Abstract
Azospirillum is a well-studied genus of plant growth-promoting rhizobacteria (PGPR) and one of the most extensively researched diazotrophs. This genus can colonize rhizosphere soil and enhance plant growth and productivity by supplying essential nutrients to the host. Azospirillum–plant interactions involve multiple mechanisms, including nitrogen fixation, the production of phytohormones (auxins, cytokinins, indole acetic acid (IAA), and gibberellins), plant growth regulators, siderophore production, phosphate solubilization, and the synthesis of various bioactive molecules, such as flavonoids, hydrogen cyanide (HCN), and catalase. Thus, Azospirillum is involved in plant growth and development. The genus Azospirillum also enhances membrane activity by modifying the composition of membrane phospholipids and fatty acids, thereby ensuring membrane fluidity under water deficiency. It promotes the development of adventitious root systems, increases mineral and water uptake, mitigates environmental stressors (both biotic and abiotic), and exhibits antipathogenic activity. Biological nitrogen fixation (BNF) is the primary mechanism of Azospirillum, which is governed by structural nif genes present in all diazotrophic species. Globally, Azospirillum spp. are widely used as inoculants for commercial crop production. It is considered a non-pathogenic bacterium that can be utilized as a biofertilizer for a variety of crops, particularly cereals and grasses such as rice and wheat, which are economically significant for agriculture. Furthermore, Azospirillum spp. influence gene expression pathways in plants, enhancing their resistance to biotic and abiotic stressors. Advances in genomics and transcriptomics have provided new insights into plant-microbe interactions. This review explored the molecular mechanisms underlying the role of Azospirillum spp. in plant growth. Additionally, BNF phytohormone synthesis, root architecture modification for nutrient uptake and stress tolerance, and immobilization for enhanced crop production are also important. A deeper understanding of the molecular basis of Azospirillum in biofertilizer and biostimulant development, as well as genetically engineered and immobilized strains for improved phosphate solubilization and nitrogen fixation, will contribute to sustainable agricultural practices and help to meet global food security demands.
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Claims 8
Claim · model-written summary
Azospirillum enhances plant growth and productivity by supplying nutrients.
- Taxon
- plante0
- Interactor
- Azospirillum
Azospirillume1symbiont - Outcome
- plant growth and productivitye0
- Qualifier
- supplying essential nutrientse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This genus can colonize rhizosphere soil and enhance plant growth and productivity by supplying essential nutrients to the host”
e1“Azospirillum is a well-studied genus”
Claim · model-written summary
Azospirillum modifies membrane phospholipids and fatty acids and maintains fluidity under water deficiency.
- Taxon
- plante1
- Interactor
- AzospirillumAzospirillume0symbiont
- Outcome
- membrane fluiditye0
- Qualifier
- under water deficiencye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azospirillum also enhances membrane activity by modifying the composition of membrane phospholipids and fatty acids, thereby ensuring membrane fluidity under water deficiency”
e1“Azospirillum–plant interactions”
Claim · model-written summary
Azospirillum promotes adventitious root development.
- Taxon
- plante1
- Interactor
- AzospirillumAzospirillume1symbiont
- Outcome
- development of adventitious root systemse0
- Direction
- promotese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It promotes the development of adventitious root systems”
e1“Azospirillum–plant interactions”
Claim · model-written summary
Azospirillum increases mineral and water uptake.
- Taxon
- plante1
- Interactor
- AzospirillumAzospirillume1symbiont
- Outcome
- mineral and water uptakee0
- Direction
- increasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increases mineral and water uptake”
e1“Azospirillum–plant interactions”
Claim · model-written summary
Azospirillum mitigates biotic and abiotic stressors.
- Taxon
- plante1
- Interactor
- AzospirillumAzospirillume1symbiont
- Outcome
- environmental stressorse0
- Direction
- mitigatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mitigates environmental stressors (both biotic and abiotic)”
e1“Azospirillum–plant interactions”
Claim · model-written summary
Azospirillum exhibits antipathogenic activity.
- Taxon
- plante1
- Interactor
- AzospirillumAzospirillume1symbiont
- Outcome
- antipathogenic activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exhibits antipathogenic activity”
e1“Azospirillum–plant interactions”
Claim · model-written summary
Structural nif genes govern biological nitrogen fixation in Azospirillum.
- Taxon
- AzospirillumAzospirillume0
- Gene
- nif genese0
- Outcome
- Biological nitrogen fixatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biological nitrogen fixation (BNF) is the primary mechanism of Azospirillum, which is governed by structural nif genes present in all diazotrophic species”
e1“Azospirillum–plant interactions”
Claim · model-written summary
Azospirillum influences plant gene expression pathways associated with resistance.
- Taxon
- plantsViridiplantaee0
- Interactor
- Azospirillum spp.Azospirillume0symbiont
- Outcome
- resistance to biotic and abiotic stressorse0
- Qualifier
- gene expression pathwayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azospirillum spp. influence gene expression pathways in plants, enhancing their resistance to biotic and abiotic stressors”