INFORM October 2025

inform October 2025, Vol. 36 (9) • 33

and fungi) using CYP76AD1 , DOD1 , and cDOPA5GT or B5GT, corresponding to the enzymatic steps mentioned above. For the red-violet color formation through heterologous expression of the pathway genes in non-betalainic plants, a simplified reporter gene called RUBY has been developed recently. Without any systems engineering, expression of RUBY in non-betalainic plants resulted in accumulation of up to 203 mg betalains/100 g fresh weight of peanut leaves. In yeasts, Saccharomyces cerevisiae and Yarrowia lipolytica, and fungus Fusarium venenatum, betanin production has been achieved through overexpression of the pathway genes, with productivity reaching up to 0.62 mg/L/h, 26 mg/L/h, and 26.4 mg/L/h from d-glucose as carbon source, respectively, after considerable systems engineering and gene copy number aug mentation. This review critically analyzes recent biotechnolog ical production of betalains to highlight the advancements and strategies for improvement in the technology. Also, emerging applications of betalain biosynthetic gene products or betalains as biosensors, fluorescent probes, meat analog colors, and others are discussed to strengthen the need for systems engineering and process optimization for large-scale industrial production of these pigments. Red-leaf hazelnut: Biotechnological approaches for secondary metabolite production and potential biological activities Lupo, M., et al. , Plant Physiology and Biochemistry , 229, Part A, 110329, 2025. https://doi.org/10.1016/j.plaphy.2025.110329 This study provides the first evidence of anthocyanin and secondary metabolite production in the red-leaf hazelnut culti var Corylus avellana L. cv. Fructo Rubro. Phenols, flavonoids and

anthocyanins were analyzed in both field-grown leaves and in vitro callus cultures, assessing the effects of light quality, physical and chemical elicitors. Field-grown Fructo Rubro leaves exhib ited higher content of anthocyanins early in the vegetative sea son, which then decreased as the chlorophyll content increased. In vitro cultures were successfully established from leaf explants, with callus cultures demonstrating significant anthocyanin biosynthesis under controlled conditions. To enhance metabolite production in callus culture, different LED spectra were used for physical elicitation, with NS1 (a spectrum close to natural sunlight) and G2 (rich in red and far-red light) being the most effective in stimulating anthocyanin biosynthesis. Chemical elicitation with jasmonic and abscisic acid, tested in combination with LED treat ments, had a limited impact on anthocyanins. The HPLC analy sis identified delphinidin 3 -O- glucoside, cyanidin 3 -O- glucoside, and cyanidin 3 -O- rutinoside as the predominant anthocyanins; furthermore, elicitation of callus culture demonstrated that the levels of these anthocyanins are comparable to or even exceed ing those found in field-grown leaves. Additionally, polyphenols and flavonoids showed distinct accumulation patterns influenced by both physical and chemical elicitation. Furthermore, the effect of the extracts on the cell viability of human breast cells, both cancerous and non-cancerous, was preliminarily tested using the MTT assay. Extracts from field-grown leaves exhibited very low IC 50 values, indicating a strong ability to reduce the viability of cancerous cells. Notably, physical elicitation with LED light allowed in production of callus-derived extracts with comparable or even enhanced effects. Relevant, none of the extracts showed significant toxicity toward non-cancerous cells, highlighting their promising selectivity and potential safety for therapeutic applications. These findings highlight the potential of LED enhanced in vitro cultures as a scalable and sustainable alternative for anthocyanin production, providing a controlled platform for optimizing bioactive compound synthesis. This research supports