Pathogenicity Differences and Comparative Analysis of Genomes Between Two Ralstonia solanacearum Strains

Abstract

【Objective】The pathogenicity and genomic differences between two Ralstonia solanacearum strains were compared to analyze the key genes leading to the differences, and help the control of tobacco bacterial wilt disease in the future.【Method】Different R. solanacearum strains were isolated and purified from tobacco plants infected with bacterial wilt disease. The infestation tests were conducted to compare pathogenicity differences and the genomes of two strains were obtained by high-throughput sequencing technique to analyze the sequence difference, to explore the key genes affecting the pathogenicity of the strains.【Result】Two strains RsTP2 and RsTY2 were isolated from diseased tobacco plants in Guangchang county and Nanfeng county of Fuzhou, Jiangxi Province. egl gene sequencing results revealed that both strains were sequevar 13 belonged to Asian phylotype I. The infestation test results indicated that strain RsTP2 was more aggressive to Yunyan87 tobacco plants, in contrast to less pathogenicity of strain RsTY2. Draft genome maps of strains RsTP2 and RsTY2 (5.43 MB and 5.23 MB, respectively) were obtained by high-throughput sequencing technique. Then, the gene and protein sequences were compared with relevant databases to obtain gene function and species annotation information. Through analysis, it was found that 52 proteins of RsTY2 and 44 proteins of RsTP2 were different in the alignment with similarity between 50% and 99.88%. Most of the differential proteins were lectin-like protein, followed by cytolysin secretory activator protein and perforin family protein【Conclusion】By comparing the genomic sequences of strains RsTP2 and RsTY2 with different pathogenicity, it was found that there were significant differences in the coding sequences of lectin-like protein, cytolysin secretory activator protein and perforin family protein. These proteins mainly participated in bacterial adhesion, membrane lysis and penetration, and other functions, which were closely related to the ability of bacteria to invade host cells. The differences in these types of coding proteins are speculated to be one of the important factors leading to the differences in pathogenicity in strains RsTP2 and RsTY2.

Keywords

• ralstonia solanacearum
• sequevar
• pathogenicity
• genes sequencing
• lectin protein