Xanthomonas oryzae pv. oryzicola(Xoc) causes bacterial leaf streak, a devastating disease in rice-growing regions worldwide. A Tn5-insertion mutant in Xoc_3248, encoding an inner membrane protein(Imp), showed reduced virulence in rice. To explore the potential function of this gene in virulence, a deletion mutant Rimp was constructed in the wild-type RS105. The Rimp mutant was significantly impaired for bacterial virulence and growth in planta. The mutation in imp made the pathogen insufficiently utilize glucose, fructose, mannose or pyruvate as a sole carbon source, leading to less extracellular polysaccharide(EPS) production and reduced motility. The deficiencies noted for the mutant were restored to wild-type levels when imp was introduced in trans. Transcription of imp was significantly declined when hrp G and hrp X was mutated and the expression of hrp G and hrp X was also significantly declined when imp was deleted. Cell sublocalization in planta showed Imp membrane-binding feature. These results suggest that Imp is a virulence factor with roles in the catabolism of sugars, EPS production, and bacterial motility. Xanthomonas oryzae pv. Oryzicola (Xoc) causes bacterial leaf streak, a devastating disease in rice-growing regions worldwide. A Tn5-insertion mutant in Xoc_3248, encoding an inner membrane protein (Imp), showed reduced virulence in rice. To explore the potential function of this gene in virulence, a deletion mutant Rimp was constructed in the wild-type RS105. The Rimp mutant was significantly implicit for bacterial virulence and growth in planta. The mutation in imp made the pathogen insufficiently utilize glucose, fructose, mannose or pyruvate The deficiencies noted for the mutant were restored to wild-type levels when imp was introduced in trans. Transcription of imp was significantly declined when hrp G and hrp X was mutated and the expression of hrp G and hrp X was also significantly declined when imp was deleted. Cell sublocalization in planta showed Imp membrane-binding featu re. These results suggest that Imp is a virulence factor with roles in the catabolism of sugars, EPS production, and bacterial motility.