Molecular Pathogens 2024, Vol.15, No.2, 93-105 http://microbescipublisher.com/index.php/mp 98 Henry et al. (2020) studied the distribution characteristics of Fusarium communities in different soil and root environments after 18 years of cover crops or conservation tillage treatments. The study showed (Figure 2) that Fusariumcommunities differed significantly among the various treatments (standard tillage without cover crops (STNO), standard tillage with cover crops (STCC), conservation tillage without cover crops (CTNO), and conservation tillage with cover crops (CTCC)). This indicates that long-term tillage and cover crop practices significantly influence the structure of Fusariumcommunities in soil and roots, highlighting the importance of soil health management in optimizing agricultural management strategies. 5 Biological Control Strategies 5.1 Use of antagonistic microorganisms Antagonistic microorganisms have shown significant potential in controlling Fusarium and other fungal pathogens in maize. Bacillus subtilis, for instance, has been identified as an effective biological control agent against Fusarium moniliforme. This bacterium occupies the same ecological niche within the plant as F. moniliforme, operating on the principle of competitive exclusion to reduce mycotoxin accumulation during the endophytic growth phase (Bacon et al., 2001). Similarly, Clonostachys rosea and a Gram-negative bacterium (BCA5) have demonstrated efficacy in reducing fumonisin B1 (FB1) contamination in maize cobs, with C. rosea achieving a reduction of over 70% at 25°C (Samsudin et al., 2017). These findings underscore the importance of understanding the ecophysiology of both the pathogen and the antagonists to ensure effective control. In addition to bacteria, fungal antagonists such as Trichoderma spp. have also been explored for their biocontrol potential. Trichoderma gamsii, for example, has been shown to induce systemic resistance in maize, enhancing the expression of marker genes associated with both Induced Systemic Resistance (ISR) and Systemic Acquired Resistance (SAR) pathways (Galletti et al., 2019). This dual mechanism not only reduces the endophytic development of Fusarium verticillioides but also promotes plant growth. The use of such antagonistic fungi offers a sustainable and environmentally friendly alternative to chemical fungicides, which are often expensive and have negative environmental impacts (Zhang et al., 2022). 5.2 Biopesticides and natural products Biopesticides and natural products derived from microorganisms offer another promising avenue for managing Fusariumand other fungal pathogens in maize. Bacillus amyloliquefaciens and Microbacterium oleovorans have been tested as seed treatments and have shown significant efficacy in reducing Fusarium verticillioides counts in maize seedlings without altering the microbial richness and diversity in the rhizosphere (Pereira et al., 2009). These biopesticides not only control the pathogen but also maintain the ecological balance of the soil microbiome, which is crucial for plant health. Natural products produced by antagonistic microorganisms also play a vital role in biocontrol strategies. For instance, Pseudomonas chlororaphis and Pseudomonas fluorescens have been identified for their production of antifungal metabolites that inhibit the growth of Aspergillus flavus and Fusarium verticillioides (Palumbo et al., 2007). These metabolites can be harnessed to develop natural biopesticides that are both effective and environmentally benign. Additionally, Bacillus siamensis GL-02 has shown significant inhibitory effects on Fusariumgraminearum, both in vitro and in vivo, making it a potential candidate for biopesticide development (Zhang et al., 2022). 5.3 Enhancing plant microbiome Enhancing the plant microbiome is a holistic approach to managing Fusarium and other fungal pathogens in maize. The maize-soybean relay strip intercropping system, for example, has been shown to reshape the rhizosphere bacterial community, recruiting beneficial bacteria such as Pseudomonas, Bacillus, and Streptomyces species that suppress Fusarium root rot (Figure 3) (Chang et al., 2022). This intercropping system not only increases microbial diversity but also enhances the abundance of beneficial microorganisms, thereby improving plant health and resistance to pathogens.
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