放线菌A5295激发子的稳定性及活性物质分析

为明确对致病疫霉无拮抗作用但能显著诱导马铃薯抗晚疫病的放线菌A5295发酵液的稳定性及其有效激发物质,以不同pH、温度和蛋白酶K处理A5295菌株发酵原液(激发子),用硫酸铵、乙醇和丙酮分别沉淀发酵液中的有效物质,通过马铃薯块茎切片测试其诱导抗病效果,并以考马斯亮蓝法和蒽酮法测定乙醇粗提物中蛋白质和糖的含量。结果显示,该激发子耐高温、耐强酸和强碱,对蛋白酶K不敏感,不同处理下的诱抗效果均接近发酵原液(69%)、甚至高达93%;乙醇粗提物的诱抗效果达到73%,明显优于硫酸铵和丙酮粗提物;该粗提物中蛋白和糖的含量分别为1.32%和53.4%,且发现经Sevag法去除蛋白后的诱抗效果略有增加(80%),能耐受121℃高温高压和强酸强碱。表明A5295的有效物质为糖类或以糖类为主,对环境稳定。

Stability and active substances of elicitors from Streptomyces sp. A5295

The purpose of this experiment is to make clear the stabilities of fermentation liquid,as an elicitor,and the active substances,from Streptomyces sp.A5295 that did not inhibit the mycelial growth of Phytophthora infestans but could induce resistance in potato against late blight.After treatments with different pH,temperature,and protease K,respectively,the induction-resistance effects(IRE) of the fermentation liquid were evaluated with potato tuber slices.And the IRE of active substances extracted from fermentation liquid by ammonium sulfate,ethanol,and acetone,respectively,were also tested with potato tuber slices.The content of protein and sugar in ethanol crude extract(ECE) were measured by Bradford method and Anthrone method,respectively.The results showed that A5295 fermentation liquid,after treatment with high temperature,strong acid,strong alkali,as well as protease K,still had significant IRE,which was as same as that of untreatment control(69%),even reached 93%.Among the three crude extracts precipitated by ammonium sulfate,ethanol and acetone paticipation,ECE had the best IRE(73%);Contents of protein and sugar in ECE were 1.32% and 53.4%, respectively.After removing the protein by Sevag method, IRE of ECE achieved 80%.In addition, ECE had strong resistance to treatments of 121 ℃, pH2, and pH12, respectively, also.These findings indicate that the effective eliciting substances from A5295 might be sugar or the main substance is sugar, which was hermostable, resistant to strong acid and alkali, as well as protease K.