Surface-motility induction, attraction and hitchhiking between bacterial species promote dispersal on solid surfaces

Abstract

The ability to move on solid surfaces provides ecological advantages for bacteria, yet many bacterial species lack this trait. We found that Xanthomonas spp. overcome this limitation by making use of proficient motile bacteria in their vicinity. Using X. perforans and Paenibacillus vortex as models, we show that X. perforans induces surface motility, attracts proficient motile bacteria and 'rides' them for dispersal. In addition, X. perforans was able to restore surface motility of strains that lost this mode of motility under multiple growth cycles in the lab. The described interaction occurred both on agar plates and tomato leaves and was observed between several xanthomonads and motile bacterial species. Thus, suggesting that this motility induction and hitchhiking strategy might be widespread and ecologically important. This study provides an example as to how bacteria can rely on the abilities of their neighboring species for their own benefit, signifying the importance of a communal organization for fitness.

Kin discrimination between sympatric Bacillus subtilis isolates

“…Bacterial surface motility is an adaptive trait that allows bacteria to disperse and invade new environments when nutrients are limited (31). However, in a spatially structured and less hydrated environment, such as soil, dispersal rates are low (32), and thus closely related bacteria may remain in the vicinity of each other and compete for the same nutrients and space (33).…”

Volatile affairs in microbial interactions

“…Volatile compounds can also have a role in the attraction of other microorganisms. During interaction between X. perforans and Paenibacillus vortex, volatiles produced by X. perforans were found to attract the proficient swarmer P. vortex (Hagai et al, 2014). Interestingly, the volatiles released by X. perforans did not only attract the swarmer but also increased its dispersal without affecting its growth rate.…”

“…Interestingly, the volatiles released by X. perforans did not only attract the swarmer but also increased its dispersal without affecting its growth rate. Using fluorescent-stained X. perforans, Hagai et al (2014) revealed that this hitch-hiking strategy also occurs on tomato leaves with different swarming bacterial species, suggesting that this might be a widespread and ecologically important phenomenon.…”

Signaling in the Phytomicrobiome

“…Some of the regulatory activity by the plant is through availability of metabolites, but it is also increasingly evident that signals (exo-hormones or hormones of the holobiont) are being exchanged between the plant and members of its phytomicrobiome. Activities within the phytomicrobiome are also regulated through signaling, for instance through quorum sensing (Hartmann et al, 2014;Sitaraman;Smith et al;Smith et al), and other less well characterized signaling systems (e.g., Hagai et al, 2014).…”