Formation of Protein Bodies in the Starchy Endosperm of Rice (Oryza sativa L.): A Re-investigation*

Bechtel, Donald B.; Juliano, B. O.

doi:10.1093/oxfordjournals.aob.a085852

Cited by 101 publications

(60 citation statements)

References 14 publications

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“…The synthesis and accumulation of the glutelin molecule in the starchy endosperm of developing rice thus is very different from those processes during zein synthesis in maize seeds (4). During zein synthesis, the precursor polypeptides are only 1,100 and 2,000 D heavier than the native polypeptides.…”

Section: And B)mentioning

confidence: 90%

“…4). Mainly 57-and 13-kD polypeptides were synthesized; no synthesis of the 22-to 23-and 37-to 39-kD peptide groups was observed up to 4 h. Thus, the processing of the 57-kD precursor to mature glutelin subunits was not detected in dissected Figure 6. Labeled, nascent 57-kD polypeptide was present mainly in the 0.5 M NaCl-soluble globulin fraction.…”

Section: And B)mentioning

confidence: 91%

“…The homogenate of 10-DAF starchy endosperm was prepared as described in "Materials and Methods," then fractionated into RER, membrane-bound polysomes, and free-polysomes. mRNA was isolated from the membrane-bound polysomes according to the methods of Larkins and Davies (15) and Burr and Burr (4). The homogenate, RER, free and membrane-bound polysomes, and mRNA were added to the wheat germ cell-free translation system.…”

Section: And B)mentioning

confidence: 99%

“…Several storage protein polypeptides of cereals (4,8,16,20) and legumes (9,11,24,28) are synthesized as short-lived precursor polypeptides which may undergo modification during or after translation. Some of these precursors seem to be the equivalents of precursor polypeptides of secretory or membrane proteins in that a 'signal' peptide may be present on the polypeptide (2).…”

mentioning

confidence: 99%

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Biosynthesis of Storage Proteins in Developing Rice Seeds

Yamagata

Sugimoto²,

Tanaka³

et al. 1982

Plant Physiol.

289

203

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Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the starchy endosperm protein of rice (Oryza sativa L. Japonica cv Koshihikari) during seed development confirmed that storage protein begins to accumulate about 5 days after flowering. Two polypeptide groups, 22 to 23 and 37 to 39 kilodaltons, the components of glutelin, the major storage protein in rice seed, appeared 5 days after flowering. A 26-kilodalton polypeptide, the globulin component, also appeared 5 days after flowering. Smaller polypeptides (10-to 16-kilodaltons) including prolamin components, appeared about 10 days after flowering. In contrast, the levels of the 76-and 57-kilodalton polypeptides were fairly constant throughout seed development. Transmission electron microscopy and fractionation by sucrose density gradient centrifugation of the starchy endosperms at various stages of development showed that protein body type II, the accumulation site of glutelin and globulin, was formed faster than protein body type I, the accumulation site of prolamin.The 57-kilodalton polypeptide but not the glutelin subunits was labeled in a 2-hour treatment with I14CIleucine given between 4 and 12 days after flowering to developing ears. In vivo pulse-chase labeling studies showed the 57-kllodalton polypeptide to be a precursor of the 22 to 23 and 37 to 39 kilodalton subunits. The 57-kilodalton polypeptide was salt-soluble, but the mature glutelin subunits were almost salt insoluble.In vitro protein synthesis also showed that the mRNAs directly coding the 22 to 23 and 37 to 39 kilodalton components were absent in developing seeds and that the 57-kilodalton polypeptide was the major product. Thus, it was concluded that the two subunits of rice glutelin are formed through post-translational cleavage of the 57-kilodalton polypeptide.The major storage proteins of most cereal grains are glutelin and prolamin. In rice grains, however, glutelin is the major protein of the starchy endosperm, constituting at least 80%o of the total protein, prolamin accounting for less than 5% (12). Rice glutelin has a mol wt of 6 x I05 according to Tecson et al. (27), but Takeda et a!. (25) demonstrated that it has a heterogeneous mol wt. The increase in glutelin in the developing rice grain coincides with the appearance of PB' in the starchy endosperm 7 to 8 DAF (7,29), and glutelin is found exclusively in PB (7,26,30). In a previous paper (26), we reported two types of PB in the starchy endosperm of rice grains and described their isolation. One (type I, PB-I) is spherical with a concentric ring structure, whereas the other (type II, PB-II) is stained homogeneously by osmium tetroxide and does not have this structure. PB-I contains prolamin, and PB-II is rich in glutelin and globulin. The glutelin in PB-II is composed of two principal subunits, the 22-to 23-and 37-to 39-kD complexes, and the prolamin in PB-I is composed mainly of 13-kD polypeptide.

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Section: And B)mentioning

confidence: 90%

Section: And B)mentioning

confidence: 91%

Section: And B)mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Biosynthesis of Storage Proteins in Developing Rice Seeds

Yamagata

Sugimoto²,

Tanaka³

et al. 1982

Plant Physiol.

289

203

View full text Add to dashboard Cite

show abstract

“…Transmission electron microscopy (TEM) analyses have revealed that two types of morphologically distinct PB exist in rice endosperm: type I PB (PB-I) is a spherical and lamellar PB with a diameter of 1-2 μm; type II PB (PB-II) is a crystalline PB that shows dense, uniform staining with osmium tetroxide and shows an irregular shape with a diameter of 2-4 μm Pomeranz 1978, Tanaka et al 1980). PB-I develops within rough endoplasmic reticulum (ER); PB-II is a protein storage vacuole which deposits proteins via Golgi apparatus (Bechtel and Juliano 1980). PB-I consists mainly of prolamins and comprises approximately 20% of milled rice protein.…”

Section: Introductionmentioning

confidence: 99%

Ultrastructure of protein bodies in mutant rice (Oryza sativa L.) with altered storage protein composition

et al. 2011

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Many rice mutants with altered storage protein composition, which relate to protein body II (PB-II), have been produced in order to obtain rice with new cooking properties or lowered protein digestibility, but the PB structures in the endosperm of such mutants remain obscure. We examined the polypeptide composition and ultrastructure of the endosperm during seed development using rice mutants with the low-glutelin-content gene (Lgc1) and/or 26 kDa globulin deficient gene (glb1). Lgc1 and glb1 have deletions of a region including glutelin structural genes and 26 kDa globulin gene, respectively. Mutants with Lgc1 accumulated prolamin polypeptides from an early stage of seed development, and numerous intact PB-I and a few, small, chipped PB-II were observed in the endosperm. The glb1 mutant showed deformed PB-II structures, which had similar electron density to wild-type PB-II. Both glutelins and globulins accumulate in PB-II, but the influence of the change in their composition on PB-II structure would be different. The unique PB-II structure in the glb1 mutant may bring about new processing properties for rice.

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Germ Oils from Different Sources

Dunford

2005

Bailey's Industrial Oil and Fat Products

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Plant germ oils of high nutritional quality can be obtained from cereal grains. Germ oil processing presents a challenge because of the high content of biologically active heat labile components. Physical refining methods improve retention of these compounds in the final product. Currently plant germ oils, except corn germ oil, are produced for specialty markets in the United States. However, increasing consumer demand for healthy food products may change the market trends in the future. Several reviews have been published on wheat corn, and rice bran oils over the years. Therefore, this chapter, with sufficient background information, will emphasize the latest literature on composition, nutritional characteristics, and processing methods of plant germ oils.

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Formation of Protein Bodies in the Starchy Endosperm of Rice (Oryza sativa L.): A Re-investigation*

Cited by 101 publications

References 14 publications

Biosynthesis of Storage Proteins in Developing Rice Seeds

Biosynthesis of Storage Proteins in Developing Rice Seeds

Ultrastructure of protein bodies in mutant rice (Oryza sativa L.) with altered storage protein composition

Germ Oils from Different Sources

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