外源茉莉酸甲酯诱导对香菇多糖代谢及关键酶基因表达的影响

香菇多糖是重要的生物活性成分,其药用价值高,茉莉酸甲酯有助于提高食用菌多糖含量,但关于其对香菇多糖合成的影响尚不清楚。本研究以香菇新808为实验材料,对不同浓度茉莉酸甲酯（MeJA）诱导下香菇菌丝生物量和生长速率、香菇多糖代谢关键酶活性及基因相对表达量、香菇多糖含量进行比较分析。结果表明：10μmol/L的茉莉酸甲酯可显著促进香菇菌丝生长并提高菌丝体生物量,分别是对照的1.14倍、1.2倍;与香菇多糖代谢相关的UDP-葡萄糖焦磷酸化酶（UGPase）、葡萄糖磷酸异构酶（PGI）、α-葡萄糖磷酸变位酶（α-PGM）活性增加,为对照组的1.58、1.13、3.21倍;其基因相对表达量较对照组也显著上调,为对照组的5.73、1.4、1.77倍;香菇多糖合成量显著增加,为对照组1.58倍。10μmol/L的MeJA处理后,香菇多糖代谢关键酶活性及基因相对表达量与多糖含量间存在显著的正相关关系,表明添加适宜浓度的茉莉酸甲酯会影响香菇菌丝的生长及多糖合成。

Effects of exogenous methyl jasmonate induction on polysaccharide metabolism and key enzyme gene expression in Lentinula edodes

Lentinan is an important bioactive compound with high medicinal value. Methyl jasmonate contributes to increase the content of polysaccharide in edible fungi, but the knowedge about its effect on lentinan synthesis is still limited. In this study, using widely cultivated Lentinula edodes Xin-808 as tested strains, the impact of different concentrations of methyl jasmonate (MeJA) on the mycelial biomass and growth rate, the activity of key enzymes in the metabolism of polysaccharide, the relative expression of genes and the content of polysaccharide of L. edodes was analyzed. The results showed that 10μmol/L methyl jasmonate could significantly promote the mycelium growth and increase the mycelium biomass, respectively reaching 1.14 and 1.2 times higher than those of the experimental control (P<0.05). The activities of UDP-glucose pyrophosphorylase, glucose phosphate isomerase and α-phosphoglucomutase related to polysaccharide metabolism of L. edodes was respectively 1.58, 1.13 and 3.21 times higher than those of CK. The relative abundance of gene expressions was also significantly up-regulated, being 5.73, 1.40 and 1.77 times higher as compared with that of the CK, respectively. The quantity of lentinan also increased 1.58 times as compared with the control treatment. Under 10μmol/L MeJA treatment there was a positive correlation among the key enzymes’ activities, relative expression, and the polysaccharides’ content of L. edodes. In conclusion, appropriate concentration of MeJA would affect the growth of L. edodes mycelium and its crude polysaccharide synthesis.