Foliar herbivory affects the rhizosphere microbial assembly processes and association networks

Abstract

Insect herbivores are prevalent in terrestrial ecosystems, and plants inevitably and continuously suffer damage by insect herbivores. Numerous studies have reported the effect of insect herbivory on plants; however, its effect on the belowground soil microbial community remains understudied. In the present study, using high-throughput sequencing, we investigated the effect of foliar insect herbivory on rhizosphere soil bacterial community. Our results showed that both herbivory intensity and duration after herbivory had no significant effect on the rhizosphere microbial community structure, but microbial assembly processes and association networks were strongly affected by the above two factors. Under moderate and high herbivory and at 6 weeks after herbivory, variable selection explained 55.56% and 51.52% of the community variation indicating that deterministic processes played a dominant role. Network complexity decreased from no herbivory (1.07) to high herbivory (0.97), and network complexity at 2 weeks after herbivory (0.92) was higher than that at 4 and 6 weeks after herbivory (0.79 and 0.84, respectively). The proportion of negative correlations decreased with increasing herbivory intensity and duration after herbivory. The number of keystone species decreased with increasing duration after herbivory but showed no change with increasing herbivory intensity. To our knowledge, this is among the first studies to illustrate the response mechanisms of rhizosphere microbial assembly processes and association networks to foliar herbivory. Our findings suggest that the assembly process and association network patterns of microbes are closely associated with herbivory intensity and duration after herbivory and enhance the understanding of insect-plant-soil microbe interactions.