[Objective] The aim of the study was to determine whether phytotoxicity of TeA against Echinochloa crus-galli leaves was correlated with oxidative stress caused by generation of reactive oxygen and the changes of antioxidant enzymes activity.[Method] The changes of malondialdehyde（MDA）content,hydrogen peroxide（H2O2）,and activities of superoxide dismutase（SOD）,glutathione reductase（GR）and catalase（CAT）were studied by leaf segment method in vitro.[Result] After the treatment of 500 μmol/L TeA,the content of MDA and H2O2 increased by 247.86% and 67.00%,respectively,indicating that the accumulation of MDA and H2O2 in E.crus-galli leaves was due to the reactive oxygen burst induced by TeA.TeA induced a significant increase in activities of SOD,GR and CAT.At 500 μmol/L TeA,activities of SOD,GR and CAT increased more than one fold compared with the control.[Conclusion] TeA could not only cause oxidative stress in leaves of E.crus-galli through the induction of reactive oxygen,but also induce the increasing of antioxidant enzyme activity.
[Objective] The aim was to clone the up-regulated expression gene of rice induced by Rhizoctonia solani.[Method] The EST fragment K16 obtained by suppression subtraction hybridization（SSH）was cloned and confirmed by reverse transcription-polymerase chain reaction（RT-PCR）.Then RT-PCR products were cloned into the PMD18-T vector and sequenced.The functions of the sequence were predicted with bioinformatics method.[Result] A 1 079 bp gene was obtained.The gene encoded a protein with 236 amino acids.The protein contains many motif sites,two WRKY domains and a C2H2 zinc finger motif.The gene showed high identities with WRKY8,WRKY24 and WRKY30 gene of rice.[Conclusion] The up-regulated expression gene induced by R.solani was representative WRKY family gene.The gene could play an important role on rice sheath blight resistance.
