Traits analysis of an aphid-killing Pantoea agglomerans strain for use in biological control.

INTRODUCTION: In crop pest control, microbial bioinsecticides are considered promising for overcoming the critical limitations of traditional chemical pesticides regarding environmental and health impact. In this study, we report a strain of Pantoea agglomerans (ELIV) lethal to black bean aphid Aphis fabae: we investigated the effects of this bacterium on aphids and host plants to test its potential as a natural insecticide. METHODS AND RESULTS: We found that the entomopathogenic properties of P. agglomerans ELIV occur only through ingestion via oral infection assays, with no pathogenicity by contact observed via spraying tests. The bacterium does not appear to circulate within the plant after watering, remaining at the root level and having only slight effects on tested plant growth parameters. Genome analysis of P. agglomerans ELIV reveals its richness in genes encoding virulence factors, particularly iron-chelating siderophores, possibly explaining its ability to rapidly kill infected insects. DISCUSSION: Overall, our results present the strengths and limitations of the species P. agglomerans for the development of new bioinsecticides. Although the use of P. agglomerans may be of limited interest for controlling piercing-sucking insects as they feed internally, it may be relevant against chewing insect pests, e.g. lepidopteran caterpillars and beetles.