Beneficial soil microbes and zoophytophagous predators as plant ‘vaccination’ agents against arthropod pests

Abstract: Unable to run away from their enemies, plants are continuously challenged by biotic stressors. Besides herbivorous arthropods and pathogenic microorganisms, plant interactors also include beneficial organisms such as predators and microbes that can be promising biocontrol agents. Beneficial soil microbes in particular are known to elicit plant responses and therefore may be capable of protecting plants against herbivores. Similarly, beneficial arthropods such as zoophytophagous predators have been shown to elicit defense-related responses in plants impacting herbivores indirectly, via their phytophagy. On the other hand, beneficial soil microbes showing intimate relationships with plants may not only affect herbivores but also their natural enemies through the induction of plant defenses. Here, I explore promising opportunities for controlling pests on the basis of our current knowledge on parameters that determine plant defense. I specifically refer to soil microbes and zoophytophagous predators and address their use as plant ‘vaccination’ agents to prime plants against future attackers. Research on plant-arthropod-microbe interactions is relatively poor but necessary to identify beneficial interactions and further develop biocontrol strategies for sustainable crop production.