The effects of high temperature treatment on soybean Glycine max (L.) Merr. seed composition, vigor, and proteome were investigated using mature dry seeds harvested from plants grown in ...environment-controlled chambers. High day/night temperatures (37/30°C) from stages R5 through R8 altered ratios of individual fatty acids to total fatty acid compared to the control (27/18°C). Concentration of sugars decreased, but total protein and phytic acid concentration were unchanged. High temperature resulted in a greater proportion of abnormal seeds, but normal-appearing seed exhibited reduced germination and vigor. Proteomic analysis detected 20 protein identities whose accumulations were changed by the high temperature. Fourteen spots were identified as seven subunits of seed storage proteins. The remaining six proteins were identified as those responding to abiotic stresses or having a function in respiration: (i) sucrose binding protein, (ii) Class III acidic endochitinase, (iii) heat shock protein (HSP22), (iv) late embryo abundant protein, (v) Bowman-Birk proteinase inhibitor, and (vi) formate dehydrogenase. High temperature during seed development changed soybean seed composition and decreased seed vigor, but also changed seed protein expression profiles.
Three independent genetic loci have been shown to contribute to soybean Glycine max (L.) Merrill seed linolenic acid levels, including the well-characterized Fan locus. Linolenic acid is the product ...of omega-3 fatty-acid desaturase enzyme activity. The objective of this study was to identify and characterize the family of soybean omega-3 fatty-acid desaturase genes and link them to low seed linolenic acid as a tool for the development of molecular markers for low linolenic acid soybean. Using database homology searches and gene cloning, we identified and characterized three soybean microsomal omega-3 fatty-acid desaturase genes that contribute to seed linolenic acid levels. Relative expression was characterized by quantitative real-time RT-PCR (reverse transcriptase-polymerase chain reaction). One of the three genes was predominantly expressed in developing seeds. We determined that the low linolenic acid breeding line A5 (fan fan) contains two of the genes, but is missing the third sequence. Therefore, the Fan locus can be definitively assigned to one of the three microsomal omega-3 fatty-acid desaturase genes present in the soybean genome. Molecular markers for defects in the three genes will enhance soybean programs breeding for low linolenic acid.
Phytic acid (PA) contains the major portion of the phosphorus in the soybean (Glycine max) seed and chelates divalent cations. During germination, both minerals and phosphate are released upon ...phytase-catalyzed degradation of PA. We generated a soybean line (CAPPA) in which an Escherichia coli periplasmic phytase, the product of the appA gene, was expressed in the cytoplasm of developing cotyledons. CAPPA exhibited high levels of phytase expression, >=90% reduction in seed PA, and concomitant increases in total free phosphate. These traits were stable, and, although resulted in a trend for reduced emergence and a statistically significant reduction in germination rates, had no effect on the number of seeds per plant or seed weight. Because phytate is not digested by monogastric animals, untreated soymeal does not provide monogastrics with sufficient phosphorus and minerals, and PA in the waste stream leads to phosphorus runoff. The expression of a cytoplasmic phytase in the CAPPA line therefore improves phosphorus availability and surpasses gains achieved by other reported transgenic and mutational strategies by combining in seeds both high phytase expression and significant increases in available phosphorus. Thus, in addition to its value as a high-phosphate meal source, soymeal from CAPPA could be used to convert PA of admixed meals, such as cornmeal, directly to utilizable inorganic phosphorus.
Marker assisted selection (MAS) procedures potentially can make breeding more efficient, as genotypes can be identified before pollination allowing breeders to cross or backcross only suitable ...materials. Our objective was to assess the accuracy of our phenotypic selections in soybean Glycine max (L.) Merr. for linolenic acid using molecular markers specific for mutations in two fatty acid desaturase genes, GmFAD3A and GmFAD3C The markers were not available earlier in the selection process and were used retrospectively to determine that phenotypic selection for seed linolenic acid ≤ 35 g kg−1oil was successful in capturing genotypes homozygous for mutant alleles at both loci, but phenotypic selection was not perfect. Chemical analysis for seed linolenic acid concentration was not an accurate predictor of genotype. The advancement of heterozygotes reduced the selection efficiency relative to what would have been possible using molecular markers specific for mutations in the two fatty acid desaturase genes. Errors are thought to have derived from inaccurate sample tracking or identification, contamination, or errors in chemical analyses. Use of mutation‐specific molecular markers to identify F2 lines homozygous for mutant alleles in GmFAD3A and GmFAD3C, combined with diligence in reducing sampling errors, would eliminate the need for chemical testing for linolenic acid content in subsequent generations where screening can emphasize other traits.
Cyanogenic glucosides, generally considered antinutritional factors, are important defense molecules against predators and, in some cases, diseases. The objectives of this study were: (i) to ...determine the seasonal variations in hydrogen cyanide (HCN) concentration of three widely grown Lotus spp. and (ii) to assess the overall cyanogenic potential of the different plant components of a rhizomatous cultivar of broadleaf birdsfoot trefoil Lotus corniculatus L. (BFT). In this study, we used BFT cultivars Norcen and ARS‐2620, narrowleaf trefoil (L. glaber Mill.) germplasm ARS‐1207, and big trefoil (L. uliginosus Schkur.) germplasm ARS‐1221. The experiments were conducted in the field and greenhouse using a randomized complete block design. Significant seasonal variations in HCN concentrations in Norcen, ARS‐2620, and ARS‐1207 were observed. Hydrogen cyanide concentrations were greatest in spring and summer and least in winter. ARS‐1221 was acyanogenic. Of the three cyanogenic entries grown in the field study, ARS‐1207 had the greatest concentration of HCN, averaging 900 μg g−1 dry matter while Norcen and ARS‐2620 had similar levels of HCN. In the greenhouse, Norcen and ARS‐1207 had greater HCN concentrations than ARS‐2620. Partitioning of the rhizomatous BFT cultivar ARS‐2620 demonstrated that leaves and flowers produced the greatest concentration of HCN, five times as much as stems and ripe‐seed pods. Rhizomes, which are typically produced in winter and fall, did not exhibit HCN production. Seeds of Norcen and ARS‐2620 were acyanogenic, but ARS‐1207 seeds were weakly cyanogenic. However, as seeds germinated and seedlings formed cotyledons, Norcen, ARS‐2620, and ARS‐1207 exhibited HCN. Roots of all species were acyanogenic.
The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for pair-produced charged Higgs bosons in the framework of Two Higgs Doublet Models (2HDMs). The data of the four experiments ...have been statistically combined. The results are interpreted within the 2HDM for Type I and Type II benchmark scenarios. No statistically significant excess has been observed when compared to the Standard Model background prediction, and the combined LEP data exclude large regions of the model parameter space. Charged Higgs bosons with mass below 80
(Type II scenario) or 72.5
(Type I scenario, for pseudo-scalar masses above 12
) are excluded at the 95 % confidence level.
Rhizome production has been transferred from wild germplasm of Lotus corniculatus L. (broadleafed birdsfoot trefoil) into domesticated germplasm to produce 'ARS-2620' and 'ARS-2424' (a L. ...corniculatus x L. uliginosus hybrid). The objective of this study was to determine if field environments in the United States differing in latitude affect rhizome expression in genotypes of ARS-2620 and ARS-2424. Ramets of rhizomatous genotypes of ARS-2620 and ARS-2424, and nonrhizomatous 'Norcen' were planted at seven locations in late July and August 1999. At five locations in 2000 and 2001, dormant plants were hand-dug in late autumn or winter. Traits measured were mean crown-plus-root mass, crown circumference, and percentage survival for all entries, and rhizome mass for the two rhizomatous entries. Significant (P less than or equal to 0.001) location x genotype effects were observed for all traits in 2000, but only for percentage survival in 2001. In 2001, the effect of locations was significant for all traits (P less than or equal to 0.001), but genotype effects were significant (P less than or equal to 0.001) only for crown circumference and percentage survival. The rhizomatous entries were larger in circumference and had a greater crown-plus-root mass than Norcen. Rhizomes appeared to be beneficial to plant survival and plant growth, but rhizomes did not assure performance or survival, as we did not identify a genotype that performed well across locations. High plant mortality and extensive tissue necrosis caused by root and crown-rot complex reduced overall plant performance and rhizome expression and masked the interpretive value of the data from the five locations. Plants grown in Logan, UT, were notable for their large size and rhizome production relative to the other locations, and as having advantageous, but undefined, environmental conditions beneficial to the performance of rhizomatous birdsfoot trefoil.
Condensed tannins (CTs) are commonly found in herbage of Lotus spp. and can have beneficial or detrimental effects on feed value and animal performance. Our objectives were to (i) determine the level ...of CT concentration and its seasonal variations in three widely grown Lotus spp.; (ii) assess the distribution of CTs in leaves, stems, and flowers; and (iii) determine if herbage of greenhouse‐grown Lotus spp. contains CT concentrations with equivalent rank to field‐grown plants. Field herbage samples were taken in spring, summer, and fall and analyzed for CTs by near infrared reflectance spectroscopy (NIRS). Herbage of big trefoil (L. uliginosus Schkur.) germplasm ARS‐1221 and narrowleaf trefoil (L. glaber Mill.) germplasm ARS‐1207 had the greatest and lowest CT concentrations averaging 154 and 8 g catechin equivalent (CE) kg−1 dry matter (DM), respectively. The birdsfoot trefoil (L. corniculatus L.) cultivar ARS‐2620 had a greater CT concentration than ‘Norcen’, but both had moderate CT levels averaging 39 and 23 g CE kg−1 DM, respectively. Herbage CT concentration of Norcen, ARS‐2620, and ARS‐1221 was higher in spring and summer compared with fall while that of ARS‐1207 was low in spring, summer, and fall. Generally, stems had less CT than leaves and flowers, but there was no detectable CTs in stems of ARS‐1207. The rankings of the four entries for herbage CT concentration in the greenhouse and field were the same. This is the first report of CT concentrations for the germplasms ARS‐1221 and ARS‐1207, which are suitable candidates for genetic improvement to develop cultivars with desirable CT levels.
Domesticated soybean Glycine max (L.) Merr. is a major crop with an established ancestral relationship to wild soybean (Glycine soja Sieb. & Zucc.) native to Asia. Soybean genetic diversity can be ...assessed at different levels by identification of polymorphic alleles at genetic loci, in either the plastid or nuclear genomes. The objective of this study was to evaluate genetic diversity based on chloroplast haplotypes for soybean genotypes present in the USDA germplasm resource collection. Shared chloroplast haplotypes represent broad groups of genetic relatedness. Previous work categorized three-quarters of the cultivated soybeans from Asia into a single haplotype group. Our results confirmed the close relationship of North American soybean ancestors and G. max plant introductions previously identified as representing potential sources of soybean genetic variation with the finding that these genotypes belonged to a single chloroplast haplotype group. Genetic diversity was identified in soybean genotypes determined to have a high density of single nucleotide polymorphisms and in a screen of accessions with resistance to soybean cyst nematode. Characterization of soybean plant introduction lines into chloroplast haplotype group may be an important initial step in evaluating the appropriate use of particular soybean genotypes.
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