Identification of seven novel virulence genes from Xanthomonas citri subsp. citri by Tn5-based random mutagenesis.
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.
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Xue
X
Song
Jing
J
Guo
Wen-xiu
WX
Ma
Zhi-yuan
ZY
Ji
Li-fang
LF
Zou
Gong-you
GY
Chen
Hua-song
HS
Zou
D032083:Citrus paradisi / Q000382:microbiology*; D004251:DNA Transposable Elements; D015723:Gene Library; D016254:Mutagenesis, Insertional; D009154:Mutation; D016366:Open Reading Frames; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D060888:Real-Time Polymerase Chain Reaction; D015854:Up-Regulation; D014774:Virulence / Q000235:genetics; D014974:Xanthomonas / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity*
D004251:DNA Transposable Elements