Root-Associated Bacteria Are Biocontrol Agents for Multiple Plant Pests

Abstract

Biological control is an important process for sustainable plant production, and this trait is found in many plant-associated microbes. This study reviews microbes that could be formulated into pesticides active against various microbial plant pathogens as well as damaging insects or nematodes. The focus is on the beneficial microbes that colonize the rhizosphere where, through various mechanisms, they promote healthy plant growth. Although these microbes have adapted to cohabit root tissues without causing disease, they are pathogenic to plant pathogens, including microbes, insects, and nematodes. The cocktail of metabolites released from the beneficial strains inhibits the growth of certain bacterial and fungal plant pathogens and participates in insect and nematode toxicity. There is a reinforcement of plant health through the systemic induction of defenses against pathogen attack and abiotic stress in the plant; metabolites in the beneficial microbial cocktail function in triggering the plant defenses. The review discusses a wide range of metabolites involved in plant protection through biocontrol in the rhizosphere. The focus is on the beneficial firmicutes and pseudomonads, because of the extensive studies with these isolates. The review evaluates how culture conditions can be optimized to provide formulations containing the preformed active metabolites for rapid control, with or without viable microbial cells as plant inocula, to boost plant productivity in field situations.

Bacillus subtilis 26D Triggers Induced Systemic Resistance against Rhopalosiphum padi L. by Regulating the Expression of Genes AGO, DCL and microRNA in Bread Spring Wheat

“…Priming induced by bacteria provides faster and longer-term plant protection throughout the growing season with low physiological costs [56,57]. The mechanisms of priming have not been fully disclosed, but it has been established that during the development of PGPB-mediated ISR, ROS are generated, hormonal signaling pathways are activated, and PR proteins are accumulated [58,59]. Recently, sRNAs have been considered important regulators of plant protection against pathogens and pests [21,36].…”

Plant growth promoting characterization of indigenous phosphate solubilizing rhizobacteria and effects on germination of some crops in Vietnam

“…Extracellular hydrolytic enzymes have played an important role in the metabolism of organic polymers that improve soil health (da Silva et al, 2021). These enzymes, especially chitinase, cellulase and protease, have also been important in the biological control of fungal and bacterial phytopathogens (Mishra et al, 2020), insects (Lee et al, 2022), and nematodes (Migunova and Sasanelli, 2021). The isolates that had the ability to fix nitrogen or dissolve K and Zn-bearing minerals could produce available N, K, and Zn nutrients for plants (Glick, 2012).…”

Metabolomics Approach to Explore Bioactive Natural Products Derived From Plant-Root-Associated Streptomyces

“…While much attention has been given to soil-dwelling Streptomyces, recent research has unveiled the potential of plant root-associated microbial populations as a promising source of novel natural products [7]. Plant root-associated Streptomyces, adapted to the unique challenges posed by the rhizosphere environment, exhibit distinct genetic and metabolic pro les compared to their soil counterparts.…”