Molecular Microbiology Research 2024, Vol.14, No.5, 208-217 http://microbescipublisher.com/index.php/mmr 211 3.1.3 Overcoming host defenses Predatory bacteria have evolved mechanisms to overcome the defenses of their prey. For instance, Bdellovibrio bacteriovorus can evade the immune responses of its prey by expressing few surface epitopes, making it less recognizable to the host's immune system. Prey organisms like Pseudomonas aeruginosa have developed resistance strategies, such as effective metal/oxidative stress systems and mechanisms for detoxifying antimicrobial peptides, to protect themselves from predation (Sydney et al., 2021). 3.2 Secretion of lytic enzymes The secretion of lytic enzymes is a common strategy among microbial predators to break down the cell walls of their prey. Bdellovibrio and like organisms (BALOs) secrete a range of enzymes, including lytic transglycosylases, which target the peptidoglycan layer of Gram-negative bacteria, facilitating invasion and digestion. Myxococcus xanthus also secretes a variety of lytic enzymes that degrade the cell walls of its prey, contributing to its broad prey range (Dong et al., 2022). 3.3 Interaction with host microbiome Microbial predators can influence the structure and function of host-associated microbiomes. For example, Halobacteriovorax, a genus of predatory bacteria, is prevalent on the surface of reef-building corals and preys on potential coral pathogens, thereby potentially protecting the host by regulating the microbiome composition (Welsh et al., 2015). Similarly, the presence of predatory bacteria like Bdellovibrio bacteriovorus can transform the landscape and community assembly of biofilms, impacting the spatial ecology of microbial communities (Wucher et al., 2021; Tang, 2024). 4 Potential Applications in Agriculture 4.1 Control of soil-borne pathogens Soil-borne pathogens pose a significant threat to crop yield and quality, leading to substantial economic losses in agriculture. The use of microbial predators as biocontrol agents offers a promising solution to manage these pathogens in an environmentally friendly manner. Beneficial microorganisms, such as certain bacterial and fungal species, can inhibit the growth of soil-borne pathogens through various mechanisms, including antibiosis, competition for nutrients, and enzymatic degradation (Niu et al., 2020; Tariq et al., 2020). For instance, the application of Trichoderma species has been shown to effectively suppress soil-borne fungal pathogens by producing a range of metabolites that inhibit pathogen growth. The use of multi-strain microbial consortia can enhance the efficacy of biocontrol by leveraging the synergistic interactions among different microbial species. 4.2 Biocontrol in crop rhizosphere The rhizosphere, the narrow region of soil influenced by root secretions and associated microbial activity, is a critical zone for plant health. Microbial predators in the rhizosphere can play a vital role in promoting plant growth and protecting against pathogens. Rhizosphere bacteria, such as plant growth-promoting rhizobacteria (PGPR), can enhance plant growth by producing growth hormones, solubilizing phosphate, and fixing nitrogen (Saeed et al., 2021). These bacteria also exhibit biocontrol properties by producing antibiotics, siderophores, and hydrolytic enzymes that inhibit pathogenic microbes. For example, the amendment of soil with Metarhizium species has been shown to increase the abundance of beneficial microbes in the rhizosphere, thereby enhancing plant growth and disease resistance. The complex interactions between microbial predators, plant roots, and other soil microbes in the rhizosphere are crucial for the successful implementation of biocontrol strategies (Shahriar et al., 2022). 4.3 Use in integrated pest management Integrated pest management (IPM) is a holistic approach that combines biological, cultural, physical, and chemical methods to control pests in an environmentally sustainable manner. Microbial predators can be an integral component of IPM by providing a natural means of pest suppression. For instance, soil predatory mites can be conserved and utilized to control plant-parasitic nematodes and arthropod pests, thereby reducing the
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