Background and Aims Grape flavonoids impart colour and mouthfeel to wines. This work aimed to understand how genetic manipulation of the hydroxylation of flavonoids affected grape flavonoid composition and wine properties. Methods and Results We produced transgenic grapevines with decreased expression of flavonoid 3′‐hydroxylase (F3′H) and flavonoid 3′5′‐hydroxylase (F3′5′H) to investigate how this altered the composition of flavonoids in grapes and wine. Grapes from transgenic grapevines with decreased expression of F3′5′H genes had a concentration of anthocyanin and skin tannin similar to that of Shiraz Controls but had increased seed tannin and a greatly decreased proportion of trihydroxylated anthocyanin and tannin. Lines with decreased expression of F3′H had a decreased concentration of seed tannin and an increased proportion of trihydroxylated flavonoids. When expression of both F3′H and F3′5′H was decreased, concentration of anthocyanin and tannin in the grapes was decreased to 20–30% of the Shiraz Controls. Wines made from grapes with decreased expression of F3′5′H had lower wine colour, and a lower concentration of anthocyanin, tannin and phenolic substances. Conclusions In grapes, the flavonoid pathway does not effectively use monohydroxylated intermediates so F3′H and F3′5′H are required to produce dihydroxylated and trihydroxylated intermediates. The hydroxylation status of flavonoids in grapes determines grape and wine colour and tannin composition. Significance of the Study The composition as well as the total amount of anthocyanin and tannin in grapes is important for wine colour and quality. The expression of genes encoding F3′H and F3′5′H in grapes is dependent on viticultural factors including temperature, light exposure and vine water stress, providing the potential to manipulate flavonoid composition of existing cultivars in the vineyard.
Biosynthesis and metabolism of phytochemicals in aromatic and medicinal plants are vigorously affected by environmental agents. This study was undertaken to investigate the variations in the growth, nutrient status and the essential oils content and composition of pennyroyal (Mentha pulegium L.) plant exposed to different concentrations of copper (Cu; 0, 5, 25 mg kg-1 soil) and zinc (Zn; 0, 10, 50 mg kg-1 soil). The results of the plant treatment responses revealed that the highest plant height, shoot dry weight, essential oil content and yield were achieved in plants treated with Cu and Zn at 5 and 10 mg kg-1. Low Zn concentration showed a synergistic effect on the uptake of Cu, Fe, Mn and K, whereas it revealed **contrary effect on phosphorus (P) status. However, Cu in 5 mg kg-1 poses positive effect on Fe, Mn and P content in root and shoot tissues. Moreover, the addition of Cu and Zn especially at 5 and 10 mg kg-1 was the optimal level in increasing the status of K, Mn, Fe, Cu and Zn in shoot, infusion and decoction. The constituents and quality of M. pulegium essential oils in terms of its major volatile components, namely pulegone, cis-isopulegone, a-pinene, sabinene, 1,8cineol and thymol, improved significantly with Cu and Zn treatment as compared to control. From this standpoint, M. pulegium can be grown as alternative crop for mildly Cuand Zn-polluted agricultural soils without contamination of the its industrial products.
Satureja khuzistanica Jamzad has been used in pharmaceutical industry because of its interesting pharmacological and biological activities. This study was undertaken to evaluate the level of genetic diversity and differentiation of S. khuzistanica populations. For this purpose, 84 individual plants from seven populations of this species were studied using inter-simple sequence repeat (ISSR) markers. A total of 157 bands were generated by 13 ISSR primers, of which 120 (88.35%) bands were polymorphic. Nei's gene diversity and Shannon information index varied between 0.24 and 0.28 and 0.35 and 0.42, respectively. Analyses of molecular variance detected 90% of variation within populations. Structure analysis showed the highest DK at K = 4, representing the individuals into four groups. In contrast to limited distribution and wild collection, the present study showed high level of genetic diversity in natural populations.
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