Plant growth-promoting rhizobacteria (PGPR) modulates sweet corn-corn earworm interactions

Abstract

Plant Growth-Promoting Rhizobacteria (PGPR) induces systemic resistance against plant diseases and insect herbivores in plants. The impact of single and blends of PGPR strains on plant-insect interactions with a focus on feeding and oviposition behavior of insect herbivores was studied using sweet corn (Zea mays) and corn earworm (CEW) (Helicoverpa zea) as a model system. Sweet corn plants were treated with single and blends of PGPR strains that include Blend 5 consists of PGPR strains AP-209 and AP-136, whereas Blend 8 consists of three strains, AP-136, AP-218, and AP-219, and a single strain, AP-209. The control sweet corn plants were untreated with PGPR. Adult female CEWs laid a significantly low number of eggs on PGPR-treated plants compared to the number of eggs laid on untreated sweet corn plants. Moreover, the leaf area damage inflected by the larvae was higher in untreated corn plants when compared with the PGPR-treated plants. Interestingly, plants treated with blends of PGPR are less preferred than the single-strain treated plants by the adult and larvae. These findings reveal that treating plants with rhizobacteria may induce significant physiological changes with potential ramifications for plant-insect interactions.