Impact of copper treatment on phenylpropanoid biosynthesis in adventitious root culture of Althaea officinalis L

Copper Sulfate Elicitation Effect on Biomass Production, Phenolic Compounds Accumulation, and Antioxidant Activity of Morus nigra L. Stem Node Culture

Phenolic compounds are strong antioxidant and antibacterial agents with great pharmacological, medicinal, nutritional, and industrial value. The potential of Morus nigra in stem node culture was investigated for the production of phenolic compounds and their elicitation with CuSO4. Individual phenolic compounds in the samples were identified and quantified by using HPLC-PDA and HPLC-MS methods, while the content of total phenolic compounds, the content of total flavonoids, and the antioxidant activity of methanolic extracts were evaluated spectrophotometrically. The highest fresh and dry weights were obtained in plantlets treated with 0.5 mM CuSO4 for 42 days. The highest total phenolic content, total flavonoid content, and antioxidant activity of the extracts were determined in stem node cultures treated with 3 mM CuSO4 for 42 days. Under the latter conditions, the predominant representatives of the caffeoylquinic acids, p-coumaric acid derivatives, kaempferol derivatives, and quercetin derivatives also achieved the highest content. The most abundant phenolic compound in all samples was the chlorogenic acid. The nodal culture of M. nigra elicited with CuSO4 could potentially be used for the industrial production of phenolic compounds, especially caffeoylquinic acids. Moreover, considering the biochemical response to CuSO4 treatment and the ability to tolerate and accumulate copper, the potential application of M. nigra in phytoremediation is also highlighted.

An update on biotechnological intervention mediated by plant tissue culture to boost secondary metabolite production in medicinal and aromatic plants

Since prehistoric times, medicinal and aromatic plants (MAPs) have been employed for various therapeutic purposes due to their varied array of pharmaceutically relevant bioactive compounds, i.e. secondary metabolites. However, when secondary metabolites are isolated directly from MAPs, there is occasionally very poor yield and limited synthesis of secondary metabolites from particular tissues and certain developmental stages. Moreover, many MAPs species are in danger of extinction, especially those used in pharmaceuticals, as their natural populations are under pressure from overharvesting due to the excess demand for plant-based herbal remedies. The extensive use of these metabolites in a number of industrial and pharmaceutical industries has prompted a call for more research into increasing the output via optimization of large-scale production using plant tissue culture techniques. The potential of plant cells as sources of secondary metabolites can be exploited through a combination of product recovery technology research, targeted metabolite production, and in vitro culture establishment. The plant tissue culture approach provides low-cost, sustainable, continuous, and viable secondary metabolite production that is not affected by geographic or climatic factors. This study covers recent advancements in the induction of medicinally relevant metabolites, as well as the conservation and propagation of plants by advanced tissue culture technologies.

Full-length transcriptome and RNA-Seq analyses reveal the resistance mechanism of sesame in response to Corynespora cassiicola

BACKGROUND

Corynespora leaf spot is a common leaf disease occurring in sesame, and the disease causes leaf yellowing and even shedding, which affects the growth quality of sesame. At present, the mechanism of sesame resistance to this disease is still unclear. Understanding the resistance mechanism of sesame to Corynespora leaf spot is highly important for the control of infection. In this study, the leaves of the sesame resistant variety (R) and the sesame susceptible variety (S) were collected at 0-48 hpi for transcriptome sequencing, and used a combined third-generation long-read and next-generation short-read technology approach to identify some key genes and main pathways related to resistance.

RESULTS

The gene expression levels of the two sesame varieties were significantly different at 0, 6, 12, 24, 36 and 48 hpi, indicating that the up-regulation of differentially expressed genes in the R might enhanced the resistance. Moreover, combined with the phenotypic observations of sesame leaves inoculated at different time points, we found that 12 hpi was the key time point leading to the resistance difference between the two sesame varieties at the molecular level. The WGCNA identified two modules significantly associated with disease resistance, and screened out 10 key genes that were highly expressed in R but low expressed in S, which belonged to transcription factors (WRKY, AP2/ERF-ERF, and NAC types) and protein kinases (RLK-Pelle_DLSV, RLK-Pelle_SD-2b, and RLK-Pelle_WAK types). These genes could be the key response factors in the response of sesame to infection by Corynespora cassiicola. GO and KEGG enrichment analysis showed that specific modules could be enriched, which manifested as enrichment in biologically important pathways, such as plant signalling hormone transduction, plant-pathogen interaction, carbon metabolism, phenylpropanoid biosynthesis, glutathione metabolism, MAPK and other stress-related pathways.

CONCLUSIONS

This study provides an important resource of genes contributing to disease resistance and will deepen our understanding of the regulation of disease resistance, paving the way for further molecular breeding of sesame.

Enhanced wedelolactone content in in vitro-raised genetically uniform Wedelia chinensis under the influence of CuSO4

In the present study, we addressed the imperative for potent anticancer agents through Wedelia chinensis, a medicinal plant abundant in the robust antihepatotoxic and antitumor compound wedelolactone. Hindrances in conventional propagation methods due to cross-pollination and habitat degradation prompted us to pioneer in vitro rapid multiplication using plant tissue culture. Optimal outcomes were attained employing Murashige and Skoog (MS) medium supplemented with Indole-3-butyric acid (IBA) (0.5 mg/L) and Kinetin (KN) (5.0 mg/L), yielding 97.67% shoot regeneration and 81.67% rooting from nodal explants. Transplanted plantlets exhibited a 92% survival rate. We established a wedelolactone extraction protocol using toluene:ethyl acetate:formic acid (5:4:1) for High-performance thin-layer chromatography (HPTLC) analysis, trailblazing wedelolactone quantification and 2C DNA analysis in W. chinensis via flow cytometry. Experiments under heavy metal stress with CuSO4 unveiled physiological responses, with peak wedelolactone content [193.90 μg/g dry weight (dw)] in vitro at 75 μM CuSO4, surpassing in vivo levels (89.95 μg/g dw) by 116%. By pioneering successful in vitro rapid multiplication and enhanced wedelolactone content, we bridge a critical gap in the conservation and production of this medicinal plant. Our findings not only offer a sustainable means of propagation but also present a viable strategy for elevating the yield of potent bioactive molecules like wedelolactone, holding immense promise for the development of novel therapeutic interventions and addressing the pressing healthcare challenges of our time.

Copper boosts the biostimulant activity of a vegetal-derived protein hydrolysate in basil: morpho-physiological and metabolomics insights

In addition to be used as a plant protection agent, copper (Cu) is also an essential micronutrient for plant growth and development. The bioavailability of Cu in agricultural systems can be limited due to its specific physical-chemical characteristics, leading to imbalances in plant production. To address this issue, an experimental trial was conducted on Genovese basil (Ocimum basilicum L.) in protected conditions to comparatively evaluate the effects of a vegetable protein hydrolysate (VPH), free Cu and Cu complexed with peptides and amino acids of vegetal origin (Cu and Cu-VPH, respectively), and a combination of VPH and Cu-VPH (VPH+Cu-VPH). The study showed that the combined application of VPH+Cu-VPH led to a significant average increase of 16.3% in fresh yield compared to the untreated Control and Cu treatment. This finding was supported by an improved photosynthetic performance in ACO2 (+29%) and Fv/Fm (+7%). Furthermore, mineral analysis using ICP OES demonstrated that Cu and Cu-VPH treatments determined, on average, a 15.1-, 16.9-, and 1.9-fold increase in Cu in plant tissues compared to control, VPH, and VPH+Cu-VPH treatments, respectively. However, the VPH+Cu-VPH treatment induced the highest contents of the other analyzed ions, except for P. In particular, Mg, Mn, Ca, and Fe, which take part in the constitution of chlorophylls, water splitting system, and photosynthetic electron transport chain, increased by 23%, 21%, 25%, and 32% compared to respective controls. Indeed, this improved the photosynthetic efficiency and the carboxylation capacity of the plants, and consequently, the physiological and productive performance of Genovese basil, compared to all other treatments and control. Consistently, the untargeted metabolomics also pointed out a distinctive modulation of phytochemical signatures as a function of the treatment. An accumulation of alkaloids, terpenoids, and phenylpropanoids was observed following Cu treatment, suggesting an oxidative imbalance upon metal exposure. In contrast, a mitigation of oxidative stress was highlighted in Cu-VPH and VPH+Cu-VPH, where the treatments reduced stress-related metabolites. Overall, these results highlight an interaction between Cu and VPH, hence paving the way towards the combined use of Cu and biostimulants to optimize agronomic interventions.

Ultraviolet-B and Heavy Metal-Induced Regulation of Secondary Metabolites in Medicinal Plants: A Review

Despite a rich history and economic importance, the potential of medicinal plants has not been fully explored under different abiotic stress conditions. Penetration of UV-B radiation and contamination of heavy metals are two important environmental stress for plants with remarkable influence on the defense-related and pharmaceutically important secondary metabolites of medicinal plants. UV-B and heavy metal contamination may become a critical issue that either positively or negatively affects the quality and quantity of secondary metabolites. Such effects may result from changes in the expression level of genes that encode the corresponding enzymes or the inactivation and/or stimulation of specific enzymes involved in the different biosynthetic pathways of the secondary metabolites. Therefore, a comprehensive study of the impact of UV-B and heavy metals individually and in combination on the biosynthesis and accumulation of secondary metabolites in medicinal plants is discussed in the present review.