Molecular cloning and expression analysis of germacrene A synthase gene in Chamaemelum nobile / 中草药

Objective: Chamaemelum nobile is renowned for its production of essential oils, in which major components are sesquiterpenoids. Germacrene A synthase (GAS) is one of core enzymes involved in sesquiterpenoids. The present study aims to clone the full-length cDNA of GAS gene from C. nobile (CnGAS), and characterize and analyze tissue expression pattern of GAS gene. Methods: The specific primers were designed based on the results of previous transcriptome sequencing and the full-length cDNA of CnGAS was cloned by RT-PCR. The nucleotide sequence and its encoding amino-acid sequence were analyzed by bioinformatics method, and the physicochemical property and function of the encoding protein were predicted. The expression levels of the gene in different organs of C. nobile were determined by qRT-PCR technology. Results: The full-length cDNA of GAS gene, designated as CnGAS, was 1 785 bp (GenBank accession number: KU589283) and contained a 1 683 bp open reading frame (ORF), which encoded a 561 amino-acid protein. The theoretical molecular weight and PI of the deduced CnGAS protein were 6 470 and 5.21, respectively. The encoding amino-acid sequence of CnGAS showed high similarity to GAS proteins in other plants, which contained conserved DDxxD motif. Phylogenetic tree analysis revealed that CnGAS had closer genetic relationship with GASs from Asteracae plants. The result of qRT-PCR showed that CnGAS gene was expressed in different organs of C. nobile, and highly expressed in the flower. Conclusion: The CnGAS gene is isolated from C. nobile and the expression levels of this gene in different organs are analyzed, which will lay a foundation for further study of sesquiterpene biosynthesis pathway in C. nobile.

Antibacterial, anti-swarming and anti-biofilm formation activities of Chamaemelum nobile against Pseudomonas aeruginosa

Chamomile ( Chamaemelum nobile ) is widely used throughout the world, and has anti-inflammatory, deodorant, bacteriostatic, antimicrobial, carminative, sedative, antiseptic, anti-catarrhal, and spasmolytic properties. Because of the increasing incidence of drug-resistant bacteria, the development of natural antibacterial sources such as medical herbs for the treatment of infectious diseases is necessary. Extracts from different plant parts such as the leaves, flowers, fruit, and bark of Combretum albiflorum, Laurus nobilis , and Sonchus oleraceus were found to possess anti-quorum sensing (QS) activities. In this study, we evaluated the effect of C. nobile against Pseudomonas aeruginosa biofilm formation