Table 2: The most significant studies addressing the impact of inoculation on soil microbial communities.
S. meliloti L33
The bacterial diversity in the rhizosphere of Medicago sativa was qualitatively and quantitatively affected. While the number of members of -proteobacteria decreased, the number of members of -proteobacteria increased.
Field inoculation showed a significant increase of total bacterial diversity due to seasonal changes, but no effect of rhizobial inoculation was observed. DGGE offered little information about bacterial communities.
Field inoculation showed significant effects on bacterial structure and diversity in the bulk soil of common bean. Both - and -proteobacteria together with Firmicutes and Actinobacteria were enhanced, including beneficial bacterial communities with PGPM potentialities. Dual inoculation was less effective than simple inoculation and induced distinct effects.
The bacterial genes involved in nitrogen turnover were affected by inoculation. The effectiveness of inoculation was related to the abundance of nifH genes in the late flowering phase. A higher number of amoA copies were observed during flowering.
Inoculation affected the composition of the rhizosphere bacterial community of pea. Four to five specific bands were suppressed. Before flowering, the AMF decreased rhizosphere respiration and number of protozoa, but it did not affect bacterial number. During flowering and pod formation, the AMF stimulated rhizosphere respiration and the negative effect on protozoa decreased.
Inoculation induced shifts in fatty acid methyl ester profiles of cultivable bacteria fractions, as well as total microbial communities in the rhizosphere of maize. The rhizosphere composition shifted from a Gram-positive-dominated community to more Gram-negative populations.
Inoculation induced a significant modification in the bacterial community structure. The type of PGPM consortium had more impact on the bacterial community structure than the presence of AMF. A synergistic effect of coinoculation was observed.
Inoculation with the biocontrol agent did not show significant effects on fungal (18S rRNA) and bacterial (16S rRNA) communities in the rhizosphere of tomato. Combination of the two rhizobacteria had no synergistic or comparable effects on plant biomass, with respect to their single applications.