Persistence of root-colonizing Pseudomonas protegensin herbivorous insects throughout different developmental stages and dispersal to new host plants

Autor: Flury, Pascale, Vesga, Pilar, Dominguez-Ferreras, Ana, Tinguely, Camille, Ullrich, Cornelia I., Kleespies, Regina G., Keel, Christoph, Maurhofer, Monika
Zdroj: The ISME Journal; April 2019, Vol. 13 Issue: 4 p860-872, 13p
Abstrakt: The discovery of insecticidal activity in root-colonizing pseudomonads, best-known for their plant-beneficial effects, raised fundamental questions about the ecological relevance of insects as alternative hosts for these bacteria. Since soil bacteria are limited in their inherent abilities of dispersal, insects as vectors might be welcome vehicles to overcome large distances. Here, we report on the transmission of the root-colonizing, plant-beneficial and insecticidal bacterium Pseudomonas protegensCHA0 from root to root by the cabbage root fly, Delia radicum. Following ingestion by root-feeding D. radicumlarvae, CHA0 persisted inside the insect until the pupal and adult stages. The emerging flies were then able to transmit CHA0 to a new plant host initiating bacterial colonization of the roots. CHA0 did not reduce root damages caused by D. radicumand had only small effects on Deliadevelopment suggesting a rather commensal than pathogenic relationship. Interestingly, when the bacterium was fed to two highly susceptible lepidopteran species, most of the insects died, but CHA0 could persist throughout different life stages in surviving individuals. In summary, this study investigated for the first time the interaction of P. protegensCHA0 and related strains with an insect present in their rhizosphere habitat. Our results suggest that plant-colonizing pseudomonads have different strategies for interaction with insects. They either cause lethal infections and use insects as food source or they live inside insect hosts without causing obvious damages and might use insects as vectors for dispersal, which implies a greater ecological versatility of these bacteria than previously thought.
Databáze: Supplemental Index