Multi-host lifestyle in plant-beneficial bacteria: an evolutionary advantage for survival and dispersal?

Abstract

Plants harbour a wide diversity of microorganisms that efficiently colonize different internal and external plant organs and compartments, including the phyllosphere (above-ground plant surface), spermosphere (seeds and area surrounding seeds), endosphere (internal tissues) and rhizosphere (roots and soil in the vicinity of plant roots), establishing complex and dynamic interactions with the host plants (Trivedi et al., 2020). The plant microbiome plays major roles in the nutrition, growth and resistance against biotic and abiotic threats (Trivedi et al., 2020; Bakker and Berendsen, 2022; Yuan et al., 2022) and there is complex communication between microorganisms and their plant hosts (Berlanga- Clavero et al., 2020; Rico-Jiménez et al., 2022). Indeed, the secretion of a great variety of plant compounds directs the assembly of plant-associated microbial communities and it has been proposed that plants produce a range of chemical signals to selectively recruit specific microorganisms in order to assemble protective microbiomes that enable them to cope with the imposed biotic and abiotic stresses (Rizaludin et al., 2021; Rolli et al., 2021; Trivedi et al., 2022). As a consequence of this selective pressure exerted by the plants, the microbial composition of the rhizosphere and the non-rooted bulk soil differ – with the rhizosphere having a larger microbial abundance but lower diversity (Berlanga- Clavero et al., 2020; Sokol et al., 2022).