Effect of Agrobacterium rhizogenes and elicitation on the asiaticoside production in cell cultures of Centella asiatica

Polyacetylenes from the adventitious roots of Centella asiatica with glucose uptake stimulatory activity

Centella asiatica (L.) Urban is an herbaceous perennial plant of the Apiaceae family that has diverse medicinal uses. Its active components are saponin, phenolics, and polyacetylenes. Plant cell cultures have been exploited for the efficient production of metabolites with pharmacological activity. In this work, we prepared adventitious root cultures of C. asiatica and analyzed their content and biological activity. Adventitious root extracts were found to increase glucose uptake by differentiated L6 skeletal muscle cells and to be more efficient than the extract of whole plants. Chromatographic fractionation of the extracts from adventitious roots of C. asiatica led to the isolation of two known polyacetylenes, araliadiol (1) and 8-acetoxy-1,9-pentadecadiene-4,6-diyn-3-ol (2), in addition to a new polyacetylene, which we have named centellidiol (3). All the three polyacetylenes stimulated glucose uptake in a dose-dependent manner. The methanol extract of adventitious roots contained 0.53% and 0.82% of compounds 1 and 2, respectively, which are values that were 15 and 21 times higher that are found in mother plants. We therefore suggest that the high content of these polyacetylenes contributes to the high efficacy of C. asiatica adventitious root cultures. Overall, adventitious root cultures of C. asiatica can be part of a secure supply of effective ingredients including polyacetylenes.

Using machine learning to link the influence of transferred Agrobacterium rhizogenes genes to the hormone profile and morphological traits in Centella asiatica hairy roots

Hairy roots are made after the integration of a small set of genes from Agrobacterium rhizogenes in the plant genome. Little is known about how this small set is linked to their hormone profile, which determines development, morphology, and levels of secondary metabolite production. We used C. asiatica hairy root line cultures to determine the putative links between the rol and aux gene expressions with morphological traits, a hormone profile, and centelloside production. The results obtained after 14 and 28 days of culture were processed via multivariate analysis and machine-learning processes such as random forest, supported vector machines, linear discriminant analysis, and neural networks. This allowed us to obtain models capable of discriminating highly productive root lines from their levels of genetic expression (rol and aux genes) or from their hormone profile. In total, 12 hormones were evaluated, resulting in 10 being satisfactorily detected. Within this set of hormones, abscisic acid (ABA) and cytokinin isopentenyl adenosine (IPA) were found to be critical in defining the morphological traits and centelloside content. The results showed that IPA brings more benefits to the biotechnological platform. Additionally, we determined the degree of influence of each of the evaluated genes on the individual hormone profile, finding that aux1 has a significant influence on the IPA profile, while the rol genes are closely linked to the ABA profile. Finally, we effectively verified the gene influence on these two specific hormones through feeding experiments that aimed to reverse the effect on root morphology and centelloside content.

Development of Hairy Root Cultures for Biomass and Triterpenoid Production in Centella asiatica

Centella asiatica (Apiaceae) is a tropical/subtropical medicinal plant, which contains a variety of triterpenoids, including madecassoside, asiaticoside, madecassic acid, and asiatic acid. In this study, we tested the efficiency of hairy root (HR) induction in C. asiatica from leaf and petiole explants. Leaves and petioles collected from C. asiatica plants were suspended in agro-stock for 30 min and co-cultured with Agrobacterium rhizogenes for 3 days to induce HR formation. The transformation efficiency of leaf and petiole explants was approximately 27% and 12%, respectively. A total of 36 HR lines were identified by PCR-based amplification of rol genes, and eight of these lines were selected for further analysis. Among all eight HR lines, the petiole-derived lines HP4 and HP2 displayed the highest growth index (37.8) and the highest triterpenoids concentration (46.57 mg∙g⁻¹), respectively. Although triterpenoid concentration was >2-fold higher in leaves than in petioles of C. asiatica plants, the accumulation of triterpenoids in petiole-derived HR cultures was 1.4-fold higher than that in leaf-derived HR cultures. Additionally, in both leaf- and petiole-derived HR cultures, terpenoid production was higher in HRs than in adventitious roots. These results demonstrate that the triterpenoid content in the explant does not affect the triterpenoid content in the resultant HRs. The HR culture of C. asiatica could be scaled up to enable the mass production of triterpenoids in bioreactors for the pharmaceutical and cosmetic industries.

Raise up of Scopolamine in Hairy Roots Via Agrobacterium rhizogenes ATCC15834 as Compared with Untransformed Roots in Atropa komarovii

Atropa komarovii generates tropane alkaloids and three other compounds such as hyoscyamine. Racemate atropine and scopolamine (hyoscine) are the main alkaloids with anticholinergic, antispasmodic, and sedative agents. A proficient convention has been reported for the formation of transgenic Atropa komarovii by the use of Agrobacterium rhizogenes. Root culture, by utilizing leaves explants was contaminated by Agrobacterium rhizogenes ATCC 15834, a strain with the paired vector. The hairy roots after contamination for three weeks were specifically shaped from the cut edges of the leaves. The PCR intensification demonstrated that rol B genes of Ri plasmid of Agrobacterium rhizogenes were coordinated and communicated into the genome of the changed hairy roots. Examination of HPLC revealed that hairy roots can produce scopolamine and hyoscyamine and it was appeared that scopolamine content was essentially expanded in changed roots and hyoscyamine was extremely expanded in non-transgenic roots. According to the results, it was perceived that the scopolamine content in hairy roots was raised significantly compared to the control roots. It was evidenced that hairy roots gather a great number of metabolites that have a commercial significance. Thus, later on we can enhance efficiency for example by building up the biosynthetic route overexpression of gene codifying enzymes in the metabolic route for expanding valuable secondary metabolites in the plant cures.

Use of a temporary immersion bioreactor system for the sustainable production of thapsigargin in shoot cultures of Thapsia garganica

BACKGROUND

Thapsigargin and nortrilobolide are sesquiterpene lactones found in the Mediterranean plant Thapsia garganica L. Thapsigargin is a potent inhibitor of the sarco/endoplasmic reticulum calcium ATPase pump, inducing apoptosis in mammalian cells. This mechanism has been used to develop a thapsigargin-based cancer drug first by GenSpera and later Inspyr Therapeutics (Westlake Village, California). However, a stable production of thapsigargin is not established.

RESULTS

In vitro regeneration from leaf explants, shoot multiplication and rooting of T. garganica was obtained along with the production of thapsigargins in temporary immersion bioreactors (TIBs). Thapsigargin production was enhanced using reduced nutrient supply in combination with methyl jasmonate elicitation treatments. Shoots grown in vitro were able to produce 0.34% and 2.1% dry weight of thapsigargin and nortrilobolide, respectively, while leaves and stems of wild T. garganica plants contain only between 0.1 and 0.5% of thapsigargin and below detectable levels of nortrilobolide. In addition, a real-time reverse transcription PCR (qRT-PCR) study was performed to study the regulatory role of the biosynthetic genes HMG-CoA reductase (HMGR), farnesyl diphosphate synthase (FPPS), epikunzeaol synthase (TgTPS2) and the cytochrome P450 (TgCYP76AE2) of stem, leaf and callus tissues. Nadi staining showed that the thapsigargins are located in secretory ducts within these tissues.

CONCLUSIONS

Shoot regeneration, rooting and biomass growth from leaf explants of T. garganica were achieved, together with a high yield in vitro production of thapsigargin in TIBs.

Enhanced Stilbene Production and Excretion in Vitis vinifera cv Pinot Noir Hairy Root Cultures

Stilbenes are defense molecules produced by grapevine in response to stresses including various elicitors and signal molecules. Together with their prominent role in planta, stilbenes have been the center of much attention in recent decades due to their pharmaceutical properties. With the aim of setting up a cost-effective and high purity production of resveratrol derivatives, hairy root lines were established from Vitis vinifera cv Pinot Noir 40024 to study the organ-specific production of various stilbenes. Biomass increase and stilbene production by roots were monitored during flask experiments. Although there was a constitutive production of stilbenes in roots, an induction of stilbene synthesis by methyl jasmonate (MeJA) after 18 days of growth led to further accumulation of ε-viniferin, δ-viniferin, resveratrol and piceid. The use of 100 µM MeJA after 18 days of culture in the presence of methyl-β-cyclodextrins (MCDs) improved production levels, which reached 1034µg/g fresh weight (FW) in roots and 165 mg/L in the extracellular medium, corresponding to five-and 570-foldincrease in comparison to control. Whereas a low level of stilbene excretion was measured in controls, addition of MeJA induced excretion of up to 37% of total stilbenes. The use of MCDs increased the excretion phenomenon even more, reaching up to 98%. Our results demonstrate the ability of grapevine hairy roots to produce various stilbenes. This production was significantly improved in response to elicitation by methyl jasmonate and/or MCDs. This supports the interest of using hairy roots as a potentially valuable system for producing resveratrol derivatives.

Production of asiaticoside from centella (Centella asiatica L. Urban) cells in bioreactor

OBJECTIVE

To investigate the effects of some culture conditions on production of asiaticoside from centella (Centella asiatica L. Urban) cells cultured in 5-L bioreactor.

METHODS

The centell cell suspension culture was conducted in 5-L bioreactor to investigate the growth and asiaticoside accumulation under various conditions. Asiaticoside content was determined by HPLC analysis.

RESULTS

The results showed that the cell growth and asiaticoside accumulation peaked after 24 d of culture at an agitation speed of 150 r/min and aeration rate of 2.5 L/min. The cell biomass reached a maximum value of 302.45 g fresh weight (31.45 g dry weight) and growth index of 3.03 with inoculum size of 100 g. However, asiaticoside content was the highest (60.08 mg/g dry weight) when culture was initiated with an inoculum size of 50 g.

CONCLUSIONS

The present study found the suitable conditions for growth of centella cells and their asiaticoside production in bioreactor.