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Cited by 211Plant-Microbe Interactions and ImmunityAgriculture, Plant Science, Crop ManagementLegume Nitrogen Fixing Symbiosis

Phytohormones and induction of plant-stress tolerance and defense genes by seed and foliar inoculation with Azospirillum brasilense cells and metabolites promote maize growth

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Fukami, Josiane, Ollero, Francisco Javier, Megías, Manuel, Hungria, Mariangela·2017·AMB Express
DOI 10.1186/s13568-017-0453-7PMC PMC5514007
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Abstract

Azospirillum spp. are plant-growth-promoting bacteria used worldwide as inoculants for a variety of crops. Among the beneficial mechanisms associated with Azospirillum inoculation, emphasis has been given to the biological nitrogen fixation process and to the synthesis of phytohormones. In Brazil, the application of inoculants containing A. brasilense strains Ab-V5 and Ab-V6 to cereals is exponentially growing and in this study we investigated the effects of maize inoculation with these two strains applied on seeds or by leaf spray at the V2.5 stage growth-a strategy to relieve incompatibility with pesticides used for seed treatment. We also investigate the effects of spraying the metabolites of these two strains at V2.5. Maize growth was promoted by the inoculation of bacteria and their metabolites. When applied via foliar spray, although A. brasilense survival on leaves was confirmed by confocal microscopy and cell recovery, few cells were detected after 24 h, indicating that the effects of bacterial leaf spray might also be related to their metabolites. The major molecules detected in the supernatants of both strains were indole-3-acetic acid, indole-3-ethanol, indole-3-lactic acid and salicylic acid. RT-PCR of genes related to oxidative stress (APX1, APX2, CAT1, SOD2, SOD4) and plant defense (pathogenesis-related PR1, prp2 and prp4) was evaluated on maize leaves and roots. Differences were observed according to the gene, plant tissue, strain and method of application, but, in general, inoculation with Azospirillum resulted in up-regulation of oxidative stress genes in leaves and down-regulation in roots; contrarily, in general, PR genes were down-regulated in leaves and up-regulated in roots. Emphasis should be given to the application of metabolites, especially of Ab-V5 + Ab-V6 that in general resulted in the highest up-regulation of oxidative-stress and PR genes both in leaves and in roots. We hypothesize that the benefits of inoculation of Azospirillum on seeds or by leaf spray, as well as of leaf spraying of Azospirillum metabolites, are strongly correlated with the synthesis of phytohormones and by eliciting genes related to plant-stress tolerance and defense against pathogens.

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Cited by

Sorted by citations

Authors
Fukami, J., Ollero, F. J., Megías, M., & Hungria, M.
Affiliations
  • Universidade Estadual de Londrina (BR)
  • Universidad de Sevilla (ES)
ORCID
Venue
AMB Express
Publisher
Springer Science and Business Media LLC
Published
2017-07-17
Volume
7
Issue
1
Pages
153-153
ISSN
2191-0855 (ISSN-L)
DOI
10.1186/s13568-017-0453-7
PMC
PMC5514007
OpenAlex
W2735120924
Cited by
211
References
0
Citations by year
2026: 14 · 2025: 26 · 2024: 21 · 2023: 25 · 2022: 25 · 2021: 38 · 2020: 32 · 2019: 16 · 2018: 11 · 2017: 2 · 2016: 1
FWCI
16.43
Type
journal article
Language
en
Open access
Licence
Locations
  • AMB Express (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Deposito de Investigacion Universidad de Sevilla (University of Seville) (publishedVersion, cc-by-nc-nd)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (submittedVersion, cc-by-nc-nd)
  • Americanae (AECID Library) (submittedVersion, other-oa)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • Empresa Brasileira de Pesquisa Agropecuária (02.13.08.003.00.00)
  • INCT-Plant-Growth Promoting Microorganisms for Agricultural Sustainability and Environmental Responsibility (465133/2014-2, Fundação Araucária)
  • Consejo Superior de Investigaciones Científicas (Mineco, AGL2016-77163-R)
Topics
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Plant-Microbe Interactions and Immunity
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Agriculture, Plant Science, Crop Management
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Legume Nitrogen Fixing Symbiosis
Keywords
Azospirillum brasilense, plant growth-promoting bacteria, maize, foliar inoculation, seed inoculation, bacterial metabolites, indole-3-acetic acid, indole-3-lactic acid, salicylic acid, indole-3-ethanol, oxidative stress genes, pathogenesis-related genes, plant defense, stress tolerance, nitrogen fixation

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