硝普钠对香菇多糖代谢及关键酶基因表达的影响

Effects of sodium nitroprusside on polysaccharide metabolism and key enzyme gene expression in Lentinula edodes

香菇多糖是香菇中特有的生物活性成分。硝普钠在调控食用菌生长方面具有重要影响,但其对香菇生长及多糖合成的影响尚不清楚。本文以香菇新808为研究材料,通过添加不同浓度硝普钠作为外源一氧化氮对新808菌丝的生物量、生长速率、香菇多糖含量、香菇多糖代谢关键酶活性及其表达调控基因相对表达量进行综合研究。结果表明:硝普钠浓度为100μmol/L可显著提高香菇菌丝生物量,与对照组相比增加了1.61倍;生长速率与对照组无显著差异;香菇菌丝的香菇多糖含量显著提高,为对照组的3.71倍;漆酶、锰过氧化物酶和木质素过氧化物酶活性显著提高,分别为对照组的1.73倍、2.23倍和1.55倍;与多糖合成有关的辅助模块酶基因LENED_010207、碳水化合物结合模块基因LENED_012941和多糖裂解酶基因LENED_004566基因相对表达量有所上调,其中LENED_010207基因上调最明显,而多糖合成关键酶基因UDP-葡萄糖焦磷酸化酶基因(UGP)、葡萄糖磷酸变位酶基因(PGM)与葡萄糖磷酸异构酶基因(PGI)相对表达量均显著下调。在100μmol/L浓度硝普钠处理下,香菇生物量、多糖含量、多糖代谢关键酶活性及部分多糖合成关键酶的基因相对表达量均显著高于对照组,表明添加适宜浓度的硝普纳能有效地促进香菇多糖的合成,提高香菇多糖的含量。本文为进一步探索香菇多糖的代谢通路提供了理论依据,为选育高多糖含量的香菇新品种提供了新思路,对改进香菇栽培技术有一定的参考意义。

Lentinan is a specific bioactive compound.Sodium nitroprusside can provide exogenous nitric oxide for edible fungi to regulate their growth,but its effect on Lentinula edodes growth and lentinan synthesis is not clear yet.By adding different concentrations of sodium nitroprusside as exogenous nitric oxide,the mycelial biomass,growth rate,content of polysaccharide,activity of key enzymes in polysaccharide metabolism and relative expression of genes of experimental Lentinula edodes xin808 were comprehensively studied.The results showed that the mycelial biomass of Lentinula edodes treated with 100μmol/L of sodium nitroprusside was increased by 1.63 times as compared with that of untreated control.There was no significant difference in growth rate between experimental group and control group.The lentinan content in the mycelia was significantly increased,being 3.71 times that of the control group.The activities of laccase,manganese peroxidase and lignin peroxidase were 1.73,2.23 and 1.55 times higher than those of control group,respectively.The relative expression levels of LENED_010207,LENED_012941 and LENED_004566 genes related to polysaccharide synthesis were up-regulated,among which LENED_010207 gene was the most obviously up-regulated.The relative expression levels of UDP-glucose pyrophosphorylase gene(UGP),gluconophosphate mutase gene(PGM)and gluconophosphate isomerase gene(PGI)were significantly down-regulated.At the concentration of 100μmol/L sodium nitroprusside,the mycelial biomass,polysaccharide,key enzyme activity of polysaccharide synthesis and gene expression level of some key enzymes in polysaccharide synthesis of Lentinula edodes were significantly higher than those of the control,showing that adding suitable concentration of nitrate pune could effectively promote the synthesis of lentinan and raise the content of lentinan.This paper provides a reference for further exploring the metabolic pathway of lentinan,so as to provide a new idea for breeding new cultivated varieties with high polysaccharide content of Lentinula edodes.