Crop Science Journal of Natural Resources and Life Sciences Education
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (59)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wilcox, J. R.
Right arrow Articles by Raboy, V.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Wilcox, J. R.
Right arrow Articles by Raboy, V.
Agricola
Right arrow Articles by Wilcox, J. R.
Right arrow Articles by Raboy, V.
Crop Science 40:1601-1605 (2000)
© 2000 Crop Science Society of America

CROP BREEDING, GENETICS & CYTOLOGY

Isolation of High Seed Inorganic P, Low-Phytate Soybean Mutants

James R. Wilcoxa, Gnanasiri S. Premachandrab, Kevin A. Youngc and Victor Raboyc

a USDA-ARS, Crop Production and Pathology Research and Dep. of Agronomy, Purdue Univ., West Lafayette, IN 47907-1150 USA
b Dep. of Agronomy, Purdue Univ., Aberdeen, ID USA
c USDA-ARS, Small Grain and Potato Germplasm Research, 1691 South 2700 West, Aberdeen, ID 83210 USA

jwilcox{at}purdue.edu


   ABSTRACT
TOP
 NOTES
 ABSTRACT
INTRODUCTION
 Materials and methods
 Results and discussion
 REFERENCES
 
Phosphorous in soybean [Glycine max (L.) Merr.] seed is stored primarily as phytic acid, which is nutritionally unavailable to nonruminant livestock. The objective of this study was to isolate mutations that reduce soybean seed phytic acid P and increase seed inorganic P. Following treatment with ethyl methanesulfonate, M2 through M6 plants were screened for high seed inorganic P. Seeds of M2 plants high in inorganic P produced progenies high in inorganic P through the M6 generation. M6 progenies of one plant averaged 6.84 g kg-1 seed phytic acid and inorganic P varied from 2.34 to 4.41 g kg-1 or 60 to 66% of phytic acid P plus inorganic P. M6 progenies of a second plant averaged 10.89 g kg-1 phytic acid and varied from 1.21 to 3.84 g kg-1 inorganic P, representing from 47 to 51% of the sum of phytic acid P plus inorganic P. In contrast, nonmutant seeds of the check cultivar Athow contained 15.33 g kg-1 phytic acid and averaged 0.74 g kg-1 inorganic P, representing 15% of the sum of phytic acid P plus inorganic P. Low phytic acid and high inorganic P in these progenies should increase the nutritional value of soy meal and reduce excess P in livestock manure.


   INTRODUCTION
TOP
 NOTES
 ABSTRACT
 INTRODUCTION
Materials and methods
 Results and discussion
 REFERENCES
 
SOYBEAN MEAL is an important source of protein in livestock feeds and is important in human nutrition as well. Most of the P in soybean seed is stored in the form of phytic acid (myo-inositol 1,2,3,4,5,6-hexaphosphate), and phytic acid P is nutritionally unavailable to nonruminant livestock (Erdman, 1979). Additionally, phytic acid is a strong chelating agent that can bind metal ions, reducing availability of iron, zinc, calcium, and magnesium (Brown and Solomons, 1991; Erdman, 1981; McCance and Widdowson, 1935; Mendoza et al., 1998). Soy meal is commonly supplemented with inorganic P, and more recently with the enzyme phytase to increase the bioavailability of P and of these metal ions (Adeola, 1995; Adeola et al., 1995).

Mutants of corn (Zea mays L.) and of barley (Hordeum vulgare L.) have been isolated with genetically reduced amounts of phytic acid in the seed (Ertl et al., 1998; Larson et al., 1998; Raboy and Gerbasi, 1996; Rasmussen and Hatzack, 1998). These low phytic acid (lpa) mutants have as much as a 70% reduction in seed phytic acid with corresponding increases in inorganic P. Substitution in feeds of wild-type or normal phytic acid grains with low-phytate grains demonstrates that grain phytic acid P is "nonavailable" P in nonruminant diets. Observed reductions in animal waste P were proportional to the genetically conferred reductions in grain phytic acid P. A growing number of poultry, swine, and fish nutrition studies have shown that the amount of "available P" in low-phytate grains, P absorbed and utilized by an animal, is increased in proportion to the decrease in grain phytic acid P. Depending on the diet formulation, animals can absorb from 25 to 50% more P from the low-phytate grain, and excrete that much less grain P as fecal P, when compared with the amount of P these animals absorb from normal grains (Ertl et al., 1998; Huff, et al., 1998; Pierce et al., 1998; Sugiura et al., 1999; Veum et al., 1998). Low-phytate soy feed formulations had a beneficial effect on zinc and copper absoption and status in infant rhesus monkeys (Macaca mulatta) (Lonnerdal et al., 1999). Iron absorption from tortillas made from genetically modified low phytate maize was greater than from wild-type maize in human diets (Mendoza et al., 1998). Supplementing swine diets with phytase also has resulted in a reduction of fecal P excretion (Lei et al., 1993).

Since corn-soybean meal and soy meal are commonly fed livestock rations, reducing phytic acid in soybean would contribute to more efficient livestock feeds and reduced P in livestock manure. Previous evaluations of soybean have not identified genotypes with low levels of phytic acid in the seed. A large number of previous studies have surveyed the total P and phytic acid P content of soybean cultivars and lines and those of other legumes (Raboy, 1997). These studies found that one can observe heritable variation for seed phytic acid P among soybean lines ranging up to 50% of the mean value. However, this variation mostly reflects variation in seed total P, with the proportion of seed total P found as phytic acid P remaining relatively constant. Raboy et al. (1984) reported that phytic acid P varied from 67 to 77% of total P among seeds of 38 soybean cultivars. Differences among cultivars in the percent of seed total P represented by phytic acid P were not statistically significant. Little variation in seed nonphytic acid P, equivalent to "available P" in nonruminant nutrition, has been observed in these surveys.

The objective of this research was to isolate soybean mutants with decreased phytic acid P and increased seed inorganic P, similar to the low phytic acid mutants isolated previously in cereal grains.


   Materials and methods
TOP
 NOTES
 ABSTRACT
 INTRODUCTION
 Materials and methods
Results and discussion
 REFERENCES
 
Plant Culture and Screening for High Inorganic P (HIP) Seed
About 2500 seeds of the soybean breeding line CX1515-4 were soaked for 24 h in a 18 mM solution of ethyl methanesulfonate (EMS), a mutagenic agent. The breeding line CX1515-4 is an F4 plant selection from the cross CRS3-998-24-1 x C1813. CRS3-998-24-1 is a selection from cycle 1 of a recurrent selection program for high seed protein (478 g kg-1 protein, dry basis). C1813 is a selection from the cross C1655 x `Pella 86'. The parentage of C1665 is `Nebsoy' (Williams et al., 1980) x A75-305022, and A75-305022 is a selection from the cross `Wye' x [`Amsoy' (Weber, 1966) x `Wayne' (Bernard, 1966)]. Following the 24-h soak, seeds were rinsed in distilled water and planted in rows spaced 10 cm apart in a sand bench. Emerged seedlings were transplanted to clay pots containing a sand-soil-peat mixture, and these M1 plants were grown to maturity.

Seeds were harvested from about 1000 individual M1 plants and the M2 generation grown at the Purdue University Agronomy Research Center in 1996. Ten to 20 seeds from each M1 plant were sown in a Chalmers soil (fine-silty, mixed, mesic Typic Haplaquoll) in rows 1 m in length, spaced 0.75 m apart. At maturity, M3 seed were threshed from the pods of five M2 plants from each row.

M3 seeds from a total of 3,994 M2 plants were individually tested for the High Inorganic P (HIP) phenotype associated with homozygosity for a low phytic acid mutation. A preliminary analysis of seed produced by nonmutant soybean cultivars grown under standard field conditions indicated that these seed typically contained about 0.2 g inorganic P kg-1. For purposes of comparison, each P fraction (inorganic P or phytic acid P) is expressed as its P content, atomic weight 31. These seed typically contain about 5 g or more total P kg-1, so that inorganic P typically represents about 5% of total seed P. These data are similar to data reported in an earlier study (Raboy and Dickinson, 1987). Seeds were screened for those containing substantial increases in inorganic P as compared with the typically low levels found in nonmutant seeds.

For routine screening, one M3 seed representing each M2 was individually crushed, and extracted overnight in 2.5 mL 12.5% (v/w) TCA:25 mM MgCl2 at 4°C, with gentle shaking. Extracts were allowed to settle for 30 min, and aliquots of each single-seed extract were assayed for inorganic P by a modification of the method of Chen et al. (1956), designed for use in microtitre plates. The assay total volume was 200 µL. A 10-µL aliquot of each single-seed extract was placed in a microtitre plate well, to which was added 90 µL DD H2O, a 100 µL of colorimetric reagent that was 1 vol 3 M H2SO4, 1 vol 0.02 M ammonium molybdate, 1 vol 10% (v/v) ascorbic acid and 2 vol DD H2O. Assays were incubated at room temperature for 1.5 h, and the results were scored visually for the presence or absence of HIP.

Each microtitre plate included five P standards made by appropriate dilutions of 1mM K2HPO4 to achieve (i) 0.0 µg P; 2) 0.15 µg P; (ii) 0.46 µg P; (iii) 0.93 µg P; and (iv) 1.39 µg P. In practice, nonmutant seeds give a visual result equal to or less than the second colorimetric standard (0.15 µg P). Any seed extracts testing higher than the third standard (0.46 µg P) were deemed HIP. Previous screening for low phytic acid mutants in cereal crops used 0.4 M HCl for seed extraction, but preliminary development of methods for use in soybean screening found that this reagent resulted in a low frequency of artificial results falsely indicating HIP in seed actually containing low levels of inorganic P. Few such artifacts were observed when using the TCA solution.

Initial Test for Correspondence of High Inorganic P and Reduced Phytic Acid
To provide an initial test of the correspondence between increased inorganic P and reduced phytic acid P, additional seeds from selected progenies were subjected to a more rigorous single-seed extraction and assay of inorganic P and phytic acid P. Single seeds were weighed, crushed and extracted overnight in 20 (v/w) 12.5% TCA:25 mM MgCl2 at 4°C, with magnetic stirring. Extracts were then sonicated for 1 min at 4°C. Following centrifugation (10 000 g, 10 min), inorganic P in the supernatants was assayed colorimetrically in triplicate as described by Chen et al. (1956).

Anion-exchange HPLC analyses of phytic acid in these single-seed supernatants was then performed using the following modification of the methods as described (Phillippy and Bland, 1988; Rounds and Nielsen, 1993). The supernatants were first diluted from 3- to 6-fold with DD H2O (as needed to yield phytic acid peaks within the limits of the standard curve described below), filtered through Whatman No. 1 filter paper, and passed through Millipore HV 0.45-µm filters. Aliquots were then fractionated on a Dionex IonPac AS7 anion-exchange column, equipped with a Dionex IonPac AG7 guard column (Dionex Corp., Sunnyvale, CA), which had been equilibrated with 10 mM methyl piperazine, pH 4.0 (Buffer A). Phytic acid and other inositol phosphates were then eluted with the following gradient system at a flow rate of 0.5 min-1:0 to 1 min 100% Buffer A; 1 to 26 min a concave gradient from 0 to 15% M NaNO3, pH 4.0 (Buffer B); 21 to 41 min a linear gradient from 15 to 100% Buffer B. The column elutant was mixed with colorimetric reagent [0.015% (w/v) FeCl3:0.15% (w/v) sulfosalicylic acid] at a flow rate of 0.5 mL min-1, using an Alltech PEEK tee (Alltech, Inc., Nicholasville, KY) and a pulseless pump, and the mixture passed through a 290-cm reaction coil prior to peak detection via absorbance at 550 nm. Phytic acid peaks were identified as those eluting at the same time as standard phytic acid, and quantitated by the following standard curve, obtained via the analysis of four potassium phytate standards containing 25, 50, 75, and 100 nM potassium phytate; nM phytic acid =1.30 x 10-5 +5.79, R2 = 0.997 .

Segregation of the HIP/low-phytate trait in M3 through M6 Progenies of M153 and M766
Two progenies were identified as containing putative low phytic acid mutations, M153 and M766. To test for segregation of the HIP trait in their decedents, the following variation of the above colorimetric assay for inorganic P was used. A 50-µL aliquot of a TCA extract was transferred to a test tube with a disposable cuvette, to which was added 950 µL distilled water plus 1 mL of colorimetric reagent as described above. After 1 h, intensity of blue color was observed and visually compared with the pale colored solution from seed of `Athow' (Wilcox and Abney, 1997) that has normal levels of inorganic P. In subsequent tests, color was measured after 1 h at 820 nm wavelength in a spectrophotometer. In the M6 generation, inorganic P was determined on each of four to six seeds from each M6 plant. In all tests, comparisons were made with inorganic P levels in the cultivar Athow. Seeds with >1.20 g kg-1 P were classified as high, and those with <0.90 g kg-1 P were classified as low in inorganic P.

Remnant seed of M3 progenies that tested for the HIP phenotype were grown in the greenhouse at West Lafayette, IN, in 1996 to 1997, with one seedling per 15-cm clay pot. Seeds from individual M3 plants, either high or low in inorganic P, were seeded in progeny rows at the Agronomy Research Center, West Lafayette, IN, to produce the M4 generation. Rows were spaced 1 m apart, and length of the row was determined by the number of M4 seeds harvested from each M3 plant. The M5 generation was grown in the greenhouse during the 1997 to 1998 winter months, and the M6 generation grown in the field at West Lafayette, IN, in 1998, using plots similar to those in 1997. The number of plants per M5 progeny row varied from 5 to 30.

Individual plants were harvested from these rows at maturity. A composite of four to six seeds from specific M6 plants were analyzed for inorganic P with methods described above, and for phytic acid P using the "ferric precipitation" method as described by Raboy et al. (1984). Briefly, samples were extracted in 0.4 M HCl: 10% (w/v) sodium sulfate. Following centrifugation, supernatant phytic acid was precipitated as a ferric salt. Ferric phytates were washed, wet ashed, and digest phytic acid phosphorus content determined colorimetrically using the method as described (Chen et al., 1956). Phytic acid P (186 g per mole of phytic acid) is converted to phytic acid (MW 660) by multiplying by the conversion factor 3.5484.


   Results and discussion
TOP
 NOTES
 ABSTRACT
 INTRODUCTION
 Materials and methods
 Results and discussion
REFERENCES
 
Initial screening identified seed high in inorganic P (HIP), based on color intensity observations, from several M2 plants. Additional seeds from these plants and full-sibs of these plants were then screened for HIP. These screenings determined that seeds from M2 plant M153 were segregating for high versus low inorganic P (Table 1) . Seeds produced on two seedling progeny from M2 plant M153 indicated that progeny M153-1 produced seeds both high and low in inorganic P. The M4 progenies of plant M153-1 also produced plants that were both high and low in inorganic P, suggesting that M153-1 was heterozygous for loci controlling this trait.


View this table:
[in this window]
[in a new window]
  		Table 1 Distribution of plants producing seed with high or low inorganic P concentrations in succeeding generations of soybean mutant line M153, and for the cultivar Athow

 
Progenies of the M4 plant M153-1-1 were all low in inorganic P in the M5 generation (Table 1). All four M5 progenies bred true for low inorganic P in the M6 generation. Means and standard errors for inorganic P for the four M4 plants varied from 0.29 ± 0.01 to 0.42 ± 0.07 g kg-1 P, based on spectrophotometer evaluations. The cultivar Athow averaged 0.21 ± 0.03 g kg-1 P.

Progenies of M4 plant M153-1-4 were all high in inorganic P (Table 1). Sixteen M5 progeny rows were grown, and 15 of these progeny rows produced plants all high in inorganic P. One progeny row, M153-1-4-6, segregated for plants both high and low in inorganic P. Quantities of inorganic P among all M6 plants varied from a low of 2.34 to a high of 4.69 g kg-1 P in the seed.

A second M2 plant, designated M766, produced progeny that were both high and low for inorganic P (Table 2) . Progenies of M3 plants high in inorganic P were evaluated in the M4 through M6 generations. M4 plants M766-3-5, -3-8, -8-3, -8-4, and -8-5 produced lines all high in inorganic P. In the M5 generation, several of these lines bred true for high inorganic P and a few lines were segregating for this trait. Amounts of inorganic P among all HIP plants varied from 1.22 to 3.84 g kg-1 P in the seed, lower than the quantities observed among progenies of M153.


View this table:
[in this window]
[in a new window]
  		Table 2 Distribution of plants producing seed with high or low inorganic P concentrations in succeeding generations of soybean mutant line M766, and for the cultivar Athow

 
As a routine test to determine if these heritable increases in seed inorganic P are matched by equivalent reductions in seed phytic acid, individual seeds from selected progenies were extracted, and these extracts tested for both phytic acid P using HPLC, and inorganic P using the colorimetric assay. Typical results (Table 3) of these analyses show two M4 progenies that appeared to be homozygous nonmutant (low seed inorganic P), M153-1-1 and M766-3-8, and two M4 progenies that appeared to be homozygous mutant (HIP), M153-1-4 and M766-3-12. The seed phytic acid P and inorganic P levels of M153-1-1 and M766-3-8 were similar to values expected of nonmutant soybean seeds (Table 3). In M153-1-4 seed, phytic acid P appears to be reduced 80%, as compared with its sibling nonmutant line M153-1-1, and this reduction in phytic acid P is essentially matched by an equivalent, in terms of P, increase in inorganic P. As a result, the sum of phytic acid P and inorganic P in M153-1-4 is similar to that of M153-1-1. Similar results were observed for M766-3-12 (mutant) when compared with M766-3-8 (nonmutant). In these and other results of the single-seed HPLC tests of these progenies, increases in seed inorganic P were in every case matched by equivalent decreases in phytic acid P, so that the sum of the two remains constant. This conclusion was supported by the fact that these HPLC analyses revealed no unusual accumulations of other myo-inositol polyphosphates related to phytic acid, such as myo-inositol pentaphosphates (data not shown).


View this table:
[in this window]
[in a new window]
  		Table 3 Correspondence between increased inorganic P and decreased phytic acid P, as determined by anion-exchange HPLC, in individual M5 soybean seeds of selected M4 parents

 
These results were confirmed in an analysis of seeds produced by selected M6 plants both high and low for seed inorganic P (Table 4) . Seeds of selected M6 plants, both low and high in inorganic P, were analyzed for phytic acid P using a second method, ferric precipitation. As observed before, the sum of seed phytic acid P and inorganic P remained relatively constant across the check cultivar Athow, and both mutant and nonmutant progenies of M153 and M766. The overall mean value was 5.42 g phytic acid P + inorganic P kg-1, and the range was 4.73 to 6.23 g kg-1 (Table 4). Those progenies producing seed with high inorganic P therefore were low-phytate. The M6 progenies of M2 plant M153 that were high in inorganic P, were low in phytic acid and all had less phytic acid P than inorganic P. Inorganic P of these progenies varied from 60 to 70% of the sum of phytic acid P + inorganic P. The M6 progenies of M766 had about half of the seed P as inorganic P, somewhat less than that of the progenies of M153. Seeds of M766-3-5-4-156 were from a plant with low seed inorganic P. Both phytic acid and phytic acid P from this plant were very high compared to values for progenies of M153-1-4 or M766-8. In comparison, in seeds of Athow inorganic P represented only 15% of the sum of phytic acid P + inorganic P.


View this table:
[in this window]
[in a new window]
  		Table 4 Seed phytic acid, phytic acid P, and inorganic P of Athow and of selected soybean mutants

 
These results indicate that two independent, heritable and nonlethal soybean low phytic acid mutants have been isolated in progenies descending from M2 plants M153 and M766. These are phenotypically similar to the low phytic acid 1 mutants previously reported in corn, barley, and rice (Ertl et al., 1998; Larson et al., 1998, Larson et al., 2000; Raboy and Gerbasi, 1996). In such mutants, seed phytic acid P is reduced by 50% or more, as compared with wild-type or nonmutant seed, and this reduction is matched almost entirely by an equivalent increase in seed inorganic P, so that there is little or no effect on seed total P. When expressed as a percent of seed total P or percentage of the sum of phytic acid P and inorganic P, the reductions in soybean seed phytic acid P, and accompanying increases in inorganic P, are proportional in magnitude to those observed in cereal grain low phytic acid mutants. However, since soybean seed typically contain 50% or more seed total P than do cereal grains, in absolute terms the amount of P represented by these changes in seed P chemistry are far greater than that observed in the cereal mutant. As an example, the increases in inorganic P concentrations in M153-1-4 or M766-3-12 represent an amount of P greater than the concentration of total P typically found in most cereal grains.

While the development of low phytic acid feed grains such as corn and barley may contribute to improved management of P in livestock production, the fullest value of this crop genetics and breeding approach to improved P management requires the development soybean lines with reduced phytic acid P, since most livestock rations consist of a cereal grain and soymeal. Animal trials evaluating low phytic acid grains have confirmed that the amount of seed total P that is "available P" for nonruminants basically consists of the total of seed nonphytic acid P, and "nonavailable P" is phytic acid P (Ertl et al., 1998; Huff et al., 1998; Pierce et al., 1998; Veum et al., 1998). It is therefore likely that in seed produced by these soybean low phytic acid mutants, "available P" is probably about 75% of seed total P, as compared with approximately 25% of seed total P that would be predicted for nonmutant soybean seed. In standard rations for poultry or swine, the soy meal component can contribute up to approximately 50% of the phytic acid P and total P in the feed, not counting supplementary P. Therefore, soybean lines developed using these mutants, or similar genetic resources, would represent an improved source of P for animal feeds. Use of such seed would reduce the need for P supplementation of feeds, or reduce the need for phytase supplementation. In addition, use of such seed in feeds would represent a valuable tool in reducing the amount of phytic acid P in animal waste, contributing to the current efforts to improve the management of P in agricultural production and efforts to reduce the impact of this production on the environment. Soybean low phytic acid lines may also have value in other uses of soybean, both in human foods and in industrial applications.


   NOTES
TOP
 NOTES
ABSTRACT
 INTRODUCTION
 Materials and methods
 Results and discussion
 REFERENCES
 
Journal Paper no. 16079 of the Purdue Univ. Agric. Res. Programs.

Received for publication August 30, 1999.


   REFERENCES
TOP
 NOTES
 ABSTRACT
 INTRODUCTION
 Materials and methods
 Results and discussion
 REFERENCES
 




This article has been cited by other articles:


Home page
 J Exp BotHome page
N. Mitsuhashi, M. Kondo, S. Nakaune, M. Ohnishi, M. Hayashi, I. Hara-Nishimura, A. Richardson, H. Fukaki, M. Nishimura, and T. Mimura
Localization of myo-inositol-1-phosphate synthase to the endosperm in developing seeds of Arabidopsis
J. Exp. Bot., August 1, 2008; 59(11): 3069 - 3076.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
Y. Gao, R.M. Biyashev, M.A. S. Maroof, N.M. Glover, D.M. Tucker, and G.R. Buss
Validation of Low-Phytate QTLs and Evaluation of Seedling Emergence of Low-Phytate Soybeans
Crop Sci., July 1, 2008; 48(4): 1355 - 1364.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
B. P. Anderson and W. R. Fehr
Seed Source Affects Field Emergence of Low-Phytate Soybean Lines
Crop Sci., May 1, 2008; 48(3): 929 - 932.
[Abstract] [Full Text] [PDF]

Home page
 Poult. Sci.Home page
P. W. Plumstead, A. B. Leytem, R. O. Maguire, J. W. Spears, P. Kwanyuen, and J. Brake
Interaction of Calcium and Phytate in Broiler Diets. 1. Effects on Apparent Prececal Digestibility and Retention of Phosphorus
Poult. Sci., March 1, 2008; 87(3): 449 - 458.
[Abstract] [Full Text] [PDF]

Home page
 Poult. Sci.Home page
A. B. Leytem, P. W. Plumstead, R. O. Maguire, P. Kwanyuen, J. W. Burton, and J. Brake
Interaction of Calcium and Phytate in Broiler Diets. 2. Effects on Total and Soluble Phosphorus Excretion
Poult. Sci., March 1, 2008; 87(3): 459 - 467.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
K. D. Bilyeu, P. Zeng, P. Coello, Z. J. Zhang, H. B. Krishnan, A. Bailey, P. R. Beuselinck, and J. C. Polacco
Quantitative Conversion of Phytate to Inorganic Phosphorus in Soybean Seeds Expressing a Bacterial Phytase
Plant Physiology, February 1, 2008; 146(2): 468 - 477.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
Y. Gao, C. Shang, M. A. S. Maroof, R. M. Biyashev, E. A. Grabau, P. Kwanyuen, J. W. Burton, and G. R. Buss
A Modified Colorimetric Method for Phytic Acid Analysis in Soybean
Crop Sci., September 1, 2007; 47(5): 1797 - 1803.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
D. W. Israel, P. Kwanyuen, J. W. Burton, and D. R. Walker
Response of Low Seed Phytic Acid Soybeans to Increases in External Phosphorus Supply
Crop Sci., September 1, 2007; 47(5): 2036 - 2046.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
J. D. Spear and W. R. Fehr
Genetic Improvement of Seedling Emergence of Soybean Lines with Low Phytate
Crop Sci., July 30, 2007; 47(4): 1354 - 1360.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
D. E. Bowen, E. J. Souza, M. J. Guttieri, V. Raboy, and J. Fu
A Low Phytic Acid Barley Mutation Alters Seed Gene Expression
Crop Sci., July 16, 2007; 47(S2): S-149 - S-159.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
Y. Sun, M. Thompson, G. Lin, H. Butler, Z. Gao, S. Thornburgh, K. Yau, D. A. Smith, and V. K. Shukla
Inositol 1,3,4,5,6-Pentakisphosphate 2-Kinase from Maize: Molecular and Biochemical Characterization
Plant Physiology, July 1, 2007; 144(3): 1278 - 1291.
[Abstract] [Full Text] [PDF]

Home page
 J ANIM SCIHome page
T. L. Veum, D. R. Ledoux, and V. Raboy
Low-phytate barley cultivars improve the utilization of phosphorus, calcium, nitrogen, energy, and dry matter in diets fed to young swine
J Anim Sci, April 1, 2007; 85(4): 961 - 971.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
D. E. Bowen, M. J. Guttieri, K. Peterson, K. Peterson, V. Raboy, and E. J. Souza
Phosphorus Fractions in Developing Seeds of Four Low Phytate Barley (Hordeum vulgare L.) Genotypes
Crop Sci., November 21, 2006; 46(6): 2468 - 2473.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
M. J. Guttieri, K. M. Peterson, and E. J. Souza
Agronomic Performance of Low Phytic Acid Wheat
Crop Sci., November 21, 2006; 46(6): 2623 - 2629.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
M. J. Guttieri, K. M. Peterson, and E. J. Souza
Mineral Distributions in Milling Fractions of Low Phytic Acid Wheat
Crop Sci., November 21, 2006; 46(6): 2692 - 2698.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
M. J. Guttieri, K. M. Peterson, and E. J. Souza
Milling and Baking Quality of Low Phytic Acid Wheat
Crop Sci., October 2, 2006; 46(6): 2403 - 2408.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
P. S. Baenziger, W. K. Russell, G. L. Graef, and B. T. Campbell
Improving Lives: 50 Years of Crop Breeding, Genetics, and Cytology (C-1)
Crop Sci., September 8, 2006; 46(5): 2230 - 2244.
[Abstract] [Full Text] [PDF]

Home page
 J ANIM SCIHome page
T. L. Veum, D. W. Bollinger, C. E. Buff, and M. R. Bedford
A genetically engineered Escherichia coli phytase improves nutrient utilization, growth performance, and bone strength of young swine fed diets deficient in available phosphorus
J Anim Sci, May 1, 2006; 84(5): 1147 - 1158.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
P. Bregitzer and V. Raboy
Effects of Four Independent Low-Phytate Mutations on Barley Agronomic Performance
Crop Sci., April 25, 2006; 46(3): 1318 - 1322.
[Abstract] [Full Text] [PDF]

Home page
 J ANIM SCIHome page
R. N. Dilger and O. Adeola
Estimation of true phosphorus digestibility and endogenous phosphorus loss in growing pigs fed conventional and low-phytate soybean meals
J Anim Sci, March 1, 2006; 84(3): 627 - 634.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
D. R. Walker, A. M. Scaboo, V. R. Pantalone, J. R. Wilcox, and H. R. Boerma
Genetic Mapping of Loci Associated with Seed Phytic Acid Content in CX1834-1-2 Soybean
Crop Sci., January 24, 2006; 46(1): 390 - 397.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
D. W. Israel, P. Kwanyuen, and J. W. Burton
Genetic Variability for Phytic Acid Phosphorus and Inorgaic Phosphorus in Seeds of Soybeans in Maturity Groups V, VI, and VII
Crop Sci., December 2, 2005; 46(1): 67 - 71.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
N. Mitsuhashi, M. Ohnishi, Y. Sekiguchi, Y.-U. Kwon, Y.-T. Chang, S.-K. Chung, Y. Inoue, R. J. Reid, H. Yagisawa, and T. Mimura
Phytic Acid Synthesis and Vacuolar Accumulation in Suspension-Cultured Cells of Catharanthus roseus Induced by High Concentration of Inorganic Phosphate and Cations
Plant Physiology, July 1, 2005; 138(3): 1607 - 1614.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
S. E. Oltmans, W. R. Fehr, G. A. Welke, V. Raboy, and K. L. Peterson
Agronomic and Seed Traits of Soybean Lines with Low-Phytate Phosphorus
Crop Sci., February 23, 2005; 45(2): 593 - 598.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
B. S. Hulke, W. R. Fehr, and G. A. Welke
Agronomic and Seed Characteristics of Soybean with Reduced Phytate and Palmitate
Crop Sci., November 1, 2004; 44(6): 2027 - 2031.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Clin. Nutr.Home page
K M. Hambidge, J. W Huffer, V. Raboy, G. K Grunwald, J. L Westcott, L. Sian, L. V Miller, J. A Dorsch, and N. F Krebs
Zinc absorption from low-phytate hybrids of maize and their wild-type isohybrids
Am. J. Clinical Nutrition, June 1, 2004; 79(6): 1053 - 1059.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
M. Guttieri, D. Bowen, J. A. Dorsch, V. Raboy, and E. Souza
Identification and Characterization of a Low Phytic Acid Wheat
Crop Sci., March 1, 2004; 44(2): 418 - 424.
[Abstract] [Full Text] [PDF]

Home page
 Crop Sci.Home page
S. E. Oltmans, W. R. Fehr, G. A. Welke, and S. R. Cianzio
Inheritance of Low-Phytate Phosphorus in Soybean
Crop Sci., March 1, 2004; 44(2): 433 - 435.
[Abstract] [Full Text] [PDF]

Home page
 J. Environ. Qual.Home page
C. A. Baxter, B. C. Joern, D. Ragland, J. S. Sands, and O. Adeola
Phytase, High-Available-Phosphorus Corn, and Storage Effects on Phosphorus Levels in Pig Excreta
J. Environ. Qual., July 1, 2003; 32(4): 1481 - 1489.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
J. Shi, H. Wang, Y. Wu, J. Hazebroek, R. B. Meeley, and D. S. Ertl
The Maize Low-Phytic Acid Mutant lpa2 Is Caused by Mutation in an Inositol Phosphate Kinase Gene
Plant Physiology, February 1, 2003; 131(2): 507 - 515.
[Abstract] [Full Text] [PDF]

Home page
 J ANIM SCIHome page
T. L. Veum, D. R. Ledoux, D. W. Bollinger, V. Raboy, and A. Cook
Low-phytic acid barley improves calcium and phosphorus utilization and growth performance in growing pigs
J Anim Sci, October 1, 2002; 80(10): 2663 - 2670.
[Abstract] [Full Text] [PDF]

Home page
 J. Nutr.Home page
V. Raboy
Progress in Breeding Low Phytate Crops
J. Nutr., March 1, 2002; 132(3): 503S - 505.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
W. D. Hitz, T. J. Carlson, P. S. Kerr, and S. A. Sebastian
Biochemical and Molecular Characterization of a Mutation That Confers a Decreased Raffinosaccharide and Phytic Acid Phenotype on Soybean Seeds
Plant Physiology, February 1, 2002; 128(2): 650 - 660.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow