Rhizosphere interactions between microorganisms and plants have great influence on plant health. Bacillus cereus C1L, an induced systemic resistance (ISR)-eliciting rhizobacterium from Lilium formosanum, can protect monocot and dicot plants from disease challenges. To identify the ISR-involved bacterial genes, the systemic protection effect of transposon-tagged mutants of B. cereus C1L against southern corn leaf blight (SCLB) was surveyed, and a mutant of the
ptsG gene encoding
glucose-specific
permease of the
phosphotransferase system was severely impaired in the abilities of disease suppression and root colonization. The
ptsG mutant lost the preferential utilization of
glucose and showed reduction of
glucose-assisted growth in minimal medium. A promoter-based reporter assay revealed that
ptsG expression could be activated by certain
sugar constituents of maize root exudates, among which B. cereus C1L exhibited the highest chemotactic response toward
glucose, whereas neither of them could attract the
ptsG mutant. Additionally,
ptsG deficiency almost completely abolished
glucose uptake of B. cereus C1L. Metabolite analysis indicated that the lack of
ptsG undermined
glucose-induced accumulation of
acetoin and
2,3-butanediol in B. cereus C1L, both eliciting maize ISR against SCLB. Pretreatments with B. cereus C1L,
ptsG mutant,
acetoin, and
2,3-butanediol enhanced defense-related
reactive oxygen species accumulation and
callose deposition at different levels that were positively correlated to their ISR-eliciting activities. Thus,
glucose uptake-mediating
ptsG participates in ISR elicitation by endowing B. cereus C1L with the full capacities for root colonization and beneficial
glucose metabolite production, providing a clue regarding how ISR-mediating rhizobacteria create a mutually beneficial relationship with various plant species.