Cloning and expression analysis of dihydroxyflavonol 4-reductase (DFR) in Ascocenda spp.

Dihydroflavonol 4-reductase (DFR) gene is a key gene of anthocyanins biosynthesis pathway, which represent an importance pathway for orchid flower. In this study, cloning and expression analysis of DFR gene in Ascocenda spp. were carried out. Nucleotide analysis revealed that the Ascocenda DFR gene was 1,056 bp in length, and encoded a protein of 351 amino acid residues. A typical translation initiation codon (ATG) and translation termination codon (TGA), the most frequently found codon in plant were identified, indicating a full-length coding sequence of the DFR gene. The calculated molecular mass of the deduced polypeptide was 39.8 kDa and the predicted isoelectric point was 5.58. Homology analysis revealed that the amino acid sequence of the Ascocenda DFR gene product was 80 to 87% identity to amino acid sequences of DFR gene products of other orchids such as Bromheadia, Dendrobium, Cymbidium and Oncidium. It also showed a high degree of identity to the DFR gene products of other flowers such as Lilium, Tilipa, Allium, Gentiana and Chrysanthenum. Southern blot analysis indicate that DFR is presented as a single copy in the Ascocenda spp. genome. The AscoDFR gene was highly expressed in the flower stages 2 and 3 of development as well as in the sepal and petal of the orchid flower.Keywords: Orchid, dihydroxyflavonol 4-reductase, anthocyanins, gene clonin

Sorbitol required for cell growth and ethanol production by Zymomonas mobilis under heat, ethanol, and osmotic stresses

BACKGROUND: During ethanol fermentation, the ethanologenic bacterium, Zymomonas mobilis may encounter several environmental stresses such as heat, ethanol and osmotic stresses due to high sugar concentration. Although supplementation of the compatible solute sorbitol into culture medium enhances cell growth of Z. mobilis under osmotic stress, the protective function of this compound on cell growth and ethanol production by this organism under other stresses such as heat and ethanol has not been described yet. The formation of sorbitol in Z. mobilis was carried out by the action of the glucose-fructose oxidoreductase (GFOR) enzyme which is regulated by the gfo gene. Therefore, the gfo gene in Z. mobilis was disrupted by the fusion-PCR-based construction technique in the present study, and the protective function of sorbitol on cell growth, protein synthesis and ethanol production by Z. mobilis under heat, ethanol, and osmotic stresses was investigated. RESULTS: Based on the fusion-PCR-based construction technique, the gfo gene in Z. mobilis was disrupted. Disruption of the Z. mobilis gfo gene resulted in the reduction of cell growth and ethanol production not only under osmotic stress but also under heat and ethanol stresses. Under these stress conditions, the transcription level of pdc, adhA, and adhB genes involved in the pyruvate-to-ethanol (PE) pathway as well as the synthesis of proteins particularly in Z. mobilis disruptant strain were decreased compared to those of the parent. These findings suggest that sorbitol plays a crucial role not only on cell growth and ethanol production but also on the protection of cellular proteins from stress responses. CONCLUSION: We showed for the first time that supplementation of the compatible solute sorbitol not only promoted cell growth but also increased the ethanol fermentation capability of Z. mobilis under heat, ethanol, and osmotic stresses. Although the molecular mechanism involved in tolerance to stress conditions after sorbitol supplementation is still unclear, this research has provided useful information for the development of the effective ethanol fermentation process particularly under environmental conditions with high temperature or high ethanol and sugar concentration conditions

Production of isoflavones, daidzein and genistein in callus cultures of Pueraria candollei Wall. ex Benth. var. mirifica

Callus cultures of Pueraria candollei var. mirifica were first established from various parts of explants with the objective of isoflavones, daidzein and genistein production. The cultures were studied on their growth and isoflavone production by various combinations of growth regulators, auxins and cytokinins at 25±2ºC. Daidzein and genistein accumulated in the cells were determined. The results revealed that callus of P. candollei var. mirifica was capable of producing high level of both isoflavones consistently. The culture temperature played an important role in the growth and isoflavone production. Over twofold of growth and threefold of isoflavone production were demonstrated at 32±2ºC. The callus established from the stems in MS medium supplemented with 4.5 µM 2,4-D and 0.46 µM kinetin produced the highest yield of daidzein (5.12 mg/g, DW) and genistein (2.77 mg/g, DW), which was remarkably higher than the intact plants

In Vitro Propagation of <i>Philodendron erubescens</i> ‘Pink Princess’ and Ex Vitro Acclimatization of the Plantlets

This study describes the in vitro propagation and ex vitro acclimatization of Philodendron erubescens pink princess, one of the most popular ornamental variegated foliage plants. For shoot proliferation, the protocorm-like bodies of the Philodendron pink princess were cultured on solid Murashige and Skoog (MS) media supplemented with 6-benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA) at different concentrations. The results revealed that supplementation with BAP alone at a concentration of 1.0 mg/L yielded the maximum number of shoots and leaves. Furthermore, the application of BAP at 1.0 mg/L significantly enhanced the shoot proliferation of Philodendron pink princess when grown in liquid MS medium, yielding 11.2 shoots/explant and 4.7 leaves/explant. When the established microshoots were subjected to root induction using solid MS media supplemented with different kinds and concentrations of auxins, indole-3-butyric acid (IBA) at 3 mg/L resulted in the highest number of roots (3.2 roots/explant) and longest root length (1.9 cm). Three supporting materials, i.e., peat moss, vermiculite, and perlite, were used as planting media for the ex vitro acclimatization of the Philodendron pink princess plantlets. The results demonstrated that the in vitro plantlets acclimatized and exhibited a relatively high survival frequency in all planting media without morphological abnormalities. Peat moss outperformed all other types of planting media in terms of sustaining the vegetative growth of the plantlets. In the future, the approach established in this study could be employed for the extensive production of Philodendron pink princess

Sorbitol production from mixtures of molasses and sugarcane bagasse hydrolysate using the thermally adapted Zymomonas mobilis ZM AD41

Abstract Byproducts from the sugarcane manufacturing process, specifically sugarcane molasses (SM) and sugarcane bagasse (SB), can be used as alternative raw materials for sorbitol production via the biological fermentation process. This study investigated the production of sorbitol from SM and sugarcane bagasse hydrolysate (SBH) using a thermally adapted Zymomonas mobilis ZM AD41. Various combinations of SM and SBH on sorbitol production using batch fermentation process were tested. The results revealed that SM alone (FM1) or a mixture of SM and SBH at a ratio of 3:1 (FM2) based on the sugar mass in the raw material proved to be the best condition for sorbitol production by ZM AD41 at 37 °C. Further optimization conditions for sorbitol production revealed that a sugar concentration of 200 g/L and a CaCl2 concentration of 5.0 g/L yielded the highest sorbitol content. The maximum sorbitol concentrations produced by ZM AD41 in the fermentation medium containing SM (FM1) or a mixture of SM and SBH (FM2) were 31.23 and 30.45 g/L, respectively, comparable to those reported in the literature using sucrose or a mixture of sucrose and maltose as feedstock. These results suggested that SBH could be used as an alternative feedstock to supplement or blend with SM for sustainable sorbitol production. In addition, the fermentation conditions established in this study could also be applied to large-scale sorbitol production. Moreover, the thermally adapted Z. mobilis ZM AD41 is also a promising sorbitol-producing bacterium for large-scale production at a relatively high fermentation temperature using agricultural byproducts, specifically SM and SB, as feedstock, which could reduce the operating cost due to minimizing the energy required for the cooling system