We present here a method for the in vitro propagation of Anthurium andraeanum cv. Fantasia through direct somatic embryogenesis. The embryos were directly formed at the cut end of most of the leaf explants when cultured on MS basal medium supplemented with N 6 -benzyladenine (BA) plus α-naphthalene acetic acid (NAA). MS basal media supplemented with BA (0.27 μM) and NAA (2.68 μM) induced maximum number of somatic embryos per leaf explant (15.33 ± 1.45) after 28 d of continuous culture. The highest numbers of embryos (12.33 ± 0.88) were matured into plantlets in MS basal medium augmented with 0.27 μM BA and 58.4 mM sucrose. Histology showed the presence of scutellum, coleoptile, welldeveloped root, and shoot initials at different stages of somatic embryo (SE) development directly on leaf explants. About 85% of the plantlets were successfully acclimatized, and of these, 80.3% plants survived after secondary hardening under greenhouse conditions. The embryo-derived plants successfully flowered. The presence of monomorphic DNA bands in random amplified polymorphic DNA (RAPD) marker analysis confirmed the genetic homogeneity of direct somatic embryo-derived plantlets in respect to their mother plant.

We present here an efficient micropropagation protocol through direct regeneration of plants from meristemoids in Anthurium andraeanum Linden cv. Tinora. About 96.6±0.33 of in vitro grown nodal segments having axillary buds were induced to form meristemoids on modified MS basal medium supplemented with 0.92 µM Thidiazuron (TDZ). The significantly highest numbers of shoots (25.6±0.23) were regenerated from 93.3±0.33% of meristemoids in the same culture medium. The histological and scanning electron microscopic (SEM) study confirmed direct organogenesis from the meristemoid.

Therapeutic monoclonal antibodies (mAbs) have evolved into an important class of effective medicine in treatment of various diseases. Since the antibody molecule consists of two identical heavy chains (HC) and two light chains (LC), each chain encoded by two different genes, their expressions at similar levels are critical for efficient assembly of functional recombinant mAbs. Although the plant-based expression system has been tested to produce fully assembled recombinant mAbs, coordinately expressing HC and LC at similar levels in a transgenic plant remains a challenge. A sequence coding for a foot-and-mouth disease virus (FMDV) 2A peptide has been successfully used to link two or more genes, which enable the translated polyprotein to be “self-cleaved” into individual protein in various genetically modified organisms. In the present study, we exploited the usage of F2A in Ebola virus monoclonal antibody (EBOV mAb) production. We found that transgenic tobacco plants carrying a transcription unit containing HC and LC linked by 2A not only produced similar levels of HC and LC but also rendered a higher yield of fully assembled EBOV mAb compared to those expressing HC and LC in two independent transcription units. Purified EBOV mAb bound to an Ebola epitope peptide with apparent Kd-values of 90.13–149.2 nM, indicating its proper assembly and high affinity binding to Ebola epitope peptide. To our knowledge, this is the first report showing mAb production by overexpressing a single transcription unit consisting of HC, LC and 2A in stable transformed tobacco plants.

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Chloroplasts are organelles responsible for chlorophyll biosynthesis, photosynthesis, and biosynthesis of many metabolites, which are one of key targets for crop improvement. Elucidating and engineering genes involved in chloroplast development are important approaches for studying chloroplast functions as well as developing new crops. In this study, we report a long-lived albino mutant derived from a popular ornamental plant Epipremnum aureum ‘Golden Pothos’ which could be used as a model for analyzing the function of genes involved in chloroplast development and generating colorful plants. Albino mutant plants were isolated from regenerated populations of variegated ‘Golden Pothos’ whose albino phenotype was previously found to be due to impaired expression of EaZIP, encoding Mg-protoporphyrin IX monomethyl ester cyclase. Using petioles of the mutant plants as explants with a traceable sGFP gene, an efficient transformation system was developed. Expressing Arabidopsis CHL27 (a homolog of EaZIP) but not EaZIP in albino plants restored green color and chloroplast development. Interestingly, in addition to the occurrence of plants with solid green color, plants with variegated leaves and pale-yellow leaves were also obtained in the regenerated populations. Nevertheless, our study shows that these long-lived albino plants along with the established efficient transformation system could be used for creating colorful ornamental plants. This system could also potentially be used for investigating physiological processes associated with chlorophyll levels and chloroplast development as well as certain biological activities, which are difficult to achieve using green plants.

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