Abstract: The strain Bacillus velezensis JS6-1 obtained from the saline soil of Gashi County, Kashgar, Xinjiang and had good preventive effect on pear fire blight, grape mildew, grape powdery mildew and other crop diseases. JS6-1 was labeled by rifampicin in order to study its colonization characteristics. The whole genome was sequenced for gene prediction and functional annotation. The results showed that the colonization density of JS6-1 was 6.00×10⁵ CFU/g in the stems and leaves of Pyrus betulifolia Bunge 3 d after being sprayed, and that was 6.00×10⁵ CFU/g 45 d after being sprayed.The colonization density decreased at first and increased 7 days after being irrigated in potting soil of Pyrus betulifolia Bunge, The colonization quantities reached 4.46×10⁵ CFU/g after 15 d and 3.10×10⁵ CFU/g 45d The colonization density ofJS6-1 in the stem and leaves and in the soil were both decreasing.The colonization densities in the stem and leaves and in the inter-root soil were 3×10² CFU/g and 1.32×10⁴ CFU/g, respectively, after 45 d of application. The whole genome sequencing results show that JS6-1 was 4014208 bp, encoding 3885 ORF, containing 86 tRNA genes, 27 rRNA, 82 sRNA, 76 tandem repeats. Amino acid transport and metabolism, encoding multidrug transporters and other genes that may be related to bacteriostatic ability were annotated by COG. There were 96 transmembrane transporter active genes annotated by GO database; 45 metabolic pathways of terpenoids and polyketides were annotated through the KEGG database. In conclusion, strain JS6-1 can colonizate in stem, leaf and root soil of potted Pyrus betulifolia Bunge and grape steadily, and contains a variety of resistance genes, which is valuable for further research and development.

Key words: Bacillus velezensis, colonization dynamics, complete genome sequence, gene annotation