Beneficial Insects Deliver Plant Growth-Promoting Bacterial Endophytes between Tomato Plants

Nikoletta Galambos, Stéphane Compant, Felix Wäckers, Angela Sessitsch, Gianfranco Anfora, Valerio Mazzoni, Ilaria Pertot and Michele Perazzolli

INFORMATIVE ABSTRACT - Macrolophus pygmaeus and Nesidiocoris tenuis are two beneficial insects of the Miridae family widely used in biocontrol programs against many crop pests, such as whiteflies, aphids, lepidopterans and mites.

These mirid predators frequently complement their carnivore diet by feeding plant sap with their piercing–sucking mouthparts, acting as vectors of phytopathogenic and beneficial microorganisms, such as plant growth-promoting bacterial endophytes. This study aims to develop a better comprehension of the role of Macrolophus pygmaeus and Nesidiocoris tenuis in the acquisition and transmission of specific plant growth-promoting bacteria. These two PGPB are Paraburkholderia phytofirmansstra in PsJN (PsJN) and Enterobacter sp. strain 32A (32A).

The transport of the bacteria takes place through the body of the insects: in fact, both bacterial strains were detected on the exoskeleton and the internal body of both mirids at the end of the mirid-mediated transmission. Specifically, both mirids were able to transmit PsJN and 32A between tomato plants, and these bacterial strains could be re-isolated from tomato shoots after mirid-mediated transmission. Thanks to the beneficial mirids, this work provided novel evidence that PsJN and 32A endophytically colonised tomato plants and moved from the shoots to roots after mirid-mediated transmission.

Macrolophus pygmaeus (left) and Nesidiocoris tenuis (right)