北冬虫夏草角鲨烯单氧酶基因的类胡萝卜素生物合成功能解析

Functional Analysis of Squalene Monooxygenase Gene for the Carotenoid Biosynthesis in Cordyceps militaris

摘要:

以转录组数据为依据推测北冬虫夏草erg1基因可能参与其类胡萝卜素合成过程，进一步检测和分析erg1基因在添加不同胁迫因子高锰酸钾和氯化钠之后mRNA的相对表达量，探究其在类胡萝卜素合成途径中的调控作用。为了验证erg1基因的功能，该论文构建了erg1基因过表达载体pCambia0390-blpR-Pcmgpd-erg1，通过根瘤农杆菌侵染北冬虫夏草孢子的方式将erg1基因表达框导入北冬虫夏草基因组中，测定类胡萝卜素生物合成量及erg1基因的表达水平。结果表明，高锰酸钾（氧化）和氯化钠（渗透）胁迫下的重组Cmerg1菌株的类胡萝卜素产量分别为6757.17 μg/g和6363.93 μg/g，依次是对照组的1.22倍和1.20倍。因此，erg1基因的过表达引起了北冬虫夏草Cmerg1菌株的类胡萝卜素累积能力的提升，也即说明角鲨烯单氧酶基因参与北冬虫夏草类胡萝卜素的合成过程。研究结果为北冬虫夏草类胡萝卜素生物合成的研究和利用奠定了实验基础。

Abstract:

Based on transcriptome data, it was speculated that erg1 gene may be involved in carotenoid synthesis in Cordyceps militaris. Under the stress factors of KMnO4 and NaCl, the mRNA relative expression level of erg1 gene was further detected and analyzed to explore its regulatory role in carotenoid synthesis pathway. In order to verify erg1 gene function, an over-expressing vector pCambia0390- blpR-Pcmgpd-erg1of the erg1 gene was constructed. Subsequently, the expression cassette was introduced into the C. militaris by Agrobacterium tumefaciens. Finally, the expression level of erg1 gene and the amount of carotenoid biosynthesis were determined. The results indicated that the carotenoid production of recombinant strain Cmerg1 under KMnO4 (oxidative) and NaCl (osmotic) stress reached 6757.17 μg/g and 6363.93 μg/g respectively, which were 1.22 and 1.20 times of the control strain CM10, respectively. In conclusion, the overexpression of erg1gene caused the increase of carotenoid production of Cmerg1 strain. In other words, the squalene monoxygenase gene is involved in the carotenoid synthesis of C. militaris. The results laid the experimental foundation for the research and utilization of carotenoid biosynthesis in C. militaris.