Identification of several gy4 nulls from the USDA soybean germplasm collection provides new genetic resources for the development of high-quality tofu cultivars

Tofu, a cheese-like food made by curdling soy milk, is a major dietary staple of Asian countries. Consumption of tofu and other soy products is steadily increasing in North America due to its well-known health benefits. Soybean A(5), A(4), and B(3) peptide null lines 'Enrei' and 'Raiden' are commonly utilized in breeding programs to develop high-quality tofu cultivars. To expand the genetic diversity it is desirable to identify and utilize other A(5), A(4), and B(3) null genotypes in the development of improved tofu cultivars that are adapted to North American conditions. In this study were screened diverse soybean accessions from the USDA Soybean Germplasm Collection to identify Gy4 mutants, the locus that controls A(5), A(4), and B(3) peptide production. Analysis of total seed proteins from 485 soybean lines by SDS-PAGE enabled the identification of 38 accessions that lacked the A(5), A(4), and B(3) peptides. These accessions showed marked differences in seed size and seed coat color and represented different maturity groups ranging from 0 to IX. To ascertain the molecular basis for the lack of A(5), A(4), and B(3) peptides in the newly identified Gy4 mutants, the nucleotide sequence of a portion of the Gy4 gene was determined from eight soybean accessions representing different maturity groups. These eight Gy4 mutants revealed a single point mutation that changed the translation initiation codon ATG to ATA, resulting in the A(5), A(4), and B(3) null phenotype. The newly identified Gy4 mutants from this study will enable plant breeders to expand the genetic diversity of North American food-quality soybeans and also aid in the development of hypoallergenic soybeans.     

Development and validation of class I SSR markers targeting (GATA) n repeat motifs in rice

SSR markers targeting (GATA) _n motifs are known to be highly polymorphic and useful in many organisms. (GATA) _n motif specific SSR markers covering the whole rice genome are not available. The present study was carried out with an objective to identify class I rice microsatellites in the rice genome with (GATA)_n motifs, in-silico, and validate their potential as molecular markers. A total of 243 such motifs were identified; 65 of these were present in the genic region, 59 were in the upstream region and the remaining motifs were found in the intergenic regions. Many of the (GATA) _n motifs were found within and/or upstream of genes associated with biotic or abiotic stress tolerance. A total of 230 PCR-based markers targeting all the class I (GATA) _n microsatellites were developed and 35 of these markers spread across the rice genome were validated in a set of 24 representative rice varieties belonging to five distinct cultivar groups. All the markers were polymorphic, with average polymorphism information content (PIC) value of 0.61, and the rice cultivars could be uniquely distinguished into different cultivar groups based on marker analysis. These informative markers targeting (GATA) _n motifs representing a new set of markers in rice will be highly useful for genetic studies and marker-assisted selection. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Passoupathy Rajendrakumar, Akshaya Kumar Biswal and Kannabiran Sakthivel contributed equally.     

大豆种子寿命的遗传

大豆种子的储存寿命较短,在潮湿、酷热的环境晚是如此。然而,已经筛选出几个种子寿命较长的品种。本研究旨在了解大豆种子寿命（或耐贮性）的遗传,以便通过育种程序来改良该性状。     

Impact of tillage and crop establishment methods on crop yields,profitability and soil physical properties in rice–wheat system of Indo‐Gangetic Plains of India

Conservation agriculture (CA) based on best‐bet crop management practices may increase crop and water productivity, as well as conserve and sustain soil health and natural resources. In a 2‐year study, we assessed the effects of tillage and crop establishment (TCE) methods on productivity, profitability and soil physical properties in a rice–wheat (RW) system. The six TCE treatments were used to study the impact, which are puddled transplanted rice followed by conventionally tilled wheat (CTPR–CTW), direct‐seeded rice on the flat followed by zero‐till wheat (CTDSR–ZTW), zero‐till direct‐seeded rice with residue followed by zero‐till wheat with residue (ZTDSR+R–ZTW+R), transplanted rice after rotavator puddling followed by zero‐till wheat (RTTPR–ZTW), transplanted rice after rotavator puddling followed by rotary till wheat (RTTPR–RTW) and farmer practice rice–wheat (FP–RW). Result of the study revealed that mean rice yield was not significantly affected by different TCE methods. Wheat planted with ZTDSR+R–ZTW+R gave 30% larger grain yield than FP‐RW. Overall, among all the TCE treatments, the RW system yields and net returns were maximum under ZTDSR+R–ZTW+R. The fastest mean infiltration rate (0.10 cm hr^–1) was registered in ZTDSR+R–ZTW+R plots, whereas the slowest was in FP‐RW plots (0.05 cm hr^–1). Bulk density at 15–20 cm soil depth was least in ZTDSR+R–ZTW+R (1.70 Mg m^–3) and greatest in FP‐RW (1.73 Mg m^–3). Results from this study revealed that conventionally tilled (CT) and transplanting of rice could be successfully replaced by adoption of the profitable double ZT–RW system.     

Effect of six decades of selective breeding on soybean protein composition and quality: a biochemical and molecular analysis

To evaluate the extent of the genetic change and its effects on the seed protein composition of soybean cultivars released during the past 60 years, representative ancestral cultivars and those derived from selective breeding were grown in a side-by-side comparison. Total seed protein content, determined by combustion analysis of nitrogen, revealed a decline in the protein content after decades of selection and breeding. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis comparison of protein profiles of the soybean cultivars indicated that relative expression of most of the seed storage proteins had not varied substantially from the ancestral lines to the present commercial cultivars. There was noticeably less beta-subunit of beta-conglycinin, a protein devoid of sulfur amino acids, in the modern cultivars represented by Mustang, Pioneer 93B09, and Asgrow 3602. Comparison of the amino acid profiles of soybean seed, a benchmark of the protein's nutritional quality, revealed that the ancestral progenitor, G. soja, was significantly higher in cysteine, glutamic acid, histidine, and arginine than either the ancestral or the modern cultivars. Selective breeding over the past 60 years minimally affected the overall amino acid composition. The degree of divergence in the DNA sequence of the genes encoding glycinin and beta-conglycinin in the ancestral and modern cultivars was investigated using Southern hybridization and the polymerase chain reaction. Even though some restriction fragment polymorphisms could be detected, overall, the banding patterns were remarkably similar among the ancestral cultivars and those derived from them, suggesting a high degree of conservation of seed-storage protein genes. The results of our study suggest that selection and breeding for yield during the past 60 years had no major influence on the protein composition, ostensibly because of limited genetic diversity among the parental lines.     

Unimpeded permeation of water through helium-leak-tight graphene-based membranes

Permeation through nanometer pores is important in the design of materials for filtration and separation techniques and because of unusual fundamental behavior arising at the molecular scale. We found that submicrometer-thick membranes made from graphene oxide can be completely impermeable to liquids, vapors, and gases, including helium, but these membranes allow unimpeded permeation of water (H(2)O permeates through the membranes at least 10(10) times faster than He). We attribute these seemingly incompatible observations to a low-friction flow of a monolayer of water through two-dimensional capillaries formed by closely spaced graphene sheets. Diffusion of other molecules is blocked by reversible narrowing of the capillaries in low humidity and/or by their clogging with water.     

Quantum phase extraction in isospectral electronic nanostructures

Quantum phase is not directly observable and is usually determined by interferometric methods. We present a method to map complete electron wave functions, including internal quantum phase information, from measured single-state probability densities. We harness the mathematical discovery of drum-like manifolds bearing different shapes but identical resonances, and construct quantum isospectral nanostructures with matching electronic structure but divergent physical structure. Quantum measurement (scanning tunneling microscopy) of these "quantum drums"-degenerate two-dimensional electron states on the copper(111) surface confined by individually positioned carbon monoxide molecules-reveals that isospectrality provides an extra topological degree of freedom enabling robust quantum state transplantation and phase extraction.     

Influence of rare alleles of β‐carotene hydroxylase and lycopene epsilon cyclase genes on accumulation of provitamin A carotenoids in maize kernels

Vitamin A deficiency is one of the major health problems worldwide. Traditional yellow maize possesses very low provitamin A (proA) concentration in endosperm. The influence of rare alleles of β‐carotene hydroxylase (crtRB1) and lycopene epsilon cyclase (lcyE) genes capable of enhancing proA concentration was studied in four BC₂F₂ populations generated using subtropical inbreds and CIMMYT‐HarvestPlus lines. The occurrence of severe segregation distortion for crtRB1 gene was observed, while lcyE gene was segregated as per Mendelian ratio. Genotype with favourable allele of crtRB1 (CC) had a significant effect on β‐carotene (BC) (7.9‐fold), β‐cryptoxanthin (BCX) (twofold) and proA (5.5‐fold) accumulation, compared to unfavourable genotype (C⁺C⁺). Genotype with favourable allele of lcyE (LL) showed 2.1‐fold, 1.6‐fold and twofold significant enhancement in BC, BCX and proA, respectively, over unfavourable genotype (L⁺L⁺) in pooled analysis. Of the nine genotypes, double homozygote (CC/LL) had the highest mean BC (12.60 μg/g), BCX (4.44 μg/g) and proA (14.82 μg/g), and combined effect was significantly better than individual gene effects or any other combinations. The information generated here would be useful in designing strategy for proA enrichment in subtropical maize.     

Nitrogen lowers the sulfur amino acid content of soybean (Glycine max [L.] Merr.) by regulating the accumulation of Bowman-Birk protease inhibitor

Soybeans in general contain 35-40% protein. Efforts are underway to increase further this protein content, thus enhancing their nutritive value. Even though higher protein is a desirable characteristic, whether such an increase will be accompanied by enhanced protein quality is not known. Soybean protein quality could be significantly improved by increasing the concentration of the sulfur-containing amino acids, cysteine and methionine. To ascertain if a correlation existed between protein quantity and quality, a comparison of the amino acids of soybeans differing in protein content was made. Soybeans with higher protein content had a significantly lower percentage of sulfur amino acids, while those with lower protein exhibited a higher content of cysteine and methionine. Nitrogen application elevated the protein content but lowered that of the sulfur amino acids. Transmission electron microscopy examination of thin sections of low protein soybean seeds revealed several protein storage vacuoles that were partially filled with storage proteins. Fluorescence two-dimensional difference gel electrophoresis of soybean seed proteins revealed that nitrogen application favored the accumulation of the beta-subunit of beta-conglycinin while decreasing the accumulation of Bowman-Birk protease inhibitor (BBI), a protein rich in cysteine. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of 60% 2-propanol-extracted proteins showed a drastic reduction in the accumulation of BBI with increasing protein content. Northern blot analysis indicated that nitrogen had a negative influence on the expression of the BBI gene. Our results indicate that the negative correlation between total protein and sulfur amino acid content is mostly mediated by the differential accumulation of BBI.