Fungal diseases pose a persistent and costly threat to global agriculture and turfgrass management, demanding innovative and sustainable solutions to curb their impact. Among these, dollar spot disease, caused by the fungal pathogen Clarireedia jacksonii, is notorious for damaging turfgrass on golf courses, athletic fields, and residential lawns. Manifesting as distinctive circular lesions approximately the size of a silver dollar, this disease inflicts significant economic losses estimated at over $35,000 annually for an average golf course in the United States alone. The urgency to develop biologically based treatments stems from the limitations and environmental risks associated with traditional chemical fungicides, propelling research into beneficial soil microbes that can enhance plant health and disease resistance.
Recent advances from the University of Delaware (UD) spotlight a groundbreaking development involving a bacterium dubbed UD1022, a novel strain of Bacillus subtilis uniquely isolated and characterized by plant biologist Harsh Bais and colleagues. This beneficial microbe has demonstrated remarkable capabilities in priming plant immune responses, fostering enhanced root-to-shoot growth, and boosting drought tolerance across various plant species. Unlike conventional fungicides, UD1022 operates by directly antagonizing pathogens and augmenting the plant’s innate defense mechanisms, positioning it as a promising agent in integrated disease management strategies.
Previous laboratory research underscored UD1022’s potency against Clarireedia jacksonii, revealing its capability to suppress fungus growth effectively under controlled conditions. However, more recent investigations, detailed in the journal Plant Stress, have unraveled a nuanced mode of action that differentiates thus bacterium from classical systemic defense inducers. When introduced to turfgrass soil, UD1022 surprisingly failed to prime the plant’s systemic immune response sufficiently enough to prevent dollar spot infections on the foliar parts. This contradicts prior findings in species like tomato, Arabidopsis, and rice, where root colonization by UD1022 robustly activated systemic acquired resistance against diverse pathogens.
This unexpected discovery emphasizes the spatial specificity of UD1022’s antagonistic activity against dollar spot fungus. The research elucidates that direct application of UD1022 onto infected foliage precipitates a substantial 43.6% decline in disease severity, a clear indication that proximity is a critical factor for its efficacy. The inability of root-applied UD1022 to confer similar protection on distant leaf tissues highlights a disruption in the signaling pathways required for communication between root and shoot defense mechanisms in turfgrass. Such specificity aligns with a model where UD1022 must physically confront the fungal pathogen to exert biocontrol effects, rather than relying solely on systemically induced resistance.
Intriguingly, the longevity of UD1022’s protective influence also depends on the bacterium’s viability. The fungus proliferated unabated when dead UD1022 cells were applied, underscoring the necessity for live bacterial populations to maintain continuous antagonism against the fungal pathogen. This obligates future formulation efforts to prioritize microbial shelf life and persistence on leaf surfaces to harness optimal disease suppression in field applications.
Acknowledging these findings, researchers advocate for a multifaceted disease management framework incorporating UD1022 as part of an integrated approach rather than a standalone solution. Combining biological agents like UD1022 with existing chemical or cultural control measures could yield synergistic benefits, enhancing sustainability while mitigating environmental and resistance concerns. Moreover, the dual functionality of UD1022—as a drought tolerance enhancer and antifungal agent—further elevates its potential utility in turfgrass management, where abiotic and biotic stresses frequently converge.
The University of Delaware team envisions expanding this research trajectory by developing synthetic microbial consortia that amalgamate multiple beneficial microbes for amplified plant health benefits. During upcoming sabbatical work at the Pacific Northwest National Laboratory (PNNL) in 2027, Bais plans to investigate the compatibility, viability, and root colonization proficiency of a consortium composed of 10-15 microbial strains isolated over two decades. Root colonization emerges as the paramount determinant of microbe-mediated plant resilience, triggering efficient defense responses and improving nutrient uptake under stress conditions.
Future research endeavors will extend into assessing the functionality of these microbial communities within turfgrass and staple monocot crops such as sorghum and corn, especially under compounded stress scenarios like simultaneous drought and pathogen attacks. This integrative approach seeks to mimic realistic agricultural environments, wherein plants face multiple concurrent stresses challenging their physiology and survival. Understanding the interplay between microbial consortia, plant immune signaling, and environmental factors promises to revolutionize biological disease control paradigms.
This work practically redefines the landscape of biological fungicide development by highlighting the limitations and opportunities intrinsic to microbe-plant-pathogen interactions. It stresses the imperative of evolving beyond singular biological agents to holistic microbial networks that sustain plant health through dynamic and context-dependent mechanisms. As the agricultural sector grapples with ecological constraints and rising pathogen resistance, such innovative science fosters hope for durable, effective, and environmentally sound plant protection strategies.
The implications of this research resonate broadly, not only for turfgrass industry economics but for global efforts to reduce reliance on chemical pesticides in sustainable farming. Insights into the spatial dynamics of microbial antagonism present new avenues for biocontrol product formulation, application timing, and delivery systems tailored to specific pathosystems. Ultimately, integrating precise microbial management with conventional agronomic practices could profoundly advance crop protection resilience, yield stability, and ecosystem health in a changing climate.
Subject of Research: Biological control of fungal diseases in turfgrass using beneficial bacteria
Article Title: [Not available]
News Publication Date: [Not specified]
Web References:
- University of Delaware article: https://www.udel.edu/udaily/2023/august/ud-beneficial-bacteria-ud1022-antifungal-turfgrass/
- Journal paper: https://www.sciencedirect.com/science/article/pii/S2667064X25004257
References:
Bais, H., Kaur, C., Ervin, E., et al. (2025). Effects of UD1022 on dollar spot disease in turfgrass. Plant Stress. https://doi.org/10.1016/j.stress.2025.101158
Image Credits: Evan Krape / University of Delaware
Keywords: Turfgrass, Biological control, Bacillus subtilis, Dollar spot disease, Plant-microbe interactions, Fungal pathogens, Soil bacteria, Plant immune response, Microbial consortia, Sustainable agriculture, Root colonization, Drought tolerance
