Iron-clad defense: How microbes shield tomato crops from bacterial wilt
image: Structural equation model linking siderophore production, siderophore-mediated interactions, and biomass with pathogen abundance and disease incidence (AUDPC) of plant bacterial wilt. Siderophore production, siderophore-mediated interactions in supernatant experiments, and biomass were major contributors to pathogen abundance in co-culture experiments. In the rhizosphere invasion experiment, siderophore-mediated interactions were crucial for the spread of bacterial wilt disease. R2 denotes the proportion of variance explained. The numbers on the arrows denote indicate the effect size of the relationship. The width of the arrows is proportional to the strength of path coefficients. Asterisks (*) indicate significant correlation (*P < 0.1, **P < 0.05, ***P < 0.01).
Credit: Horticulture Research
A new study has discovered that siderophores, molecules produced by certain bacteria, are instrumental in the microbiome's defense against Ralstonia solanacearum, a pathogen causing severe crop losses. The research indicates that siderophores significantly boost the inhibitory effects of Pseudomonas strains on the pathogen, particularly under iron-limited conditions, offering a new avenue for developing eco-friendly disease control strategies in agriculture.
Ralstonia solanacearum is a soil-borne pathogen that devastates tomato and other Solanaceae crops globally. Traditional chemical controls have proven inadequate and environmentally damaging. The plant root microbiome offers a potential solution by naturally inhibiting pathogens or competing for resources. However, limited understanding of these interactions, particularly iron competition, hinders effective field applications. Due to these challenges, it is essential to investigate mechanisms like siderophore-mediated iron competition more thoroughly.
A collaborative team from Nanjing Agricultural University, in partnership with international researchers, published their findings (DOI: 10.1093/hr/uhae186) on July 12, 2024, in Horticulture Research. The study highlights that Pseudomonas consortia employing siderophore-mediated competition suppress Ralstonia solanacearum more effectively than other mechanisms. This work pioneers a new strategy for utilizing microbial interactions to defend crops from bacterial wilt.
The researchers examined Pseudomonas strains known for their diverse siderophore production, revealing how these molecules disrupt the pathogen’s access to iron. Through experiments under iron-limited and iron-rich conditions, they demonstrated that siderophores significantly enhanced pathogen inhibition. A greenhouse assay validated these findings, showing reduced disease incidence in tomato plants inoculated with siderophore-producing consortia. Interestingly, the study found that while siderophores were highly effective, other antimicrobial metabolites had limited impact in iron-deficient environments. The researchers concluded that iron competition drives microbial community dynamics and is pivotal in disease suppression.
Dr. Tianjie Yang, lead researcher, emphasized, “Our findings spotlight the importance of iron-mediated microbial interactions. By engineering microbial consortia optimized for iron competition, we can sustainably control soil-borne diseases. This could revolutionize crop protection by reducing dependence on synthetic chemicals.”
This research paves the way for microbiome-based agricultural innovations. Leveraging siderophore-producing consortia offers a natural, eco-friendly approach to managing plant diseases. As iron deficiency commonly occurs in soil, applying this strategy could benefit global crop production, boosting food security while mitigating environmental impact.
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References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhae186
Funding information
This research was funded by the National Natural Science Foundation of China (42090060, 42325704, 42277113, and 42107140), the Fundamental Research Funds for the Central Universities (KYT2024001), the Natural Science Foundation of Jiangsu Province (BK20230102), the Jiangsu Agricultural Science and Technology Innovation Fund (CX(22)1004, SCX(24)3511) and the Jiangsu Carbon Peak & Carbon Neutrality Science and Technology Innovation Special Fund (BE2022423).
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, 2022. 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.