Abstract：
Flavin-containing monooxygenase (FMO) is the key enzyme in the biosynthesis pathway of CSOs with sulfur oxidation. In order to explore the molecular regulatory mechanism of FMO in the synthesis of onion CSOs, based on transcriptome database and phylogenetic analysis, one AcFMO gene that may be involved in alliin synthesis was obtained, the AcFMO had a cDNA of 1 374 bp and encoded 457 amino acids, which was evolutionarily closest to the AsFMO of garlic. Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) indicated that AcFMO was the highest in the flowers and the lowest in the leaf sheaths. The results of subcellular localization showed that the AcFMO gene product was widely distributed throughout the cell A yeast expression vector was constructed, and the AcFMO gene was ecotopically overexpressed in yeast to further study the enzyme function in vitro and could catalyze the synthesis of alliin by S-allyl-l-cysteine. In summary, the cloning and functional identification of AcFMO have important reference value for understanding the biosynthesis of CSOs in onions.
摘要：
含黄素的单加氧酶（FMO）是硫氧化CSO生物合成途径中的关键酶。为了探讨FMO在洋葱CSOs合成中的分子调控机制,基于转录组数据库和系统发育分析，获得了一个可能参与蒜氨酸合成的AcFMO基因，AcFMO的cDNA为1374bp，编码457个氨基酸，在进化上最接近大蒜的AsFMO。实时荧光定量聚合酶链反应（qRT-PCR）表明，AcFMO在花中最高，在叶鞘中最低。亚细胞定位结果表明，AcFMO基因产物广泛分布于整个细胞中。构建了酵母表达载体，并且AcFMO基因在酵母中生态过表达，以进一步研究酶的体外功能，并可以催化S-烯丙基-1-半胱氨酸合成蒜氨酸。总之,AcFMO的克隆和功能鉴定对了解洋葱中CSO的生物合成具有重要的参考价值。
