Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Mar 19;9(3):639.
doi: 10.3390/microorganisms9030639.

Allium cepa L. Inoculation with a Consortium of Plant Growth-Promoting Bacteria: Effects on Plants, Soil, and the Autochthonous Microbial Community

Marika Pellegrini  1   2 , Daniela M Spera  1 , Claudia Ercole  2 , Maddalena Del Gallo  2
Affiliations

Allium cepa L. Inoculation with a Consortium of Plant Growth-Promoting Bacteria: Effects on Plants, Soil, and the Autochthonous Microbial Community

Marika Pellegrini et al. Microorganisms. .

Abstract

The present work was aimed at investigating the effects of a four bacterial strain consortium-Azospirillum brasilense, Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae, and Burkholderia ambifaria-on Allium cepa L. and on soil health. The bacterial consortium was inoculated on seeds of two different onion varieties; inoculated and Control seeds (treated with autoclaved inoculum) were sown in an open-field and followed until harvest. Plant growth development parameters, as well as soil physico-chemical and molecular profiles (DNA extraction and 16S community sequencing on the Mi-Seq Illumina platform), were investigated. The results showed a positive influence of bacterial application on plant growth, with increased plant height (+18%), total chlorophylls (+42%), crop yields (+13%), and bulb dry matter (+3%) with respect to the Control. The differences between Control and treatments were also underlined in the bulb extracts in terms of total phenolic contents (+25%) and antioxidant activities (+20%). Soil fertility and microbial community structure and diversity were also positively affected by the bacterial inoculum. At harvest, the soil with the presence of the bacterial consortium showed an increase in total organic carbon, organic matter, and available phosphorus, as well as higher concentrations of nutrients than the Control. The ecological indexes calculated from the molecular profiles showed that community diversity was positively affected by the bacterial treatment. The present work showed the effective use of plant growth-promoting bacteria as a valid fertilization strategy to improve yield in productive landscapes whilst safeguarding soil biodiversity.

Keywords: PGPB; biostimulants; illumina sequencing; seed inoculation; sustainable agriculture.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Figures

Figure 1
Figure 1
Scanning electron microscope (SEM) micrographs obtained for (a) Control (CNT) and inoculated (PGPB) Allium cepa seeds the same day of the inoculation (a–d) and after 30 days (e–g). Magnitudes: 5000× (a,c,e,g) and 10,000× (b,d,f,h). Scale bars 2 µm.
Figure 2
Figure 2
Height dynamics recorded for Meranto (A) and Moondance (B). In the figure: CNT = Control; PGPB = treated seed; DAS = days after sowing; * = p < 0.001.
Figure 3
Figure 3
Dry weight dynamics recorded for Meranto (A) and Moondance (B). In the figure: CNT = Control; PGPB = treated seed; DAS = days after sowing; * = p < 0.001.
Figure 4
Figure 4
Dynamics of the total chlorophyll content (mg 100g−1 FW) recorded for Meranto (A) and Moondance (B). In the figure: CNT = Control; PGPB = treated seed; DAS = days after sowing; * = p < 0.001; ** = p < 0.01.
Figure 5
Figure 5
Bulbs harvested from the Control (CNT) and treated (PGPB) experimental units of Meranto and Moondance crops.
Figure 6
Figure 6
Heat-map and clustering of the soil microbial community composition of the Control (CNT) and treated (PGPB) experimental conditions of Meranto (Mer) and Moondance (Moon) crops. The color changes in the panel show the percentage occupied by the genus inside each sample (color scale at the top). Taxonomy is indicated by the color keys on the right.
See this image and copyright information in PMC

References

    1. Rouphael Y., Colla G. Editorial: Biostimulants in Agriculture. Front. Plant Sci. 2020;11:40. doi: 10.3389/fpls.2020.00040. - DOI - PMC - PubMed
    1. du Jardin P. Plant biostimulants: Definition, concept, main categories and regulation. Sci. Hortic. 2015;196:3–14. doi: 10.1016/j.scienta.2015.09.021. - DOI
    1. Colla G., Nardi S., Cardarelli M., Ertani A., Lucini L., Canaguier R., Rouphael Y. Protein hydrolysates as biostimulants in horticulture. Sci. Hortic. 2015;196:28–38. doi: 10.1016/j.scienta.2015.08.037. - DOI
    1. Djebaili R., Pellegrini M., Smati M., Del Gallo M., Kitouni M. Actinomycete Strains Isolated from Saline Soils: Plant-Growth-Promoting Traits and Inoculation Effects on Solanum lycopersicum. Sustain. J. Rec. 2020;12:4617. doi: 10.3390/su12114617. - DOI
    1. Khoshru B., Mitra D., Khoshmanzar E., Myo E.M., Uniyal N., Mahakur B., Das Mohapatra P.K., Panneerselvam P., Boutaj H., Alizadeh M., et al. Current scenario and future prospects of plant growth-promoting rhizobacteria: An economic valuable resource for the agriculture revival under stressful conditions. J. Plant Nutr. 2020;43:3062–3092. doi: 10.1080/01904167.2020.1799004. - DOI

LinkOut - more resources