Boosting Plant Defenses: Using Microbial Allies to Protect Cumin from Blight

Greg Howard
2nd September, 2024

Boosting Plant Defenses: Using Microbial Allies to Protect Cumin from Blight

Image Source: Natural Science News, 2024

Key Findings

  • Researchers from ICAR-Central Arid Zone Research Institute developed a microbial consortium to combat Alternaria blight in cumin
  • The consortium, consisting of four microbial isolates, significantly reduced disease severity and increased disease control in cumin plants
  • The treatment also enhanced plant growth, increasing chlorophyll content, plant height, dry weight, and seed yield
Alternaria blight is a significant disease affecting cumin crops, leading to substantial yield losses. The disease is caused by the fungal pathogen Alternaria burnsii, which thrives in arid environments and poses a severe threat to cumin cultivation. To address this issue, researchers from ICAR-Central Arid Zone Research Institute conducted a study aimed at developing an efficient microbial consortium to combat Alternaria blight in cumin[1]. The study involved isolating and characterizing biocontrol agents that could inhibit the growth of A. burnsii and promote plant growth. The researchers selected four microbial isolates: Trichoderma afroharzianum 1F, Aneurinibacillus aneurinilyticus 16B, Pseudomonas lalkuanensis 31B, and Bacillus licheniformis 223B. These isolates were chosen based on their ability to significantly inhibit A. burnsii growth in dual plate assays, with an inhibition rate of approximately 86%. The research team conducted a pot experiment during the rabi season of 2022-2023 to evaluate the bioefficacy of these biocontrol agents, both individually and in consortium. The focus was on disease severity, plant growth promotion, and defense responses in cumin plants challenged with A. burnsii. The results were promising, with the consortium of all four biocontrol agents showing the least percent disease index (32.47%) and the highest percent disease control (64.87%). The study found that the microbial consortium significantly enhanced the production of secondary metabolites such as total phenol, flavonoids, antioxidants, and tannins. These compounds play crucial roles in plant defense mechanisms. Additionally, the consortium activated antioxidant-defense enzymes like peroxidase (POX), polyphenol oxidase (PPOX), catalase (CAT), superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), and tyrosine ammonia-lyase (TAL), which are essential for mitigating oxidative stress in plants. Moreover, the consortium treatment effectively reduced electrolyte leakage, a common indicator of cell membrane damage, compared to individual biocontrol treatments and infected control plants. This reduction in electrolyte leakage suggests that the consortium helps maintain cell membrane integrity under pathogen stress. The researchers also observed significant improvements in plant growth parameters. Cumin plants treated with the microbial consortium exhibited a 154% increase in chlorophyll content, an 88% increase in carotenoid content, a 78.77% increase in plant height, a 72.81% increase in dry weight, and a 104% increase in seed yield compared to infected control plants. These enhancements indicate that the microbial consortium not only mitigates disease but also promotes overall plant health and productivity. The findings of this study align with previous research on the potential of biocontrol agents and plant growth-promoting rhizobacteria (PGPR) in managing plant diseases and enhancing growth. For instance, earlier studies have demonstrated the effectiveness of Bacillus species in producing biocatalysts for plant growth promotion and providing protection against plant pathogens[2]. Additionally, research on PGPR isolated from arid soils has shown their ability to inhibit phytopathogenic fungi and nematodes, produce growth-promoting substances, and improve plant adaptation to extreme environments[3]. The use of a microbial consortium for disease management is not a new concept. Previous studies have shown that combining different microbial strains can lead to synergistic effects, enhancing their biocontrol and growth-promoting activities. For example, a consortium of Bacillus strains and quercetin was found to effectively manage Fusarium wilt disease in tomato plants, significantly reducing disease incidence and promoting plant growth under pathogen stress conditions[4]. In the present study, the microbial consortium comprising T. afroharzianum, A. aneurinilyticus, P. lalkuanensis, and B. licheniformis demonstrated excellent compatibility and synergistic effects. This combination proved to be more effective than individual treatments in controlling Alternaria blight and promoting cumin plant growth. The success of this environmentally friendly approach suggests that it could be recommended for managing Alternaria blight in cumin, offering a sustainable and eco-friendly alternative to chemical pesticides. In conclusion, the study conducted by ICAR-Central Arid Zone Research Institute provides valuable insights into the development of an efficient microbial consortium for combating Alternaria blight in cumin. By leveraging the biocontrol and growth-promoting traits of multiple microbial strains, this research offers a promising solution to enhance cumin crop health and productivity in arid regions.

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References

Main Study

1) Harnessing nature's defenders: unveiling the potential of microbial consortia for plant defense induction against Alternaria blight in cumin.

Published 30th August, 2024

https://doi.org/10.1007/s12223-024-01191-y

Related Studies

2) Characterization and assessment of two biocontrol bacteria against Pseudomonas syringae wilt in Solanum lycopersicum and its genetic responses.

https://doi.org/10.1016/j.micres.2017.09.003

3) In vitro antagonistic activity, plant growth promoting traits and phylogenetic affiliation of rhizobacteria associated with wild plants grown in arid soil.

https://doi.org/10.3389/fmicb.2014.00651

4) The Imperative Use of Bacillus Consortium and Quercetin Contributes to Suppress Fusarium Wilt Disease by Direct Antagonism and Induced Resistance.

https://doi.org/10.3390/microorganisms11102603


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