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Background Flower color is one of the main characteristics of ornamental plants. Aurones are light yellow flavonoids produced in the petals of a limited number of plant species including snapdragon (Antirrhinum majus). As a commercially-recognized species, African violet can be found in various colors except yellow. This research, aiming at changing the petals’ color of African violet from white to yellow, was conducted using the simultaneous expressions of chalcone 4’-O-glucosyltransferase (4’CGT) and aureusidin synthase (AS1) genes without the need for silencing anthocyanin biosynthesis pathway genes via both transient and stable transfer methods. Results The transient gene transfer among transgenic plants led to a clear change of petals’ color from white to light yellow. This occurs while no change was observed in non-transgenic (Wild type) petals. In total, 15 positive transgenic plants, produced via stable gene transfer, were detected. Moreover, since their flower color was yellow, both genes were present. Meanwhile, the corresponding transformation yield was determined 20-30%. The transformation, expression and integration of genes among T0 transgenic plants were verified using the PCR, qRT-PCR and Southern blotting techniques, respectively. Furthermore, the probable color change of petals’ cross-section and existence of Aureusidin 6-O-glucoside (AOG) compound were determined using a light microscope and HPLC-DAD-MSn analysis, correspondingly. Conclusions Generally, the creation of aurones biosynthesis pathway is only viable through the simultaneous expression of genes which leads to color change of African violet’s petal from white to yellow. This conclusion can lead to an effective strategy to produce yellow color in ornamental plant species.

ABSTRACT.Stevia (Stevia rebaudiana Bertoni), with great potential as a natural sweeteners source, has a high content of sweeteners, which are up to 150 times sweeter than sugar, but virtually with no calories. Stevia also suitable to be cultivated in semiarid climates and coastal areas, which are characterized by the low quality of the irrigation water. Soil salinity occupies a prominent place among the soil problems that threaten the sustainability of agriculture over a vast area in the world. Glycine betaine is an osmoprotectant, that plays an important role and accumulates rapidly in many plants during salinity or drought stress. In order to evaluation of glycine betaine amending effects on salinity stress in stevia under in vitro condition, a factorial experiment was conducted in 2015. Four NaCl levels, including 0, 50, 75 and 100 mM, along with 0, 1, 12.5, 25 and 50 mM of glycine betaine concentrations were used in Murashige and Skoog (MS) medium. The results showed that salinity levels had significant reduction effects on plant height, root length, shoot fresh weight, number of leaf, total chlorophyll, rebaudioside A and stevioside of the stevia genotype. Due to increasing of glycine betaine, levels all the traits were increased. Owing to amending effect of glycine betaine, its high concentrations made less hazarding effects of salinity on the researched traits. The highest mean value of rebaudioside A (10.62rt) and stevioside (23.38rt) determined at 50 mM of glycine betaine with 0 mM of NaCl concentration.

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Ruta graveolens, locally called sodab or sadab, is a known medicinal plant in north of Iran. The plant is a source for the production of secondary metabolites such as Glycosides, lignins, alkaloids, Coumarins, flavonoids and phenolic acids. In this work, the effect of salicylic acid on phenols and flavonoids contents of R. graveolens were investigated in the cell suspension culture. A significant enhancement in total phenolic and flavonoids contents were observed in salicylic acid treated samples. The results revealed that salicylic acid (10 mg/ml) showed as maximum as 3.14 fold enhancement in total flavonoid content (40.35 mg/g) and salicylic acid (20 mg quercetin equivalent/g of extract powder) showed as maximum as 18.33 fold improvement in total phenolic content (438.75 mg gallic acid equivalent/g of extract powder). Also in this study, salicylic acid (10 mg/ml) showed as maximum as 3.55 fold increase in DPPH radical-scavenging activity compared to control. These results suggest that the positive effect of salicylic acid on phenols and flavonoids content and DPPH scavenging activity in cell suspension culture. This effect was dose dependent.