Mode of Attack of Microbiological Control Agents against Plant Pathogens for Sustainable Agriculture and Food Security

Abstract

Plant diseases accounts for huge losses in agriculture. To ensure food security and sustainability, an agricultural yield must be improved to meet the growing world population. Due to growing awareness of the effect of pesticides and herbicides on human health and the environment, an alternative safe method of controlling phytopathogens has become a subject of intense research. Biological control of plant diseases is the use of living organisms to suppress or inhibit plant pathogens. Microbiological control agents (MBCAs) employ microorganisms to protect crops from destruction by phytopathogens through different modes of action. They may act by direct interaction with the pathogens through hyperparasitism. Indirect antagonistic interaction with the pathogen through induction of host resistance and priming is another mode of attack by MBCAs. Competition for nutrients and space is another important indirect mode of attack by which MBCAs suppress the growth of pathogens through nutrient deprivation. The MBCAs can also interact with the plant through secretion of antibiotics or antimicrobial secondary metabolites with inhibitory effect against the pathogens. A clear understanding of the mode of action of MBCAs is vital to achieving a successful biocontrol operation as well as improving the biocontrol process that is devoid of risks to humans and the environment. Such improvement could be achieved through the use of microbial consortia to enhance the stability and efficiency of the biocontrol process. Further studies on aspects of mass production and formulation to produce more effective, stable, safer and cost effective MBCAs are needed.

The potential of facultative predatory Actinomycetota spp. and prospects in agricultural sustainability

“…Recent years have been marked by an expanding array of virulent infectious diseases caused by pests which are increasingly recognized as presenting a worldwide threat to food security ( Olsen et al, 2011 ; Bosso et al, 2015 ; Hartmann, 2022 ). In addition, the extensive use of agrochemicals molecules has led to the development of bacterial resistance, causing significant risks to the environment and human health ( Ebele Mbachu et al, 2022 ). Consequently, providing food for the world’s population without disrupting the environmental balance is becoming eminent ( Pandit et al, 2022 ).…”

“…Different microorganisms are used as biocontrol agents, such as bacteria, fungi, and Actinomycetota ( Table 3 ). Direct antagonism and predation are the possible modes of action of biocontrol agents to eliminate plant parasites ( Ebele Mbachu et al, 2022 ).…”

Analysis of Endophytic Bacterial Communities and Investigation of Core Taxa in Apple Trees

“…Alternative methods for controlling plant pathogens have gained attention in recent years. These methods rely on the use of antagonistic microorganisms that interact with the pathogen and compete for resources through hyperparasitism ( Mbachu et al, 2022 ). Among these biocontrol agents, Bacillus subtilis BD170 ( Broggini et al, 2005 ), Pseudomonas fluorescens EPS62e ( Pujol et al, 2005 ), P. fluorescens A506 ( Wilson and Lindow, 1993 ), and Pantoea agglomerans E325 ( Pusey et al, 2011 ) have been demonstrated to suppress the fire blight pathogen.…”

“…These biological agents have been isolated from the ecological niche of plants, cultivated under classical methods, and assessed for their antagonistic activity using in vitro and in vivo analyses ( Köhl et al, 2019 ). As the occurrence of plant diseases is influenced by micro-ecological interactions, analyzing the indigenous microbiome of the host can provide insights into potential sources of natural antagonistic strains that reduce the severity of the pathogen and the genetic mechanisms underlying their beneficial functions ( Köhl et al, 2019 ; Mbachu et al, 2022 ). Ultimately, this can provide a better understanding of the genetic variability of biocontrol agents and another direct mode of action used in biocontrol through ecological microbiome analysis ( Köhl et al, 2019 ).…”