Regulation on superoxide anion production in Xanthomonas oryzae pv.oryzae,JXOIII and JXOV by host-pathogen interaction

Xanthomonas oryzae pv.oryzae(Xoo) causes bacterial leaf blight,a serious disease of rice.With electron spin resonance,we found that the superoxide anion productions in JXOⅢ and JXOV,two Xoo strains,were distinct from each other,and this difference was also observed in their subcellular fractions.It implies that the superoxide anion likely plays different roles,such as signaling molecule or virulence factor,in strains with various pathogenicities.Strikingly,interactions between rice and JXOⅢ or JXOⅤ also had different impacts on the superoxide anion production by bacteria.For JXOⅢ,superoxide anion production was intensely increased by either compatible or incompatible interactions with plants.But for JXOⅤ,the original high superoxide anion production was further enhanced by the compatible interaction while depressed by the incompatible interactions with plants.Furthermore,these impacts were maintained in both JXOⅢ and JXOⅤ cells separated from plants correspondingly treated with each of them,which indicated the transmissibility of the effects on bacteria by interaction between plant and pathogen.It elucidates that the regulation of superoxide anion depends on the compatibility between plant and pathogens.However,the pathological mechanisms remain unclear.