Next Generation Sequencing and Comparative Genomic Analysis Reveal Extreme Plasticity of Two Burkholderia glumae Strains HN1 and HN2

Abstract

Burkholderia glumae is an important rice pathogen, thus the genomic and evolutionary history may be helpful to control this notorious pathogen. Here, we present two complete genomes of the B. glumae strains HN1 and HN2, which were isolated from diseased rice seed in China. Average nucleotide identity (ANI) analysis shows greater than 99% similarity of the strains HN1 and HN2 with other published B. glumae genomes. Genomic annotation revealed that the genome of strain HN1 consists of five replicons (6,680,415 bp) with an overall G + C content of 68.06%, whereas the genome of strain HN2 comprises of three replicons (6,560,085 bp) with an overall G + C content of 68.34%. The genome of HN1 contains 5434 protein-coding genes, 351 pseudogenes, and 1 CRISPR, whereas the genome of HN2 encodes 5278 protein-coding genes, 357 pseudogenes, and 2 CRISPR. Both strains encode many pathogenic-associated genes (143 genes in HN1 vs. 141 genes in HN2). Moreover, comparative genomic analysis shows the extreme plasticity of B. glumae, which may contribute to its pathogenicity. In total, 259 single-copy genes were affected by positive selection. These genes may contribute to the adaption to different environments. Notably, six genes were characterized as virulence factors which may be an additional way to assist the pathogenicity of B. glumae.