Friendly Bacteria Fight Fungus and Boost Tomato Plant Health

Jim Crocker
17th April, 2024

Friendly Bacteria Fight Fungus and Boost Tomato Plant Health

Tomato plant (Solanum lycopersicum).

Photo adapted from: Victoria J. Burton / CC BY (Source)

Key Findings

  • Scientists at the University of Sfax found a bacterium, Bacillus methylotrophicus DCS1, that produces antifungal compounds
  • These compounds, called lipopeptides, can effectively protect tomato plants from Fusarium wilt, a harmful fungus
  • The treatment with DCS1 was more effective as a cure after infection than as a preventive measure
In the pursuit of sustainable agriculture, scientists from the University of Sfax have made a breakthrough in the fight against plant diseases[1]. The study focuses on the antifungal properties of a specific strain of Bacillus, known as Bacillus methylotrophicus DCS1. This research is particularly relevant as plant-pathogenic fungi pose a major threat to crops worldwide, and understanding how to control these pathogens is crucial for food security[2]. Bacillus methylotrophicus DCS1 is a bacterium that produces substances called lipopeptides. These molecules have the ability to inhibit the growth of fungi, making them potential biocontrol agents against plant diseases. The study aimed to understand not just if, but how effectively these lipopeptides can protect plants, specifically tomato plants, from diseases such as Fusarium wilt, a disease caused by the fungus Fusarium oxysporum. To begin, the researchers cultivated the DCS1 strain in a nutrient-rich environment called Landy medium. They then monitored the production of lipopeptides over a 72-hour fermentation period. Using mass spectrometry, a technique that identifies molecules based on their mass and charge, the team discovered that the DCS1 strain produces various lipopeptide isoforms, including bacillomycin D and fengycins A and B. These compounds are known for their antifungal properties. The effectiveness of these lipopeptides was tested both in the laboratory (in vitro) and on actual plants (in vivo). In vitro methods included direct confrontation and agar well diffusion tests, which showed that the lipopeptides could inhibit the growth of several phytopathogenic fungi. In vivo, the researchers treated tomato plants with a bacterial suspension of the DCS1 strain and evaluated the plants' health over 30 days. They found that the curative treatment, applied after infection, was more effective at protecting the plants than preventive treatment, which is applied before infection. This study's findings are significant in that they demonstrate a biological method to control plant diseases, offering an alternative to chemical pesticides. This aligns with the goal of sustainable agriculture, which is to increase productivity while reducing the reliance on synthetic chemicals that can harm the environment[3]. Previous research has shown that hexanoic acid can prime tomato plants to defend themselves against Botrytis cinerea, another plant pathogen, by activating specific plant genes[4]. The current study expands on this idea by showing that Bacillus methylotrophicus DCS1 can suppress Fusarium wilt in tomato plants, potentially by a similar mechanism of inducing the plant's own defenses. Moreover, Bacillus spp. have been recognized for their role in promoting plant growth and soil fertility, as well as their antagonistic activity against phytopathogens[3]. The DCS1 strain's ability to produce a diverse mix of lipopeptides that can be used as biopesticides is a testament to the versatility and potential of Bacillus species in sustainable agriculture. The outcomes of this research are promising for the future of farming. By using Bacillus methylotrophicus DCS1 as a biocontrol agent, farmers could potentially reduce their reliance on harmful pesticides, leading to healthier crops and a more sustainable agricultural practice. This study not only adds to our understanding of the complex interactions between plants, microbes, and pathogens but also offers practical solutions for protecting crops against diseases. The University of Sfax's work could pave the way for new, environmentally friendly approaches to agriculture that are both effective and sustainable.

AgricultureBiotechPlant Science

References

Main Study

1) Bacillus methylotrophicus DCS1: Production of Different Lipopeptide Families, In Vitro Antifungal Activity and Suppression of Fusarium Wilt in Tomato Plants.

Published 16th April, 2024

https://doi.org/10.1007/s00284-024-03660-6

Related Studies

2) Transcription factor control of virulence in phytopathogenic fungi.

https://doi.org/10.1111/mpp.13056

3) Bacillus spp. as Bioagents: Uses and Application for Sustainable Agriculture.

https://doi.org/10.3390/biology11121763

4) Hexanoic acid protects tomato plants against Botrytis cinerea by priming defence responses and reducing oxidative stress.

https://doi.org/10.1111/mpp.12112


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