Coffee Cell Suspensions as a Platform for Transient Gene Expression Analysis.

Coffea arabica L. is a crucial crop globally, but its genetic homogeneity leads to its susceptibility to diseases and pests like the coffee berry borer (CBB). Chemical and cultural control methods are difficult due to the majority of the CBB life cycle taking place inside coffee beans. One potential solution is the use of the gene cyt1Aa from Bacillus thuringiensis as a biological insecticide. To validate candidate genes against CBB, a simple, rapid, and efficient transient expression system is necessary. This study uses cell suspensions as a platform for expressing the cyt1Aa gene in the coffee genome (C. arabica L. var. Catuaí) to control CBB. The Agrobacterium tumefaciens strain GV3101::pMP90 containing the bar and cyt1Aa genes are used to genetically transform embryogenic cell suspensions. PCR amplification of the cyt1Aa gene is observed 2, 5, and 7 weeks after infection. This chapter describes a protocol that can be used for the development of resistant varieties against biotic and abiotic stresses and CRISPR/Cas9-mediated genome editing.

[Cloning and expression analysis of U6 promoters in Panax quinquefolius].

The U6 promoter is an important element driving sgRNA transcription in the CRISPR/Cas9 system. Seven PqU6 promo-ter sequences were cloned from the gDNA of Panax quinquefolium, and the transcriptional activation ability of the seven promoters was studied. In this study, seven PqU6 promoter sequences with a length of about 1 300 bp were cloned from the adventitious roots of P. quinquefolium cultivated for 5 weeks. Bioinformatics tools were used to analyze the sequence characteristics of PqU6 promoters, and the fusion expression vectors of GUS gene driven by PqU6-P were constructed. Tobacco leaves were transformed by Agrobacterium tumefaciens-mediated method for activity detection. The seven PqU6 promoters were truncated from the 5'-end to reach 283, 287, 279, 289, 295, 289, and 283 bp, respectively. The vectors for detection of promoter activity were constructed with GUS as a reported gene and used to transform P. quinquefolium callus and tobacco leaves. The results showed that seven PqU6 promoter sequences(PqU6-1P to PqU6-7P) were cloned from the gDNA of P. quinquefolium, with the length ranged from 1 246 bp to 1 308 bp. Sequence comparison results showed that the seven PqU6 promoter sequences and the AtU6-P promoter all had USE and TATA boxes, which are essential elements affecting the transcriptional activity of the U6 promoter. The results of GUS staining and enzyme activity test showed that all the seven PqU6 promoters had transcriptional activity. The PqU6-7P with a length of 1 269 bp had the highest transcriptional activity, 1.31 times that of the positive control P-35S. When the seven PqU6 promoters were truncated from the 5'-end(PqU6-1PA to PqU6-7PA), their transcriptional activities were different in tobacco leaves and P. quinquefolium callus. The transcriptional activity of PqU6-7PA promoter(283 bp) was 1.59 times that of AtU6-P promoter(292 bp) when the recipient material was P. quinquefolium callus. The findings provide more ideal endogenous U6 promoters for CRISPR/Cas9 technology in ginseng and other medicinal plants.

Combining in silico and in vitro approaches to understand the involvement of methylerythritol 4-phosphate and shikimate pathways in Agrobacterium tumefaciens for enhanced coenzyme Q10 production.

AIMS: To perform an integrated comparative analysis of metabolic pathway to understand coenzyme Q10 (CoQ10) production in Agrobacterium tumefaciens. METHODS AND RESULTS: Comparative analysis of the CoQ10 metabolic pathway in 10 organisms using a genome to KEGG orthology program (G2KO) and the KEGG database elucidated the completeness of the production pathway in A. tumefaciens. The specific roles of the key precursors and the enzymes in the metabolic network were subsequently confirmed using pathway inhibitors and enhancers. While the use of fosmidomycin and glyphosate was found to inhibit CoQ10 production by 54.54% to 99%, the supplementation of polyprenyl pyrophosphate of the methylerythritol 4-phosphate pathway and 4-hydroxybenzoate precursor of the shikimate pathway did increse the production of CoQ10 by 2.3-fold. CONCLUSIONS: The present study provides a comprehensive understanding of the CoQ10 biosynthetic pathway in A. tumefaciens, which would assist rational metabolic engineering strategies for augmenting CoQ10 biosynthesis.

Cloning and expression analysis of U6 promoters in Panax quinquefolius / 中国中药杂志

The U6 promoter is an important element driving sgRNA transcription in the CRISPR/Cas9 system. Seven PqU6 promo-ter sequences were cloned from the gDNA of Panax quinquefolium, and the transcriptional activation ability of the seven promoters was studied. In this study, seven PqU6 promoter sequences with a length of about 1 300 bp were cloned from the adventitious roots of P. quinquefolium cultivated for 5 weeks. Bioinformatics tools were used to analyze the sequence characteristics of PqU6 promoters, and the fusion expression vectors of GUS gene driven by PqU6-P were constructed. Tobacco leaves were transformed by Agrobacterium tumefaciens-mediated method for activity detection. The seven PqU6 promoters were truncated from the 5'-end to reach 283, 287, 279, 289, 295, 289, and 283 bp, respectively. The vectors for detection of promoter activity were constructed with GUS as a reported gene and used to transform P. quinquefolium callus and tobacco leaves. The results showed that seven PqU6 promoter sequences(PqU6-1P to PqU6-7P) were cloned from the gDNA of P. quinquefolium, with the length ranged from 1 246 bp to 1 308 bp. Sequence comparison results showed that the seven PqU6 promoter sequences and the AtU6-P promoter all had USE and TATA boxes, which are essential elements affecting the transcriptional activity of the U6 promoter. The results of GUS staining and enzyme activity test showed that all the seven PqU6 promoters had transcriptional activity. The PqU6-7P with a length of 1 269 bp had the highest transcriptional activity, 1.31 times that of the positive control P-35S. When the seven PqU6 promoters were truncated from the 5'-end(PqU6-1PA to PqU6-7PA), their transcriptional activities were different in tobacco leaves and P. quinquefolium callus. The transcriptional activity of PqU6-7PA promoter(283 bp) was 1.59 times that of AtU6-P promoter(292 bp) when the recipient material was P. quinquefolium callus. The findings provide more ideal endogenous U6 promoters for CRISPR/Cas9 technology in ginseng and other medicinal plants.

De Novo Shoot Bud Induction from the Catharanthus roseus Leaf Explants and Agrobacterium tumefaciens-Mediated Technique to Raise Transgenic Plants.

The regeneration of a whole plant from a single cell or organ explant was a valuable task for plant biotechnology. However, important medicinal plants such as Catharanthus roseus have shown recalcitrance to regeneration protocols, thus limiting investigations on MIA metabolism and metabolic engineering in this plant system. In this chapter, successful regeneration protocols were detailed for Catharanthus roseus, either by direct shoot bud induction from leaf explants and Agrobacterium-mediated genetic transformation.

Production of Recombinant Proteins in Transgenic Tobacco Plants.

Nicotiana tabacum (the tobacco plant ) has numerous advantages for molecular farming, including rapid growth, large biomass and the possibility of both cross- and self-fertilization. In addition, genetic transformation and tissue culture protocols for regeneration of transgenic plants are well-established. Here, we describe the production of transgenic tobacco using Agrobacterium tumefaciens and the analysis of recombinant proteins, either in crude plant extracts or after purification, by enzyme-linked immunosorbent assays, sodium dodecyl sulfate polyacrylamide gel electrophoresis with western blotting and surface plasmon resonance.

Comparative Transcriptome Analysis of Agrobacterium tumefaciens Reveals the Molecular Basis for the Recalcitrant Genetic Transformation of Camellia sinensis L.

Tea (Camellia sinensis L.), an important economic crop, is recalcitrant to Agrobacterium-mediated transformation (AMT), which has seriously hindered the progress of molecular research on this species. The mechanisms leading to low efficiency of AMT in tea plants, related to the morphology, growth, and gene expression of Agrobacterium tumefaciens during tea-leaf explant infection, were compared to AMT of Nicotiana benthamiana leaves in the present work. Scanning electron microscopy (SEM) images showed that tea leaves induced significant morphological aberrations on bacterial cells and affected pathogen-plant attachment, the initial step of a successful AMT. RNA sequencing and transcriptomic analysis on Agrobacterium at 0, 3 and 4 days after leaf post-inoculation resulted in 762, 1923 and 1656 differentially expressed genes (DEGs) between the tea group and the tobacco group, respectively. The expressions of genes involved in bacterial fundamental metabolic processes, ATP-binding cassette (ABC) transporters, two-component systems (TCSs), secretion systems, and quorum sensing (QS) systems were severely affected in response to the tea-leaf phylloplane. Collectively, these results suggest that compounds in tea leaves, especially gamma-aminobutyrate (GABA) and catechins, interfered with plant-pathogen attachment, essential minerals (iron and potassium) acquisition, and quorum quenching (QQ) induction, which may have been major contributing factors to hinder AMT efficiency of the tea plant.

LaCl3 treatment improves Agrobacterium-mediated immature embryo genetic transformation frequency of maize.

KEY MESSAGE: We report an optimized transformation system that uses a LaCl3 pretreatment (a Ca2+ channel blocker) for enhancing Agrobacterium-mediated infection of immature embryos and improving the genetic transformation frequency of maize. Agrobacterium-mediated genetic transformation of immature embryos is important for gene-function studies and molecular breeding of maize. However, the relatively low genetic transformation frequency remains a bottleneck for applicability of this method, especially on commercial scale. We report that pretreatment of immature embryos with LaCl3 (a Ca2+ channel blocker) improves the infection frequency of Agrobacterium tumefaciens, increases the proportion of positive callus, yields more positive regenerated plantlets, and increases the transformation frequency from 8.40 to 17.60% for maize. This optimization is a novel method for improving the frequency of plant genetic transformations mediated by Agrobacterium tumefaciens.

Transcriptional responses of Hypericum perforatum cells to Agrobacterium tumefaciens and differential gene expression in dark glands.

Hypericum perforatum L. (St. John's wort) is a well-known medicinal plant that possesses secondary metabolites with beneficial pharmacological properties. However, improvement in the production of secondary metabolites via genetic manipulation is a challenging task as H. perforatum remains recalcitrant to Agrobacterium tumefaciens-mediated transformation. Here, the transcripts of key genes involved in several plant defence responses (secondary metabolites, RNA silencing, reactive oxygen species (ROS) and specific defence genes) were investigated in H. perforatum suspension cells inoculated with A. tumefaciens by quantitative real-time PCR. Results indicated that key genes from the xanthone, hypericin and melatonin biosynthesis pathways, the ROS-detoxification enzyme HpAOX, as well as the defence genes Hyp-1 and HpPGIP, were all upregulated to rapidly respond to A. tumefaciens elicitation in H. perforatum. By contrast, expression levels of genes involved in hyperforin and flavonoid biosynthesis pathways were markedly downregulated upon A. tumefaciens elicitation. In addition, we compared the expression patterns of key genes in H. perforatum leaf tissues with and without dark glands, a major site of secondary metabolite production. Overall, we provide evidence for the upregulation of several phenylpropanoid pathway genes in response to elicitation by Agrobacterium, suggesting that production of secondary metabolites could modulate H. perforatum recalcitrance to A. tumefaciens-mediated transformation.

First-generation genome editing in potato using hairy root transformation.

Genome editing and cis-gene breeding have rapidly accelerated crop improvement efforts, but their impacts are limited by the number of species capable of being genetically transformed. Many dicot species, including some vital potato relatives being used to accelerate breeding and genetics efforts, remain recalcitrant to standard Agrobacterium tumefaciens-based transformation. Hairy root transformation using Agrobacterium rhizogenes (A. rhizogenes) provides an accelerated approach to generating transgenic material but has been limited to analysis of hairy root clones. In this study, strains of A. rhizogenes were tested in the wild diploid potato relative Solanum chacoense, which is recalcitrant to infection by Agrobacterium tumefaciens. One strain of A. rhizogenes MSU440 emerged as being capable of delivering a T-DNA carrying the GUS marker and generating transgenic hairy root clones capable of GUS expression and regeneration to whole plants. CRISPR/Cas9 reagents targeting the potato PHYTOENE DESATURASE (StPDS) gene were expressed in hairy root clones and regenerated. We found that 64%-98% of transgenic hairy root clones expressing CRISPR/Cas9 reagents carried targeted mutations, while only 14%-30% of mutations were chimeric. The mutations were maintained in regenerated lines as stable mutations at rates averaging at 38% and were capable of germ-line transmission to progeny. This novel approach broadens the numbers of genotypes amenable to Agrobacterium-mediated transformation while reducing chimerism in primary events and accelerating the generation of edited materials.

The role of cyanide-resistant respiration in Solanum tuberosum L. against high light stress.

Cyanide-resistant respiration in potato mitochondria is an important pathway for energy dissipation. It can be activated by high light; however, it is unclear what roles cyanide-resistant respiration plays in the response to high light stress in potato. We designed a CRISPR vector for the functional gene StAOX of the potato cyanide-resistant respiratory pathway. Agrobacterium tumefaciens GV3101 was transformed into potato. Hydrogen peroxide level, MDA content, antioxidant activity and cyanide-resistant respiratory capacity of potato leaves under high light stress were determined. Photosynthetic efficiency and chlorophyll content were determined. In addition, the operation of the malate-oxaloacetate shuttle route and transcription level of photorespiration-related enzymes were also examined. The results showed that two base substitutions occurred at the sequencing target site on leaves of the transformed potato. Accumulation of ROS and increased membrane lipid peroxidation were detected in the transformed potato leaves and lower photosynthetic efficiency was observed. The transcription level of the malate-oxaloacetate shuttle route and photorespiration-related enzymes also significantly increased. These results indicate that the cyanide-resistant respiration is an important physiological pathway in potato in response to high light stress. It also suggests that plant cyanide-resistant respiration is closely related to photosynthesis. This implies the unexplored importance of plant cyanide-resistant respiration in plant photosynthesis, energy conversion and carbon skeleton formation.

Agrobacterium tumefaciens-Mediated Stable Transformation of Daucus carota.

Daucus carota L. (carrot) is one of the ten most important vegetables cultivated and consumed worldwide and is a main source of provitamin A. Carrot storage root is rich in dietary fiber, antioxidants, and other nutrients but especially in carotenoids. It has been also used as plant model for studding embryogenesis, as well as the genetic and genomic evolution of carrots and for carotenoid synthesis regulation, among others. Research in carrot often needs genetic transformation. Here we describe a step-by-step protocol on the nuclear and stable transformation of carrot through Agrobacterium tumefaciens and somatic embryogenesis in vitro culture. Somatic embryos, induced by supplementation of Murashige-Skoog medium with the 2,4D hormone, develop into seedlings after 6 months approximately when plants are ready to be transferred to a greenhouse. The protocol has over 85% of transformation efficiency.

Progress in Tissue Culture and Genetic Transformation of Oil Palm: An Overview.

Oil palm (Elaeis guineensis, Jacq.) is a prominent vegetable-oil-yielding crop. Cultivating high-yielding oil palm with improved traits is a pre-requisite to meet the increasing demands of palm oil consumption. However, tissue culture and biotechnological approaches can resolve these concerns. Over the past three decades, significant research has been carried out to develop tissue culture and genetic transformation protocols for oil palm. Somatic embryogenesis is an efficient platform for the micropropagation of oil palm on a large scale. In addition, various genetic transformation techniques, including microprojectile bombardment, Agrobacterium tumefaciens mediated, Polyethylene glycol mediated mediated, and DNA microinjection, have been developed by optimizing various parameters for the efficient genetic transformation of oil palm. This review mainly emphasizes the methods established for in vitro propagation and genetic transformation of oil palm. Finally, we propose the application of the genome editing tool CRISPR/Cas9 to improve the various traits in this oil yielding crop.

Efficient Transformation of the White Jelly Mushroom Tremella fuciformis (Tremellomycetes) and Its Companion Fungus Annulohypoxylon stygium (Ascomycetes) Mediated by Agrobacterium tumefaciens.

Tremella fuciformis is an edible white jelly mushroom with medicinal qualities. The formation of T. fuciformis fruiting bodies is highly dependent on the presence of Annulohypoxylon stygium under natural conditions and during artificial cultivation. A lack of efficient transformation systems restricts the ability of researchers to functionally characterize the genes in these two interacting fungi. In this study, we tested the utility of the Agrobacterium tumefaciens-mediated transformation of T. fuciformis and A. stygium protoplasts. A. tumefaciens strain EHA105 cells harboring the pTrGEH plasmid, which contains genes for enhanced green fluorescent protein (egfp) and hygromycin B phosphotransferase (hph), was co-cultured with T. fuciformis protoplasts. Meanwhile, EHA105 cells harboring the pAnGRH plasmid, which contains the red fluorescent protein (rfp) and hph genes, was co-cultured with A. stygium protoplasts. The egfp, rfp, and hph genes were under the control of the promoter for gpd, which encodes glyceraldehyde-3-phosphate dehydrogenase. Optimal co-cultivation was achieved with a 1:1 mixture of bacteria (OD600 0.4-0.6) and fungal protoplasts (105/mL) incubated at 25°C in a medium containing 200 µM acetosyringone. The subsequent selection on hygromycin B-containing medium yielded 45 and 187 stable transformants per 105 protoplasts for T. fuciformis and A. stygium, respectively. The integration of the transformed DNA into the two fungal genomes was confirmed by polymerase chain reaction (PCR), Southern blot analysis, fluorescence imaging, and a quantitative real-time PCR. All results confirmed the feasibility of our transformation approach, which may facilitate future functional analyses of T. fuciformis and A. stygium genes.

Agrobacterium-Mediated Transformation of Solanum tuberosum L., Potato.

Potato is considered the fourth most important food crop in the world, and the most important non-cereal crop. Potato is transformed using Agrobacterium tumefaciens with relative ease. Several improvements have been made in the last 20 years with respect to tissue culture, transformation, and regeneration of potato. This chapter describes a reliable and efficient potato transformation system using internodal explants. Plasmid preparation, Agrobacterium transformation, potato transformation, regeneration, and recovery are described in detail, as well as molecular characterization of resulting putative transgenic plants.

Coexpression of octopine and succinamopine Agrobacterium virulence genes to generate high quality transgenic events in maize by reducing vector backbone integration.

Agrobacterium-mediated transformation is a complex process that is widely utilized for generating transgenic plants. However, one of the major concerns of this process is the frequent presence of undesirable T-DNA vector backbone sequences in the transgenic plants. To mitigate this deficiency, a ternary strain of A. tumefaciens was modified to increase the precision of T-DNA border nicking such that the backbone transfer is minimized. This particular strain supplemented the native succinamopine VirD1/VirD2 of EHA105 with VirD1/VirD2 derived from an octopine source (pTi15955), the same source as the binary T-DNA borders tested here, residing on a ternary helper plasmid containing an extra copy of the succinamopine VirB/C/G operons and VirD1. Transformation of maize immature embryos was carried out with two different test constructs, pDAB101556 and pDAB111437, bearing the reporter YFP gene and insecticidal toxin Cry1Fa gene, respectively, contained in the VirD-supplemented and regular control ternary strains. Molecular analyses of ~ 700 transgenic events revealed a significant 2.6-fold decrease in events containing vector backbone sequences, from 35.7% with the control to 13.9% with the VirD-supplemented strain for pDAB101556 and from 24.9% with the control to 9.3% with the VirD-supplemented strain for pDAB111437, without compromising transformation efficiency. In addition, while the number of single copy events recovered was similar, there was a 24-26% increase in backbone-free events with the VirD-supplemented strain compared to the control strain. Thus, supplementing existing VirD1/VirD2 genes in Agrobacterium, to recognize diverse T-DNA borders, proved to be a useful tool to increase the number of high quality events in maize.

Agrobacterium tumefaciens-Mediated Transformation of the King Tuber Medicinal Mushroom Lentinus tuber-regium (Agaricomycetes).

Lentinus tuber-regium is a sclerotium-forming basidiomycetous mushroom. It has increasingly aroused people's attention for its medicinal effects. In this study, we investigated the applicability of the Agrobacterium tume-faciens-mediated transformation (ATMT) method in L. tuber-regium. A. tumefaciens strain GV 3101 harboring the vector pPEH was used to transform the mycelium of L. tuber-regium strain ACCC50657. The genes for hygromycin B phosphotransferase (hph) and enhanced green fluorescent protein (egfp) under the control of the glyceraldehyde-3-phosphate dehydrogenase (gpd) gene promoter of Pleurotus ostreatus were employed as the selection marker and reporter gene, respectively. The optimal cocultivation temperature and time for transformation were 3 days and 4 days at 25°C and 20°C, respectively. Southern blot analysis showed the variation in the copy number and position of hph, which indicated random integration of hph. Polymerase chain reaction and fluorescence microscopy indicated that the P. ostreatus gpd promoter can drive the fused hph-egfp gene expression in L. tuber-regium. This is the first report that the ATMT method was successfully applied to L. tuber-regium. This reliable and efficient transformation method could be a powerful tool for strain genetic improvement and gene function study in L. tuber-regium.

Doubled Haploid Transgenic Wheat Lines by Microspore Transformation.

Microspores are preferred explant choice for genetic transformation, as their use shortens the duration of obtaining homozygous transformants. All established gene-delivery methods of particle bombardment, electroporation, and cocultivation with Agrobacterium tumefaciens were optimized on androgenic microspores or derived tissues. In the biolistic gene delivery method 35-40 days old haploid microspore embryoids were used for genetic transformation, whereas freshly isolated androgenic microspores were used for genetic transformation in the electroporation and Agrobacterium cocultivation-based methods. The genetic transformation methods of biolistic gene-delivery and electroporation gave rise to the chimeric plants, whereas the method involving cocultivation with Agrobacterium yielded homozygous transformants. These methods were tested on a large number of cultivars belonging to different market classes of wheat, and found to be fairly independent of the explant genotype. Other benefits of using microspores or derived tissues for transformation are: (1) a few explant donors are required to obtain desired transformants and (2) the time required for obtaining homozygous transformants is about 8 months in case of spring wheat genotypes and about a year in case of winter wheat genotypes.

Silencing of Agrobacterium tumefaciens oncogenes ipt and iaaM induces resistance to crown gall disease in plum but not in apricot.

BACKGROUND: In this study, two vectors with short-length chimeric transgenes were used to produce Prunus rootstocks resistant to crown gall disease through RNA-interference-mediated gene silencing of the Agrobacterium tumefaciens oncogenes ipt and iaaM. RESULTS: Transgenic plum and apricot lines were produced with efficiencies of up to 7.7 and 1.1% respectively. An in vitro evaluation method allowed identification of susceptible lines and reduction in the number of lines to be evaluated in the greenhouse. Five transgenic plum lines, expressing transgene-derived small interfering RNA (siRNA) and low levels of transgene hairpin RNA (hpRNA), showed a significant reduction in the development of the disease after infection with Agrobacterium strains C58 and A281 under greenhouse conditions. However, unexpectedly, all transgenic apricot lines were gall susceptible. The infection of apricot plants with a binary vector containing only the 6b oncogene demonstrated that the expression of this gene is involved in the induction of tumours in the apricot species. CONCLUSION: RNAi-mediated gene silencing can be used for inducing crown gall resistance in plum rootstocks. These could be used to graft non-genetically modified commercial fruit cultivars reducing, or eliminating, the disease symptoms. © 2017 Society of Chemical Industry.

Genetic enhancement of palmitic acid accumulation in cotton seed oil through RNAi down-regulation of ghKAS2 encoding ß-ketoacyl-ACP synthase II (KASII).

Palmitic acid (C16:0) already makes up approximately 25% of the total fatty acids in the conventional cotton seed oil. However, further enhancements in palmitic acid content at the expense of the predominant unsaturated fatty acids would provide increased oxidative stability of cotton seed oil and also impart the high melting point required for making margarine, shortening and confectionary products free of trans fatty acids. Seed-specific RNAi-mediated down-regulation of ß-ketoacyl-ACP synthase II (KASII) catalysing the elongation of palmitoyl-ACP to stearoyl-ACP has succeeded in dramatically increasing the C16 fatty acid content of cotton seed oil to well beyond its natural limits, reaching up to 65% of total fatty acids. The elevated C16 levels were comprised of predominantly palmitic acid (C16:0, 51%) and to a lesser extent palmitoleic acid (C16:1, 11%) and hexadecadienoic acid (C16:2, 3%), and were stably inherited. Despite of the dramatic alteration of fatty acid composition and a slight yet significant reduction in oil content in these high-palmitic (HP) lines, seed germination remained unaffected. Regiochemical analysis of triacylglycerols (TAG) showed that the increased levels of palmitic acid mainly occurred at the outer positions, while C16:1 and C16:2 were predominantly found in the sn-2 position in both TAG and phosphatidylcholine. Crossing the HP line with previously created high-oleic (HO) and high-stearic (HS) genotypes demonstrated that HP and HO traits could be achieved simultaneously; however, elevation of stearic acid was hindered in the presence of high level of palmitic acid.