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Background Taxus is a rare gymnosperm plant that is the sole producer of the anticancer drug paclitaxel. The growth and development of Taxus is affected by environmental factors such as light. However, little is known about how light conditions affect growth and metabolic processes, especially paclitaxel biosynthesis. Results In this study, we applied three different light conditions to Taxus chinensis young saplings and investigated the physiological response and gene expression. Our observations showed that exposure to high light led to oxidative stress, caused photoinhibition, and damaged the photosynthetic systems in T. chinensis. The paclitaxel content in T. chinensis leaves was significantly decreased after the light intensity increased. Transcriptomic analysis revealed that numerous genes involved in paclitaxel biosynthesis and phenylpropanoid metabolic pathways were downregulated under high light. We also analyzed the expression of JA signaling genes, bHLH, MYB, AP2/ERF transcription factors, and the CYP450 families that are potentially related to paclitaxel biosynthesis. We found that several CYP450s, MYB and AP2/ERF genes were induced by high light. These genes may play an important role in tolerance to excessive light or heat stress in T. chinensis. Conclusions Our study elucidates the molecular mechanism of the effects of light conditions on the growth and development of T. chinensis and paclitaxel biosynthesis, thus facilitating the artificial regeneration of Taxus and enhancing paclitaxel production.

Background Taxol from Taxus species is a precious drug used for the treatment of cancer and can effectively inhibit the proliferation of cancer cells. However, the growth of Taxus plants is very slow and the content of taxol is quite low. Therefore, it is of great significance to improve the yield of taxol by modern biotechnology without destroying the wild forest resources. Endophytic fungus which symbiosis with their host plants can promote the growth and secondary metabolism of medicinal plants. Results Here, an endophytic fungus KL27 was isolated from T. chinensis, and identified as Pseudodidymocyrtis lobariellae. The fermentation broth of KL27 (KL27-FB) could significantly promote the accumulation of taxol in needles of T. chinensis, reaching 0.361 ± 0.082 mg/g·DW (dry weight) at 7 days after KL27-FB treatment, which is 3.26-fold increase as compared to the control. The RNA-seq and qRT-PCR showed that KL27-FB could significantly increase the expression of key genes involved in the upstream pathway of terpene synthesis (such as DXS and DXR) and those in the taxol biosynthesis pathway (such as GGPPS, TS, T5OH, TAT, T10OH, T14OH, T2OH, TBT, DBAT and PAM), especially at the early stage of the stimulation. Moreover, the activation of jasmonic acid (JA) biosynthesis and JA signal transduction, and its crosstalk with other hormones, such as gibberellin acid (GA), ethylene (ET) and salicylic acid (SA), explained the elevation of most of the differential expressed genes related to taxol biosynthesis pathway. Moreover, TF (transcriptional factor)-encoding genes, including MYBs, ethylene-responsive transcription factors (ERFs) and basic/helix-loop-helix (bHLH), were detected as differential expressed genes after KL27-FB treatment, further suggested that the regulation of hormone signaling on genes of taxol biosynthesis was mediated by TFs. Conclusions Our results indicated that fermentation broth of endophytic fungus KL27-FB could effectively enhance the accumulation of taxol in T. chinensis needles by regulating the phytohormone metabolism and signal transduction and further up-regulating the expression of multiple key genes involved in taxol biosynthesis. This study provides new insight into the regulatory mechanism of how endophytic fungus promotes the production and accumulation of taxol in Taxus sp.

Background Taxol is an efficient anticancer drug accumulated in Taxus species. Pseudotaxus chienii is an important member of Taxaceae, however, the level of six taxoids in P. chienii is largely unknown. Results High accumulation of 10-DAB, taxol, and 7-E-PTX suggested that P. chienii is a good taxol-yielding species for large-scale cultivation. By the omics approaches, a total of 3,387 metabolites and 61,146 unigenes were detected and annotated. Compared with a representative Taxus tree (Taxus yunnanensis), most of the differentially accumulated metabolites and differential expressed genes were assigned into 10 primary and secondary metabolism pathways. Comparative analyses revealed the variations in the precursors and intermediate products of taxol biosynthesis between P. chienii and T. yunnanensis. Taxusin-like metabolites highly accumulated in P. chienii, suggesting a wider value of P. chienii in pharmaceutical industry. Conclusions In our study, the occurrence of taxoids in P. chienii was determined. The differential expression of key genes involved in the taxol biosynthesis pathway is the major cause of the differential accumulation of taxoids. Moreover, identification of a number of differentially expressed transcription factors provided more candidate regulators of taxol biosynthesis. Our study may help to reveal the differences between Pseudotaxus and Taxus trees, and promote resource utilization of the endangered and rarely studied P. chienii.

BackgroundTaxusspp. produces the anticancer drug, taxol, and hence is planted as an industrial crop in China. APETALA2/ethylene response element binding proteins (AP2/EREBPs) are the key regulators of plant development, growth, and stress responses. Several homologues control taxol biosynthesis. Identifying the AP2/EREBP proteins fromTaxusis important to increase breeding and production and clarify their evolutionary processes.ResultsAmong the 90 genes from multiTaxus chinensistranscriptome datasets, 81 encoded full-length AP2-containing proteins. A domain structure highly similar to that of angiosperm AP2/EREBPs was found in 2 AP2, 2 ANT, 1 RAV, 28 dehydration-responsive element-binding proteins, and 47 ethylene-responsive factors contained, indicating that they have extremely conservative evolution processes. A new subgroup protein, TcA3Bz1, contains three conserved AP2 domains and, a new domain structure of AP2/EREBPs that is different from that of known proteins. The new subtype AP2 proteins were also present in several gymnosperms (Gingko biloba) and bryophytes (Marchantia polymorpha). However, no homologue was found inSelaginella moellendorffii, indicating unknown evolutionary processes accompanying this plant’s evolution. Moreover, the structures of the new subgroup AP2/EREBPs have different conserved domains, such as B3, zf-C3Hc3H, and agent domains, indicating their divergent evolution in bryophytes and gymnosperms. Interestingly, three repeats of AP2 domains have separately evolved from mosses to gymnosperms for most of the new proteins, but the AP2 domain of Gb_11937 has been replicated.ConclusionThe new subtype AP2/EREBPs have different origins and would enrich our knowledge of the molecular structure, origin, and evolutionary processes of AP2/EREBP transcription factors in plants.

Background Taxus cuspidata is well known worldwide for its ability to produce Taxol, one of the top-selling natural anticancer drugs. However, current Taxol production cannot match the increasing needs of the market, and novel strategies should be considered to increase the supply of Taxol. Since the biosynthetic mechanism of Taxol remains largely unknown, elucidating this pathway in detail will be very helpful in exploring alternative methods for Taxol production. Results Here, we sequenced Taxus cuspidata transcriptomes with next-generation sequencing (NGS) and third-generation sequencing (TGS) platforms. After correction with Illumina reads and removal of redundant reads, more than 180,000 nonredundant transcripts were generated from the raw Iso-Seq data. Using Cogent software and an alignment-based method, we identified a total of 139 cytochrome P450s (CYP450s), 31 BAHD acyltransferases (ACTs) and 1940 transcription factors (TFs). Based on phylogenetic and coexpression analysis, we identified 9 CYP450s and 7 BAHD ACTs as potential lead candidates for Taxol biosynthesis and 6 TFs that are possibly involved in the regulation of this process. Using coexpression analysis of genes known to be involved in Taxol biosynthesis, we elucidated the stem biosynthetic pathway. In addition, we analyzed the expression patterns of 12 characterized genes in the Taxol pathway and speculated that the isoprene precursors for Taxol biosynthesis were mainly synthesized via the MEP pathway. In addition, we found and confirmed that the alternative splicing patterns of some genes varied in different tissues, which may be an important tissue-specific method of posttranscriptional regulation. Conclusions A strategy was developed to generate corrected full-length or nearly full-length transcripts without assembly to ensure sequence accuracy, thus greatly improving the reliability of coexpression and phylogenetic analysis and greatly facilitating gene cloning and characterization. This strategy was successfully utilized to elucidate the Taxol biosynthetic pathway, which will greatly contribute to the goals of improving the Taxol content in Taxus spp. using molecular breeding or plant management strategies and synthesizing Taxol in microorganisms using synthetic biological technology. Electronic supplementary material The online version of this article (10.1186/s12870-019-1809-8) contains supplementary material, which is available to authorized users.

Background Plants of the genus Taxus have attracted much attention owing to the natural product taxol, a successful anti-cancer drug. T. fuana and T. yunnanensis are two endangered Taxus species mainly distributed in the Himalayas. In our study, an untargeted metabolomics approach integrated with a targeted UPLC-MS/MS method was applied to examine the metabolic variations between these two Taxus species growing in different environments. Results The level of taxol in T. yunnanensis is much higher than that in T. fuana, indicating a higher economic value of T. yunnanensis for taxol production. A series of specific metabolites, including precursors, intermediates, competitors of taxol, were identified. All the identified intermediates are predominantly accumulated in T. yunnanensis than T. fuana, giving a reasonable explanation for the higher accumulation of taxol in T. yunnanensis. Taxusin and its analogues are highly accumulated in T. fuana, which may consume limited intermediates and block the metabolic flow towards taxol. The contents of total flavonoids and a majority of tested individual flavonoids are significantly accumulated in T. fuana than T. yunnanensis, indicating a stronger environmental adaptiveness of T. fuana. Conclusions Systemic metabolic profiling may provide valuable information for the comprehensive industrial utilization of the germplasm resources of these two endangered Taxus species growing in different environments.

Genes for plant nitric oxide synthase (NOS) now help explain how NO is produced from nitrate, nitrite, and/or L-arginine in the culture medium and in cells. Evidence is presented that under aseptic conditions; plant NOS activity, NO bursts, and cell death (apoptosis) are important factors in the recovery of taxol (paclitaxel) from cell suspensions of several Taxus sp. Cell-suspension responses to mechanical stresses, simulated microgravity, and hypergravity were dominated by NO bursts and cell death (apoptosis) and by the overproduction and release of free and bound taxol into the culture medium. The synthesis of the taxane ring in the chloroplasts and gravisensing amyloplasts, and the subsequent assembly of taxol and related taxane diterpenoids were visualized by immunocytochemical, laser confocal and scanning electron microscopy. Drug-producing cells and taxane-bearing materials in the culture medium were recovered using immunoparamagnetic beads. Bound taxol and taxanes were recovered from xylanase hydrolyates. Binding was associated with the expression of two proteins for ‘touch’ genes expressed under mechanical forces. Taxol recovery was increased by 64% by the use of a NO donor. NOS inhibition with guandino compounds, and the use of a NO trap, reduced taxol recovery and reduced taxane diterpenoid biosynthesis. This offered countermeasures to NO-mediated stress, and reduced apoptosis. In hypergravity, the taxol and taxanes released from cells by syneresis were recovered on hydrophobic PVDF (polyvinylidene fluoride) filters. Cyclodextrins added to the culture medium enhanced biomass yield and altered the solubility of taxanes to improve the recovery of taxol and taxanes.