Symbiotic and Antagonistic Functions of the Bacterium Burkholderia cepacia BsNLG8, from the Nilaparvata lugens (Stal)

Bacterial symbionts are widespread in insects and other animals. These microbes play crucial roles in many aspects of insect physiology and biology, including immunity, nutrition and confronting plant defenses. In the present study, we isolated and identified the bacterium Burkholderia cepacia BsNLG8 from the brown planthopper (BPHs), Nilaparvata lugens, a devastating pest of rice crops worldwide. Plate confrontation assay indicated that BsNLG8 significantly inhibited the growth of phytopathogenic fungi. In addition, the BsNLG8 strain demonstrated the ability to produce siderophores, which explains its antagonistic mechanism. Lastly, we explored the nicotine degradation ability of BsNLG8 using in vitro and in vivo methods. In vitro, HPLC analysis results showed that BsNLG8 could significantly reduce the concentration of nicotine in the medium at 36 h. Moreover, microinjection of BsNLG8 in axenic BPHs increased the survival rate of the host on nicotine-containing rice seedlings. These findings could serve as the basis of future research in deciphering the interaction between host and symbionts.