Comparative and functional genomic analyses of the pathogenicity of phytopathogen Xanthomonas campestris pv. campestris.
Xanthomonas campestris pathovar campestris (Xcc) is the causative agent of crucifer black rot disease, which causes severe losses in agricultural yield world-wide. This bacterium is a model organism for studying plant-bacteria interactions. We sequenced the complete genome of Xcc 8004 (5,148,708 bp), which is highly conserved relative to that of Xcc ATCC 33913. Comparative genomics analysis indicated that, in addition to a significant genomic-scale rearrangement cross the replication axis between two IS1478 elements, loss and acquisition of blocks of genes, rather than point mutations, constitute the main genetic variation between the two Xcc strains. Screening of a high-density transposon insertional mutant library (16,512 clones) of Xcc 8004 against a host plant (Brassica oleraceae) identified 75 nonredundant, single-copy insertions in protein-coding sequences (CDSs) and intergenic regions. In addition to known virulence factors, full virulence was found to require several additional metabolic pathways and regulatory systems, such as fatty acid degradation, type IV secretion system, cell signaling, and amino acids and nucleotide metabolism. Among the identified pathogenicity-related genes, three of unknown function were found in Xcc 8004-specific chromosomal segments, revealing a direct correlation between genomic dynamics and Xcc virulence. The present combination of comparative and functional genomic analyses provides valuable information about the genetic basis of Xcc pathogenicity, which may offer novel insight toward the development of efficient methods for prevention of this important plant disease.
Qian
Wei
W
National Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, PR China.
Jia
Yantao
Y
Ren
Shuang-Xi
SX
He
Yong-Qiang
YQ
Feng
Jia-Xun
JX
Lu
Ling-Feng
LF
Sun
Qihong
Q
Ying
Ge
G
Tang
Dong-Jie
DJ
Tang
Hua
H
Wu
Wei
W
Hao
Pei
P
Wang
Lifeng
L
Jiang
Bo-Le
BL
Zeng
Shenyan
S
Gu
Wen-Yi
WY
Lu
Gang
G
Rong
Li
L
Tian
Yingchuan
Y
Yao
Zhijian
Z
Fu
Gang
G
Chen
Baoshan
B
Fang
Rongxiang
R
Qiang
Boqin
B
Chen
Zhu
Z
Zhao
Guo-Ping
GP
Tang
Ji-Liang
JL
He
Chaozu
C
D001426:Bacterial Proteins / Q000235:genetics*; D001937:Brassica / Q000235:genetics / Q000382:microbiology; D004251:DNA Transposable Elements; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009875:Operator Regions, Genetic; D010935:Plant Diseases / Q000235:genetics; D017422:Sequence Analysis, DNA; D037521:Virulence Factors / Q000235:genetics*; D016959:Xanthomonas campestris / Q000235:genetics* / Q000472:pathogenicity*
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D037521:Virulence Factors