α-PGM过表达对灵芝多糖发酵的影响

Effects of Overexpression of α-PGM on Ganoderma lucidum Polysaccharide Fermentation

为了探究灵芝多糖合成途径中磷酸葡萄糖变位酶(α-PGM)的过表达对灵芝多糖发酵产生的影响,利用农杆菌介导法将同源性基因pgm转化灵芝原生质体,筛选灵芝转化子,测定灵芝胞外多糖产量及胞内多糖含量,并研究多糖合成过程中相关酶基因转录水平的相对表达量和酶的活性。结果发现在PGM过表达的重组型灵芝菌株中胞内多糖含量和胞外多糖量最高分别为21.02 mg/100 mg菌体和0.71 g/L,分别比野生型菌株高9.1%和39.2%;灵芝多糖生物合成途径中pgm、pgi基因转录水平表达量较野生型灵芝菌株处于上调状态,且多糖合成代谢中相关酶活性有显著提高。

α-Phosphogluconate,an important enzyme in polysaccharide synthesis pathway in Ganaderma lucidum,was overexpressed to determine polysaccharide production in submerged fermentation.In this study,the homologous pgm gene was transformed into G.lucidum protoplasts by Agrobacterium tumefaciens mediated method.The intracellular polysaccharides(IPS)and extracellular polysaccharides(EPS)production of G.lucidum transformant was 21.02 mg/100 mg mycelium and 0.71 g/L,respectively.The overexpression of pgmin G.lucidum effectively enhanced IPS(9.1%)and EPS(39.2%)production comparing with wild strain.Moreover,the transcription levels of pgm and pgi gene in polysaccharide synthesis pathway were up-regulated,and intracellular activities of these two enzymes were also significantly enhanced in comparison to wild strain.