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Background Codonopsis pilosula (Franch.) Nannf. is a medicinal plant traditionally used in China, Korea, and Japan to treat many diseases including poor gastrointestinal function, low immunity, gastric ulcers, and chronic gastritis. The increasing therapeutic and preventive use of C. pilosula has subsequently led to depletion of the natural populations of this species thus necessitating propagation of this important medicinal plant. Here, we developed an efficient and effective in vitro propagation protocol for C. pilosula using apical shoot segments. We tested various plant tissue culture media for the growth of C. pilosula and evaluated the effects of plant growth regulators on the shoot proliferation and rooting of regenerated C. pilosula plants. Furthermore, the tissues (roots and shoots) of maternal and in vitro-regenerated C. pilosula plants were subjected to Fourier-transform near-infrared (FT-NIR) spectrometry, Gas chromatography-mass spectrometry (GC–MS), and their total flavonoids, phenolics, and antioxidant capacity were determined and compared. Results Full-strength Murashige and Skoog (MS) medium augmented with vitamins and benzylaminopurine (1.5 mg·L−1) regenerated the highest shoot number (12 ± 0.46) per explant. MS medium augmented with indole-3-acetic acid (1.0 mg·L−1) produced the highest root number (9 ± 0.89) and maximum root length (20.88 ± 1.48 mm) from regenerated C. pilosula shoots. The survival rate of in vitro-regenerated C. pilosula plants was 94.00% after acclimatization. The maternal and in vitro-regenerated C. pilosula plant tissues showed similar FT-NIR spectra, total phenolics, total flavonoids, phytochemical composition, and antioxidant activity. Randomly amplified polymorphic DNA (RAPD) test confirmed the genetic fidelity of regenerated C. pilosula plants. Conclusions The proposed in vitro propagation protocol may be useful for the rapid mass multiplication and production of high quality C. pilosula as well as for germplasm preservation to ensure sustainable supply amidst the ever-increasing demand.

The medicinal plant, Aspilia africana, has been traditionally used in several African countries to treat many diseases such as tuberculosis, cough, inflammation, malaria, osteoporosis, and diabetes. In this study, we developed a protocol for in vitro propagation of A. africana using indirect shoot organogenesis from leaf and root explants of in vitro-grown seedlings and assessed the tissues at different developmental stages. The highest callus induction (91.9 ± 2.96%) from leaf explants was in the Murashige and Skoog (MS) medium augmented with 1.0 mg/L 6-Benzylaminopurine (BAP) and 1.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) while from root explants, the highest callus induction (92.6 ± 2.80%) was in the same plant tissue culture medium augmented with 0.5 mg/L BAP and 1.0 mg/L 2,4-D. The best shoot regeneration capacity from leaf-derived calli (i.e., 80.0 ± 6.23% regeneration percentage and 12.0 ± 6.23 shoots per callus) was obtained in medium augmented with 1.0 mg/L BAP and 0.05 mg/L α-Naphthaleneacetic acid (NAA); the best regeneration capacity for root-derived calli (i.e., 86.7 ± 6.24% shoot regeneration percentage and 14.7 ± 1.11 shoots per callus) was obtained in the MS medium augmented with 1.0 mg/L BAP, 0.05 mg/L NAA, and 0.1 mg/L Thidiazuron (TDZ). Regenerated plantlets developed a robust root system in 1/2 MS medium augmented with 0.1 mg/L NAA and had a survival rate of 93.6% at acclimatization. The in vitro regenerated stem tissue was fully differentiated, while the young leaf tissue consisted of largely unorganized and poorly differentiated cells with large intercellular airspaces typical of in vitro leaf tissues. Our study established a protocol for the indirect regeneration of A. africana and offers a basis for its domestication, large-scale multiplication, and germplasm preservation. To the best of our knowledge, this is the first study to develop an indirect regeneration protocol for A. africana and conduct anatomical assessment through the different stages of development from callus to a fully developed plantlet.

Trichosanthes kirilowii Maxim. is a vital traditional herbal medicinal plant found in northeastern Asia. Its roots, fruits, and seeds are used as food and medicine. Roots harvested for medicinal use take over 3 yr to mature when the plant is grown in a traditional way through cultivation in the field. This coupled with uncertainty in identification of the plant when collected from the wild calls for a standard in vitro propagation system to meet the increasing demand for it. The purpose of this study was to develop a standard protocol for the in vitro micropropagation of T. kirilowii. Ten different media supplemented with different concentrations of plant growth regulators were evaluated. At 5 wk, De Greef and Jacobs medium supplemented with 0.1 mg L−1 kinetin led to optimal shoot growth, while the same medium supplemented with 0.5 mg L−1 indole 3-butyric acid induced optimal root growth, also at 5 wk. The micropropagated plants that were acclimatized for 8 wk in the greenhouse produced mature root tubers after planted in the field for 3 mo. Therefore, these findings provide a basis for future large-scale in vitro propagation of T. kirilowii.

Prunus africana is an endangered medicinal plant and hence new propagation methods are urgently required to increase its populations. Unfortunately, propagation through seeds is challenging due to its long flowering cycle and recalcitrant seeds. We developed a protocol for micropropagation using nodal segment explants. A woody plant medium supplemented with vitamins, 15 g L−1 sucrose, and 1.0 mg L−1 6-benzylaminopurine (BAP) supported the optimum rate (100%) of axillary shoot initiation. Supplementation with 15 g L−1 sucrose and 1.5 mg L−1 indole-3-acetic acid (IAA) provided the optimum rate (75%) of root initiation. Rooted plantlets were successfully planted in sterilized horticultural soil containing perlite (2:1 v/v) and the survival rate was 98% following acclimatization. The photosynthetic rate assessed using FlourPen FP110 series showed that the ratio of variable fluorescence to maximum fluorescence mean value for in vitro regenerated P. africana (0.830 ± 0.0008) was similar to that of the maternal P. africana plant (0.825 ± 0.005), indicating similarity in their photosynthetic performance; a pivotal process for growth and development. The Fourier transform near-IR (FT-NIR) spectrometer analysis of the in vitro regenerated and the maternal P. africana plant samples exhibited homogeneity in the absorbance peaks at 8,273, 6,344, and 4,938–4,500 cm−1 associated with lipids, starch, and proteins. The genetic fidelity of regenerated plants was confirmed using the randomly amplified polymorphic DNA (RAPD) technique. Our protocol is suitable for use in large-scale P. africana to meet the increasing demands for it in the global market.

Rehmannia glutinosa (Gaertn.) DC is a perennial plant belonging to the family Scropulariidae. The root of R. glutinosa is used in oriental medicine and mainly grown using rootstock rather than seed cultivation, which gives rise to several problems including root rot, and results in a low productivity and poor quality. To solve the challenges involved in R. glutinosa seed cultivation, our team previously used the formative features and genetic analysis of R. glutinosa to determine the optimal in vitro tissue culture conditions for producing sterile culture seedlings and rootstocks of R. glutinosa. The aim of the present study was to identify differences between R. glutinosa standard rootstock seedlings (SR), R. glutinosa culture rootstock seedlings (CR), and culture seedlings (CS) under field conditions. The reproductive characteristics of the aerial part were more robust while the area and length of leaves were smaller for SR than those for CR and CS. The characteristic that differed the most in SR was flowering, which did not occur in CR and CS. In addition, the fresh and dry weights of the subterranean parts of CR and CS were two-fold greater than those of SR. Fourier transform near-infrared (FT-NIR) analysis showed only slight differences between the chemical constituents of SR and its culture products, which was confirmed by measuring the content of catalpol, an indexing substance. Catalpol had a reduced content in the culture products compared to SR. However, this difference was not significant. Our findings will be useful for the identification of the best seedling type of R. glutinosa to enable its mass production.

The genus Fritillaria is an important herbaceous medicinal plant. The dried bulbs of many Fritillaria species are used as Fritillariae Bulbus in traditional oriental medicines. However, these herbal medicines frequently contain mixtures of different types of Fritillariae Bulbus and other Fritillaria species with little or no medicinal value. The accurate identification of different types of Fritillariae Bulbus is very difficult due to the morphological similarities between the plants and dried bulbs; therefore, it is necessary to accurately identify these herbal medicines and other Fritillaria species based on their genetic characteristics. To find molecular markers for Fritillaria species and elucidate the genomic characteristics of F. thunbergii, we sequenced the complete chloroplast (cp) genome of F. thunbergii and performed a comparative analysis with related plant taxa. The complete cp genome of F. thunbergii is 152,155 bp with a quadripartite structure, which is similar to other plants, and was highly similar to previously reported Fritillaria cp genomes in regard to gene content, order, orientation, and GC contents. Comparative analysis of the cp genomes identified two genes, matK and rps16, that contained sufficient markers to distinguish between two herbal medicines (Fritillariae Thunbergii and Fritillariae Hupehensis Bulbus) and five Fritillaria species. These results provide useful information for identification of Fritillaria species and quality control of Fritillariae Bulbus.

The authentication of components from plant species is vital for the quality control and standardization of herbal medicines. Due to morphological similarities when dried, it is very difficult to distinguish authentic medicinal plants Patrinia villosa and P. scabiosifolia from adulterants of P. rupestris and P. saniculifolia in the herbal medicine Patriniae Radix. To establish a reliable authentication tool distinguishing authentic Patriniae Radix species from adulterants, we used random amplified polymorphic DNA (RAPD) genomic profiling and obtained several species-specific DNA fragments for each of the four Patrinia species. Based on the sequences of these amplicons, we developed sequence characterized amplified region (SCAR) markers as stable molecular authentication tools. SCAR markers to identify the authentic Patriniae Radix species, P. villosa and P. scabiosifolia, were developed. To accurately identify adulterants, we also developed SCAR markers able to identify the inauthentic P. rupestris and P. saniculifolia species. Furthermore, we established multiplex-PCR SCAR assays to simultaneously distinguish all four species using combinations of species-specific SCAR marker primer sets. These efforts resulted in reliable DNA-based molecular markers to identify authentic Patriniae Radix species from their adulterants and a rapid authentication assay for the efficient identification of Patrinia species. These markers will facilitate the standardization of Patriniae Radix preparations and therefore prevent the distribution of adulterants.

To determine whether metabolite fingerprinting for whole cell extracts based on Fourier transform infrared (FT-IR) spectroscopy can be used to discriminate and compare metabolic equivalence, standard medicinal parts from four medicinal plants (Cynanchum wilfordii Hemsley, Atractylodes japonica Koidz, Polygonum multiflorum Thunberg and Astragalus membranaceus Bunge) and their in vitro-produced adventitious roots were analyzed by FT-IR spectroscopy. The principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) from the FT-IR spectral data showed that the whole metabolic pattern from Cynanchum wilfordii was highly similar to Astragalus membranaceus. However, Atractylodes japonica and Polygonum multiflorum showed significantly different metabolic patterns. Furthermore, adventitious roots from Cynanchum wilfordii and Astragalus membranaceus also showed similar metabolic patterns compared to their standard medicinal parts. These results clearly show that mass proliferation of adventitious roots may be applied to aquire novel supply of standard medicinal parts from medicinal plants. However, the whole metabolic pattern from adventitious roots of Atractylodes japonica and Polygonum multiflorum were not similar to their standard medicinal parts. Furthermore, FT-IR spectroscopy combined with multivariate analyses established in this study may be applied as an alternative tool to discriminate the whole metabolic equivalence from several standard medicinal parts. Thus, we suggest that these metabolic discrimination systems may be applied for metabolic standardization of herbal medicinal resources.

Background Grafting has been widely practiced for centuries in the propagation and production of many vegetable and fruit species. However, the underlying molecular and genetic mechanisms for how the graft partners interact with each other to produce a successful graft remain largely unknown. We hypothesized that genome-wide mRNA exchanges, which were recently documented in grafted model plant species, are a general phenomenon widely present in grafted plants, including those in vegetable and fruit species, and have specific genotype- and environment-dependent characteristics modulating plant performance. Methods Using diagnostic SNPs derived from high throughput genome sequencing, we identified and characterized the patterns of genome-wide mRNA exchanges across graft junctions in grafted grapevines grown in the in vitro and field conditions. Results We identified more than 3000 genes transporting mRNAs across graft junctions. These genes were involved in diverse biological processes and those involved in basic cellular, biosynthetic, catabolic, and metabolic activities, as well as responses to stress and signal transduction, were highly enriched. Field-grown mature grafts had much fewer genes transmitting mRNAs than the in vitro young grafts (987 vs. 2679). These mobile mRNAs could move directionally or bi-directionally between scions and rootstocks. The mRNA transmission rates of these genes were generally low, with 65 % or more having transmission rates lower than 0.01. Furthermore, genotypes, graft combinations and growth environments had impact on the directions of mRNA movement as well as the numbers and species of mRNAs being exchanged. Moreover, we found evidence for the presences of both passive and selective mechanisms underlying long distance mRNA trafficking in grafted grapevines. Conclusions We extended the studies of mRNA exchanges in model species to grapevines and demonstrated that genomic-scale mRNA exchange across graft junctions occurred in grapevines in a passive or genotype and environment-dependent manner. Electronic supplementary material The online version of this article (doi:10.1186/s12870-015-0626-y) contains supplementary material, which is available to authorized users.