Cleome spinosa is widely used as a garden ornamental in many countries. Here we determined the optimal conditions for plant regeneration from different tissue explants grown in vitro. Induction medium containing MS salts, MS vitamins, 3% sucrose, 1 mg l⁻¹ BA, 200 mg l⁻¹ timentin, and 0.8% agar was sufficient for shoot regeneration of all the tissue explants examined, including leaf, hypocotyl, and cotyledon. Subsequently, an Agrobacterium tumefaciens-mediated method was developed to transform the vector pCHS, which carries the transgenes Petunia chalcone synthase (chs) and selection marker neomycin phosphotransferase II (nptII), into C. spinosa. From a total of 368 cotyledon explants, 13 putative transgenic lines were regenerated from selection medium supplemented with 50 mg l⁻¹ kanamycin and 200 mg l⁻¹ timentin, and transferred to the greenhouse. Genomic PCR and Southern blot analyses revealed that the nptII transgene was present in all 13 transgenic plants. Similarly, when the Petunia chs transgene was used as a probe in Southern blot analysis, single or multiple hybridization bands were detected in 12 out of the 13 transgenic plants. In addition, T₁ progeny assay from selected transformants showed that the nptII transgene can be transmitted in a Mendelian manner from transgenic parents into their progeny. This is the first report of stable transformation of the C₃ dicotyledon C. spinosa, which will facilitate functional comparison of cell-type specific genes with counterpart C₄ dicotyledon C. gynandra using transgenic approaches.

Wedelia chinensis, which belongs to the Asteraceae family, is a procumbent, perennial herb. It has medicinal anti-inflammatory properties and has been traditionally used as folk medicine in East and South Asia for treating fever, cough and phlegm. In Taiwan, W. chinensis is a common ingredient of herbal tea. Previous studies showed that the plant leaves contain four major bioactive compounds, wedelolactone, demethylwedelolactone, luteolin and apigenin, that have potent antihepatoxic activity, and are thus used as major ingredients in phytopharmaceutical formulations. In this study, we set up optimal conditions for induction of ploidy in W. chinensis. Ploidy can be an effective method of increasing plant biomass and improving medicinal and ornamental characteristics. By using flow cytometry and chicken erythrocyte nuclei as a reference, the DNA content (2C) or genome size of W. chinensis was determined to be 4.80 picograms (pg) in this study for the first time. Subsequently, we developed the successful induction of five triploid and three tetraploid plants by using shoot explants treated with different concentrations (0, 0.25, 0.5, 1, 1.5, 2 g/L) of colchicine. No apparent morphological changes were observed between these polyploid plants and the diploid wild-type (WT) plant, except that larger stomata in leaves were found in all polyploid plants as compared to diploid WT. Ultra-performance liquid chromatography coupled with tandem mass spectrometry was used to quantify the four index compounds (wedelolactone, demethylwedelolactone, luteolin, apigenin) in these polyploid plants, and fluctuating patterns were detected. This is the first report regarding polyploidy in the herbal plant W. chinensis.

Wedelia chinensis, belonging to the Asteraceae family, has been used in folk medicine in East and South Asia for the treatment of common inflammatory diseases and protection against liver toxicity. Previously, in vitro propagation through different tissue explants has been reported, including through nodal segments, axillary buds, and shoot tips, whereas leaf segments failed to proliferate. Here, we report on the in vitro propagation of W. chinensis by culturing young leaf explants in MS medium supplemented with 0.5 mg/L α-naphthaleneacetic acid (NAA), 0.75 mg/L thidiazuron (TDZ), 1 mg/L gibberellic acid (GA3), 3.75 mg/L adenine, 3% sucrose, and 0.8% agar at pH 5.8. Calli were observed in all explants derived from the youngest top two leaves, and the average percentage of shoot regeneration was 23% from three independent experiments. Then, several shoots were excised, transferred onto MS basal medium supplemented with 3% sucrose and 0.8% agar at pH 5.8, and cultured in a growth chamber for 1 to 2 months. Roots were easily induced. Finally, plantlets carrying shoots and roots were transferred into soil, and all of them grew healthily in a greenhouse. No morphological variation was observed between the regenerated plantlets and the donor wild-type plants. In addition, we also established root cultures of W. chinensis in culture medium (MS medium, 3 mg/L NAA, 3% sucrose, pH 5.8) with or without 0.8% agar. To the best of our knowledge, this is the first paper reporting plant regeneration from leaf explants in the herbal plant W. chinensis.

Bidens pilosa is commonly used as an herbal tea component or traditional medicine for treating several diseases, including diabetes. Polyacetylenes have two or more carbon–carbon triple bonds or alkynyl functional groups and are mainly derived from fatty acid and polyketide precursors. Here, we report the cloning of full-length cDNAs that encode 12-fatty acid acetylenase (designated BPFAA) and 12-oleate desaturase (designated BPOD) from B. pilosa, which we predicted to play a role in the polyacetylene biosynthetic pathway. Subsequently, expression vectors carrying BPFAA or BPOD were constructed and transformed into B. pilosa via the Agrobacterium-mediated method. Genomic PCR analysis confirmed the presence of transgenes and selection marker genes in the obtained transgenic lines. The copy numbers of transgenes in transgenic lines were determined by Southern blot analysis. Furthermore, 4–5 FAA genes and 2–3 OD genes were detected in wild-type (WT) plants. Quantitative real time-PCR revealed that some transgenic lines had higher expression levels than WT. Western blot analysis revealed OD protein expression in the selected transformants. High-performance liquid chromatography profiling was used to analyze the seven index polyacetylenic compounds, and fluctuation patterns were found.

Plastid transformation has a number of advantages in comparison with nuclear transformation. Currently, only tobacco (Nicotiana tabacum) is routinely used in plastid transformation. Here we constructed a series of chloroplast expression vectors specific for spinach (pCEV1), tomato (pCEV2 and pCEV3), and N. benthamiana (pCEV4). Selection marker aminoglycoside 3 0-adenyltransferase (aadA) conferring spectinomycin resistance was used in pCEV1, pCEV2, and pCEV4, while selection marker neomycin phosphotransferase II (nptII) was used in pCEV3. The expression cassette in these vectors was integrated in the intergenic spacer between trnI and trnA of plastid genome via homologous recombination. Several transgenes, including a reporter gene encoding GFP:GUS fusion protein and genes from tomato (lycopene b-cyclase, z-carotene desaturase) and bamboo mosaic virus satellite RNA (encoding coat protein CP20), were independently cloned into some of these vectors. Transient GUS expression was detected in spinach leaves bombarded by pCEV1/GFP-GUS. Functional expression of selection markers aadA and nptII was demonstrated for spinach, tomato, and N. benthamiana. Seedling assay from T 0 self-pollinated plant of transplastomic N. benthamiana confirmed maternal inheritance of transgenes, and genomic PCR analysis confirmed integration of transgenic expression cassette into the plastid genome of N. benthamiana. Moreover, auxiliary vectors pECaad and pECnpt are also reported.