Insecticidal effect of recombinant endophytic bacterium containing Pinellia ternata agglutinin against white backed planthopper, Sogatella furcifera

White backed planthopper (WBPH; Sogota furcifera Horvath) has become the major threat to rice crops throughout Asia, damaging plants both through its feeding behavior and by acting as a virus vector. Here, we developed a novel method for biologically controlling WBPH by using endophytic bacterium to express anti-pest plant lectins. Strain SJ-10 of an endophytic bacterium, characterized as Enterobacter cloacae by morphological, physiological, biochemical and 16s rDNA characteristics, was isolated from rice seedlings. The Pinellia ternate agglutinin (PTA) gene was cloned into SJ-10 for expression. The positive transformant, selected by antibiotic resistance, was evaluated using PCR, SDS-PAGE and Western blot assay. After inoculation, rSJ-10 could colonize rice plants so that they expressed PTA, and then the rice was shown to have insecticidal activity against WBPH. The results showed that rSJ-10 could significantly decrease the survival and fecundity of WBPH fed on rice seedlings (p < 0.01). At day 19, the fecundity of WBPH inoculated with rSJ-10, or with wild-type SJ-10 was decreased by 86.1%, and 25.6%, respectively. At day 22, numbers of WBPH on rice in the control were 19.4 times greater than on rice inoculated with rSJ-10. At day 26, the rice seedlings all died in the control group, but the seedlings inoculated with rSJ-10 grew well. The results showed that the rice seedlings inoculated with rSJ-10 expressing PTA protein were endowed with the anti-pest activity against WBPH. Further work is needed to investigate whether the rice plants expressing rPTA are toxic to mammals. This research highlights a way to biologically control planthoppers by recombinant endophytic bacteria expressing plant lectins. 2011 Elsevier Ltd. All rights reserved.