不同添加物对小花棘豆内生真菌酵母氨酸还原酶基因缺失突变株M1合成苦马豆素的影响

The Influence of Different Additives on the Swainsonine Biosynthesis in Saccharopine Reductase Gene Disruption Mutant M1 of an Endophytic Fungus from Oxytropis glabra

苦马豆素(swainsonine,SW)是由小花棘豆等疯草植物中内生真菌通过酵母氨酸还原酶催化产生的一种吲哚里西啶生物碱,牲畜过量采食含SW的疯草植物会中毒,但是SW具有抗肿瘤和免疫调节活性等医学作用。文中以小花棘豆内生真菌野生株OW7.8及其酵母氨酸还原酶基因缺失突变株M1为研究对象,在固体培养基中添加酵母氨酸、α-氨基己二酸、赖氨酸和哌啶酸培养内生真菌野生株和突变株,利用高效液相色谱-质谱联用(HPLC-MS)技术测定SW,比较不同培养时间下内生真菌野生株和突变株中SW合成动态变化,并对所得数据用统计学软件进行方差分析。研究结果显示:对照组OW7.8中SW含量高于M1;添加前体物可提高菌体内SW的含量;不同前体对SW合成的影响不同,其中添加哌啶酸对SW影响最大。统计学分析结果表明:菌株(基因型)、添加前体化合物对真菌SW合成均有显著影响。

Swainsonine（SW） is an indolizidine alkaloid produced by saccharopine dehydrogenase of endophytic fungi in locoweeds such as Oxytropis glabra, and causes severe toxicity in livestock. However, SW also has antitumor and immunomodulatory activity. Herein, the wild type strain of an endophytic fungus（OW7.8）in O. glabra and the saccharopine reductase gene disruption mutant（M1） were chosen as materials. Saccha-ropine, α-aminoadipic acid, lysine and pipecolic acid were added to the solid medium separately（but not added to the control medium）, and the SW content was determined by the high-performance liquid chromatogra-phy-mass spectrometry（HPLC-MS）. The dynamic changes of SW synthesis in the wild and the mutant strains of endophytic fungus were compared under different culture times, and the data obtained were analyzed by statistical software. The results showed that in the CK groups, the contents of SW in OW7.8 were higher than that in M1. And the SW content was increased when any of the precursors was added into the medium. Dif-ferent precursors had different effects on SW synthesis, and addition of pipecolic acid had the greatest effect.The statistical analysis showed that the strain type and precursor compounds had significant impacts on the content of SW.