The factors affecting the development of medicinal plants from a value chain perspective.

MAIN CONCLUSION: From a value chain perspective, this paper examines the important factors from the selection of planting areas to storage, which restrict the development of medicinal plants. The purpose of this paper is to provide theoretical basis for the sustainable development of medicinal plants. Medicinal plants have significant economic and medicinal value. Due to the gradual depletion of wild medicinal plant resources, cultivators of medicinal plants must resort to artificial cultivation to cope. However, there are still many problems in the production process of medicinal plants, resulting in decreases in both yield and quality, thus hindering sustainable development. To date, research on the value chain of medicinal plants is still limited. Therefore, this paper analyzes the factors affecting the development of medicinal plants from the perspective of the value chain, including the selection of growing areas to the storage process of medicinal plants, and summarizes the challenges faced in the production process of medicinal plants. The purpose of this paper is to provide theoretical basis for the sustainable development of medicinal plants.

Plants as Biofactories for Therapeutic Proteins and Antiviral Compounds to Combat COVID-19.

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had a profound impact on the world's health and economy. Although the end of the pandemic may come in 2023, it is generally believed that the virus will not be completely eradicated. Most likely, the disease will become an endemicity. The rapid development of vaccines of different types (mRNA, subunit protein, inactivated virus, etc.) and some other antiviral drugs (Remdesivir, Olumiant, Paxlovid, etc.) has provided effectiveness in reducing COVID-19's impact worldwide. However, the circulating SARS-CoV-2 virus has been constantly mutating with the emergence of multiple variants, which makes control of COVID-19 difficult. There is still a pressing need for developing more effective antiviral drugs to fight against the disease. Plants have provided a promising production platform for both bioactive chemical compounds (small molecules) and recombinant therapeutics (big molecules). Plants naturally produce a diverse range of bioactive compounds as secondary metabolites, such as alkaloids, terpenoids/terpenes and polyphenols, which are a rich source of countless antiviral compounds. Plants can also be genetically engineered to produce valuable recombinant therapeutics. This molecular farming in plants has an unprecedented opportunity for developing vaccines, antibodies, and other biologics for pandemic diseases because of its potential advantages, such as low cost, safety, and high production volume. This review summarizes the latest advancements in plant-derived drugs used to combat COVID-19 and discusses the prospects and challenges of the plant-based production platform for antiviral agents.

Optimal harvest-time to maximize the annual camptothecin production by Ophiorrhiza pumila in a plant factory with artificial light.

Ophiorrhiza pumila is a medicinal plant that grows in subtropical forests and produces camptothecin (CPT). To determine an optimal harvest time of O. pumila in a plant factory with artificial light (PFAL), we investigated the CPT distribution in each organ and at the developmental stage and estimated the annual CPT production. For this study, the O. pumila plants were grown in controlled environments (16 h light period, photosynthetic photon flux density of 100 µmol m-2 s-1 under white light-emitting diode lamps, air temperature of 28 °C, relative humidity of 80%, and CO2 concentration of 1000 µmol mol-1). First, the stem, root, and seed pod had higher CPT contents than the leaves, flower, and ovary. The optimal harvest time of O. pumila in a PFAL was 63 days after transplanting (DAT), because the CPT content in the whole organs was the highest at the seed-ripening stage. Second, based on these results, the estimated annual CPT production of O. pumila cultivated in a PFAL was 380 mg m-2 y-1 (63 DAT). This value was 4.3 times greater than the annual CPT production by Camptotheca acuminata in a greenhouse. We concluded that the CPT production by O. pumila in a PFAL throughout the year has many advantages, although the demand for electrical energy was high compared to that of Camptotheca acuminata in a greenhouse.

The chromosome-level reference genome assembly for Dendrobium officinale and its utility of functional genomics research and molecular breeding study.

Dendrobium officinale, an important medicinal plant of the genus Dendrobium in Orchidaceae family, has been used as traditional Chinese medicine (TCM) for nearly thousands of years. Here, we report the first chromosome-level reference genome of D. officinale, based on PacBio long-reads, Illumina short-reads and Hi-C data. The high-quality assembled genome is 1.23 Gb long, with contig N50 of 1.44 Mb. A total of 93.53% genome sequences were assembled into 19 pseudochromosomes with a super scaffold N50 of 63.07 Mb. Through comparative genomic analysis, we explored the expanded gene families of D. officinale, and also their impact on environmental adaptation and biosynthesis of secondary metabolites. We further performed detailed transcriptional analysis of D. officinale, and identified the candidate genes involved in the biosynthesis of three main active ingredients, including polysaccharides, alkaloids and flavonoids. In addition, the MODIFYING WALL LIGNIN-1 (MWL1) gene, which inferred from Genome-Wide Association Studies (GWAS) based on the resequencing date from D. officinale and five related species and their morphologic features, may contribute to the plant production (yield of stems) of D. officinale. Therefore, the high-quality reference genome reported in this study could benefits functional genomics research and molecular breeding of D. officinale.

Promotion of Zinc Tolerance, Acquisition and Translocation of Phosphorus in Mimosa pudica L. Mediated by Arbuscular Mycorrhizal Fungi.

Heavy metal contamination of soil is of increasing concern because of its potential risk to human health. In this study, two AMFs (Rhizophagus intraradices and Funneliformis mosseae) substantially increased the biomass of bashfulgrass in Zn-contaminated soil, even at Zn levels of up to 600 mg kg-1. Zn uptake in R. intraradices- and F. mosseae-mycorrhizal bashfulgrass was increased by 40-fold and 7-fold, respectively, when plants grown in Zn-contaminated (400 mg kg-1) soil. Elemental analysis showed that neither AMF had an effect on Zn concentration in plant tissues, including the roots and shoots. However, a significant increase of phosphorus (P) concentration was observed, suggesting the increased is from the improved use efficiency of soil nutrients by AMFs. Comparing the two AMFs, better growth performance with more biomass occurred with R. intraradices-inoculated bashfulgrass in Zn-contaminated soil. This is consistent with R. intraradices being more tolerant to Zn than F. mosseae, indicated by a higher colonization percentage in bashfulgrass roots. Taken together, our data indicate that AMFs possibly improve acquisition and translocation of P to promote increased biomass. Moreover, mycorrhiza did not enhance Zn accumulation in shoots and roots of bashfulgrass at the same Zn level. In the future, developing AMF (especially R. intraradices) inoculation of plants might be a desirable means of safe production of ornamental plants in metal-polluted soil.

UVA Radiation Is Beneficial for Yield and Quality of Indoor Cultivated Lettuce.

Understanding the wavelength dependence of plant responses is essential for optimizing production and quality of indoor plant cultivation. UVA is the main component of solar UV radiation, but its role on plant growth is poorly understood. Here, two experiments were conducted to examine whether UVA supplementation is beneficial for indoor plant cultivation. Lettuce (Lactuca sativa L. cv. "Klee") was grown under mixed blue, red, and far-red light with photon flux density of 237 µmol m-2 s-1 in the growth room; photoperiod was 16 h. In the first experiment, three UVA intensities with peak wavelengths at 365 nm were used: 10 (UVA-10), 20 (UVA-20), and 30 (UVA-30) µmol m-2 s-1, respectively. In the second experiment, 10 µmol m-2 s-1 UVA radiation were given for 5 (UVA-5d), 10 (UVA-10d), and 15 (UVA-15d) days before harvest on day 15, respectively. Compared with control (no UVA), shoot dry weight was increased by 27%, 29%, and 15% in the UVA-10, UVA-20, and UVA-30 treatments, respectively, which correlated with 31% (UVA-10), 32% (UVA-20), and 14% (UVA-30) larger leaf area. Shoot dry weight under the treatments of UVA-5d, UVA-10d, and UVA-15d was increased by 18%, 32%, and 30%, respectively, and leaf area was increased by 15%-26%. For both experiments, UVA radiation substantially enhanced secondary metabolites accumulation, e.g. anthocyanin and ascorbic acid contents were increased by 17%-49% and 47%-80%, respectively. Moreover, plants grown under the UVA-30 treatment were stressed, as indicated by lipid peroxidation and lower maximum quantum efficiency of photosystem II photochemistry (Fv/Fm). We conclude that UVA supplementation not only stimulates biomass production in controlled environments, but also enhances secondary metabolite accumulation.

Regulation of antioxidant production, ion uptake and productivity in potato (Solanum tuberosum L.) plant inoculated with growth promoting salt tolerant Bacillus strains.

The exchangeable sodium (Na+) in salt affected soils is a major constraint in potassium (K+) availability to plants that disturb ion transport and inhibit plant growth, adversely. Salt tolerant plant growth promoting rhizobacteria (PGPR) may regulate the Na+/K+ efflux and increase K+ uptake by the plant from the soil. Therefore, a pot study was performed to examine the effect of salt tolerant PGPR Bacillus sp. alone and in consortium, on antioxidant enzyme activity, ion uptake and potato (Solanum tuberosum L.) tuber yield in normal and salt affected soils. We observed that Bacillus sp. (strains SR-2-1 and SR-2-1/1) solubilized insoluble phosphorous and produced indole-3-acetic acid while only SR-2-1/1 produced ACC deaminase in culture medium supplemented with various concentrations of NaCl (0-6%). In the pot experiment, the consortium treatment of strains was found to increase relative leaf water contents whereas decreased the electrolyte leakage and antioxidant enzyme activity both in normal and salt affected soils. Similarly, consortium treatment decreased Na+ whereas increased K+, Ca+2, K+/Na+ and Ca+2/Na+ in plant dry matter in both soils. It has been investigated that inoculation of PGPR significantly (p < 0.05) increased plant biomass, number of tubers per plant and tuber weight as compared to un-inoculated plants in both soils. In addition, PGPR inoculation enhanced auxin production in root exudates of young potato plants and bacterial population dynamics in both soils. Na+ ion regulation (R2 = 0.95) and tuber weight (R2 = 0.90) in salt affected soil were significantly correlated with auxin production in the rhizosphere. Results of this study conferred that consortium of Bacillus strains (SR-2-1, SR-2-1/1) enhanced auxin production in the rhizosphere of potato plants and that ultimately regulated antioxidant enzyme production and uptake of Na+, K+ and Ca+2 in potato plants resulted into a higher tuber yield in both normal and salt affected soils.

Phytoremediated marine sediments as suitable peat-free growing media for production of red robin photinia (Photinia x fraseri).

Sediments dredged by an industrial port, slightly contaminated by heavy metals and petroleoum hydrocarbons, were phytoremediated and used as peat-free growing media for the red robin photinia (Photinia x fraseri L.). Plants were grown on sediment only (S), sediment mixed with composted pruning residues (S + PR), sediment fertilized with controlled release fertilizers (S + F) and peat-based growing media as control (C). Plant elongation and dry weight, leaf contents of chlorophyll, malondialdehyde (MDA), macronutrients and heavy metals were determined at the end of one growing season. Environmental impact related to the use of sediment-based as compared to peat-based growing media was assessed by the Life Cycle Analysis (LCA). Sediment-based growing media presented significantly higher bulk density, pH and electrical conductivity values, lower C and N contents, and significantly higher total and available P. Red robin photinia grown on S + F growing media showed morphological and chemical parameters similar to those of control plants (C), whereas plants grown on S and S + PR showed lower growth. Leaf concentration of nutrients and heavy metals varied depending on the considered element and growing media, but were all within the common values for ornamental plants, whereas the highest MDA concentrations were found in plants grown on traditional growing media. The LCA indicated the use of sediments as growing media reduced the C footprint of ornamental plant production and the contribute of growing media to the environmental impact per produced plant. We concluded that sediments phytoremediation and use in plant nursery is a practical alternative re-use option for dredged sediments.

Avaliação agronômica e química de dezessete acessos de erva-cidreira [Lippia alba (Mill. ) N. E. Brown] - quimiotipo citral, cultivados no Distrito Federal / Agronomic and chemical evaluation of seventeen accessions of "erva-cidreira" [Lippia alba (Mill. ) N. E. Brown] - citral chemotype, cultivated at the Federal District, Brazil

A erva-cidreira [Lippia alba (Mill.) N.E.Brown] é uma espécie nativa utilizada como planta medicinal em todo o Brasil. O citral é responsável pela ação sedativa da erva cidreira, sendo um dos principais componentes do óleo essencial. O objetivo deste trabalho foi avaliar o comportamento agronômico, teor e rendimento de óleo essencial e de citral em 17 acessos de L. alba da coleção da Universidade de Brasília - UnB. O experimento foi realizado no período de 19/02/2005 a 18/03/2006, em latossolo vermelho, no Distrito Federal. O delineamento experimental utilizado foi o de blocos ao acaso, com três repetições, contendo três plantas por parcela. Foram avaliados os parâmetros área foliar, comprimento da haste, produção de massa fresca (folhas e hastes), produção de massa foliar seca, teor de óleo essencial e de citral, rendimento estimado de óleo essencial e de citral por planta, além da caracterização do perfil aromático do óleo essencial. Os acessos L.41 (0,75 por cento), L.45 (0,66 por cento) e L.08 (0,62 por cento) apresentaram os maiores teores de óleo essencial. O acesso L.45 (1,32 g pl-1) apresentou o maior rendimento de óleo, seguido dos acessos L.47 (0,73 g pl-1), L.41 (0,67 g pl-1), L.34 (0,67 g pl-1) e L.33 (0,62 g pl-1). Os acessos apresentaram teores de citral variando de 51,7 por cento (L.34) a 75,1 por cento (L.09), com média de 63,6 por cento e predominância do isômero geranial (36,4 por cento) sobre o neral (27,8 por cento). O acesso L.45 (0,83 g pl-1) apresentou o maior rendimento de citral. Treze acessos apresentaram o quimiotipo citral; três o quimiotipo citral-limoneno e apenas um apresentou o quimiotipo citral-mirceno. Os resultados evidenciam o potencial de produção de citral do acesso L.45, o qual poderá ser utilizado para melhorar a qualidade da matéria prima de erva-cidreira utilizada nos programas de fitoterapia no país ou em programas de melhoramento genético para esta finalidade.

"Erva-cidreira" [Lippia alba (Mill.) N.E.Brown] is a native species used as a medicinal plant all over Brazil. Citral, a major constituent of L. alba essential oil, is responsible for its sedative activity. The aim of this study was to evaluate the agronomic behavior, content and yield of essential oil and citral in 17 accessions of L. alba from the germplasm bank of University of Brasília - UnB, Brazil. The experiment was carried out from 02/19/2005 to 03/18/2006, in red latosol, at the Federal District, Brazil. The adopted experimental design was in randomized blocks, with three replicates and three plants per plot. The following parameters were evaluated: leaf area, stem length, fresh mass (leaves and stems) production, dry leaf mass production, essential oil and citral content, estimated yield of essential oil and citral per plant, besides characterization of the essential oil aromatic profile. Accessions L41 (0.75 percent), L45 (0.66 percent) and L08 (0.62 percent) showed the highest essential oil content. Accessions L45 (1.32 g pl-1) presented the highest essential oil yield, followed by L47 (0.73 g pl-1), L41 (0.67 g pl-1), L34 (0.67 g pl-1) and L33 (0.62 g pl-1). Citral content varied from 51.7 percent (L34) to 75.1 percent (L09), with an average of 63.6 percent and predominance of the isomer geranial (36.4 percent) over neral (27.8 percent). Accession L45 (0.83 g pl-1) showed the highest citral yield. Thirteen accessions presented the chemotype citral; three, the chemotype citral-limonene, and only one had the chemotype citral-myrcene. The results evidenced the potential of accession L45 to produce citral, which can be used to improve the quality of "erva-cidreira" raw material in phytotherapy programs in the country or in breeding programs.