A New Leaf Bacterial Disease of Foxtail Millet Caused by Pantoea ananatis in China

Long-term continuous monocropping of foxtail millet (Setaria italica) in China has increased crop vulnerability to emerging diseases and threatens yield stability and grain quality. This practice may also influence inoculum carryover and host–pathogen interactions, making foxtail millet health a central issue for sustainable production. This study reports the first occurrence in China of a previously undescribed bacterial leaf disease of foxtail millet. Early symptoms are characterized by water-soaked lesions at leaf tips that spread basipetally along the veins and gradually desiccate as the tissue dehydrates. Koch’s postulates were fulfilled to isolate and identify the causal agent. Multilocus sequence analysis of three concatenated housekeeping genes (gyrB, infB, and rpoB) classified the pathogen as Pantoea ananatis. The isolate was further characterized for metabolic profile; its colonization pattern and spatial distribution within foxtail millet tissues were elucidated, revealing features of host–pathogen interaction. A high-quality de novo whole-genome assembly was generated, and candidate virulence determinants were identified by integrated genome annotation and cell wall hydrolase activity assays. This genomic resource is intended as a supporting tool for plant protection research, including disease surveillance, resistance breeding, and management. Collectively, this study represents the first report of P. ananatis causing bacterial leaf disease on foxtail millet in China. It clarifies the colonization and distribution of the pathogen in host tissues, reveales reveals its interaction characteristics with foxtail millet, and provided genomic resources to support research on foxtail millet health protection and plant protection under continuous cropping conditions.