Marta Libik-Konieczny

Medicinal plants remain one of the most important sources of therapeutically relevant compounds for pharmaceutical, nutraceutical, and biotechnological applications. However, the naturally low abundance of many specialized metabolites, considerable phytochemical variability, and increasing environmental pressures continue to limit the sustainable exploitation of plant-derived bioactive compounds. This review summarizes current strategies aimed at identifying, understanding, and enhancing the production of medicinally valuable metabolites while highlighting both biological limitations and emerging technological opportunities. Particular attention is given to the interplay between primary and secondary metabolism and its role in determining biosynthetic efficiency in both natural and engineered systems. Beyond discussing established methodologies, this review adopts a broader perspective by incorporating less frequently addressed aspects, including the influence of climate change on metabolite production, the application of bioinformatics-supported approaches to improve bioprospecting efficiency, and the growing role of nanoparticles as elicitors in plant biotechnology. These topics are considered alongside advances in tissue culture technologies, metabolic engineering, molecular approaches, and systems-level analyses aimed at improving metabolite yield and production stability. Current evidence suggests that no single technological framework is sufficient to address the complexity of medicinal plant metabolism. Hence, rather than presenting individual technologies as isolated solutions to specific biosynthetic bottlenecks, this review emphasizes that medicinal plant metabolism should be considered a highly interconnected system in which environmental, molecular, and physiological factors collectively determine production outcomes.

Kwas pipekolowy jest niebiałkowym aminokwasem, występującym powszechnie w świecie roślin, zwierząt i mikroorganizmów. Biosynteza tego związku może przebiegać na drodze dwóch szlaków chemicznych, w których kluczowymi produktami pośrednimi są piperydyno-6-karboksylan oraz piperydyno-2-karboksylan, skąd pochodzą skrócone nazwy szlaków P6C oraz P2C. Poza naturalnym występowaniem, kwas pipekolowy może być produkowany na dużą skalę na potrzeby przemysłu farmaceutycznego czy chemicznego poprzez indukcję jego biosyntezy w organizmach bakteryjnych. Związek ten jest bowiem istotnym prekursorem substancji wykorzystywanych w medycynie jako immunosupresanty czy miejscowe anestetyki. Kwas pipekolowy pełni także ważną rolę w systemicznej odporności nabytej roślin, zwanej SAR (ang. Systemic acquired resistance), podczas patogenezy infekcji. W niniejszej pracy zebrano dostępne informacje dotyczące, sposobu syntezy i degradacji tego ważnego aminokwasu w organizmach żywych, a także przybliżono funkcje jakie pełni w naturze oraz możliwości wykorzystania tego związku na potrzeby medycyny.

Editorial: Plant-microbe interactions and their role in salinity tolerance

Haldane’s rule (HR, impairment of fertility and/or viability of interracial hybrids) seems to be one of few generalizations in evolutionary biology. The validity of HR has been confirmed in animals, and more recently in some dioecious plants (Silene and Rumex). Dioecious Rumex hastatulus has two races differing in the sex chromosome system: Texas (T) and North Carolina (NC), and T × NC males showed both reduced pollen fertility and rarity—two classical symptoms of Haldane’s rule (HR). The reduced fertility of these plants has a simple mechanistic explanation, but the reason for their rarity was not elucidated. Here, we measured selected physiological parameters related to the antioxidant defense system in parental races and reciprocal hybrids of R. hastatulus. We showed that the X-autosome configurations, as well as asymmetries associated with Y chromosomes and cytoplasm, could modulate this system in hybrids. The levels and quantitative patterns of the measured parameters distinguish the T × NC hybrid from the other analyzed forms. Our observations suggest that the rarity of T × NC males is caused postzygotically and most likely related to the higher level of oxidative stress induced by the chromosomal incompatibilities. It is the first report on the physiological aspects of HR in plants.

Steviol glycosides (SvGls) are plant secondary metabolites belonging to a class of chemical compounds known as diterpenes. SvGls have been discovered only in a few plant species, including in the leaves of Stevia rebaudiana Bertoni. Over the last few decades, SvGls have been extensively researched for their extraordinary sweetness. As a result, the nutritional and pharmacological benefits of these secondary metabolites have grown increasingly apparent. In the near future, SvGls may become a basic, low-calorie, and potent sweetener in the growing natural foods market, and a natural anti-diabetic remedy, a highly competitive alternative to commercially available synthetic drugs. Commercial cultivation of stevia plants and the technologies of SvGls extraction and purification from plant material have already been introduced in many countries. However, new conventional and biotechnological solutions are still being sought to increase the level of SvGls in plants. Since many aspects related to the biochemistry and metabolism of SvGls in vivo, as well as their relationship to the overall physiology of S. rebaudiana are not yet understood, there is also a great need for in-depth scientific research on this topic. Such research may have positive impact on optimization of the profile and SvGls concentration in plants and thus lead to obtaining desired yield. This research summarizes the latest approaches and developments in SvGls production. Key points: • Steviol glycosides (SvGls) are found in nature in S. rebaudiana plants. • They exhibit nutraceutical properties. • This review provides an insight on different approaches to produce SvGls. • The areas of research that still need to be explored have been identified.

The ability to synthesize particular steviol glycosides (SvGls) was studied in Stevia rebaudiana Bertoni hairy roots (HR) grown in the light or in the dark under the influence of different osmotic active compounds. Manipulation of culture conditions led to changes in the morphology and growth rate of HR, as well as to an increase in oxidative stress manifested as an enhancement in endogenous hydrogen peroxide concentration in the cultured samples. The highest level of H₂O₂ was noted in HR cultured under light or in the medium with the highest osmotic potential. This correlated with the highest increase in the expression level of ent-kaurenoic acid hydroxylase, responsible for the redirection of metabolic route to SvGls biosynthesis pathway. An analysis of transcriptional activity of some UDPglucosyltransferase (UGT85c2, UGT74g1, UGT76g1) revealed that all of them were upregulated due to the manipulation of culture conditions. However, the level of their upregulation depended on the type of stress factor used in our experiment. Analysis of SvGls content revealed that HR grown under all applied conditions were able to synthesize and accumulate several SvGls but their concentration differed between the samples across the different conditions. The level of rebaudioside A concentration exceeded the content of stevioside in HR in all tested conditions. Concomitantly, the presence of some minor SvGls, such as steviolbioside and rebaudioside F, was confirmed only in HR cultured in the lowest osmotic potential of the medium while rebaudioside D was also detected in the samples cultured in the media supplemented with NaCl or PEG. Key Points ● Several steviol glycosides are synthesized in hairy roots of S. rebaudiana. ● Light or osmotic factors cause enhancement in oxidative stress level in hairy roots. ● It correlates with a significant increase in the level of KAH expression. ● UGTs expression and steviol glycosides content depends on culture conditions.