Fermented chrysanthemum stem offers a natural defense against tomato bacterial wilt

Tomato bacterial wilt, caused by Ralstonia solanacearum, is a persistent and destructive disease that leads to serious yield losses worldwide. This study demonstrates that fermented chrysanthemum stem contains natural antimicrobial compounds capable of suppressing the pathogen and reducing disease severity in tomato plants. Through comparative resource screening, fermentation, metabolomic profiling, and biological validation, the researchers identified a group of phenolic acids, among which 3-(4-hydroxyphenyl)-propionic acid (HPPA) exhibited the strongest and most consistent disease control effects. The findings highlight the value of agricultural plant residues as sources of natural antimicrobial agents and indicate that fermentation can enhance their bioactivity, offering a sustainable alternative to synthetic chemical pesticides.

Tomato is one of the most economically important horticultural crops globally, yet its production is seriously threatened by bacterial wilt disease. Ralstonia solanacearum is highly adaptable in soil environments, capable of infecting a broad range of hosts and persisting for long periods, making disease management extremely challenging. Conventional chemical pesticides provide limited and often temporary suppression while posing ecological and health concerns, including pathogen resistance. This has driven increasing interest in natural antimicrobial compounds from plant biomass and fermentation-enhanced extraction strategies. Based on these challenges, there is a need to conduct in-depth research on plant-derived natural antimicrobial compounds and effective techniques to enhance their availability and efficiency.

In a study published (DOI: 10.1093/hr/uhaf027) on May 1, 2025, in Horticulture Research, researchers from Nanjing Agricultural University investigated whether plant stems fermented with Bacillus amyloliquefaciens T-5 could suppress R. solanacearum and protect tomato plants. Screening ten plant species revealed that fermented chrysanthemum stem extracts showed the strongest inhibitory effects. Subsequent metabolomic and biological assays identified several phenolic acids, with 3-(4-hydroxyphenyl)-propionic acid (HPPA) demonstrating significant disease suppression under greenhouse conditions.

The study first evaluated ten types of plant stems through controlled fermentation and pathogen inhibition assays. Chrysanthemum stem fermented with B. amyloliquefaciens T-5 significantly reduced R. solanacearum growth compared to non-fermented controls. Greenhouse trials confirmed that tomato plants treated with the fermented extract exhibited lower disease incidence and slower disease progression.

Metabolomic profiling revealed that fermented chrysanthemum stem had the highest chemical divergence among all tested plant materials, particularly enriched in phenolic acids and flavonoids. Using differential metabolite analysis and weighted gene coexpression network analysis, the researchers identified key upregulated metabolites. Among these, three phenolic acids—2-hydroxy-3-phenylpropanoic acid, mandelic acid, and HPPA—were validated for antimicrobial activity. Although all inhibited pathogen growth in vitro, only HPPA consistently reduced bacterial wilt severity in greenhouse-treated plants. This indicates that HPPA is the primary functional compound driving disease control.

“Our work shows that plant residues, which are often discarded, can become valuable resources when combined with microbial fermentation,” said the study's corresponding author. “HPPA demonstrates strong antimicrobial activity while remaining environmentally safe, offering a promising natural alternative to chemical pesticides. This research bridges plant chemistry, microbial biotechnology, and sustainable agriculture.”

The use of fermented chrysanthemum stem extract or purified HPPA offers a promising, eco-friendly approach to manage tomato bacterial wilt. These findings encourage the development of natural compound–based plant protection products and agricultural waste valorization strategies. Future research will explore HPPA stability, scalable fermentation processes, and field-level efficacy across diverse environments and crop systems. The study demonstrates how natural plant compounds can be harnessed to improve crop health while reducing dependence on synthetic pesticides.

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References

DOI

10.1093/hr/uhaf027

Origianl Source URL

https://doi.org/10.1093/hr/uhaf027

Funding information

This research was financially supported by the National Key Research and Development Program of China (2023YFD1702200).

About Horticulture Research

Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.