Nutritional Control of Soybean Seed Storage Protein

Paek, Nam‐Chon; Imsande, John; Shoemaker, Randy C.; Shibles, Richard

doi:10.2135/cropsci1997.0011183x003700020031x

Cited by 78 publications

(76 citation statements)

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“…For those grown on mineral N, the seed contained increasingly greater protein concentration with increasing proportion of nitrogen supplied in the reduced form. Paek et al (1997) analyzed the seed produced from these treatments to investigate how change in seed protein concentration, independent of genotype, changes seed protein composition. The results of two experiments were consistent in showing that raising soya bean seed protein concentration through enhanced plant N simulation results in poorer protein quality (Fig 3).…”

Section: Variation In Total Seed Protein Compositionmentioning

confidence: 99%

Developments in plant breeding for improved nutritional quality of soya beans I. Protein and amino acid content

Clarke

Wiseman

2000

J. Agric. Sci.

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Soya beans, like other legumes, contain low concentrations of the nutritionally essential sulphur amino acid, methionine. Cysteine, although not an essential amino acid because it can be synthesized from methionine, also influences the nutritional quality of soya bean products when it is only present in low levels. A low cysteine content will also aggravate a methionine deficiency. Soya bean lines deficient in 7S protein subunits have been identified. The 7S proteins contain substantially less methionine and cysteine than the 11S proteins. With the myriad of genetic null alleles for these subunits it may be possible to tailor the 7S/11S storage protein ratio and their total composition in seeds to include only those subunits with the richest sulphur amino acid composition. Cotyledon feeding experiments, using isolated soya bean cotyledons, demonstrated that addition of methionine to the culture media caused increased synthesis of both proteins and free amino acids but the mechanism by which this takes place is not clear. Biotechnological approaches to improve nutritional value of soya beans include elevated expression of genes that originate from other species which encode high-sulphur proteins. High level expression of a 2S Brazil nut albumin gene in soya bean resulted in raised methionine concentration although the Brazil nut gene is highly antigenic and therefore will not be useful in production agriculture. Modification of glycinin to increase sulphur amino acid content is possible, and these gene products are capable of normal assembly into trimers in vitro although are rapidly degraded in vivo by the asparaginyl endopeptidase responsible for post-translational modification of proglycinin. Solutions to the methionine deficiency may be anticipated from a combination of approaches followed in laboratories worldwide. Many of these approaches are not without difficulty but, despite this, the likelihood is that soya beans with improved nutritional quality (which may not be confined to sulphur-containing amino acids as other nutritionally essential amino acids are also valuable) will be available in the near future. It will be essential to confirm that the increased total methionine (or other amino acid) is digestible to the animal to at least the same degree as conventional cultivars.

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Section: Variation In Total Seed Protein Compositionmentioning

confidence: 99%

Developments in plant breeding for improved nutritional quality of soya beans I. Protein and amino acid content

Clarke

Wiseman

2000

J. Agric. Sci.

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“…A similar phenomenon was noted in barley where a sulfur poor storage protein increased at a greater rate than a sulfur-rich protein with increasing seed protein concentration (Giese et aL, 1983;Giese and Hopp, 1984). Paek et al (1997) speculated that inability of the soybean seed to increase glycinin concentrations in parallel with P-conglycinin, may be due to a limitation in S availability to the developing seed. Increased protein production in the seed through increased nitrogen availability may dilute the otherwise high quality glycinin proteins by production of the (5 subunit, if S supply is not increased concurrently.…”

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confidence: 56%

“…Paek et al (1997) found nitrogen deficiency (here administered by allowing soybean to use Na fixation as its sole source of N) to reduce the total quantity of each subunit of both glycinin and P-conglycinin. The reduction in accumulation of these proteins was not uniform, however.…”

Section: Utilization Of S Witiiin Tiie Seedmentioning

confidence: 99%

“…Alternately, there was an increase in the relative abundance of glycinin subunits. Although the total seed protein concentration was reduced, the quality of the protein increased.Conversely, soybean seed protein concentration was found to increase as nitrate was incrementally substituted for ammonium in the nutrient solution (Paek et al, 1997). In this scenario, as the total protein concentration increased in the seed, the P-subunit came to make up a large portion of the total storage protein content.…”

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confidence: 97%

See 1 more Smart Citation

Distribution and Mobilization of Sulfur during Soybean Reproduction

Naeve

Shibles

2005

Crop Science

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This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely aflFect reproduction.In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overiaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book.Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. UMI GENERAL INTRODUCTION Dissertation OrganizationA discussion of results obtained from studies conducted on soybean sulfur metabolism is presented here as two manuscripts for the eventual submission for publication in Crop Science. A general introduction precedes these manuscripts giving a broad overview of plant sulfur metabolism, sulfur transpon, and soybean seed protein accumulation. A general conclusion chapter follows, summarizing findings of the two studies presented here.References cited in this dissertation are coalesced and listed at the end of the dissertation.The first manuscript paper discusses the distribution and mobilization of sulfur acquired by soybean during seed development, while the second takes up nitrogen and sulfur stress effects on mobilization of sulfur to developing soybean seed. RationaleSoybean seed is an important source of dietary protein for livestock and humans;however, soybean seed protein itself contains low, potentially growth-limiting concentrations of the sulfur-containing amino acids, methionine (met) and cysteine (cys), when used as the sole protein source for monogastric mammals. Methionine and cys are considered "essential amino acids" indicating that they cannot be synthesized de novo by monogastric mammals (Food and Agricultural Organization and World Health Organization, 1989). Methionine is the primary essential amino acid that is deficient in legume proteins (DeLumen et al., 1997), and soybean seed proteins contain about half of the met found in FAO's (Food and 2 Agricultural Organization) egg protein standard (Burton et al., 1982). This limitation reveals itself in high protein rations when the majority of the ingested protein is derived from soybean....

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“…Moreover, the accumulation of f3-conglycinin, especially the f3-subunit was positively correlated with the seed total nitrogen concentration (Ohtake at al. 1996;Peak et al 1997). Gayler and Sykes (1985) reported that sulfur deficiency led to a decrease in the level of glycinin, and an increase in the level of f3-conglycinin.…”

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confidence: 99%