Methanol chemoreceptor MtpA- and flagellin protein FliC-dependent methylotaxis contributes to the spatial colonization of PPFM in the phyllosphere.

Pink-pigmented facultative methylotrophs (PPFMs) capable of growth on methanol are dominant and versatile phyllosphere bacteria that provide positive effects on plant growth through symbiosis. However, the spatial behavior of PPFMs on plant surfaces and its molecular basis are unknown. Here, we show that Methylobacterium sp. strain OR01 inoculated onto red perilla seeds colonized across the entire plant surface in the phyllosphere concomitant with the plant growth. During its transmission, strain OR01 was found to be present on the entire leaf surface with a preference to sites around the periphery, vein, trichome, and stomata. We found that methanol-sensing chemoreceptor MtpA-dependent chemotaxis (methylotaxis; chemotaxis toward methanol) and flagellin protein FliC-dependent motility facilitated the bacterial entry into the stomatal cavity and their colonization in the phyllosphere.