Application of Plant Growth Regulators Modulates the Profile of Chlorogenic Acids in Cultured Bidens pilosa Cells

Fighting to thrive via plant growth regulators: Green chemical strategies for drought stress tolerance

As global climate change intensifies, the occurrence and severity of various abiotic stresses will significantly threaten plant health and productivity. Drought stress (DS) is a formidable obstacle, disrupting normal plant functions through specific morphological, physiological, biochemical, and molecular mechanisms. Understanding how plants navigate DS is paramount to mitigating its adverse effects. In response to DS, plants synthesize or accumulate various plant growth regulators (PGRs), including phytohormones, neurotransmitters, gasotransmitters, and polyamines, which present promising sustainable green chemical strategies to adapt or tolerate stress conditions. These PGRs orchestrate crucial plant structure and function adjustments, activating defense systems and modulating cellular-level responses, transcript levels, transcription factors, metabolic genes, and stress-responsive candidate proteins. However, the efficacy of these molecules in mitigating DS depends on the plant species, applied PGR dose, treatment type, duration of DS exposure, and growth stages. Thus, exploring the integrated impact of PGRs on enhancing plant fitness and DS tolerance is crucial for global food security and sustainable agriculture. This review investigates plant responses to DS, explains the potential of exogenously applied diverse PGRs, dissects the complex chemistry among PGRs, and sheds light on omics approaches for harnessing the molecular basis of DS tolerance. This updated review delivers comprehensive mechanistic insights for leveraging various PGRs to enhance overall plant fitness under DS conditions.

Hormesis management of Moringa oleifera with exogenous application of plant growth regulators under saline conditions

The study investigated the adaptability of Moringa oleifera to saline conditions, focusing on its hormesis behavior. It also examined how various plant growth regulators affected growth, physiological parameters, and bioactive compounds of moringa. In the first phase, different NaCl stress levels (0, 50, 100, 150, 200, and 250 mM) were applied. Notably, significant stimulation was observed at 100 mM stress for growth, total phenolics, total flavonoids and total chlorophyll content while 150 mM stress had a marked inhibitory effect, with survival decreasing at 200 and 250 mM NaCl levels. A 38% reduction in root attributes and shoot length, along with a 55% decrease in leaf score, was observed at 150 mM stress. Total phenolics showed a positive correlation with growth attributes. In the second phase, moringa plants grown under 50, 100, and 150 mM NaCl stress were treated with various plant growth regulators, including cytokinin (50 mg L-1), thiourea (5 mM), bezyl amino purine (BAP @50 mg L-1), salicylic acid (50 mg L-1), hydrogen peroxide (H2O2@120 μM), or ascorbic acid (50 mg L-1) to mitigate adverse effects of salinity. Cytokinin, BAP, and salicylic acid applications improved salinity tolerance, enhancing enzymatic, and non-enzymatic antioxidants, and the abundance of kaempferol, quercetin, hydroxybenzoic, and hydroxycinnamic acids. Pearson correlation and principal component analysis manifested relationships among growth parameters, antioxidant activities, flavonoids, and phenolic acids. This study provides new insights into hormesis management for moringa plants and the influence of plant growth regulators on flavonoids and phenolic acid levels in moringa leaves under saline conditions.

Farm or Lab? A Comparative Study of Oregano's Leaf and Callus Volatile Isolates Chemistry and Cytotoxicity

Oregano (Origanum vulgare, Lamiaceae plant family) is a well-known aromatic herb with great commercial value, thoroughly utilized by food and pharmaceutical industries. The present work regards the comparative assessment of in vitro propagated and commercially available oregano tissue natural products. This study includes their secondary metabolites' biosynthesis, antioxidant properties, and anticancer activities. The optimization of callus induction from derived oregano leaf explants and excessive oxidative browning was performed using various plant growth regulators, light conditions, and antioxidant compounds. The determination of oregano callus volatiles against the respective molecules in maternal herbal material was performed using gas chromatography-mass spectrometry (GC/MS) analysis. In total, the presence of twenty-seven phytochemicals was revealed in both leaf and callus extracts, from which thirteen molecules were biosynthesized in both tissues studied, seven compounds were present only in callus extracts, and seven metabolites only in leaf extracts. Carvacrol and sabinene hydrate were the prevailing volatiles in all tissues exploited, along with alkanes octacosane and triacontane and the trimethylsilyl (TMS) derivative of carvacrol that were detected in significant amounts only in callus extracts. The MTT assay was employed to assess the in vitro cytotoxic properties of oregano extracts against the epithelial human breast cancer MDA-MB-231 and the human neuroblastoma SK-N-SH cell lines. The extracts displayed concentration and time-dependent responses in cell proliferation rates.

Genome size and gas chromatography-mass spectrometry (GC-MS) analysis of field-grown and in vitro regenerated Pluchea lanceolata plants

Pluchea lanceolata is a threatened pharmacologically important plant from the family Asteraceae. It is a source of immunologically active compounds; large-scale propagation may offer compounds with medicinal benefits. Traditional propagation method is ineffective as the seeds are not viable; and root sprout propagation is a slow process and produces less numbers of plants. Plant tissue culture technique is an alternative, efficient method for increasing mass propagation and it also facilitate genetic improvement. The present study investigated a three-way regeneration system in P. lanceolata using indirect shoot regeneration (ISR), direct shoot regeneration (DSR), and somatic embryo mediated regeneration (SER). Aseptic leaf and nodal explants were inoculated on Murashige and Skoog (MS) medium amended with plant growth regulators (PGRs), 2,4-dichlorophenoxy acetic acid (2,4-D), 1-naphthalene acetic acid (NAA), and 6-benzyl amino purine (BAP) either singly or in combinations. Compact, yellowish green callus was obtained from leaf explants in 1.0 mg/l BAP (89.10%) added medium; ISR percentage was high, i.e., 69.33% in 2.0 mg/l BAP + 0.5 mg/l NAA enriched MS with 4.02 mean number of shoots per callus mass. Highest DSR frequency (67.15%) with an average of 5.62 shoot numbers per explant was noted in 0.5 mg/l BAP added MS medium. Somatic embryos were produced in 1.0 mg/l NAA fortified medium with 4.1 mean numbers of somatic embryos per culture. On BAP (1.0 mg/l) + 0.5 mg/l gibberellic acid (GA₃) amended medium, improved somatic embryo germination frequency (68.14%) was noted showing 12.18 mean numbers of shoots per culture. Histological and scanning electron microscopic (SEM) observation revealed different stages of embryos, confirming somatic embryogenesis in P. lanceolata. Best rooting frequency (83.95%) of in vitro raised shootlets was obtained in 1.0 mg/l IBA supplemented half MS medium with a maximum of 7.83 roots per shoot. The regenerated plantlets were transferred to the field with 87% survival rate. The 2C genome size of ISR, DSR, and SER plants was measured and noted to be 2.24, 2.25, and 2.22 pg respectively, which are similar to field-grown mother plant (2C = 2.26 pg). Oxidative and physiological events suggested upregulation of enzymatic activities in tissue culture regenerated plants compared to mother plants, so were photosynthetic pigments. Implementation of gas chromatography-mass spectrometry (GC-MS) technique on in vivo and in vitro raised plants revealed the presence of diverse phyto-chemicals. The yields of alpha amyrin and lupeol (medicinally important triterpenoids) were quantified using high-performance thin-layer chromatography (HPTLC) method and enhanced level of alpha amyrin (2.129 µg g^-1 dry wt) and lupeol (1.232 µg g^-1 dry wt) was noted in in vitro grown leaf tissues, suggesting in vitro conditions act as a potential trigger for augmenting secondary metabolite synthesis. The present protocol represents a reliable mass propagation technique in producing true-to-type plants of P. lanceolata, conserving 2C DNA and ploidy successfully without affecting genetic homogeneity.

Plant Tissue Culture and Secondary Metabolites Production

Plants have developed a complex biochemical system for interacting and coping with dynamic environmental challenges throughout their whole life [...].

Metabolomic Profiling, Antioxidant and Antimicrobial Activity of Bidens pilosa

Bidens pilosa L. (fam. Asteraceae) is an annual herb used globally in phytotherapy and each plant material or the whole plant have been declared to be effective. Therefore, the aim of the present study was to conduct metabolomic profiling of different plant materials, including the quali-quantitative composition of phenolic compounds. The intrinsic scavenging/reducing properties and antimicrobial effects of the extracts were assayed against numerous bacterial, Candida and dermatophytes species, whereas docking runs were conducted for tentatively unravelling the mechanism of action underlying antimicrobial effects. Oligosaccharide, disaccharide and fatty acids were present at higher concentrations in root rather than in the other plant parts. Monoglycerides were more abundant in stem than in the other plant parts, whereas peptide and diterpenoid were prominent in leaf and root, respectively. By contrast, amino acids showed very different distribution patterns in the four plant parts. Regarding the phenolic composition, appreciable levels of caftaric acid were found in most of the analyzed methanol extracts, that were also particularly efficacious as antiradical and anti-mycotic agents against C. albicans and dermatophytes. The docking experiments also showed a micromolar affinity of caftaric acid towards the lanosterol 14α-demethylase, deeply involved in fungal metabolism. In conclusion, the present study corroborates the B. pilosa as a phytotherapy remedy against infectious disease.