Improving Tomato Plant Health Using Mutant Fungi and Bacteria with Radiation

Greg Howard
3rd August, 2024

Improving Tomato Plant Health Using Mutant Fungi and Bacteria with Radiation

Impregnating the roots of tomato plants (I) with a combination of mutant Bacillus velezensis, Trichoderma harzianum, and chitosan more effectively promoted plant growth against infection by the root-knot nematode (Meloidogyne javanica) than either applying the mixture to the soil (A) or the untreated control (C).

Image adapted from: Rostami et al. / CC BY (Source)

Key Findings

  • The study by NSTRI explored using Trichoderma spp. and Bacillus spp., including their gamma radiation-induced mutants, to control root-knot nematodes in tomato plants
  • Bacillus spp. were effective in lab tests, reducing nematode egg hatching by 16-45% and killing 30-46% of juvenile nematodes
  • Greenhouse trials showed that mutant isolates combined with chitosan reduced nematode reproduction by 94%, significantly lowering plant damage
The study conducted by the Nuclear Science and Technology Research Institute (NSTRI) investigates the potential of Trichoderma spp. and Bacillus spp., along with their gamma radiation-induced mutants, as biological control agents against Meloidogyne javanica (Mj) in tomato plants[1]. This research is crucial as root-knot nematodes, like M. javanica, cause significant economic losses in agriculture worldwide[2]. The study aims to provide sustainable alternatives to chemical nematicides, which have been limited due to their environmental and health impacts[3]. The research involved a series of in vitro assays, greenhouse trials, and molecular identification techniques to evaluate the biocontrol potential of these agents comprehensively. In vitro assessments showed that Bacillus spp. were particularly effective, inhibiting nematode egg hatching by 16-45% and inducing mortality in second-stage juveniles (J2) by 30-46%. These findings are significant as they demonstrate the ability of Bacillus spp. to directly affect nematode life stages, potentially reducing their population and subsequent plant damage. Greenhouse trials further validated these findings, showing that mutant isolates, especially when combined with chitosan, significantly reduced nematode-induced damage in tomato plants. The combination of mutant isolates with chitosan decreased the reproduction factor (RF) of root-knot nematodes by 94%, indicating a substantial reduction in nematode reproduction and plant infestation levels. Additionally, by optimizing soil infection conditions and modifying the application of the effective compound, the RF of nematodes decreased by 65-76%. The molecular identification techniques used in the study identified B. velezensis and T. harzianum as promising candidates for nematode management. These strains exhibited significant nematicidal activity, underscoring their potential as effective biocontrol agents. The use of these microbial agents aligns with previous findings that highlight the role of microbial biological control agents (MBCAs) in managing plant diseases and promoting plant growth[4]. The study's findings are particularly relevant in the context of sustainable agriculture. The demonstrated efficacy of Trichoderma spp. and Bacillus spp., along with their mutants, in controlling M. javanica provides a viable alternative to chemical nematicides. This approach not only mitigates the environmental and health risks associated with chemical use but also supports the broader goal of sustainable crop protection strategies. Furthermore, the research emphasizes the importance of combined biocontrol approaches. The synergistic effect observed with the combination of mutant isolates and chitosan highlights the potential for integrating multiple biocontrol agents and compounds to enhance efficacy. This integrative approach could be a key strategy in developing robust and sustainable nematode management practices. However, the study also points out the need for further research to evaluate the practical applications and long-term efficacy of these biocontrol agents. While the initial results are promising, understanding their performance under different agricultural conditions and over extended periods is crucial for their successful implementation. In conclusion, the study by NSTRI contributes significantly to the development of sustainable alternatives to chemical nematicides. By demonstrating the efficacy of Trichoderma spp. and Bacillus spp., along with their mutants, in controlling M. javanica, the research paves the way for safer and more sustainable agricultural practices. These findings have potential implications for crop protection strategies, offering a promising solution to the global challenge of nematode management.

AgricultureSustainabilityPlant Science

References

Main Study

1) Optimizing sustainable control of Meloidogyne javanica in tomato plants through gamma radiation-induced mutants of Trichoderma harzianum and Bacillus velezensis.

Published 1st August, 2024

https://doi.org/10.1038/s41598-024-68365-z

Related Studies

2) Microbes vs. Nematodes: Insights into Biocontrol through Antagonistic Organisms to Control Root-Knot Nematodes.

https://doi.org/10.3390/plants12030451

3) Role of Trichoderma as a biocontrol agent (BCA) of phytoparasitic nematodes and plant growth inducer.

https://doi.org/10.1016/j.jip.2021.107626

4) Plant growth-promoting microorganisms as biocontrol agents of plant diseases: Mechanisms, challenges and future perspectives.

https://doi.org/10.3389/fpls.2022.923880


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