Growth-promoting Effect of <i>Enterobacter aerogenes</i> M167 isolated from the Rhizosphere of <i>Wikstroemia ganpi</i> on Lettuce ( <i>Lactuca sativa</i> )

Plant growth-promoting rhizobacteria (PGPR) enhance nutrient uptake, regulate phytohormone levels, and improve crop productivity.Thus, they can serve as eco-friendly alternative to chemical fertilizers.In the present study, we investigated the plant growth-promoting potential of Enterobacter aerogenes M167, a bacterial strain isolated from the rhizosphere of Wikstroemia ganpi, which is a threatened plant in South Korea.Physiological assays revealed multiple growth-promoting traits, including phosphate and zinc solubilization, nitrogen fixation, indole-3-acetic acid (IAA) production (37.350.57ppm), and siderophore production (17.10.4 mm).To assess its functional effects, the M167 strain was inoculated into Lactuca sativa, which was used as the model crop.Compared with the control group, M167 treatment resulted in a 78% increase in shoot fresh weight (0.890.58 g vs 0.500.24g; Welch's t-test, p <0.01), while shoot length did not significantly differ between groups (control: 5.130.91cm; M167: 5.131.02cm).These findings suggested that M167 promoted biomass accumulation rather than elongation.Collectively, these results demonstrate that M167 is a multifunctional PGPR that significantly enhances lettuce growth, underscoring the potential of rhizosphere microorganisms found in native forest plants as promising bioresources for sustainable agriculture and industrial applications.