Growth Kinetics, Metabolites Production and Expression Profiling of Picrosides Biosynthetic Pathway Genes in Friable Callus Culture of Picrorhiza kurroa Royle ex Benth

Functional trait correlation network and proteomic analysis reveal multifactorial adaptation mechanisms to a climatic gradient associated with high altitude in the Himalayan region

Globally occurring changes in environmental conditions necessitate extending our knowledge of the system-level mechanisms underlying plant adaptation to multifactorial stress conditions or stress combinations. This is crucial for designing new strategies to maintain plant performance under simultaneous abiotic pressure. Here, we conducted our study at Rohtang Pass and sampled Picrorhiza kurroa leaves along high-altitude gradient (3400, 3800 and 4100 meters above sea level) in the western Himalayas. The results showed the functional traits associated with morpho-anatomical structures and eco-physiological performances are highly variable. The air temperature and relative humidity represent dominant environmental factors among others that significantly regulate plant's physiological performance by adjusting the functional traits in altitude-specific manner. A trait coordination network is developed among significantly altered plant functional traits, which reveals high-altitude associated trait-based adaptation. Moreover, it reveals leaf area shows the highest degree, while photochemical quenching reflects the weighted degree of centrality in the network. Proteomic analysis reveals various stress-responsive proteins, including antioxidants were accumulated to deal with combined stress factors. Furthermore, a high-altitudinal protein interaction network unravels key players of alpine plant adaptation processes. Altogether, these systems demonstrate a complex molecular interaction web extending the current knowledge of high-altitudinal alpine plant adaptation, particularly in an endangered medicinal herb, P. kurroa.

Endomicrobiome of in vitro and natural plants deciphering the endophytes-associated secondary metabolite biosynthesis in Picrorhiza kurrooa, a Himalayan medicinal herb

IMPORTANCE

Picrorhiza kurrooa is a major source of picrosides, potent hepatoprotective molecules. Due to the ever-increasing demands, overexploitation has caused an extensive decline in its population in the wild and placed it in the endangered plants' category. At present plant in-vitro systems are widely used for the sustainable generation of P. kurrooa plants, and also for the conservation of other commercially important, rare, endangered, and threatened plant species. Furthermore, the in-vitro-generated plants had reduced content of therapeutic secondary metabolites compared to their wild counterparts, and the reason behind, not well-explored. Here, we revealed the loss of plant-associated endophytic communities during in-vitro propagation of P. kurrooa plants which also correlated to in-planta secondary metabolite biosynthesis. Therefore, this study emphasized to consider the essential role of plant-associated endophytic communities in in-vitro practices which may be the possible reason for reduced secondary metabolites in in-vitro plants.

Cambial meristematic cell culture: a sustainable technology toward in vitro specialized metabolites production

Cambial meristematic cells (CMCs) culture has received a fair share of scientific and industrial attention among the trending topics of plant cell culture, especially their potential toward secondary metabolites production. However, the conventional plant cell culture is often not commercially feasible because of difficulties associated with culture dedifferentiated cells. Several reports have been published to culture CMCs and bypass the dedifferentiation process in plant cell culture. Numerous mitochondria, multiple vacuoles, genetic stability, self-renewal, higher biomass, and stable metabolites accumulation are the characteristics features of CMCs compared with dedifferentiated cells (DDCs) culture. The CMCs culture has a broader application to produce large-scale natural compounds for: pharmaceuticals, food, and cosmetic industries. Cutting-edge progress in plant cellular and molecular biology has allowed unprecedented insights into cambial stem cell culture and its fundamental processes. Therefore, regarding sustainability and natural compound production, cambial cell culture ranks among the most vital biotechnological interventions for industrial and economic perspectives. This review highlights the recent advances in plant stem cell culture and understands the cambial cells induction and culture mechanisms that affect the growth and natural compounds production.

Enhanced Production of Phenylethanoids Mediated Through Synergistic Approach of Precursor Feeding and Light Regime in Cell Suspension Culture of Rhodiola imbricata (Edgew.)

Precursor feeding is a potential strategy for increasing specialized metabolite production in plant cell culture systems. In the present study, cell suspension cultures were developed and subsequently evaluated for precursor feeding investigations. Cell suspension cultures were established in Murashige and Skoog (MS) medium containing 0.5 mg/L thidiazuron (TDZ) + 1 mg/L α-naphthalene acetic acid (NAA). The growth biomass and metabolite pattern were analyzed to identify specific culture days required for prolific biomass production. The maximum cell dry weight (DW) was observed in leaf cell suspension (1.22 g/100 mL) and root cell suspension culture (1.12 g/100 mL) on day 21. Afterward, the effect of precursor concentrations (tyrosol; 0.5, 1, 2, and 3 mM) along with two light regimes, photoperiod (16L/8D h, 70 µmol/m²/s) and dark (24 h), was evaluated for cell growth and metabolite accumulation. The results revealed that leaf cell suspension treated with 3 mM tyrosol concentration detected maximum salidroside content (26.05 mg/g DW) on day 15, incubated under photoperiod (16L/8D h) condition. Similarly, under photoperiod (16L/8D h), root cell suspension treated with 3 mM tyrosol produced maximum salidroside content (26.62 mg/g DW) on day 12. Moreover, the total phenolics content increased significantly (44.21 mg/g DW) on day 12 in 3 mM tyrosol treatment under photoperiod (16L/8D h). However, precursor concentrations did not influence the total flavonoids content. The present investigation suggests that the immediate pathway precursor, tyrosol, has a strong effect on enhanced production of salidroside, irrespective of explant type and light regimes.