Colorado potato beetle microsymbiont Enterobacter BC-8 inhibits defense mechanisms of potato plants using crosstalk between jasmonate- and salicylate-mediated signaling pathways

One of the main insect potato pests is the Colorado potato beetle (Leptinotarsa decemlineata Say). It contains some microbial associates which can affect diverse interactions between host plant and the herbivorous insect. Previously, the most common L. decemlineata microsymbiont isolated from anterior and posterior parts of beetle gut was defined as Enterobacter BC-8. The role of Enterobacter BC-8 in manipulating plant defenses was investigated using antibiotics-treated beetles and model system simulating beetles attacks (wounding plants treated with Enterobacter BC-8 suspension). We demonstrated that the symbiotic bacteria suppressed plant defenses such as hydrogen peroxide and phenolic compounds accumulation and activity of peroxidases and trypsin inhibitors. It is worth noting that the influence of the insect symbionts on potato plants stimulated salicylate-sensitive genes and the marker of salicylate signaling pathway. Transcription activities of jasmonate-sensitive genes which encode some defense proteins against herbivores, were suppressed. So, Enterobacter BC-8 plays the role in salicylate/jasmonate crosstalks manipulating to suppress plant defense mechanisms.