Mutualistic interaction between Salmonella enterica and Aspergillus niger and its effects on Zea mays colonization.
Bottom Line: Aspergillus niger is a ubiquitous fungus that can often be found in soil or associated to plants and microbial consortia.In this work, we have found that this interaction is stable for weeks without a noticeable negative effect on either organism.Strikingly, co-colonization also causes a reduction in plant invasion by S. Typhimurium.
Affiliation: Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, HIM building, Room #1042, Boston, MA, 02115, USA.Show MeSH
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Mentions: Because both S. Typhimurium and A. niger can often be found associated with plants (Perrone et al., 2007; Schikora et al., 2008), plant roots may be an environmental niche where this fungal–bacterial interaction could take place. To study that possibility, we developed a tripartite system involving the bacterium, the fungus and a plant. For these studies, we used maize (Zea mays) because both microorganisms have been reported to colonize this plant (Singh et al., 2004; Palencia et al., 2010). We used a gnotobiotic system where sterile maize roots were inoculated with either 10 mM potassium phosphate buffer (pH 7), S. Typhimurium, A. niger or co-inoculated with both microbes. At 14 days post-inoculation (dpi), plants were analysed for the presence of the organisms on the roots. Salmonella Typhimurium colonized maize roots in this gnotobiotic system (Fig. 6A). Aspergillus niger was also observed associated with the roots (blue arrow, Fig. 6B). In addition, co-colonization was observed when the fungi and bacteria were both introduced to the plant (Fig. 6C). As a negative control, an uninoculated root is shown in Fig. 6D. We next wondered if the fungal–bacterial co-colonization might have a different effect on the plant than colonization by either organism alone.
Affiliation: Department of Microbiology and Immunobiology, Harvard Medical School, 77 Avenue Louis Pasteur, HIM building, Room #1042, Boston, MA, 02115, USA.