芝麻茎点枯病菌Macrophomina phaseolina纤维素降解酶活性分析

Analysis of Cellulase Activities of Macrophomina phaseolina in Sesame

测定芝麻茎点枯病菌(Macrophomina phaseolina)产生的纤维素降解酶的种类及活性大小,为进一步探讨其在致病过程中的作用奠定基础。从不同地区采集7株芝麻茎点枯病菌,液体培养提取粗酶液,采用分光光度法在540nm波长下测定离体条件下芝麻茎点枯病菌分泌的纤维素降解酶活性及变化趋势。结果表明:7个菌株均能检测到滤纸酶、天然纤维素降解酶、内切葡聚糖酶、外切葡聚糖酶和β-葡萄糖苷酶活性,酶活变化趋势表明不同采样时间酶活力大小不同,酶活变化趋势上都有峰值出现,但是不同菌株出现峰值的时间不同,酶活力综合活性大小差异极显著。说明芝麻茎点枯病菌能分泌一组胞外降解纤维素的酶系,并且该酶系能够降解芝麻秸秆纤维素,该结果为揭示芝麻茎点枯病菌对芝麻的致病机理提供理论依据。

To determine the types and activities of cellulases secreted by Macrophomina phaseolina and explore their roles in pathogenic process,seven strains of M.phaseolina were collected from different regions and studied.The crude enzyme solution was prepared by liquid culture.The activities and change graphs of cellulases in vitro were determined by spectrophotometry at 540 nm wavelength.The results showed that the activities of filter paper enzyme,natural cellulase,endoglucanase,exoglucanase andβ-glucosidase could be detected in all seven strains,and the enzyme activity of seven strains was different at different sampling time by observing the enzymatic activity curves.There were peaks on the enzyme activity curve but the time of peak value was different in different M.phaseolinas strains.In addition,there were significant differences in the comprehensive enzyme activities.It proved that M.phaseolina could secrete a group of extracellular cellulose and the cellulases could degrade cellulose of sesame straw.It provided an important theoretical basis to study the pathogenic mechanism of M.phaseolina in sesame.