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Summary: Accumulation of triacylglycerols (TAGs) is crucial during various stages of plant development. In Arabidopsis, two enzymes share overlapping functions to produce TAGs, namely acyl‐CoA:diacylglycerol acyltransferase 1 (DGAT1) and phospholipid:diacylglycerol acyltransferase 1 (PDAT1). Loss of function of both genes in a dgat1‐1/pdat1‐2 double mutant is gametophyte lethal. However, the key regulatory elements controlling tissue‐specific expression of either gene has not yet been identified.We transformed a dgat1‐1/dgat1‐1//PDAT1/pdat1‐2 parent with transgenic constructs containing the Arabidopsis DGAT1 promoter fused to the AtDGAT1 open reading frame either with or without the first intron.Triple homozygous plants were obtained, however, in the absence of the DGAT1 first intron anthers fail to fill with pollen, seed yield is c. 10% of wild‐type, seed oil content remains reduced (similar to dgat1‐1/dgat1‐1), and non‐Mendelian segregation of the PDAT1/pdat1‐2 locus occurs. Whereas plants expressing the AtDGAT1pro:AtDGAT1 transgene containing the first intron mostly recover phenotypes to wild‐type.This study establishes that a combination of the promoter and first intron of AtDGAT1 provides the proper context for temporal and tissue‐specific expression of AtDGAT1 in pollen. Furthermore, we discuss possible mechanisms of intron mediated regulation and how regulatory elements can be used as genetic tools to functionally replace TAG biosynthetic enzymes in Arabidopsis. [ABSTRACT FROM AUTHOR]

Lipid droplets (LDs) are the major sites of lipid and energy homeostasis. However, few LD biogenesis proteins have been identified. Using model microalga Chlamydomonas , we show that ABHD1, an α/β-hydrolase domain-containing protein, is localized to the LD surface and stimulates LD formation through two actions: one enzymatic and one structural. The knockout mutants contained similar amounts of triacylglycerols (TAG) but their LDs showed a higher content of lyso-derivatives of betaine lipid diacylglyceryl- N,N,N -trimethylhomoserine (DGTS). Over-expression of ABHD1 increased LD abundance and boosted TAG content. Purified recombinant ABHD1 hydrolyzed lyso-DGTS, producing a free fatty acid and a glyceryltrimethylhomoserine. In vitro droplet-embedded vesicles showed that ABHD1 promoted LD emergence. Taken together, these results identify ABHD1 as a new player in LD formation by its lipase activity on lyso-DGTS and by its distinct biophysical property. This study further suggests that lipases targeted to LDs and able to act on their polar lipid coat may be interesting tools to promote LD assembly in eukaryotic cells. [ABSTRACT FROM AUTHOR]

FatPlants, an open-access, web-based database, consolidates data, annotations, analysis results, and visualizations of lipid-related genes, proteins, and metabolic pathways in plants. Serving as a minable resource, FatPlants offers a user-friendly interface for facilitating studies into the regulation of plant lipid metabolism and supporting breeding efforts aimed at increasing crop oil content. This web resource, developed using data derived from our own research, curated from public resources, and gleaned from academic literature, comprises information on known fatty-acid-related proteins, genes, and pathways in multiple plants, with an emphasis on Glycine max, Arabidopsis thaliana , and Camelina sativa. Furthermore, the platform includes machine-learning based methods and navigation tools designed to aid in characterizing metabolic pathways and protein interactions. Comprehensive gene and protein information cards, a Basic Local Alignment Search Tool search function, similar structure search capacities from AphaFold, and ChatGPT-based query for protein information are additional features. Database URL : https://www.fatplants.net/ [ABSTRACT FROM AUTHOR]

Generating new strategies to improve plant performance and yield in crop plants becomes increasingly relevant with ongoing and predicted global climate changes. E3 ligases that function as key regulators within the ubiquitin proteasome pathway often are involved in abiotic stress responses, development, and metabolism in plants. The aim of this research was to transiently downregulate an E3 ligase that uses BTB/POZ-MATH proteins as substrate adaptors in a tissue-specific manner. Interfering with the E3 ligase at the seedling stage and in developing seeds results in increased salt-stress tolerance and elevated fatty acid levels, respectively. This novel approach can help to improve specific traits in crop plants to maintain sustainable agriculture. [ABSTRACT FROM AUTHOR]

Physaria fendleri is a burgeoning oilseed crop that accumulates the hydroxy fatty acid (HFA), lesquerolic acid, and can be a non-toxic alternative crop to castor for production of industrially valuable HFA. Recently, P. fendleri was proposed to utilize a unique seed oil biosynthetic pathway coined "triacylglycerol (TAG) remodeling" that utilizes a TAG lipase to remove common fatty acids from TAG allowing the subsequent incorporation of HFA after initial TAG synthesis, yet the lipase involved is unknown. SUGAR DEPENDENT 1 (SDP1) has been characterized as the dominant TAG lipase involved in TAG turnover during oilseed maturation and germination. Here, we characterized the role of a putative PfeSDP1 in both TAG turnover and TAG remodeling. In vitro assays confirmed that PfeSDP1 is a TAG lipase and demonstrated a preference for HFA-containing TAG species. Seed-specific RNAi knockdown of PfeSDP1 resulted in a 12%–16% increase in seed weight and 14%–19% increase in total seed oil content with no major effect on seedling establishment. The increase in total oil content was primarily due to ~4.7% to ~14.8% increase in TAG molecular species containing two HFA (2HFA-TAG), and when combined with a smaller decrease in 1HFA-TAG content the proportion of total HFA in seed lipids increased 4%–6%. The results are consistent with PfeSDP1 involved in TAG turnover but not TAG remodeling to produce 2HFA-TAG. Interestingly, the concomitant reduction of 1HFA-TAG in PfeSDP1 knockdown lines suggests PfeSDP1 may have a role in reverse TAG remodeling during seed maturation that produces 1HFA-TAG from 2HFA-TAG. Overall, our results provide a novel strategy to enhance the total amount of industrially valuable lesquerolic acid in P. fendleri seeds. [ABSTRACT FROM AUTHOR]

A newly designed and constructed sliding plate rheometer is used to measure the high frequency (210 Hz) linear viscoelastic properties of two model polymers: polybutene (PB) and polydimethylsiloxane (PDMS). Using well-known rheological models, extrapolations of the viscoelastic measurements obtained on a rotational parallel plate rheometer to a frequency of 210 Hz are used to assess the performance of the high frequency sliding plate rheometer. Good agreement between the extrapolated and measured data demonstrates the ability of the sliding plate rheometer to measure the high frequency rheological properties of both Newtonian and shear-thinning materials.

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Erucic acid concentration in oil of most camelina (Camelina sativa L. Crantz) genotypes exceeds the 2% threshold allowed by the U.S. Food and Drug Administration (FDA) for use as a food additive. Lowering erucic acid concentration below the FDA threshold enables marketing camelina as edible oil for human consumption, greatly expanding potential uses to include food ingredients such as marinades, salad dressings, spreads, and dips. A mutant camelina line, LE1914, created via ethyl methanesulfonate mutagenesis at one FAE1 locus (FAE1‐B), produces seed oil with low (∼0.6%) erucic acid concentration (LE). This mutant trait was introgressed into elite camelina breeding lines to create LE lines adapted to Pacific Northwest dryland agriculture. These LE lines were evaluated in a large, replicated field trial in Pullman, WA, in 2019. One line, 'WA‐LE1' (Reg. no. CV‐15, PI 699653), exhibited agronomic performance similar to check cultivars while maintaining the low (∼0.6%) erucic acid concentration necessary for FDA approval as a food additive. WA‐LE1 is an edible oil camelina cultivar that also contains the Group 2 herbicide resistance trait of WA‐HT1 that was released in 2018. WA‐LE1 should expand marketability and increase profitability of camelina crops in the Pacific Northwest. Core Ideas: A mutation causing low erucic acid content was incorporated into a highly productive camelina cultivar, 'WA‐LE1'.The low erucic acid trait is required by the FDA for food use.A food market will expand the utility of camelina beyond biofuels.'WA‐LE1' carries a gene for tolerance to Group 2 herbicides. [ABSTRACT FROM AUTHOR]

Plant oils are a renewable natural resource providing food, feed, bio-fuels, and chemicals. The various applications of plant oils stem the highly diverse fatty acid compositions produced by plants. However, most crop plants have a very limited fatty acid composition, and with few acceptations there has been inadequate success in controlling plant oil fatty acid composition through bioengineering. Some of the bioengineering difficulties derive from an incomplete understanding of how plants control the flux of fatty acids through the glycolipid metabolic network for fatty acid modification and accumulation of diverse triacylglycerol molecular species. This chapter summarizes current knowledge and uncertainties for the metabolic pathways that compose the glycerolipid metabolic network and the gene products involved. Current hypotheses for the cellular organization of lipid metabolism into distinct metabolons that may contribute to the differential flux through the glycerolipid biosynthetic network by different plants are also discussed. [ABSTRACT FROM AUTHOR]

Oilseed plants accumulate triacylglycerol (TAG) up to 80% of seed weight with the TAG fatty acid composition determining its nutritional value or use in the biofuel or chemical industries. Two major pathways for production of diacylglycerol (DAG), the immediate precursor to TAG, have been identified in plants: de novo DAG synthesis and conversion of the membrane lipid phosphatidylcholine (PC) to DAG, with each pathway producing distinct TAG compositions. However, neither pathway fits with previous biochemical and transcriptomic results from developing Physaria fendleri seeds for accumulation of TAG containing >60% lesquerolic acid (an unusual 20 carbon hydroxylated fatty acid), which accumulates at only the sn-1 and sn-3 positions of TAG. Isotopic tracing of developing P. fendleri seed lipid metabolism identified that PC-derived DAG is utilized to initially produce TAG with only one lesquerolic acid. Subsequently a nonhydroxylated fatty acid is removed from TAG (transiently reproducing DAG) and a second lesquerolic acid is incorporated. Thus, a dynamic TAG remodeling process involving anabolic and catabolic reactions controls the final TAG fatty acid composition. Reinterpretation of P. fendleri transcriptomic data identified potential genes involved in TAG remodeling that could provide a new approach for oilseed engineering by altering oil fatty acid composition after initial TAG synthesis; and the comparison of current results to that of related Brassicaceae species in the literature suggests the possibility of TAG remodeling involved in incorporation of very long-chain fatty acids into the TAG sn-1 position in various plants. [ABSTRACT FROM AUTHOR]

Summary: Arbuscular mycorrhizal fungi (AMF) are among the most ancient, widespread and functionally important symbioses on Earth that help feed the world. Yet, mass‐production of clean (i.e. in vitro produced), safe and robust inoculum at affordable costs remains a critical challenge. Very recently, Luginbuehl et al. (2017) found that plants supply lipids to the symbiotic partner, thus 'providing the AMF with a robust source of carbon for their metabolic needs'. Hence, engineering plants for enhanced delivery of lipids to AMF could represent an innovative avenue to produce a novel generation of high‐quality and cost‐effective bio‐fortified AMF inoculants for application in agro‐ecosystems. [ABSTRACT FROM AUTHOR]