启动子替代构建糙皮侧耳漆酶高产菌株

Construction of high laccase producing strain of Pleurotus ostreatus by promoter swapping

POXC是糙皮侧耳合成最多的一种漆酶。应用启动子替代技术,用构巢曲霉的甘油醛‐3‐磷酸脱氢酶基因(gpd)启动子替代POXC基因的启动子,构建了超量表达POXC糙皮侧耳转化子。转化子中POXC基因表达量比出发菌株提高了0.72–3倍。在PDA平板培养、PD摇瓶培养和棉籽壳试管培养条件下,转化子漆酶活力显著提高,比出发菌株提高了1.5倍以上。用棉籽壳栽培,转化子菇产量比出发菌株提高了16.2%,培养料中木质素含量比出发菌株减少21%。结果表明,应用高效启动子替代能够显著提高糙皮侧耳漆酶基因的表达量、漆酶活力及其木质纤维素降解能力。

The oyster mushroom Pleurotus ostreatus is one of the most important white rot fungi. POXC is the most abundant laccase isoenzyme produced by the Basidiomycota fungi. In this study, by employment of a promoter swapping technique, the promoter for POXC was replaced by the promoter of glyceraldehyde-3-phosphate dehydrogenase gene（gpd） of Aspergillus nidulans. The POXC gene expression level of the transformants was increased up to 0.72- to 3-fold the level of wild type. The transformants showed significant level of laccase activities in mycelia cultured in PDA plate culture, PD liquid culture, and cottonseed hull tube culture, being increased more than 1.5-fold the level of wild type. Mushroom yield increased by 16.2% and lignin content decreased by 21% in a cultivated transformant as compared with the wild type cultured on cottonseed hull medium. The results showed that using gpd promoter to drive the expression of POXC could be an effective approach for improving the lignin-degrading properties of P. ostreatus.