Effect of Volatile Compounds Produced by Selected Bacterial Endophytes in Promoting Plant Growth

Bacterial endophytes selected for their capability to suppress diverse fungal pathogens in vitro and in greenhouse studies have been shown to promote plant growth. The effect of volatile compounds emitted by selected bacteria on plant growth in Arabidopsis thaliana, tomato (Solanum lycopersicum), sweet pepper (Capsicum annuum), and cucumbers (Cucumis sativus) was evaluated on container-grown plants nested above bacterial cultures, with roots exposed to the volatiles without direct contact between bacterial cells and the plant roots. Significant increases in plant growth were observed in plant height, root length, leaf size, fresh weight, and chlorophyll content in all plants tested. Although diverse chemical compounds may be involved in promoting plant growth, including volatile and nonvolatile compounds, observations in this study have implications for the potential role of the selected bacteria in plant production as biofertilizers and biopesticides.