterium isolated from the
intercellular spaces of sugarcane, with *Arabidopsis thaliana* and the crop
plants maize (*Zea mays*), rice (*Oryza sativa*), wheat (*Triticum aestivum*),
oilseed rape (*Brassica napus*), tomato (*Lycopersicon esculentum*), and
white clover (*Trifolium repens*). Using seedlings grown aseptically in
sucrose-containing culture media, we have shown that inoculation with very
low numbers of *G. diazotrophicus* results in extensive intracellular
colonization of root meristems and progressive systemic intracellular root
colonization. Light microscopic examination of thin sections of
resin-embedded root tips of *Arabidopsis* and these crop plants inoculated
with β-glucuronidase (GUS)-labeled and with NifH promoter-GUS-labeled *G.
diazotrophicus* showed blue-stained *G. diazotrophicus* within the
cytoplasm of root cells, indicating that intracellular conditions were
suitable for nitrogenase gene expression. Electron microscopy confirmed
that these bluestained intracellular *G. diazotrophicus* were within
membrane-bounded vesicles. We discuss whether these novel inoculations with
*G. diazotrophicus* are likely to enable non-nodular endosymbiotic nitrogen
fixation and whether these inoculations can also provide a plant system to
investigate the endosymbiotic theory of the origin of eukaryotic organelles.

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