EgMADS3 directly regulates EgLPAAT to mediate medium-chain fatty acids (MCFA) anabolism in the mesocarp of oil palm.

KEY MESSAGE: EgMADS3, a pivotal transcription factor, positively regulates MCFA accumulation via binding to the EgLPAAT promoter, advancing lipid content in mesocarp of oil palm. Lipids function as the structural components of cell membranes, which serve as permeable barriers to the external environment of cells. The medium-chain fatty acid in the stored lipids of plants is an important renewable energy. Most research on MCFA production in plant lipid synthesis is based on biochemical methods, and the importance of transcriptional regulation in MCFA synthesis and its incorporation into TAGs needs further research. Oil palm is the most productive oil crop in the world and has the highest productivity among the main oil crops. In this study, the MADS transcription factor (EgMADS3) in the mesocarp of oil palm was characterized. Through the VIGS-virus induced gene silencing, it was determined that the potential target gene of EgMADS3 was related to the biosynthesis of medium-chain fatty acid (MCFA). Transient transformation in protoplasts and qRT-PCR analysis showed that EgMADS3 positively regulated the expression of EgLPAAT. The results of the yeast one-hybrid assays and EMSA indicated the interaction between EgMADS3 and EgLPAAT promoter. Through genetic transformation and fatty acid analysis, it is concluded that EgMADS3 directly regulates the mid-chain fatty acid synthesis pathway of the potential target gene EgLPAAT, thus promotes the accumulation of MCFA and improves the total lipid content. This study is innovative in the functional analysis of the MADS family transcription factor in the metabolism of medium-chain fatty acids (MCFA) of oil palm, provides a certain research basis for improving the metabolic pathway of chain fatty acids in oil palm, and improves the synthesis of MCFA in plants. Our results will provide a reference direction for further research on improving the oil quality through biotechnology of oil palm.

Efficient production of polyhydroxybutyrate using lignocellulosic biomass derived from oil palm trunks by the inhibitor-tolerant strain Burkholderia ambifaria E5-3.

Lignocellulosic biomass is a valuable, renewable substrate for the synthesis of polyhydroxybutyrate (PHB), an ecofriendly biopolymer. In this study, bacterial strain E5-3 was isolated from soil in Japan; it was identified as Burkholderia ambifaria strain E5-3 by 16 S rRNA gene sequencing. The strain showed optimal growth at 37 °C with an initial pH of 9. It demonstrated diverse metabolic ability, processing a broad range of carbon substrates, including xylose, glucose, sucrose, glycerol, cellobiose, and, notably, palm oil. Palm oil induced the highest cellular growth, with a PHB content of 65% wt. The strain exhibited inherent tolerance to potential fermentation inhibitors derived from lignocellulosic hydrolysate, withstanding 3 g/L 5-hydroxymethylfurfural and 1.25 g/L acetic acid. Employing a fed-batch fermentation strategy with a combination of glucose, xylose, and cellobiose resulted in PHB production 2.7-times that in traditional batch fermentation. The use of oil palm trunk hydrolysate, without inhibitor pretreatment, in a fed-batch fermentation setup led to significant cell growth with a PHB content of 45% wt, equivalent to 10 g/L. The physicochemical attributes of xylose-derived PHB produced by strain E5-3 included a molecular weight of 722 kDa, a number-average molecular weight of 191 kDa, and a polydispersity index of 3.78. The amorphous structure of this PHB displayed a glass transition temperature of 4.59 °C, while its crystalline counterpart had a melting point of 171.03 °C. This research highlights the potential of lignocellulosic feedstocks, especially oil palm trunk hydrolysate, for PHB production through fed-batch fermentation by B. ambifaria strain E5-3, which has high inhibitor tolerance.

EgMYB108 regulates very long-chain fatty acid (VLCFA) anabolism in the mesocarp of oil palm.

KEY MESSAGE: EgMYB108 regulates VLCFA anabolism in oil palm. Very long-chain fatty acids (VLCFAs), which are fatty acids with more than 18 C, can not only be used as a form of triglyceride (TAG) but also provide precursors for the biosynthesis of cuticle wax, and they exist in plant epidermal cells in the form of wax in higher plants. However, which and how transcriptional factors (TFs) regulate this process is largely unknown in oil palm. In this study, a MYB transcription factor (EgMYB108) with high expression in the mesocarp of oil palm fruit was characterized. Overexpression of EgMYB108 promoted not only total lipid content but also VLCFA accumulation in oil palm embryoids. Subsequently, transient transformation in protoplasts and qRT-PCR analysis indicated that the EgKCS5 and EgLACS4 genes were significantly increased with the overexpression of EgMYB108. Furthermore, yeast one­hybrid assays, dual-luciferase assays and EMSAs demonstrated that EgMYB108 binds to the promoters of EgKCS5 and EgLACS4 and regulates their transcription. Finally, EgMYB108 interacts with the promoters of EgLACS and EgKCS simultaneously and finally improves the VLCFA and total lipid contents; a pathway summarizing this interaction was depicted.. The results provide new insight into the mechanism by which EgMYB108 regulates lipid and VLCFA accumulation in oil palm.

Feeding of palm oil fatty acids or rapeseed oil throughout lactation: Effects on mammary gene expression and milk production in Norwegian dairy goats.

Lipid added as rapeseed or palm oil to the diet of dairy goats over 8 mo of one lactation alters fat secretion and milk fatty acid (FA) and protein composition. In this study, we examined the contribution of mammary gene expression to these changes and included 30 multiparous goats of Norwegian dairy goat breed for a 230-d experimental period, with indoor feeding from 1 to 120 d in milk (DIM), mountain grazing from 120 to 200 DIM, and indoor feeding from 200 to 230 DIM. After an initial period (1-60 DIM) when the control diet was given to all goats, the animals were subdivided into 3 groups of 10 goats. Treatments (60-230 DIM) were basal concentrate (control) alone or supplemented with either 8% (by weight) hydrogenated palm oil enriched with palmitic acid (POFA) or 8% (by weight) rapeseed oil (RSO). Milk was sampled individually from all animals throughout lactation, at 60, 120, 190, and 230 DIM for milk yield and composition. On d 60, 120, 190, and 230, mammary tissue was collected by biopsy to measure mRNA abundance of 19 key genes. None of the 19 genes involved in milk protein, apoptosis, lipid metabolism, transcription factors, and protein of the milk fat globule membrane, as measured by mRNA abundance, were affected by the lipid supplements, although POFA increased milk fat content, and POFA and RSO affected milk FA composition. Over the experimental period (120-230 DIM), the mRNA abundance of 13 of the 19 studied genes was affected by lactation stage. For some genes, expression either gradually increased from 120 to 230 DIM (CSN2, CASP8, CD36, GLUT4) or increased from 120 to 200 and then remained stable (XDH), or decreased (CSN3, G6PD, SREBF1, PPARG1) or increased only at 230 DIM (SCD1, SCD5, ELF3). For a second group of genes (CSN1, LALBA, FABP3, FASN, LPL, MFGE8), expression was stable over the lactation period. Our results suggest that factors other than gene expression, such as substrate availability or posttranscriptional regulation of these genes, could play an important role in the milk fat and FA responses to dietary fat composition in the goat. In conclusion, mammary gene expression in goats was more regulated by stage of lactation than by the dietary treatments applied.

Changes in the microbiota during biological treatment of palm oil mill waste: A critical review.

Palm oil mill waste has a complex cellulosic structure, is rich in nutrients, and provides a habitat for diverse microbial communities. Current research focuses on how the microbiota and organic components interact during the degradation of this type of waste. Some recent studies have described the microbial communities present in different biodegradation processes of palm oil mill waste, identifying the dominant bacteria/fungi responsible for breaking down the cellulosic components. However, understanding the degradation process's mechanisms is vital to eliminating the need for further pretreatment of lignocellulosic compounds in the waste mixture and facilitating the commercialization of palm oil mill waste treatment technology. Thus, the present work aims to review microbial community dynamics via three biological treatment systems comprehensively: composting, vermicomposting, and dark fermentation, to understand how inspiration from nature can further enhance existing degradation processes. The information presented could be used as an umbrella to current research on biological treatment processes and specific research on the bioaugmentation of indigenous microbial consortia isolated during the biological degradation of palm oil mill waste.

Expression analysis of miRNAs and their putative target genes confirm a preponderant role of transcription factors in the early response of oil palm plants to salinity stress.

BACKGROUND: Several mechanisms regulating gene expression contribute to restore and reestablish cellular homeostasis so that plants can adapt and survive in adverse situations. MicroRNAs (miRNAs) play roles important in the transcriptional and post-transcriptional regulation of gene expression, emerging as a regulatory molecule key in the responses to plant stress, such as cold, heat, drought, and salt. This work is a comprehensive and large-scale miRNA analysis performed to characterize the miRNA population present in oil palm (Elaeis guineensis Jacq.) exposed to a high level of salt stress, to identify miRNA-putative target genes in the oil palm genome, and to perform an in silico comparison of the expression profile of the miRNAs and their putative target genes. RESULTS: A group of 79 miRNAs was found in oil palm, been 52 known miRNAs and 27 new ones. The known miRNAs found belonged to 28 families. Those miRNAs led to 229 distinct miRNA-putative target genes identified in the genome of oil palm. miRNAs and putative target genes differentially expressed under salinity stress were then selected for functional annotation analysis. The regulation of transcription, DNA-templated, and the oxidation-reduction process were the biological processes with the highest number of hits to the putative target genes, while protein binding and DNA binding were the molecular functions with the highest number of hits. Finally, the nucleus was the cellular component with the highest number of hits. The functional annotation of the putative target genes differentially expressed under salinity stress showed several ones coding for transcription factors which have already proven able to result in tolerance to salinity stress by overexpression or knockout in other plant species. CONCLUSIONS: Our findings provide new insights into the early response of young oil palm plants to salinity stress and confirm an expected preponderant role of transcription factors - such as NF-YA3, HOX32, and GRF1 - in this response. Besides, it points out potential salt-responsive miRNAs and miRNA-putative target genes that one can utilize to develop oil palm plants tolerant to salinity stress.

Immobilized lipase-catalyzed transesterification for synthesis of biolubricant from palm oil methyl ester and trimethylolpropane.

The present study reports the effects of three commercial immobilized lipases namely Novozyme 435 from Candida antarctica lipase B (CALB), Lipozyme TL IM from Thermomyces lanuginosus and Lipozyme RM IM from Rhizomucor miehei on the production of trimethylolpropane (TMP) ester from high oleic palm methyl ester (HO-PME) and TMP. The TMP ester is a promising base oil for biolubricants that are easily biodegradable and non-toxic to humans and the environment. Enzymatic catalysts are insensitive to free fatty acid (FFA) content, hence able to mitigate the side reactions and consequently reduce product separation cost. The potential of these enzymes to produce TMP ester in a solvent-free medium was screened at various reaction time (8, 23, 30 and 48 h), operating pressure (0.1, 0.3 and 1.0 mbar) and enzyme dosage (1, 3, 5 and 10% w/w). The reaction was conducted at a constant temperature of 70 °C and a molar ratio of 3.9:1 (HO-PME: TMP). Novozyme 435 produced the highest yield of TMP ester of 95.68 ± 3.60% under the following conditions: 23 h reaction time, 0.1 mbar operating pressure and 5% w/w of enzyme dosage. The key lubrication properties of the produced TMP ester are viscosity index (208 ± 2), pour point (- 30 ± - 2 °C), cloud point (- 15 ± - 2 °C), onset thermal degradation temperature (427.8 °C), and oxidation stability, RPVOT (42 ± 4 min). The properties of the TMP ester produced from the enzymatic transesterification are comparable to other vegetable oil-based biolubricants produced by chemical transesterification.

Pulp Enhancement of Oil Palm Empty Fruit Bunches (OPEFBs) via Biobleaching by Using Xylano-Pectinolytic Enzymes of Bacillus amyloliquefaciens ADI2.

The present work reports the biobleaching effect on OPEFB pulp upon utilisation of extracellular xylano-pectinolytic enzymes simultaneously yielded from Bacillus amyloliquefaciens ADI2. The impacts of different doses, retention times, pH, and temperatures required for the pulp biobleaching process were delineated accordingly. Here, the OPEFB pulp was subjected to pre-treatment with xylano-pectinolytic enzymes generated from the same alkalo-thermotolerant isolate that yielded those of higher quality. Remarkable enhanced outcomes were observed across varying pulp attributes: for example, enzyme-treated pulp treated to chemical bleaching sequence generated improved brightness of 11.25%. This resulted in 11.25% of less chlorine or chemical consumption required for obtaining pulp with optical attributes identical to those generated via typical chemical bleaching processes. Ultimately, the reduced consumption of chlorine would minimise the organochlorine compounds found in an effluent, resulting in a lowered environmental effect of paper-making processes overall as a consequence. This will undoubtedly facilitate such environmentally-friendly technology incorporation in the paper pulp industry of today.

Characterization of Oil Palm Acyl-CoA-Binding Proteins and Correlation of Their Gene Expression with Oil Synthesis.

Acyl-CoA-binding proteins (ACBPs) are involved in binding and trafficking acyl-CoA esters in eukaryotic cells. ACBPs contain a well-conserved acyl-CoA-binding domain. Their various functions have been characterized in the model plant Arabidopsis and, to a lesser extent, in rice. In this study, genome-wide detection and expression analysis of ACBPs were performed on Elaeis guineensis (oil palm), the most important oil crop in the world. Seven E. guineensis ACBPs were identified and classified into four groups according to their deduced amino acid domain organization. Phylogenetic analysis showed conservation of this family with other higher plants. All seven EgACBPs were expressed in most tissues while their differential expression suggests various functions in specific tissues. For example, EgACBP3 had high expression in inflorescences and stalks while EgACBP1 showed strong expression in leaves. Because of the importance of E. guineensis as an oil crop, expression of EgACBPs was specifically examined during fruit development. EgACBP3 showed high expression throughout mesocarp development, while EgACBP1 had enhanced expression during rapid oil synthesis. In endosperm, both EgACBP1 and EgACBP3 exhibited increased expression during seed development. These results provide important information for further investigations on the biological functions of EgACBPs in various tissues and, in particular, their roles in oil synthesis.

Cellular uptake and anti-inflammatory effects of palm oil-derived delta (δ)-tocotrienol in microglia.

Tocopherols long dominated studies on vitamin E, although interest has shifted to tocotrienols. It was previously shown that δ-tocotrienol derived from palm oil reduced nitric oxide released by BV2 microglia as early as 18 h after lipopolysaccharide stimulation. The current study measured δ-tocotrienol uptake by BV2 over a 24 h incubation period and its anti-inflammatory effects on primary microglia. Uptake of 17.5 µg/mL δ-tocotrienol by BV2 microglia began as early as 5 min and rose steeply to 21 ± 3% of the amount administered at 24 h. The amount of δ-tocotrienol retained in the lipopolysaccharide-stimulated microglia at 24 h was 14 ± 2%, with no substantial difference seen in unstimulated microglia. The same δ-tocotrienol regimen reduced nitric oxide levels by 82% at 24 h after lipopolysaccharide stimulation (p < 0.05). This was accompanied by decreased inducible nitric oxide synthase protein expression by 67 ± 5% compared to untreated controls (p < 0.05). In primary microglia, δ-tocotrienol downregulated IL-1ß production, but TNF-α and IL-6 were not affected. δ-Tocotrienol also reduced prostaglandin E2 production by ~78%% and decreased transcription of COX-2 and 5-LOX, but not COX-1. This study showed the anti-inflammatory effects of δ-tocotrienol derived from palm oil and opens up interest for tocotrienol supplementation to reduce the effects of inflammatory conditions.

Comparative metabolomics of Phialemonium curvatum as an omnipotent fungus cultivated on crude palm oil versus glucose.

BACKGROUND: Sugars and triglycerides are common carbon sources for microorganisms. Nonetheless, a systematic comparative interpretation of metabolic changes upon vegetable oil or glucose as sole carbon source is still lacking. Selected fungi that can grow in acidic mineral salt media (MSM) with vegetable oil had been identified recently. Hence, this study aimed to investigate the overall metabolite changes of an omnipotent fungus and to reveal changes at central carbon metabolism corresponding to both carbon sources. RESULTS: Targeted and non-targeted metabolomics for both polar and semi-polar metabolites of Phialemonium curvatum AWO2 (DSM 23903) cultivated in MSM with palm oil (MSM-P) or glucose (MSM-G) as carbon sources were obtained. Targeted metabolomics on central carbon metabolism of tricarboxylic acid (TCA) cycle and glyoxylate cycle were analysed using LC-MS/MS-TripleQ and GC-MS, while untargeted metabolite profiling was performed using LC-MS/MS-QTOF followed by multivariate analysis. Targeted metabolomics analysis showed that glyoxylate pathway and TCA cycle were recruited at central carbon metabolism for triglyceride and glucose catabolism, respectively. Significant differences in organic acids concentration of about 4- to 8-fold were observed for citric acid, succinic acid, malic acid, and oxaloacetic acid. Correlation of organic acids concentration and key enzymes involved in the central carbon metabolism was further determined by enzymatic assays. On the other hand, the untargeted profiling revealed seven metabolites undergoing significant changes between MSM-P and MSM-G cultures. CONCLUSIONS: Overall, this study has provided insights on the understanding on the effect of triglycerides and sugar as carbon source in fungi global metabolic pathway, which might become important for future optimization of carbon flux engineering in fungi to improve organic acids production when vegetable oil is applied as the sole carbon source.

Enzyme production and oil palm empty fruit bunch bioconversion to ethanol using a hybrid yeast strain.

Oil palm empty fruit bunch (OPEFB) is a lignocellulosic biomass generated in palm oil mills. It is a sustainable resource for fuels and chemicals. In this study, OPEFB was converted to ethanol by an integrative OPEFB conversion process including dilute alkaline pretreatment, cellulolytic enzyme production, separate OPEFB hydrolysis, and cofermentation using a hybrid xylose-fermenting yeast. OPEFB was pretreated using 1% (w/v) NaOH solution followed by 1% (v/v) H2 O2 . Further, cellulolytic enzymes were produced by submerged fermentation using Trichoderma reesei Rut C30 and used for OPEFB hydrolysis. The filter paper cellulase activity of the crude cellulolytic enzymes was 15.1 IU/mL, which was higher than those obtained by reported Trichoderma strains under laboratory conditions. Glucose and xylose yields reached 66.9% and 74.2%, respectively, at 30 filter paper unit (FPU)/g-biomass enzyme dosage and 10% (w/v) biomass loading. The hybrid yeast strain ScF2 was previously constructed through recursive genome shuffling of Pichia stipitis and Saccharomyces cerevisiae and was used in OPEFB hydrolysate fermentation. About 16.9 g/L ethanol was produced with an ethanol yield of 0.34 g/g sugars, which was 67% of theoretical ethanol yield.

A MADS-box gene, EgMADS21, negatively regulates EgDGAT2 expression and decreases polyunsaturated fatty acid accumulation in oil palm (Elaeis guineensis Jacq.).

KEY MESSAGE: EgMADS21 regulates PUFA accumulation in oil palm. Oil palm (Elaeis guineensis Jacq.) is the most productive world oil crop, accounting for 36% of world plant oil production. However, the molecular mechanism of the transcriptional regulation of fatty acid accumulation and lipid synthesis in the mesocarp of oil palm by up- or downregulating the expression of genes involved in related pathways remains largely unknown. Here, an oil palm MADS-box gene, EgMADS21, was screened in a yeast one-hybrid assay using the EgDGAT2 promoter sequence as bait. EgMADS21 is preferentially expressed in early mesocarp developmental stages in oil palm fruit and presents a negative correlation with EgDGAT2 expression. The direct binding of EgMADS21 to the EgDGAT2 promoter was confirmed by electrophoretic mobility shift assay. Subsequently, transient expression of EgMADS21 in oil palm protoplasts revealed that EgMADS21 not only binds to the EgDGAT2 promoter but also negatively regulates the expression of EgDGAT2. Furthermore, EgMADS21 was stably overexpressed in transgenic oil palm embryoids by Agrobacterium-mediated transformation. In three independent transgenic lines, EgDGAT2 expression was significantly suppressed by the expression of EgMADS21. The content of linoleic acid (C18:2) in the three transgenic embryoids was significantly decreased, while that of oleic acid (C18:1) was significantly increased. Combined with the substrate preference of EgDGAT2 identified in previous research, the results demonstrate the molecular mechanism by which EgMADS21 regulates EgDGAT2 expression and ultimately affects fatty acid accumulation in the mesocarp of oil palm.

High percentage of dietary palm oil suppressed growth and antioxidant capacity and induced the inflammation by activation of TLR-NF-κB signaling pathway in large yellow croaker (Larimichthys crocea).

A 70-day feeding trial was conducted to investigate the effects of dietary fish oil (FO) replaced by palm oil (PO) on growth, biochemical and antioxidant response as well as inflammatory response in the liver of large yellow croaker (initial weight 15.87 ±â€¯0.14 g). Four iso-proteic and iso-lipidic experimental diets were formulated with 0% (the control group), 33.3%, 66.7% and 100% FO replaced by PO. Fish fed the diet with 100% PO showed significantly lower growth performance than the control group. As expected, the contents of C16:0, C18:1n-9 and C18:2n-6 were increased with increasing dietary PO levels. There were remarkable increases in total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) levels in fish fed the diet with 100% PO compared to the control group. Moreover, dietary PO significantly increased activities of plasma alanine transaminase (ALT) and aspartate aminotransferase (AST) in fish fed the diet with 100% PO compared to the control group. The total antioxidant capacity (T-AOC) and the activity of catalase (CAT) in plasma were significantly decreased in fish fed the diet with 100% PO compared to the control group, and meanwhile no significant differences were found in T-AOC and CAT activity in fish fed diets with no more than 66.7% PO. Fish fed the diet with 100% PO exerted significantly higher toll like receptors (TLRs) and myeloid differentiation factor (MyD88) mRNA expression levels than the control group. The IFNγ, IL-1ß and TNFα mRNA expressions were increased with increasing dietary PO levels. The increase of pro-inflammatory gene expression may be due to the activation of NF-κB signaling as the ratio of nucleus p65 to total p65 protein was elevated with the increase of dietary PO levels. These results showed that relatively higher PO levels in diets suppressed the growth and antioxidant capacity as well as induced the inflammatory response by activating TLR-NF-κB signaling pathway in juvenile large yellow croaker.

Effect of diets supplemented with starch and corn oil, marine algae, or hydrogenated palm oil on mammary lipogenic gene expression in cows and goats: A comparative study.

A direct comparison of cow and goat performance and milk fatty acid (FA) responses to diets that either induce milk fat depression or increase milk fat content in cows suggests species-specific regulation of lipid metabolism, including mammary lipogenesis. This experiment was conducted to highlight potential mechanisms responsible for the differences in mammary lipogenesis due to diet and ruminant species. Twelve Holstein cows and 12 Alpine goats were fed a basal diet containing no additional lipid (CTL) or a similar diet supplemented with corn oil [5% dry matter intake (DMI)] and wheat starch (COS), marine algae powder (MAP; 1.5% DMI), or hydrogenated palm oil (HPO; 3% DMI), according to a 4 × 4 Latin square design with 28-d experimental periods. Milk yield, milk composition, FA profile, and secretions were measured. On d 27 of each experimental period, the mRNA abundance of 21 genes involved in lipid metabolism or enzyme activities or both were measured in mammary tissue sampled by biopsy. The results showed significant differences in the milk fat response of cows and goats to the dietary treatments. In cows, fat content was lowered by COS (-45%) and MAP (-22%) and increased by HPO (+13%) compared with CTL, and in goats only MAP had an effect compared with CTL, with a decrease of 15%. In both species, COS and MAP lowered the yields (mmol/d per kilogram of body weight) of C16 FA in goats but not in cows, and the >C16 FA yield decreased with MAP in both species. Supplementation of HPO increased the yield of milk C16 FA (mmol/d per kilogram of body weight) in cows. These variations in milk fat content and FA secretion were not associated with modifications in the mammary expression of 21 genes involved in major lipid pathways, except for 3 transcription factors: PPARA, INSIG1, and SP1. This absence of large changes might be due to post-transcriptional regulation of these genes and related to the time of sampling of the mammary tissue relative to the previous meal and milking or to differences in the availability of substrate for the corresponding proteins. However, the abundance of 14 mRNA among the 21 encoding for genes studied in the mammary gland was significantly different among species, with 5 more abundant in cows (FADS3, ACSL1, PPARA, LXRA, and PPARG1) and 10 more abundant in goats (FASN, CD36, FABP3, LPL, GPAM, LPIN1, CSN2, MFGE8, and INSIG1). These species specificities of mammary lipid metabolism require further investigation.

Association of Pollinators of Different Species of Oil Palm with the Metabolic Profiling of Volatile Organic Compounds.

The development of studies on emissions of volatile organic compounds (VOCs) by inflorescence of oil palms deserves a special attention regarding the importance to reproduction success and for increase of production. This study aimed to evaluate metabolic profiling of VOCs expelled by male and female inflorescences of different oil palm species (African oil palm, Amazonian Caiaué and the interspecific hybrid BRS-Manicoré), associating the composition variability with main pollinators to improve the comprehension of the plant-insect relationship. The phenylpropanoids, terpenoids and the aliphatic hydrocarbons were predominant classes detected in inflorescences of oil palms and the major compound was estragole. This result may be correlated with attraction of Elaidobius pollinators, since these insects were not attracted by Caiaué, which emitted estragole only in trace amounts. However, Caiaué and the hybrid species were visited by other native species whose frequencies were low and their success as pollinators could not be expected.

WRI1-1, ABI5, NF-YA3 and NF-YC2 increase oil biosynthesis in coordination with hormonal signaling during fruit development in oil palm.

The oil biosynthesis pathway must be tightly controlled to maximize oil yield. Oil palm accumulates exceptionally high oil content in its mesocarp, suggesting the existence of a unique fruit-specific fatty acid metabolism transcriptional network. We report the complex fruit-specific network of transcription factors responsible for modulation of oil biosynthesis genes in oil palm mesocarp. Transcriptional activation of EgWRI1-1 encoding a key master regulator that activates expression of oil biosynthesis genes, is activated by three ABA-responsive transcription factors, EgNF-YA3, EgNF-YC2 and EgABI5. Overexpression of EgWRI1-1 and its activators in Arabidopsis accelerated flowering, increased seed size and oil content, and altered expression levels of oil biosynthesis genes. Protein-protein interaction experiments demonstrated that EgNF-YA3 interacts directly with EgWRI1-1, forming a transcription complex with EgNF-YC2 and EgABI5 to modulate transcription of oil biosynthesis pathway genes. Furthermore, EgABI5 acts downstream of EgWRKY40, a repressor that interacts with EgWRKY2 to inhibit the transcription of oil biosynthesis genes. We showed that expression of these activators and repressors in oil biosynthesis can be induced by phytohormones coordinating fruit development in oil palm. We propose a model highlighting a hormone signaling network coordinating fruit development and fatty acid biosynthesis.

Metabolic fingerprinting analysis of oil palm reveals a set of differentially expressed metabolites in fatal yellowing symptomatic and non-symptomatic plants.

INTRODUCTION: Oil palm (E. guineensis), the most consumed vegetable oil in the world, is affected by fatal yellowing (FY), a condition that can lead to the plant's death. Although studies have been performed since the 1980s, including investigations of biotic and abiotic factors, FY's cause remains unknown and efforts in researches are still necessary. OBJECTIVES: This work aims to investigate the metabolic expression in plants affected by FY using an untargeted metabolomics approach. METHOD: Metabolic fingerprinting analysis of oil palm leaves was performed using ultra high liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS). Chemometric analysis, using principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA), was applied to data analysis. Metabolites identification was performed by high resolution mass spectrometry (HRMS), MS/MS experiments and comparison with databases and literature. RESULTS: Metabolomics analysis based on MS detected more than 50 metabolites in oil palm leaf samples. PCA and PLS-DS analysis provided group segregation and classification of symptomatic and non-symptomatic FY samples, with a great external validation of the results. Nine differentially expressed metabolites were identified as glycerophosphorylcholine, arginine, asparagine, apigenin 6,8-di-C-hexose, tyramine, chlorophyllide, 1,2-dihexanoyl-sn-glycero-3-phosphoethanolamine, proline and malvidin 3-glucoside-5-(6″-malonylglucoside). Metabolic pathways and biological importance of those metabolites were assigned. CONCLUSION: Nine metabolites were detected in a higher concentration in non-symptomatic FY plants. Seven are related to stress factors i.e. plant defense and nutrient absorption, which can be affected by the metabolic depression of these compounds. Two of those metabolites (glycerophosphorylcholine and 1,2-dihexanoyl-sn-glycero-3-phosphoethanolamine) are presented as potential biomarkers, since they have no known direct relation to plant stress.

Production of high concentration of l-lactic acid from oil palm empty fruit bunch by thermophilic Bacillus coagulans JI12.

Thermophilic Bacillus coagulans JI12 was used to ferment hemicellulose hydrolysate obtained by acid hydrolysis of oil palm empty fruit bunch at 50 °C and pH 6, producing 105.4 g/L of l-lactic acid with a productivity of 9.3 g/L/H by fed-batch fermentation under unsterilized conditions. Simultaneous saccharification and fermentation (SSF) was performed at pH 5.5 and 50 °C to convert both hemicellulose hydrolysate and cellulose-lignin complex in the presence of Cellic Ctec2 cellulases using yeast extract (20 g/L) as the nitrogen source, giving 114.0 g/L of l-lactic acid with a productivity of 5.7 g/L/H. The SSF was also conducted by replacing yeast extract with equal amount of dry Bakers' yeast, achieving 120.0 g/L of l-lactic acid with a productivity of 4.3 g/L/H. To the best of our knowledge, these lactic acid titers and productivities are the highest ever reported from lignocellulose hydrolysates.

Effect of replacing calcium salts of palm oil with camelina seed at 2 dietary ether extract levels on digestion, ruminal fermentation, and nutrient flow in a dual-flow continuous culture system.

Camelina is a drought- and salt-tolerant oil seed, which in total ether extract (EE) contains up to 74% polyunsaturated fatty acids. The objective of this study was to assess the effects of replacing calcium salts of palm oil (Megalac, Church & Dwight Co. Inc., Princeton, NJ) with camelina seed (CS) on ruminal fermentation, digestion, and flows of fatty acids (FA) and AA in a dual-flow continuous culture system when supplemented at 5 or 8% dietary EE. Diets were randomly assigned to 8 fermentors in a 2 × 2 factorial arrangement of treatments in a replicated 4 × 4 Latin square design, with four 10-d experimental periods consisting of 7 d for diet adaptation and 3 d for sample collection. Treatments were (1) calcium salts of palm oil supplementation at 5% EE (MEG5); (2) calcium salts of palm oil supplementation at 8% EE (MEG8); (3) 7.7% CS supplementation at 5% EE (CS5); and (4) 17.7% CS supplementation at 8% EE (CS8). Diets contained 55% orchardgrass hay, and fermentors were fed 72 g of dry matter/d. On d 8, 9, and 10 of each period, digesta effluent samples were taken for ruminal NH3, volatile fatty acids, nitrogen metabolism analysis, and long-chain FA and AA flows. Statistical analysis was performed using the MIXED procedure (SAS Institute Inc., Cary, NC). We detected an interaction between FA source and dietary EE level for acetate, where MEG8 had the greatest molar proportion of acetate. Molar proportions of propionate were greater and total volatile fatty acids were lower on CS diets. Supplementation of CS decreased overall ruminal nutrient true digestibility, but dietary EE level did not affect it. Diets containing CS had greater biohydrogenation of 18:2 and 18:3; however, biohydrogenation of 18:1 was greater in MEG diets. Additionally, CS diets had greater ruminal concentrations of trans-10/11 18:1 and cis-9,trans-11 conjugated linoleic acid. Dietary EE level at 8% negatively affected flows of NH3-N (g/d), nonammonia N, and bacterial N as well as the overall AA outflow. However, treatments had minor effects on individual ruminal AA digestibility. The shift from acetate to propionate observed on diets containing CS may be advantageous from an energetic standpoint. Moreover, CS diets had greater ruminal outflow of trans-10/11 18:1 and cis-9,trans-11 conjugated linoleic acid than MEG diets, suggesting a better FA profile available for postruminal absorption. However, dietary EE at 8% was deleterious to overall N metabolism and AA outflow, indicating that CS can be fed at 5% EE without compromising N metabolism.