Enhancement of Sweet Corn Seed Quality and Early Seedling Vigor by Priestia sp. RMT2NF4: Functional and Genomic Characterization of a Plant Growth-Promoting Strain

The development of sustainable microbial inoculants for crop production requires strains with demonstrated plant growth-promoting performance and well-characterized functional potential. This study evaluated the effect of Priestia sp. RMT2NF4, isolated from the rice rhizosphere, on sweet corn (Zea mays L.) seed physiological quality and early seedling vigor, supported by whole-genome sequencing analysis. Seed treatment effects were evaluated using a between-paper germination assay under controlled conditions at 25 °C for 7 days. Seed treatment with RMT2NF4 significantly increased germination percentage, germination index, and seedling growth rate by 13.26%, 21.30%, and 23.71%, respectively (p < 0.05). Inoculated seedlings also exhibited significantly greater shoot length, while root length and abnormal seedling proportion showed numerical but non-significant improvements. Genomic analysis identified genes putatively associated with tryptophan biosynthesis, nutrient acquisition, and stress adaptation. The integration of phenotypic validation and genome-informed functional profiling highlights the potential of RMT2NF4 and provides a basis for further evaluation of RMT2NF4 as a candidate plant growth-promoting bacterium to support sustainable sweet corn production and reduce reliance on chemical inputs.