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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.

Aspilia africana (Pers.) C. D. Adams is an important medicinal plant, that has been used as traditional medicine in many African countries for the treatment of various health problems, including inflammatory conditions, osteoporosis, tuberculosis, cough, measles, diabetes, diarrhea, malaria, and wounds. We developed an efficient and reproducible protocol for in vitro regeneration of A. africana from nodes. We assessed the effects of plant tissue culture media on A. africana growth, cytokinins for in vitro shoot regeneration and proliferation, and auxins for the rooting of regenerated shoots. Furthermore, chlorophyll content, photosynthetic rates, anatomy (leaves, stems, and roots), and Fourier transform near-infrared (FT-NIR) spectra (leaves, stems, and roots) of the in vitro regenerated and maternal A. africana plants were compared. Murashige and Skoog media, containing vitamins fortified with benzylaminopurine (BA, 1.0 mg/l), regenerated the highest number of shoots (13.0 ± 0.424) from A. africana nodal segments. 1-naphthaleneacetic acid (NAA, 0.1 mg/l) produced up to 13.10 ± 0.873 roots, 136.35 ± 4.316 mm length, and was the most efficient for rooting. During acclimatization, the in vitro regenerated A. africana plants had a survival rate of 95.7%, displaying normal morphology and growth features. In vitro regenerated and mother A. africana plants had similar chlorophyll contents, photosynthetic rates, stem and root anatomies, and FT-NIR spectra of the leaf, stem, and roots. The established regeneration protocol could be used for large-scale multiplication of the plant within a short time, thus substantially contributing to its rapid propagation and germplasm preservation, in addition to providing a basis for the domestication of this useful, high-value medicinal plant.