Title |
Identification of seven novel virulence genes from Xanthomonas citri subsp. citri by Tn5-based random mutagenesis |
Author |
Xue Song, Jing Guo, Wen-xiu Ma, Zhi-yuan Ji, Li-fang Zou, Gong-you Chen*, and Hua-song Zou* |
Address |
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China |
Bibliography |
Journal of Microbiology, 53(5),330-336, 2015,
|
DOI |
10.1007/s12275-015-4589-3
|
Key Words |
Xanthomonas citri subsp. citri, mutant library,
virulence genes, canker development |
Abstract |
To identify novel virulence genes, a mutant library of Xanthomonas
citri subsp. citri 29-1 was produced using EZ-Tn5
transposon and the mutants were inoculated into susceptible
grapefruit. Forty mutants with altered virulence phenotypes
were identified. Nine of the mutants showed a complete loss
of citrus canker induction, and the other 31 mutants resulted
in attenuated canker symptoms. Southern blot analysis revealed
that each of the mutants carried a single copy of Tn5.
The flanking sequence was identified by plasmid rescue and
18 different ORFs were identified in the genome sequence.
Of these 18 ORFs, seven had not been previously associated
with the virulence of X. citri subsp. citri and were therefore
confirmed by complementation analysis. Real-time PCR analysis
showed that the seven genes were upregulated when
the bacteria were grown in citrus plants, suggesting that the
expression of these genes was essential for canker development. |