Apoptosis Induction Of HMC Toxin To The Cells From Specialized Maize Host

Southern blight of com was a king of universal fungal plant disease at the present. During infecting corn seedings,the pathogen of Bipolaris maydis race C could produce an active metabolic production,namely pathogenic toxin(HMC-Toxin).Here,apoptosis induction of HMC Toxin to the cells from specialized maize host was studied.The results were as follows:(A) Apoptosis in detached corn root cap cells treated by HMC toxin was studied under fluorescent microscope.Homokaryon maize B37(B37-C,B37-N) and Mo17(Mo17-C, Mo17-N)inbred lines was tested and the detached corn root cap cells with cell wall may be stained using AO and EB or Hoechst 33258.The root cap cells were divided into 4 groups,3 groups were induced by 50μg/mL,100μg/mL,150μg/mL of HMC toxin as the experimental group,another group induced by pH6.5 PBS as a control group,induced time were 1h,4h,7 h to study the feature of apoptotic and the change of apoptosis rate.The results showed that: the apoptotic features such as apoptotic bodies,chromosome margination or ring chromosome were found after the treatment.When treated by the same concentration of HMC toxin,the apoptosis rate of B37-C,Mo17-C maize root cap cells were significantly higher than B37-N,Mo17-N.In addition,the apoptosis rate was increased when the treatment time and concentration increasing.(B) Apoptosis in protoplasts treated by HMC toxin was studied under fluorescent microscope.Homokaryon maize B37 and Mo17 inbred lines was tested and the protoplasts may be stained using AO and EB or Hoechst 33258.The protoplasts were divided into 4 groups,3 groups were treated by 50μg/mL,100μg/mL,150μg/mL of HMC toxin as the experimental group,another group treated by isosmotic soiution as a control group,induced time were 1h,3h,6h to study the feature of apoptotic and the rate of apoptosis.The results showed that:the apoptotic features such as apoptotic bodies,chromosome margination or ring chromosome were found after the treatment.When treated by the same concentration of HMC toxin,the apoptosis rate of B37-C,Mo17-C maize protoplasts were significantly higher than B37-N,Mo17-N.In addition,the apoptosis rate was increased when the treatment time and concentration increasing. (C) The leaves of Homokaryon maize B37 and Mo17 inbred lines were treated by HMC toxin and the degradation of genomic DNA was studied.The leaves were divided into 4 groups,3 groups were induced by 200μg/mL,250μg/mL,300μg/mL of HMC toxin as the experimental group,another group induced by pH6.5 PBS as a control group,induced time were 3h,6h,9h,12h,15h.The results showed that:For the leaves of maize B37-C,the obvious DNA ladder was appeared with treatment concentration:200μg/mL;treatment time: 6h.For the leaves of maize B37-N,the obvious DNA ladder was appeared with treatment concentration:200μg/mL;treatment time:9h which was longer than leaves of maize B37-C. For the leaves of maize Mo17-C,the obvious DNA ladder was appeared with treatment concentration:250μg/mL;treatment time:12h.For the leaves of maize Mo17-N,the obvious DNA ladder was appeared with treatment concentration:250μg/mL which was higher than leaves of maize Mo17-C;treatment time:12h.