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. 2022 Dec;106(23):7963-7972.
doi: 10.1007/s00253-022-12220-6. Epub 2022 Nov 3.

Chitosan/starch beads as bioinoculants carrier: long-term survival of bacteria and plant growth promotion

Macarena Fernández  1   2 , Luciana Anabella Pagnussat  1   2 , María Paula Borrajo  1   2 , Jonas Jose Perez Bravo  2   3 , Nora Judit Francois  3 , Cecilia Mónica Creus  4
Affiliations

Chitosan/starch beads as bioinoculants carrier: long-term survival of bacteria and plant growth promotion

Macarena Fernández et al. Appl Microbiol Biotechnol. 2022 Dec.

Abstract

Immobilization of microorganisms in biodegradable polymeric matrices constitutes a promising technology for plant growth promoting to overcome the challenging conditions of the rhizosphere. Previously, we demonstrated that beads prepared from blends of chitosan/starch of analytical grades ionically cross-linked are useful carriers for Azospirillum brasilense and Pseudomonas fluorescens. The aims of this work were to study A. brasilense Az39 and P. fluorescens ZME4 immobilization in industrial quality beads produced with a blend of chitosan/starch, to assess bacterial survival during long-term storage and biofilm distribution in the beads. We also proposed to analyze the consortia root colonization and its performance as plant growth-promoting bioinoculants compared to liquid counterpart. Our results revealed that A. brasilense Az39 and P. fluorescens ZME4 can coexist in industrial grade chitosan/starch beads, and this mixed immobilization benefits the survival rates of both species, even for more than a year under shelf storage. Confocal laser scanning microscopy with fluorescent dyed strains showed that both species remain mainly in different locations inside and over the beads. Additionally, maize seed treatment with beads-loaded bacteria resulted in growth promotion of roots in a similar manner than traditional liquid-based inoculation. The evidence collected here demonstrate that low-cost chitosan/starch beads are a suitable carrier for bacteria consortia and could be a reliable alternative to liquid inoculation in agronomic practices with additional benefits for industrial management. KEY POINTS: • Mixed immobilization increases bacterial survival in chitosan/starch industrial beads • Beads increase competence of bacteria in rhizosphere of maize • Inoculation mediated by beads promotes plant growth of maize.

Keywords: Azospirillum; Beads; Co-immobilization; Maize; Plant growth–promoting microorganisms; Pseudomonas.

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References

    1. Bashan Y, De-Bashan LE (2010) How the plant growth-promoting bacterium Azospirillum promotes plant growth—a critical assessment. Adv Agron 108:77–136 - DOI
    1. Bashan Y, De-Bashan LE (2015) Inoculant preparation and formulations for Azospirillum spp. In: Cassán FD, Okon Y, Creus CM (eds) Handbook for Azospirillum. Springer, Switzerland, pp 469–485
    1. Bashan Y, de-Bashan LE, Prabhu SR, Hernandez J-P (2014) Advances in plant growth-promoting bacterial inoculant technology: formulations and practical perspectives (1998–2013). Plant Soil 378:1–33. https://doi.org/10.1007/s11104-013-1956-x - DOI
    1. Basu A, Prasad P, Das SN, Kalam S, Sayyed R, Reddy M, El Enshasy HJS (2021) Plant growth promoting rhizobacteria (PGPR) as green bioinoculants: recent developments, constraints, and prospects. Sustainability 13(3):1140 - DOI
    1. Borrajo MP, Mondino EA, Maroniche GA, Fernández M, Creus CM (2021) Potential of rhizobacteria native to Argentina for the control of Meloidogyne javanica. Rev Argent Microbiol 455:1–9. https://doi.org/10.1016/j.ram.2021.02.010 - DOI

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