曲酸对斑玉蕈子实体形成过程中木质纤维素酶的影响研究

为了探究曲酸增加子实体产量的机制,首先考察了搔菌后外源添加曲酸对不同菌丝培养时间出菇的影响。研究发现当菌丝培养时间过短或者过长添加曲酸都得不到很好的增产效果,菌丝培养时间在60-80d之间增产效率最高,并且后熟期60d的增产效率大于80d的增产效率。进一步研究发现添加曲酸可以提高菌丝利用基质中木质纤维素的利用率。更深入地研究发现,基质中的漆酶和纤维素酶活性在斑玉蕈的不同发育时期受到曲酸调控。漆酶活性在最初的菌丝恢复期和转色期酶活性低于对照组,但是在原基期、钉头期和子实体期酶活性显著地高于对照组;纤维素酶活性在整个发育周期中曲酸组都高于对照组,在子实体发育后期酶活性被提高3.16倍。最后,从分子水平上分析了漆酶基因和纤维素酶基因的表达量,研究显示添加曲酸后漆酶基因和纤维素酶基因在不同程度上被上调,这个结果与酶活的结果相一致。这些结果说明外源添加曲酸通过提高生殖生长阶段的菌丝利用培养基质中的漆酶和纤维素酶活性,进而提高菌丝利用木质纤维素,为斑玉蕈子实体生长发育提供更多的能源,实现增加子实体产量的目的。

Effects of kojic acid on lignocellulase at fruiting body formation process of Hypsizygus marmoreus

In order to explore the mechanism of kojic acid (KA) responsible for increase in yield of fruiting body of Hypsizygus marmoreus, the effect of addition of KA in different mycelial growth period on fruiting was investigated. It was found that too short or too long mycelial growth period was unfavourable for KA on increasing production, and suitable time of addition of KA for increasing yield was in mycelial growth period of 60-80d. It was also found KA could improve the mycelial utilization rate of lignocellulose in substrate, and the activities of laccase and cellulase were regulated by KA at different developmental stages of the fungus. Laccase activity was lower at mycelial regeneration and pigmentation stages after KA treatments, but it was higher at primordium, pinhead and fruiting stages as compared with experimental control. The cellulase activities were higher at total developmental stages under KA treatments, being 3.16-fold increase at fruiting body stage as compared with the control. The expression level of laccase gene and cellulase gene was analyzed. It was showed that the expressions of laccase and cellulase genes were up-regulated in varying degrees after KA treatments, showing consistency with the result of enzyme activity. These results indicated that exogenous KA could increase laccase and cellulase activities in the substrate, and thereby increase mycelial lignocellulose utilization, providing more energy for fruiting body development to achieve the purpose of increasing the production of fruiting bodies of Hypsizygus marmoreus.