Genomic Characterization of Burkholderia glumae K6 and B. gladioli UPMBG7: Causal Agents of Bacterial Panicle Blight in Malaysia

Bacterial panicle blight (BPB), caused by Burkholderia glumae and Burkholderia gladioli , poses a significant threaten to rice production in Malaysia, with yield losses reaching up to 75% in severely infected fields. In June 2021, (BPB) symptoms were observed in rice fields in Kedah, Malaysia. Phenotypic characterization revealed typical Burkholderia traits, and pathogenicity tests confirmed symptoms development within seven days after inoculating 75-day-old rice seedlings. Molecular identification using (16S rRNA and gyrB ) sequencing confirmed the isolates as B. glumae and B. gladioli . Whole-genome sequencing of B. glumae K6 and B. gladioli UPMBG7 was performed using the Illumina NovaSeq 6000 platform to investigate their genetic profiles. The assembled draft genome of B. glumae K6 contained 210 contigs, with a total genome size of 6.57 Mbp, 68.33% G + C content and 5,641 coding sequences (CDS). It harbored toxoflavin biosynthesis genes ( toxABCDE, toxJ ) and a Type III secretion system (T3SS), contributing to its pathogenicity. B. gladioli UPMBG7 contained 124 contigs, with a total genome size of 8.22 Mbp, G + C content of 67.99 and 7,022 coding proteins. Unlike B. glumae , B. gladioli lacked the toxI gene for toxoflavin production but compensated with pyoverdine siderophore genes ( pvdA ), which facilitate iron acquisition. These genomic insights unravel the virulence mechanisms of B. glumae and B. gladioli , laying the foundation for innovative disease management strategies. By identifying key pathogenic determinants, this study advances efforts in breeding resistant rice varieties, developing precision biological controls, and implementing cutting-edge molecular diagnostics for early pathogen detection, ultimately strengthening rice production against BPB devastation.