Microbial production of nematicidal agents for controlling plant-parasitic nematodes

Despite the serious damage of a wide range of agriculture and forestry by plant-parasitic nematodes, the use of many chemical pesticides has been declining in recent years due to concerns about their toxicity, tolerance, and environmental persistence issues. Therefore, there is an urgent need to develop efficient and environmentally safe alternatives to chemical pesticides. To this end, microbes have attracted great attention as sources for novel nematicidal agents, largely owing to their genetic diversity and metabolic capacity. However, their uses have often been limited due to their low productivity of natural products. Metabolic engineering of microbial cells, which entails rewiring of metabolic flux toward the target product, has emerged as a powerful method that can overcome the limitations of low yield. Here we review the recent metabolic engineering approaches for the highproduction of nematicidal agents, including heterologous expression, metabolic flux control, and engineering of regulatory elements, transporters, and genes involved in post-modification.