Ketoglutarate transport protein KgtP is secreted through the type III secretion system and contributes to virulence in Xanthomonas oryzae pv. oryzae.
The phytopathogenic prokaryote Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight (BB) of rice and utilizes a type III secretion system (T3SS) to deliver T3SS effectors into rice cells. In this report, we show that the ketoglutarate transport protein (KgtP) is secreted in an HpaB-independent manner through the T3SS of X. oryzae pv. oryzae PXO99(A) and localizes to the host cell membrane for α-ketoglutaric acid export. kgtP contained an imperfect PIP box (plant-inducible promoter) in the promoter region and was positively regulated by HrpX and HrpG. A kgtP deletion mutant was impaired in bacterial virulence and growth in planta; furthermore, the mutant showed reduced growth in minimal media containing α-ketoglutaric acid or sodium succinate as the sole carbon source. The reduced virulence and the deficiency in α-ketoglutaric acid utilization by the kgtP mutant were restored to wild-type levels by the presence of kgtP in trans. The expression of OsIDH, which is responsible for the synthesis of α-ketoglutaric acid in rice, was enhanced when KgtP was present in the pathogen. To our knowledge, this is the first report demonstrating that KgtP, which is regulated by HrpG and HrpX and secreted by the T3SS in Xanthomonas oryzae pv. oryzae, transports α-ketoglutaric acid when the pathogen infects rice.
Laboratory for Monitoring and Management for Plant Pests and Diseases (Ministry of Education of China), College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
Wei
W
Guo
Lu-Lu
LL
Cai
Hua-Song
HS
Zou
Wen-Xiu
WX
Ma
Xi-Ling
XL
Liu
Li-Fang
LF
Zou
Yu-Rong
YR
Li
Xiao-Bin
XB
Chen
Gong-You
GY
Chen
D058947:Bacterial Secretion Systems; D002244:Carbon / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D029382:Dicarboxylic Acid Transporters / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D005816:Genetic Complementation Test; D007656:Ketoglutaric Acids / Q000378:metabolism; D012275:Oryza / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D019802:Succinic Acid / Q000378:metabolism; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*; D014974:Xanthomonas / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity*
D058947:Bacterial Secretion Systems; D003470:Culture Media; D029382:Dicarboxylic Acid Transporters; D007656:Ketoglutaric Acids; D037521:Virulence Factors; D002244:Carbon; D019802:Succinic Acid