Viruses Help Control Plant Diseases and Boost Soil Health

Jenn Hoskins
24th May, 2024

Viruses Help Control Plant Diseases and Boost Soil Health

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Nanjing Agricultural University found that increasing the frequency of bacteriophage applications significantly reduced bacterial wilt disease in tomato plants
  • Frequent phage applications also increased the diversity of beneficial microbes in the soil, particularly Actinobacteria, which help suppress harmful bacteria
  • This dual approach—directly targeting pathogens with phages and indirectly boosting beneficial soil bacteria—offers a more sustainable way to manage bacterial plant diseases
Bacterial diseases pose a significant threat to global crop production, and traditional methods for managing these diseases are increasingly falling short. The use of antibiotics has been limited due to cost and the emergence of antibiotic-resistant bacteria[2]. Current strategies include a mix of cultural practices, bactericides, plant activators, and biocontrol agents, but these methods often lose efficacy over time due to evolving bacterial populations[3]. Recent research highlights the potential of genome modification for disease resistance, although more research is needed to develop sustainable and accessible solutions[3]. Amid these challenges, a promising alternative has emerged: bacteriophages. A study conducted by researchers at Nanjing Agricultural University, China, explored the use of bacteriophages—viruses that specifically target bacteria—as a biocontrol method against the plant pathogenic bacterium Ralstonia solanacearum, which causes bacterial wilt in several important crops[1]. The researchers aimed to determine whether increasing the frequency of phage applications could enhance the control of R. solanacearum and how this might interact with the existing microbial community in the rhizosphere (the soil region near plant roots). The study found that increasing the frequency of phage applications significantly improved the control of R. solanacearum, leading to a marked reduction in bacterial wilt disease in both greenhouse and field experiments with tomato plants. This result is particularly important because R. solanacearum is known for its ability to cause severe damage to crops, making effective management strategies critical. Interestingly, the high frequency of phage applications also increased the diversity of the rhizosphere microbiota. This enhanced diversity included several bacterial taxa, particularly from the Actinobacteria group, which are known for their antibiotic production and soil suppressiveness. The researchers isolated Actinobacteria from the Nocardia and Streptomyces genera and tested their ability to suppress R. solanacearum both in vitro (in a controlled environment outside a living organism) and in planta (within the plant). They found that these Actinobacteria could inhibit the growth of R. solanacearum and reduce bacterial wilt disease, especially when used in combination with the phage cocktail. This study uncovers an additional benefit of phage therapy: it not only directly targets the pathogenic bacteria but also triggers a secondary line of defense by enriching pathogen-suppressing bacteria already present in the soil. This dual mechanism—direct phage action and indirect support from beneficial microbes—offers a more robust and sustainable approach to managing bacterial plant diseases. The findings align with previous research suggesting that the plant microbiome plays a crucial role in plant health and disease resistance[4]. Stress-induced changes in the plant microbiome can enhance plant survival and offspring fitness, indicating that manipulating the microbiome could be a viable strategy for disease management[4]. This study builds on that concept by demonstrating how phage applications can enhance the diversity and beneficial functions of the rhizosphere microbiota. In summary, the study by Nanjing Agricultural University researchers demonstrates that increasing the frequency of phage applications can effectively control R. solanacearum and reduce bacterial wilt disease. Moreover, this approach enriches beneficial microbial taxa in the rhizosphere, providing a second line of defense against the pathogen. These findings suggest that phage therapies could be tailored according to the composition of the host microbiota, unlocking pre-existing benefits provided by resident microbial communities. This innovative approach could lead to more sustainable and effective strategies for managing bacterial plant diseases, addressing the limitations of conventional methods and contributing to global food security.

BiotechBiochemPlant Science

References

Main Study

1) Phages enhance both phytopathogen density control and rhizosphere microbiome suppressiveness.

Published 23rd May, 2024

https://doi.org/10.1128/mbio.03016-23

Related Studies

2) Antibiotic Resistance in Plant-Pathogenic Bacteria.

https://doi.org/10.1146/annurev-phyto-080417-045946

3) Future of Bacterial Disease Management in Crop Production.

https://doi.org/10.1146/annurev-phyto-021621-121806

4) Microbiome-Mediated Stress Resistance in Plants.

https://doi.org/10.1016/j.tplants.2020.03.014


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