Lipids, Proteins, and Structure of Seed Oil Bodies from Diverse Species

Tzen, Jason T.C.; Cao, Yi-zhi; Laurent, Pascal; Ratnayake, Chandra; Huang, Anthony H. C.

doi:10.1104/pp.101.1.267

Cited by 489 publications

(430 citation statements)

References 16 publications

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“…In addition to changes in the NDF fraction, the only other measurable difference we observed in transgenic soybean was a significant increase in oil body size. Tzen et al (1993) reported that oil bodies from different species had average diameters that were different, but the differences were within a narrow range (0.6-2.0 mm). While we observed a similar range of oil body sizes in control soybean (0.72-2.5 mm), the oil bodies in our transgenic soy were significantly larger (1-14 mm).…”

Section: Discussionmentioning

confidence: 99%

Expression of Umbelopsis ramanniana DGAT2A in Seed Increases Oil in Soybean

et al. 2008

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Oilseeds are the main source of lipids used in both food and biofuels. The growing demand for vegetable oil has focused research toward increasing the amount of this valuable component in oilseed crops. Globally, soybean (Glycine max) is one of the most important oilseed crops grown, contributing about 30% of the vegetable oil used for food, feed, and industrial applications. Breeding efforts in soy have shown that multiple loci contribute to the final content of oil and protein stored in seeds. Genetically, the levels of these two storage products appear to be inversely correlated with an increase in oil coming at the expense of protein and vice versa. One way to overcome the linkage between oil and protein is to introduce a transgene that can specifically modulate one pathway without disrupting the other. We describe the first, to our knowledge, transgenic soy crop with increased oil that shows no major impact on protein content or yield. This was achieved by expressing a codon-optimized version of a diacylglycerol acyltransferase 2A from the soil fungus Umbelopsis (formerly Mortierella) ramanniana in soybean seed during development, resulting in an absolute increase in oil of 1.5% (by weight) in the mature seed.

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Section: Discussionmentioning

confidence: 99%

Expression of Umbelopsis ramanniana DGAT2A in Seed Increases Oil in Soybean

et al. 2008

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“…have a narrow size range within a species (Tzen et al, 1993). Physcomitrella might not have evolved a mechanism to control the sizes of OBs.…”

Section: Discussionmentioning

confidence: 99%

Oil Bodies and Oleosins in Physcomitrella Possess Characteristics Representative of Early Trends in Evolution

Huang

Chung²,

Lin³

et al. 2009

Plant Physiology

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Searches of sequenced genomes of diverse organisms revealed that the moss Physcomitrella patens is the most primitive organism possessing oleosin genes. Microscopy examination of Physcomitrella revealed that oil bodies (OBs) were abundant in the photosynthetic vegetative gametophyte and the reproductive spore. Chromatography illustrated the neutral lipids in OBs isolated from the gametophyte to be largely steryl esters and triacylglycerols, and SDS-PAGE showed the major proteins to be oleosins. Reverse transcription-PCR revealed the expression of all three oleosin genes to be tissue specific. This tissue specificity was greatly altered via alternative splicing, a control mechanism of oleosin gene expression unknown in higher plants. During the production of sex organs at the tips of gametophyte branches, the number of OBs in the top gametophyte tissue decreased concomitant with increases in the number of peroxisomes and level of transcripts encoding the glyoxylate cycle enzymes; thus, the OBs are food reserves for gluconeogenesis. In spores during germination, peroxisomes adjacent to OBs, along with transcripts encoding the glyoxylate cycle enzymes, appeared; thus, the spore OBs are food reserves for gluconeogenesis and equivalent to seed OBs. The one-cell-layer gametophyte could be observed easily with confocal microscopy for the subcellular OBs and other structures. Transient expression of various gene constructs transformed into gametophyte cells revealed that all OBs were linked to the endoplasmic reticulum (ER), that oleosins were synthesized in extended regions of the ER, and that two different oleosins were colocated in all OBs.Eukaryotes and prokaryotes contain neutral lipids in subcellular droplets as food reserves and/or for other purposes (Hsieh and Huang, 2004;Martin and Parton, 2006;Goodman, 2008;Rajakumari et al., 2008). These lipid droplets are present in seeds, pollens, fruits, and flowers of higher plants; the vegetative and reproductive organs of lower plants, algae, fungi, and nematodes; mammalian organs/tissues, such as mammalian glands and adipose tissues; and bacteria. Among all these lipid droplets, oil bodies (OBs) in seeds are the most prominent and have been extensively studied.Seeds of diverse plant species store oils (triacylglycerols [TAGs]) as food reserves for germination and postgermination growth (Napier et al., 1996;Frandsen et al., 2001;Murphy, 2001;Hsieh and Huang, 2004).The TAGs are present in small subcellular, spherical OBs of approximately 0.5 to 2 mm in diameter. Each OB has a matrix of TAGs surrounded by a layer of phospholipids (PLs) and the structural protein oleosins. The massive oleosins completely cover the surface of the OBs and prevent them from coalescence; so, a large surface area per unit TAG is available for lipase binding and catalysis during germination. Each oleosin molecule has a characteristic long central hydrophobic stretch, which forms a hairpin penetrating into the matrix TAGs for stable anchorage.Other than being present in the seeds of plants, oleos...

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“…Aleurone layers were separated from kernels harvested at 35 dap. At this stage of maturation, most of the oils and oleosins had been synthesized (Tzen et aL, 1993), and the kernels were still sufficiently soft such that the aleurone layers could be removed.…”

Section: Plant Materialsmentioning

confidence: 99%

Genetic dissection of the co‐expression of genes encoding the two isoforms of oleosins in the oil bodies of maize kernel

Lee

Ratnayake

Huang³

1995

The Plant Journal

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SummaryOleosins are abundant structural proteins on the surface of intracellular oil bodies in seeds. In many maize (Zea mays L.) inbreds, there are three oleosins, OLE18, OLE17, and OLE16, termed according to their apparent molecular weight, which are present in the proportional amounts of about 1:1:2 in isolated oil bodies. In some inbreds, OLE18 and OLE17 occur as molecular weight variants with a molecular weight difference of 1000 or less. In inbreds CM555 and FR2, OLE18 and OLE17, respectively, are absent; the respective genes olel8and olel7in the inbreds are present, but are transcriptionally inactive. The F 1 of CM555 × FR2 possesses both OLE18 and OLE17, as expected from the inheritance of ole18 and ole17 genes. In all inbreds examined, including CM555, FR2, and their F 1 hybrids, and in both the diploidic embryos and triploidic aleurone layers, the quantity of OLE18 and/or OLE17 equals that of OLE16. Since OLE18 and OLE17 are close members of the high-molecular weight (H) oleosin isoform whereas OLE16 belongs to the low-molecular weight (L) oleosin isoform, the results indicate the presence of equal amounts of the H and L isoforms in the oil bodies. The equality suggests the occurrence of a hetero-dimer, or -multimer, of the two isoforms. To probe the control mechanism for such a hetero-mer formation, CM555, FR2, and their F 1 hybrids, as well as Mo17 (a common inbred) have been used to analyze oleosin gene copy number, nuclear run-off transcription activity, transcript amount, and oleosin protein content. It has been determined that equal levels of H and L oleosin isoforms accumulate in oil bodies irrespective of the dosage of functional H and L genes. Therefore, the control of equality is not the consequence of the competition among the active H isoform genes for transcriptional machineries, but occurs at the post-transcriptional level, presumably at translation and/or through oleosin interaction (formation of heteromer) and stability.

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Lipids, Proteins, and Structure of Seed Oil Bodies from Diverse Species

Cited by 489 publications

References 16 publications

Expression of Umbelopsis ramanniana DGAT2A in Seed Increases Oil in Soybean

Expression of Umbelopsis ramanniana DGAT2A in Seed Increases Oil in Soybean

Oil Bodies and Oleosins in Physcomitrella Possess Characteristics Representative of Early Trends in Evolution

Genetic dissection of the co‐expression of genes encoding the two isoforms of oleosins in the oil bodies of maize kernel

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