Enhanced specialized metabolite, trichome density, and biosynthetic gene expression in Stevia rebaudiana (Bertoni) Bertoni plants inoculated with endophytic bacteria Enterobacter hormaechei.

Stevia rebaudiana (Bertoni) Bertoni is a plant of economic interest in the food and pharmaceutical industries due its steviol glycosides (SG), which are rich in metabolites that are 300 times sweeter than sucrose. In addition, S. rebaudiana plants contain phenolic compounds and flavonoids with antioxidant activity. Endophytic bacteria promote the growth and development and modulate the metabolism of the host plant. However, little is known regarding the role of endophytic bacteria in the growth; synthesis of SG, flavonoids and phenolic compounds; and the relationship between trichome development and specialized metabolites in S. rebaudiana, which was the subject of this study. The 12 bacteria tested did not increase the growth of S. rebaudiana plants; however, the content of SG increased with inoculation with the bacteria Enterobacter hormaechei H2A3 and E. hormaechei H5A2. The SG content in leaves paralleled an increase in the density of glandular, short, and large trichome. The image analysis of S. rebaudiana leaves showed the presence of SG, phenolic compounds, and flavonoids principally in glandular and short trichomes. The increase in the transcript levels of the KO, KAH, UGT74G1, and UGT76G1 genes was related to the SG concentration in plants of S. rebaudiana inoculated with E. hormaechei H2A3 and E. hormaechei H5A2. In conclusion, inoculation with the stimulating endophytes E. hormaechei H2A3 and E. hormaechei H5A2 increased SG synthesis, flavonoid content and flavonoid accumulation in the trichomes of S. rebaudiana plants.

Chemical analysis of callus extracts from toxic and non-toxic varieties of Jatropha curcas L.

Jatropha curcas L. belongs to Euphorbiaceae family, and it synthesizes flavonoid and diterpene compounds that have showed antioxidant, anti-inflammatory, anticancer, antiviral, antimicrobial, antifungal and insecticide activity. Seeds of this plant accumulate phorbol esters, which are tigliane type diterpenes, reported as toxic and, depending on its concentration, toxic and non-toxic varieties has been identified. The aim of this work was to characterize the chemical profile of the extracts from seeds, leaves and callus of both varieties (toxic and non-toxic) of Jatropha curcas, to verify the presence of important compounds in dedifferentiated cells and consider the possibility of using these cultures for the massive production of metabolites. Callus induction was obtained using NAA (1.5 mg L-1) and BAP (1.5 mg L-1) after 21 d for both varieties. Thin layer chromatography analysis showed differences in compounds accumulation in callus from non-toxic variety throughout the time of culture, diterpenes showed an increase along the time, in contrast with flavonoids which decreased. Based on the results obtained through microQTOF-QII spectrometer it is suggested a higher accumulation of phorbol esters, derived from 12-deoxy-16-hydroxy-phorbol (m/z 365 [M+H]+), in callus of 38 d than those of 14 d culture, from both varieties. Unlike flavonoids accumulation, the MS chromatograms analysis allowed to suggest lower accumulation of flavonoids as the culture time progresses, in callus from both varieties. The presence of six glycosylated flavonoids is also suggested in leaf and callus extracts derived from both varieties (toxic and non-toxic), including: apigenin 6-C-α-L-arabinopyranosyl-8-C-ß -D-xylopyranoside (m/z 535 [M+H]+), apigenin 4'-O-rhamnoside (m/z 417 [M+H]+), vitexin (m/z 433 [M+H]+), vitexin 4'-O-glucoside-2″-O-rhamnoside (m/z 741 [M+H]+), vicenin-2 (m/z 595 [M+H]+), and vicenin-2,6″-O-glucoside (m/z 757 [M+H]+).

Cell Culture of Bursera linanoe in a Stirred Tank Bioreactor for Production of Linalool and Linalyl Acetate.

Bursera linanoe cell suspension cultures were initiated from callus grown in Murashige and Skoog medium supplemented with naphthalene acetic acid (3.0 mg L⁻¹) and 6-benzylaminopurine (0.5 mg L⁻¹). In flasks, B. linanoe cell cultures grew over a 9 day period, reaching a maximum biomass of 11.16 g DW L⁻¹. Throughout the growth phase, cell viability was constant at 60 - 70%. In contrast, B. linanoe cells growing in a bioreactor achieved a maximum biomass of 22.26 g DW L⁻¹ (after 7 days), and cell viability was constant at 75 - 85%. Production of linalool and linalyl acetate in the bioreactor (3.02 and 2.40 mg g⁻¹ DW, respectively) was significantly greater than that achieved from cells in flask cultures (1.05 and 0.97 mg g⁻¹ DW, respectively). B. linanoe cell suspension culture has potential as an alternative method for the production of essential oils.

Jatropha curcas and assisted phytoremediation of a mine tailing with biochar and a mycorrhizal fungus.

Soil pollution is an important ecological problem worldwide. Phytoremediation is an environmental-friendly option for reducing metal pollution. A greenhouse experiment was conducted to determine the growth and physiological response, metal uptake, and the phytostabilization potential of a nontoxic Jatropha curcas L. genotype when grown in multimetal-polluted conditions. Plants were established on a mine residue (MR) amended or not amended with corn biochar (B) and inoculated or not inoculated with the mycorrhizal fungus Acaulospora sp. (arbuscular mycorrhizal fungus, AMF). J. curcas was highly capable of growing in an MR and showed no phytotoxic symptoms. After J. curcas growth (105 days), B produced high desorption of Cd and Pb from the MR; however, no increases in metal shoot concentrations were observed. Therefore, Jatropha may be useful for phytostabilization of metals in mine tailings. The use of B is recommended because improved MR chemical properties conduced to plant growth (cation-exchange capacity, organic matter content, essential nutrients, electrical conductivity, water-holding capacity) and plant growth development (higher biomass, nutritional and physiological performance). Inoculation with an AMF did not improve any plant growth or physiological plant characteristic. Only higher Zn shoot concentration was observed, but it was not phytotoxic. Future studies of B use and its long-term effect on MR remediation should be conducted under field conditions.

A propagation procedure for Cuphea aequipetala Cav. (Lythraceae) and antioxidant properties of wild and greenhouse-grown plants / Procedimiento para la propagación de Cuphea aequipetala Cav. (Lythraceae) y propiedades antioxidantes de plantas silvestres y crecidas en invernadero

Cuphea aequipetala Cav. (Lythraceae) is native to Mexico and is used in folk medicine to treat tumors. An efficient protocol for in vitro shoot proliferation and plant acclimatization of C. aequipetala was developed. Total phenolic compounds and flavonoids contents were determined in methanolic extracts of roots, stems, and leaves from wild and greenhouse-grown plants. Their antioxidant properties were compared using in vitro assays (scavenging of 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals, and reducing power in the phosphomolybdenum assay). This is the first report of a successful propagation procedure for C. aequipetala. These methods offer a viable approach for long-term in vitro conservation and proliferation of this species. C. aequipetala shoots maintained their proliferation capacity during long-term subculture (3 years). The propagated shoots can successfully acclimatize and grow to maturity, and they retain the ability to accumulate antioxidants.

Cuphea aequipetala Cav. (Lythraceae) es una planta nativa de México que se utiliza en la medicina tradicional para tratar tumores. En este trabajo se desarrolló un procedimiento para la proliferación de brotes y la aclimatización de plantas de C. aequipetala. Se determinó la concentración de compuestos fenólicos totales y de flavonoides en extractos metanólicos de raíces, tallos y hojas de plantas silvestres y crecidas en invernadero. Sus propiedades antioxidantes fueron comparadas utilizando ensayos in vitro (captura de radicales DPPH y ABTS y poder reductor por el ensayo de fosfomolibdeno). Este es el primer reporte exitoso sobre un procedimiento para la propagación de C. aequipetala. Este método ofrece una alternativa viable para la conservación a largo plazo y la proliferación de esta especie. Los brotes de C. aequipetala han mantenido su capacidad de multiplicación a largo plazo (tres años). Los brotes se convirtieron en plantas adultas aclimatadas, manteniendo su habilidad para acumular compuestos antioxidantes.

Estudio del desarrollo, calidad de planta y acumulación de pigmentos en lígulas de tagetes erecta l: expuestas a dos intensidades de luz / Study of development, quality of plant and accumulation of pigments in ligules of tagetes erecta l: exposed to two light intensities

The carotenoids are photosensitive pigments during photosynthesis. The objective of this work was to study the effect on development and accumulation of carotenoids in ligules of Tagetes erecta exposed under two different lighting ambient (with mesh and without mesh of 50 percent). The plant development was evaluated measuring the height of the plant, number of floral buds, the ligules diameter. In adition, the quantification and identification of carotenoids from ligules was done by HPLC. The results showed significant differences (p<0.05) in the height of the plant, number of floral buds and ligules diameter of T. erecta. The group grown without mesh received greater UV radiation and different temperature, that under a mesh. The first conditions lead to a reduction of the ligules diameter and total content of xanthophylls (lutein and zeaxanthin). The plastids ultrastructure in the cells of T. erecta developed with mesh showed the greatest amount of thylakoid membranes and more conspicuous starch granules.

Los carotenoides son pigmentos fotosensibles frente a un exceso de intensidad luminosa durante el proceso de fotosíntesis. El objetivo de este trabajo fue el estudio del efecto en el desarrollo de la planta y la acumulación de carotenoides por la exposición a dos diferentes intensidades lumínicas (con y sin malla de sombra al 50 por ciento). Se evaluó el desarrollo de T. erecta en cuanto a la altura de la planta, número de botones florales y el diámetro de las lígulas. Adicionalmente, en las lígulas se cuantificaron e identificaron los carotenoides por HPLC. Los resultados mostraron diferencias significativas (p<0.05) en cuanto al desarrollo de las plantas expuestas a mayor radiación UV y temperatura, presentaron reducción del diámetro de las lígulas y disminución en el contenido de Xantófilas totales ( luteína y zeaxantina) con respecto a las cultivadas con malla,. La ultraestructura de los plastidios mostró mayor cantidad de membranas tilacoidales y gránulos de almidón más conspicuos en las células de las plantas de T erecta desarrolladas con malla.