A single amino acid substitution in the SdhB protein of succinate dehydrogenase determines resistance to amicarthiazol in Xanthomonas oryzae pv. oryzae.
BACKGROUND
Xanthomonas oryzae pv. Oryzae Ishiyama, a causal agent of rice bacterial leaf blight, was found to be sensitive in vitro to the systemic fungicide amicarthiazol (2-amino-4-methylthiazole -5-carboxanilide), which is a potent inhibitor of succinate dehydrogenase (SDH, EC 1.3.99.1). This paper aimed to determine the molecular resistance mechanism of X. oryzae pv. oryzae to amicarthiazol.


RESULTS
UV-induced resistant mutants of X. oryzae pv. oryzae to amicarthiazol were isolated. The activity of SDH in wild-type X. oryzae pv. oryzae was strongly inhibited by amicarthiazol, while that in resistant mutants was insensitive, although their SDH activity was decreased compared with the wild-type sensitive strain without amicarthiazol. A mutation of Histidine(229) (CAC) to Tyrosine(229) (TAC) was identified in sdhB, which encoded the iron-sulfur protein subunit of SDH. The sdhB from the mutant was ligated into a cosmid, pUFR034, to generate pUFR034RAX, which conferred resistance to amicarthiazol when transformed into the wild-type sensitive strain.


CONCLUSIONS
A mutation of His(229) (CAC) to Tyr(229) (TAC) in SdhB was responsible for determining amicarthiazol resistance. .
Zhang
Yu-Jun
YJ
Shenzhen Entry-Exit Inspection and Quarantine Bureau, Futian, Shenzhen, PR China.
Li
Jun
J
Zhao
Wei
W
Zhou
Ming-Guo
MG
D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000813:Anilides / Q000494:pharmacology*; D003001:Cloning, Molecular; D004352:Drug Resistance, Microbial / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000382:microbiology; D013385:Succinate Dehydrogenase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013844:Thiazoles / Q000494:pharmacology*; D014974:Xanthomonas / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000502:physiology*
D000813:Anilides; D004791:Enzyme Inhibitors; D013844:Thiazoles; C511341:amicarthiazol; D013385:Succinate Dehydrogenase