Do arbuscular mycorrhizal fungi (AMF) interactions change the resistance of rice plants to pests?

Plants undergo several hardships both above and below ground. Feeding by herbivores can change the physiology of plants at a systemic scale and as a consequence they can trigger a cascade of interactions that extend beyond the initial attacker. Arbuscular mycorrhizal fungi (AMF) are symbiotic associations in many plant roots thought to play a central role in plant nutrition. We hypothesize that the interaction of AMF with rice roots are activating responses that change the resistance of rice to insect pests. Our aim is to investigate the effects of colonization by AMF on performance and preference of above-ground herbivores, fall armyworm (FAW) larvae and rice water weevil (RWW) adults. Field and greenhouse studies indicated that both performance and preference of insects on rice was enhanced when plants were colonized by AMF. In the field, inoculating rice plants with mycorrhizae resulted in higher numbers of eggs and larval survival. In the greenhouse, weight gains and relative growth rates of FAW larvae were higher on rice plants treated with mycorrhizae. We conclude that AM fungi colonization influences processes in the root system of rice making them more susceptible to insect attack. Understating interactions among above- and below-ground organisms may help in developing novel methods for managing pests.