[Objective] The aim of the study was to provide the basis for researching the pathogenicity mechanism of Rhizoctonia solani.[Method] The extracellular protease was purified after ammonium sulfate precipitation through DEAE-Sephrase Fast Flow,Phenyl-Sepharose Fast Flow and Sephadex G-75 ch rom atography. [Result] The extracellular protease with molecular weight of 49.5 ku was obtained from fermentation liquid of R. solani. The optimal temperature and pH value for its activity were 6.4 and 30 ℃ respectively. Zn^2＋,Fe^3＋,Cu^2＋had inhibition on enzyme activity,while Mg^2＋,Mn^2＋had no effect on enzyme activity,and Ca^2＋ could activate enzymatic activity in low concentration.[Conclusion] R. solani could secrete extracellular protease,but the relationship between the extracellular protease and the pathogenicity of R. solani required further study.
为建立水稻抑制差减杂交技术中叶片总RNA最佳的提取方法,以5叶期水稻品种合江19为提取总RNA的材料,对Trizol法和两种改良Trizol法提取的水稻叶片总RNA纯度和完整性进行了比较研究。基因定量仪检测结果表明,Trizol法、改良Trizol法Ⅰ和改良Trizol法Ⅱ提取的RNAOD(260/280)分别为1.529、1.755和1.991;琼脂糖凝胶电泳检测结果显示,改良Trizol法Ⅱ提取的RNA具有28 s、18 s和5 s 3条清晰的条带,且无降解,而其他两种方法提取的RNA质量较差,均有降解。该研究结果说明改良Trizol法Ⅱ提取的RNA完整性好和纯度较高,该方法优于Trizol法。
[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.
