De Novo Characterization of a Cephalotaxus hainanensis Transcriptome and Genes Related to Paclitaxel Biosynthesis

Abstract

Cephalotaxus hainanensis, an endangered plant, is known to contain several metabolites with anti-cancer activity. Despite its clinical impact, the alkaloid metabolism of this species has remained largely uncharacterized. The potential of Cephalotaxus for metabolic engineering of medically interesting compounds has, so far, not been exploited, due to the almost complete lack of molecular information. We have therefore performed a high throughput RNA-seq analysis and assembled the transcriptome de novo. Raw reads comprising 4.3 Gbp were assembled de novo into 39,416 unique sequences (unigenes) with a mean length of 1,089.8 bp and a total assembly size of 45.8 Mbp, which equals to more than 50 times the number of Cephalotaxaceae sequences currently deposited in the GenBank (as of August 2013). As proof of principle for medically interesting pathways, gene fragments related to paclitaxel biosynthesis were searched and detected. To verify their functionality, the metabolic product paclitaxel, and its precursor baccatin III, were identified in the leaves of C. hainanensis by HPLC, and shown to be induced by MeJA. This finding demonstrates exemplarily the potential of the annotated transcriptome as information resource for the biotechnological exploitation of plant secondary metabolism.

Transcriptome Sequencing of Different Avocado Ecotypes: de novo Transcriptome Assembly, Annotation, Identification and Validation of EST-SSR Markers

“…Of the many DNA markers that have been developed, SSRs, which consist of repeated nucleotide motifs of between one and six bases, are widely preferred in plant genetics and breeding because they are widely distributed and abundant in plant genomes, and they are genetically codominant, highly reproducible, multi-allelic, and well suited for high-throughput genotyping [22][23][24][25]. Transcriptome sequencing, which is based on next-generation sequencing technologies, is a high-throughput technique that facilitates the acquisition of a large number of unigene sequences for expressed sequence tag (EST)-derived marker development [26][27][28]. Because they are derived from genomic coding regions, EST-derived markers have an advantage over genomic DNA-derived markers, and therefore can be efficiently amplified to reveal conserved sequences among related species [29].…”

A method to evaluate the bioactive function of fruit extracts of Chinese wild Citrus with microtubular activity

“…For instance, the harringtonines, one of the classes of alkaloids, with great potential for tumour therapy, have been recovered from the endemic conifer genus Cephalotaxus. The first transcriptome of a species from this taxon allows to conclude on pharmaceutically valuable pathways already (Qiao et al 2014). In the current work, we have extended this approach to screen Chinese Citrus for the bioactivities targeted to MTs.…”

The complete chloroplast genome of the endangered species Cephalotaxus hainanensis (Cephalotaxaceae)

“…Cephalotaxus hainanensis, an evergreen medicinal plant in the family Cephalotaxaceae, is distributed in the narrow range of the western Guangdong, Hainan, southeastern and western Guanxi, western Yunnan, and even southeastern Tibet, China (Yang and Liao 2013;Qiao et al 2014). This plant is suggested to have antileukemia, antidiabetic, anticancer and antitumor activities and is widely used as a herbal remedy in China (Pan et al 2010;Liu et al 2016).…”

“…This plant is suggested to have antileukemia, antidiabetic, anticancer and antitumor activities and is widely used as a herbal remedy in China (Pan et al 2010;Liu et al 2016). However, due to logging and more recently exploitation of bark and leaves which contain the valuable medicinal extracts, cephalotaxine and harringtonine, the number of the wild C. hainanensis has decreased sharply (Qiao et al 2014). At present, this species is listed in IUCN Red List of Threatened Species regarded as 'endangered' (Yang and Liao 2013).…”