2. Many indigenous microbes other than mycorrhizal fungi
(potentially including pathogens, but also phosphorussolubilizers) were added to all pots with soil washing, thus
partly erasing potentially confounding effects of relieving
pathogen pressure in some of the experimental treatments. We
know that lack of large sized pathogens like nematodes maystill
confound our results, but there is currently no wayaround these
limitations, and soil pathogens would again counteract the
positive effect of inoculationwith non-sterile soil, which further
stresses that our results represent conservative estimate of
mycorrhizal benefits. Maize in any of the treatments of our
experiment did not show any obvious disease symptoms. And
since potentially beneficial bacteria such as Azospirillum
(Couillerot et al., 2013) were added back to all soils, we are
confident not to have caused much biological artifact (and if any,
this was absolutely inevitable due to lack of alternatives such as
mycorrhiza-defective mutants of locally adapted maize genotypes). The role of microbes potentially involved in phosphorus
solubilization in close vicinity of AMF hyphae should, however,
be more thoroughly researched in the future e either by targeted search for such microbes (Gryndler et al., 2013) or through
establishing pot experiments with reconstituted AMF communities (Thonar et al., 2014), preferably from the AMF strains
produced in-vitro.