Unraveling the Dynamics of Pantoea ananatis : Isolation and Plant Responses

Pantoea ananatis was first reported infecting rice in the United States in 2021, causing leaf blight in research plots in Arkansas. In 2024, two breeding lines exhibited leaf blight symptoms in research plots at the Rice Research and Extension Center, Stuttgart, AR. This study aimed to recover new P. ananatis isolates and characterize their pathogenicity in rice, as well as their ability to induce plant responses in rice, tobacco, and onion. Isolates were obtained from seeds of symptomatic plants using a Pantoea genus-specific agar protocol and confirmed by PCR and sequencing of 16S rRNA and gyrB genes. P. ananatis isolates were infiltrated into tobacco and rice plants and inoculated in onion to determine their ability to elicit hypersensitive or necrotic responses. Notably, isolate PP105 consistently triggered a necrotic response in rice, tobacco and onion, suggesting distinct pathogenicity mechanisms compared with the other isolates. Overall, this study enhanced the understanding of P. ananatis characterization in rice and alternative model hosts, while highlighting challenges and raising new questions for future research.