High production of flavonols and anthocyanins in Eruca sativa (Mill) Thell plants at high artificial LED light intensities.

Eruca sativa (arugula) is a food crop containing valuable bioactive flavonoids. Plants growing with monochrome light-emitting diodes (LED) and "binary" light sources, including red/blue (RB), were tested using HPLC-DAD-ESI-MS/MS. Most artificial lighting options with a high intensity of 1000 µmol m-2s-1 (except for warm white light) resulted in an almost 20-fold increase in flavonol productivity. Monochromatic sources had no advantage over white light in terms of increasing anthocyanin productivity. However, RB light increased the anthocyanin content and productivity of E. sativa plants by more than ten times compared to white light. Plant growth on monochromatic and binary sources at high intensities was comparable to that on white light. Measurement of the content of chlorophyll and its degradation product, phyllobilins, showed that plants are not under stressful conditions. Overall, our data show that a significant increase in flavonoid content can be achieved without a loss of arugula plant biomass.

Isoflavonoid biosynthesis in cultivated and wild soybeans grown in the field under adverse climate conditions.

The cultivation of soybean plants is one of the most important crop production sectors in the world. Isoflavones are an important defence against pathogens in soybeans. The aim of the present study was to analyse isoflavone biosynthesis in wild and cultivated soybeans grown in the field conditions in an unfavourable climate. We analysed by LCMS-IT-TOF the composition and content of isoflavonoids, productivity and fungal disease resistance of wild and cultivated. The Hefeng25 and Sfera varieties have the highest isoflavonoid content and fungal tolerance. We have shown a 3-fold increase of total isoflavonoids in Sfera, comparing with wild type, and 4- and 7-fold increases of total isoflavone aglycones in Hefeng25 and Sfera, respectively. Accordingly, the expression of genes encoding enzymes of the isoflavonoid biosynthetic pathway was also maximal in these cultivars. Thus, biosynthetic status is an important indicator of soybean productivity and resistance to pathogens in adverse climates.

Increase in isoflavonoid content in Glycine max cells transformed by the constitutively active Ca2+ independent form of the AtCPK1 gene.

Calcium-dependent protein kinases (CDPKs) represent a class within a multigene family that plays an important role in biotic and abiotic plant stress responses and is involved in the regulation of secondary metabolite biosynthesis. Our previous study showed that overexpression of the mutant constitutively active Ca2+ independent form of the AtCPK1 gene (AtCPK1-Ca) significantly increased the biosynthesis of anthraquinones and stilbenes in Rubia cordifolia L. and Vitis amurensis Rupr. transgenic cell cultures, respectively. Here, we have established transgenic calli of soybean plants Glycine max (L.) Merr. that express the AtCPK1-Ca gene. Heterologous expression of the AtCPK1-Ca gene provoked a 5.2-fold increase in total isoflavone production up to 208.09 mg/L, along with an increase in isoflavone aglycones production up to 6.60 mg/L, which is 3-fold greater than that of the control culture. The production of prenylated isoflavones significantly increased, reaching 3.78 mg/L, 13-fold higher than in the control culture. The expression levels of 4-coumarate:CoA ligases, isoflavone synthases, 2-hydroxyisoflavanone dehydratase, isoflavone dimethylallyltransferase, and coumestrol 4-dimethylallyltransferase genes in transgenic cell cultures significantly increased. Thus, heterologous expression of the AtCPK1-Ca gene can be used to bioengineer plant cell cultures that produce isoflavonoids.