Plant morphology, physiological characteristics, accumulation of secondary metabolites and antioxidant activities of Prunella vulgaris L. under UV solar exclusion

BACKGROUND: Prunella vulgaris L. has been an important medicinal plant for the treatment of thyroid gland malfunction and mastitis in China for over 2000 years. There is an urgent need to select effective wavelengths for greenhouse cultivation of P. vulgaris as light is a very important factor in P. vulgaris growth. Here, we described the effects of natural light (control) and UV solar exclusion on the morphological and physiological traits, secondary metabolites contents and antioxidant activities of P. vulgaris. RESULTS: The results showed that UV solar exclusion resulted in remarkable alterations to morphological and biomass traits; significantly reduced the chlorophyll a, chlorophyll b and total chlorophyll contents; significantly enhanced the ratio of chlorophyll a to b; and significantly increased the carotenoid and anthocyanin contents in P. vulgaris. UV solar exclusion significantly increased the catalase (CAT) and peroxidase (POD) activities, increased superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities and slightly decreased the glutathione (GSH) content. UV solar exclusion significantly increased the soluble sugar and H2O2 contents and increased the soluble protein content but significantly decreased the proline content and slightly decreased the MDA content. The secondary metabolite contents (total phenolics, rosmarinic acid, caffeic acid, hyperoside, ursolic acid and oleanolic acid) and in vitro antioxidative properties (DPPH· and ABTS·+scavenging activities) were significantly increased in P. vulgaris spicas under UV solar exclusion. Additionally, the total polysaccharide and total flavonoids contents were slightly increased by UV solar exclusion. The salviaflaside content was significantly reduced by UV solar exclusion. CONCLUSION: Our study demonstrated that P. vulgaris activates several antioxidant defence systems against oxidative damage caused by UV solar exclusion.

Expression of RsMYB1 in chrysanthemum regulates key anthocyanin biosynthetic genes

Background Several MYB genes belonging to R2R3 MYB transcription factors have been used in several plant species to enhance anthocyanin production, and have shown various expression or regulation patterns. This study focused on the effect of ectopic expression of an RsMYB1 isolated from radish (Raphanus sativa) on chrysanthemum cv. ‘Shinma'. Results The RT-PCR results confirmed that RsMYB1 regulated the expression of three key biosynthetic genes (CmF3H, CmDFR, and CmANS) that are responsible for anthocyanin production in transgenic chrysanthemum, but were not detected in the non-transgenic line. In all transgenic plants, higher expression levels of key biosynthetic genes were observed in flowers than in leaves. However, the presence of RsMYB1 in chrysanthemum did not affect any morphological characteristics, such as plant height, leaf shape or size, and number of flowers. Furthermore, no anthocyanin accumulation was visually observed in the leaves and floral tissue of any of the transgenic lines, which was further confirmed by anthocyanin content estimation. Conclusion To our knowledge, this is the first time the role of an MYB transcription factor in anthocyanin production has been investigated in chrysanthemum.

Biosynthesis of flavonoids in achenes of Fragaria chiloensis ssp. chiloensis / Biosintesis de flavonoides en aquenios de Fragaria chiloensis ssp. chiloensis

Fragaria chiloensis ssp. chiloensis has two native botanical forms. Fruits from both botanical forms, Fragaria chiloensis ssp. chiloensis f. chiloensis (native white strawberry) and f. patagonica (native red strawberry), were collected from Bio-Bio Region, and a comparative study in the biosynthesis and pigment accumulation was performed from achens. The fruit was classified in four different developmental and ripening stages in order to establish the differences in the transcriptional profile of structural genes and the chemical compounds. A differential expression of those genes involved in the biosynthesis (phenylpropanoid and flavonoids) of anthocianins was found. The differential expression of genes was concomitant with the increase in the level of cyanidin 3-glucoside (C3G) along the fruit development for both botanical forms. On the contrary, undetectable level of cyanidin 3-glucoside (P3G) was observed in the f. chiloensis. Albeit, P3G increase rapidly from the development stage 2, reaching the maximum value at stage 4 in Fragaria chiloensis ssp. chiloensis f. patagonica.

Fragaria chiloensis ssp. chiloensis presenta dos formas botánicas nativas. Los frutos de ambas formas botánicas, Fragaria chiloensis ssp. chiloensis f. chiloensis (frutilla nativa blanca) y f. patagonica (frutilla nativa roja), fueron colectadas en la región del Bio-Bio, realizándose un estudio comparativo en la biosíntesis y acumulación de la pigmentación en aquenios. Para ello, el fruto fue clasificado en cuatro distintos estadios de desarrollo y maduración a fin de establecer las diferencias en los perfiles transcripcionales de genes estructurales y de compuestos químicos. Se determinó una expresión diferencial de los genes responsables de la formación de antocianinas, concomitante con un incremento en los niveles de cianidina 3-glucósido (C3G) en tanto avanza el desarrollo del fruto en ambas formas botánicas. Por el contrario, se observó niveles indetectables de pelargonidina 3-glucósido (P3G) en f. chiloensis, lo cual contrasta con lo observado en f. patagonica, donde P3G se incrementa rápidamente a partir del estadio 2, alcanzando un máximo valor en estadio 4.

Effect of sucrose and methyl jasmonate on biomass and anthocyanin production in cell suspension culture of Melastoma malabathricum (Melastomaceae)

Melastoma malabathricum, belongs to the Melastomaceae family, is an important medicinal plant widely distributed from Madagascar to Australia, that is used in traditional remedies for the treatment of variousailments. Besides its medicinal properties, it has been identified as a potential source of anthocyanin production.The present study was carried out to investigate the effect of sucrose and methyl jasmonate and feeding time oncell biomass yield and anthocyanin production in cell suspension culture of M. malabathricum. Addition of differentconcentrations of sucrose into the cell culture of M. malabathricum influenced cell biomass and pigment accumulation. The addition of methyl jasmonate was found to have no effect on cell biomass but the presence of higher amount (12.5-50mg/L) had caused a reduction in anthocyanin production and accumulation. MS medium supplemented with 30g/L sucrose and 3.5 mg/L of MeJA added on cero day and 3rd day produced high fresh cell mass at the end of nine days of culture but did not support the production of anthocyanins. However, cells cultured in the medium supplemented with 45g/L sucrose without MeJA showed the highest pigment content (0.69±0.22Cv/g-FCM). The cells cultured in MS medium supplemented with 30 g/L sucrose with 3.5mg/L MeJA added on the 3rd and 6th day of culture, showed the lowest pigment content (0.37-0.40Cv/g-FCM). This study indicated that MeJA was not necessary but sucrose was needed for the enhancement of cell growth and anthocyanin production in M. malabathricum cell cultures. Rev. Biol. Trop. 59 (2): 597-606. Epub 2011 June 01.

elastoma malabathricum pertenece a la familia de las melastomáceas, es una planta medicinal importante ampliamente distribuida desde Madagascar hasta Australia, que se utiliza en remedios tradicionales para el tratamiento de diversas dolencias. Además de sus propiedades medicinales, se ha identificado como una fuente potencial de producción de antocianinas. En esta investigación se estudió el efecto de la sucrosa, el metil jasmonato y el tiempo de ingestión en la producción de biomasa de las células y la producción de antocianinas, en el cultivo de células en suspensión de M. malabathricum. La adición de diferentes concentraciones de sucrosa al cultivo de células de M. malabathricum influencia la biomasa de las células y la acumulación de pigmento. La adición de metil jasmonato no tuvo ningún efecto sobre la biomasa celular, pero la presencia de una cantidad más alta (12.5-50mg/L) causó una reducción en la producción y acumulación de antocianinas. El medio MS complementado con sucrosa 30g/L y 3.5mg/L de MeJA en el día cero y el tercer día produjo una gran masa de células frescas al final de los nueve días de cultivo pero no se pudo mantener la producción de antocianinas. Sin embargo, las células cultivadas en el medio complementado con 45g/L de sucrosa sin MeJA mostró el mayor contenido de pigmento (0.69±0.22cv/g-fcm). Las células cultivadas en el medio MS complementado con 30 g/L de sucrosa y con 3.5 mg/l MeJA en el tercer y sexto día de cultivo, mostró el menor contenido de pigmentos (0.37-0.40cv/g-fcm). Este estudio indicó que MeJA no era necesario pero la sucrosa sí se necesitaba para mejorar el crecimiento celular y la producción de antocianinas en cultivos de células de M. malabathricum.

Effects of abiotic stress on biomass and anthocyanin production in cell cultures of Melastoma malabathricum

Plant cell cultures could be used as an important tool for biochemical production, ranging from natural coloring (pigments) to pharmaceutical products. Anthocyanins are becoming a very important alternative to synthetic dyes because of increased public concern over the safety of artificial food coloring agents. Several factors are responsible for the production of anthocynin in cell cultures. In the present study, we investigate the effects of different environmental factors, such as light intensity, irradiance (continuous irradiance or continuous darkness), temperature and medium pH on cell biomass yield and anthocyanin production in cultures of Melastoma malabathricum. Moderate light intensity (301 - 600 lux) induced higher accumulation of anthocyanins in the cells. The cultures exposed to 10-d continuous darkness showed the lowest pigment content, while the cultures exposed to 10-d continuous irradiance showed the highest pigment content. The cell cultures incubated at a lower temperature range (20 ± 2 ºC) grew better and had higher pigment content than those grown at 26 ± 2ºC and 29 ± 2ºC. Different medium pH did not affect the yield of cell biomass but anthocyanin accumulation was highest at pH 5.25 - 6.25.