Genetic transformation has emerged as an important tool for the genetic improvement of valuable plants by incorporating new genes with desirable traits. These strategies are useful especially in crops to increase yields, disease resistance, tolerance to environmental stress (cold, heat, drought, salinity, herbicides, and insects) and increase biomass and medicinal values of plants. The production of healthy plants with more desirable products and yields can contribute to sustainable development goals. The introduction of genetically modified food into the market has raised potential risks. A proper assessment of their impact on the environment and biosafety is an important step before their commercialization. In this paper, we summarize and discuss the risks and benefits of genetically modified plants and products, human health hazards by genetically transformed plants, environmental effects, Biosafety regulations of GMO foods and products, and improvement of medicinal values of plants by the genetic transformation process. The mechanisms of action of those products, their sources, and their applications to the healthcare challenges are presented. The present studies pointed out the existence of several controversies in the use of GMOs, mainly related to the human health, nutritions, environmental issues. Willingness to accept genetically modified (GM) products and the adoption of biosafety regulations varies from country to country. Knowledge about the gene engineering technology, debate between the government agencies, scientist, environmentalist and related NGOs on the GM products are the major factors for low adoptions of biosafety regulation. Therefore, the genetic transformation will help in the advancement of plant species in the future; however, more research and detailed studies are required.

In this study, the allelopathic properties of Medicago sativa on different weeds were investigated under in vitro conditions. The compounds involved in the autotoxicity of M. sativa were analyzed using high-performance liquid chromatography. The extracts of all concentrations inhibited the growth of the calluses of Digitaria ciliaris, Chenopodium album, Amaranthus lividus, Portulaca oleracea, and Commelina communis. Six allelopathic compounds in alfalfa were identified and quantified, and the most predominant phenolic compounds were salicylic acid and p-hydroxybenzoic acid. Various concentrations (10⁻², 10⁻³, and 10⁻⁵ M) of all the tested phenolic compounds exerted inhibitory effects on callus fresh weight. Rutin, salicylic acid, scopoletin, and quercetin significantly inhibited alfalfa seed germination. Of the seven identified saponins, medicagenic acid saponins exhibited the highest autotoxic effect and significantly lowered seed germination rate. Principal component analysis showed that the phenolic compounds and saponin composition significantly contributed to the different variables. The highly phytotoxic properties of the alfalfa-derived phenolic compounds and saponins indicate that these phytochemicals can be a potential source of bioherbicides.

Light is a key factor that affects phytochemical synthesis and accumulation in plants. Due to limitations of the environment or cultivated land, there is an urgent need to develop indoor cultivation systems to obtain higher yields with increased phytochemical concentrations using convenient light sources. Light-emitting diodes (LEDs) have several advantages, including consumption of lesser power, longer half-life, higher efficacy, and wider variation in the spectral wavelength than traditional light sources; therefore, these devices are preferred for in vitro culture and indoor plant growth. Moreover, LED irradiation of seedlings enhances plant biomass, nutrient and secondary metabolite levels, and antioxidant properties. Specifically, red and blue LED irradiation exerts strong effects on photosynthesis, stomatal functioning, phototropism, photomorphogenesis, and photosynthetic pigment levels. Additionally, ex vitro plantlet development and acclimatization can be enhanced by regulating the spectral properties of LEDs. Applying an appropriate LED spectral wavelength significantly increases antioxidant enzyme activity in plants, thereby enhancing the cell defense system and providing protection from oxidative damage. Since different plant species respond differently to lighting in the cultivation environment, it is necessary to evaluate specific wavebands before large-scale LED application for controlled in vitro plant growth. This review focuses on the most recent advances and applications of LEDs for in vitro culture organogenesis. The mechanisms underlying the production of different phytochemicals, including phenolics, flavonoids, carotenoids, anthocyanins, and antioxidant enzymes, have also been discussed.

There is increasing interest in the application of bioherbicides because they are less destructive to the global ecosystem than synthetic herbicides. Research has focused on reducing the dependence upon synthetic herbicides by substituting them with environmentally and economically sustainable bioproducts. Allelopathic phytochemicals may be an efficient method for controlling weeds, benefitting both the environment and human health. This study addressed the allelopathic potential of Miscanthus sacchariflorus (MS) extracts on the germination, plant growth, biomass, and biochemical parameters (electrolyte leakage, photosynthetic pigments, and antioxidant enzyme activities) of weeds using laboratory and field experiments. Liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) showed the presence of 22 phenolic compounds, including Orientin, Luteolin, Veratric acid, Chlorogenic acid, Protocatechuic acid, p-Coumaric acid, and Ferulic acid. Leaf extracts of M. sacchariflorus either completely suppressed or partially reduced seed germination and affected the development of weed seedlings (root and shoot length), in a dose-dependent manner. Aqueous extracts of M. sacchariflorus reduced the fresh weight and dry weight, affected the photosynthetic pigment content (chlorophylls, carotenoids), influenced the electrolyte ion leakage, and stimulated the activity of antioxidant enzymes in a species-specific manner. Pearson’s correlation analysis showed that the phenolic compound composition of M. sacchariflorus correlated with the variables tested, indicating that the phytochemicals present in the plant extracts of M. sacchariflorus are a potential source of bio-herbicides.

Plant phytochemical accumulation is influenced by various external factors that change with the seasons (e.g., harvesting time). Atractylodes japonica, an important medicinal plant rich in bioactive compounds, is used to treat several human diseases. We analyzed the influence of harvesting time on phenolic compound concentration and antioxidant activity of A. japonica roots. We investigated the correlation between phenolic compound and minerals contents and antioxidant activity in different harvests. Total phenolic and flavonoid contents varied significantly with the harvesting time. Liquid chromatography–mass spectrometry/mass spectrometry (LC–MS/MS) analysis revealed significant changes in the concentration of various phenolics between harvests. The content of different types of phenolics were significantly higher in the samples collected in October. Among them, chlorogenic acids (133,833.30 µg/g dry weight of root extract) were the most dominant phytochemical compounds detected. Samples harvested in October had higher concentrations of flavonoids, including rutin, orientin, vitexin, and apigenin. Roots harvested in October had a significantly higher (p < 0.05) antioxidant activity than that of those harvested later. Root mineral concentrations also varied with the harvest time. The analysis revealed that macro elements such as Ca ad Mg contents were significantly increased with delaying harvesting time, whereas a different trend was observed for the microelements including Fe, Cu, Al, and As contents in the October harvest. We also found a significant relationship between antioxidant activity and phenolic compound content. The most abundant minerals (Ca, Mg, Mn, Fe, and Al) correlated positively with the antioxidant activity indicating that these elements and compounds may be associated with the A. japonica antioxidant potential. Furthermore, A. japonica root extracts inhibited NIH/3T3 cellular proliferation in a season- and dose-dependent manner. Hence, harvesting time influenced the antioxidant properties and phenolic compound accumulation of A. japonica roots. These results indicate that the harvesting time is essential for obtaining the specific phytochemicals.

Chrysanthemum indicum is an important ornamental and medicinal plant that is often difficult to propagate commercially because of its poor germination and low seed viability. This plant is mostly propagated by cutting, but the rooting is slow and non-uniform. The present investigation evaluated the regeneration capacity of stem cutting by examining the influence of auxins, growth medium, temperature, and explant type on adventitious root formation in C. indicum. The auxin-treated cuttings were planted in different growth substrates under greenhouse conditions. Among the different auxins tested, indole-3-butyric acid (IBA) more effectively induced roots. The cutting position of stock plants influenced rooting capacity. Cutting the stock plants from the apical region enhanced root number and length in the explants. Among the different explant types, apical stem cuts with 2000 ppm IBA produced a significantly higher number of adventitious roots when grown in vermiculite and perlite (V + P) at a ratio of 1:1 at 25 °C. High-performance liquid chromatography (HPLC) analysis revealed that protocatechuic acid, gentisic acid, chlorogenic acid, biochanin A, salicylic acid, caffeic acid, glycitein, and luteolin were the most dominant phenolic compounds present in C. indicum. These results indicate that IBA treatment promoted the synthesis and accumulation of phenolic compounds in C. indicum stem cuttings at the time of root formation. The present results demonstrate that applying auxins is essential for early root initiation and higher rooting success and thus may be beneficial for vegetative C. indicum propagation.