Molecular evolution of glycinin and β-conglycinin gene families in soybean (Glycine max L. Merr.)

There are two main classes of multi-subunit seed storage proteins, glycinin (11S) and β-conglycinin (7S), which account for approximately 70% of the total protein in a typical soybean seed. The subunits of these two protein classes are encoded by a number of genes. The genomic organization of these genes follows a complex evolutionary history. This research was designed to describe the origin and maintenance of genes in each of these gene families by analyzing the synteny, phylogenies, selection pressure and duplications of the genes in each gene family. The ancestral glycinin gene initially experienced a tandem duplication event; then, the genome underwent two subsequent rounds of whole-genome duplication, thereby resulting in duplication of the glycinin genes, and finally a tandem duplication likely gave rise to the Gy1 and Gy2 genes. The β-conglycinin genes primarily originated through the more recent whole-genome duplication and several tandem duplications. Purifying selection has had a key role in the maintenance of genes in both gene families. In addition, positive selection in the glycinin genes and a large deletion in a β-conglycinin exon contribute to the diversity of the duplicate genes. In summary, our results suggest that the duplicated genes in both gene families prefer to retain similar function throughout evolution and therefore may contribute to phenotypic robustness.     

Establishment of a soybean (Glycine max Merr. L) transposon-based mutagenesis repository

Soybean is a major crop species providing valuable feedstock for food, feed and biofuel. In recent years, considerable progress has been made in developing genomic resources for soybean, including on-going efforts to sequence the genome. These efforts have identified a large number of soybean genes, most with unknown function. Therefore, a major research priority is determining the function of these genes, especially those involved in agronomic performance and seed traits. One means to study gene function is through mutagenesis and the study of the resulting phenotypes. Transposon-tagging has been used successfully in both model and crop plants to support studies of gene function. In this report, we describe efforts to generate a transposon-based mutant collection of soybean. The Ds transposon system was used to create activation-tagging, gene and enhancer trap elements. Currently, the repository houses approximately 900 soybean events, with flanking sequence data derived from 200 of these events. Analysis of the insertions revealed approximately 70% disrupted known genes, with the majority matching sequences derived from either Glycine max or Medicago truncatula sequences. Among the mutants generated, one resulted in male-sterility and was shown to disrupt the strictosidine synthase gene. This example clearly demonstrates that it is possible to disrupt soybean gene function by insertional mutagenesis and to derive useful mutants by this approach in spite of the tetraploid nature of the soybean genome.     

The isolation,characterization and sequence of two divergent β-tubulin genes from soybean (Glycine max L.)

Two divergent -tubulin genes (designated S-1 and S-2) were isolated by screening a soybean genomic library with a Chlamydomonas reinhardtii -tubulin cDNA probe. Restriction fragment analysis of the clones recovered, and of soybean genomic DNA, indicated that these represent two unique classes of structurally different -tubulin genes in the soybean genome. However, it is possible that unidentified members of these classes or additional highly divergent classes of -tubulin genes (thus far undetected) exist in the soybean genome. The S-1 and S-2 genomic clones were sequenced, revealing that both are potentially functional genes which would encode -tubulins of 445 and 449 amino acids, respectively. A comparison of their derived amino acid sequences with -tubulins from several organisms showed that they are most homologous to Chlamydomonas -tubulin (85–87%), with lesser degrees of homology to -tubulins of vertebrate species (79–83%), Trypanosoma brucei (80–81%) and Saccharomyces cerevisiae (66–68%). The amino acid sequences of S-1 and S-2 are as divergent from each other as they are from the Chlamydomonas -tubulin. The amino acids at the diverged positions in S-2 are nearly all conservative substitutions while in S-1, 18 of the 69 substitutions were non-conservative. Both soybean -tubulin genes contain two introns in exactly the same positions. The first soybean intron is located in the same position as the third intron of the Chlamydomonas -tubulin genes. Codon usage in the two soybean -tubulins is remarkably similar (D ²=0.87), but differs from codon usage in other soybean genes.     

Agrobacterium tumefaciens– mediated transformation of soybean [Glycine max (L.) Merrill.] using immature zygotic cotyledon explants

Agrobacterium tumefaciens -mediated transformation of soybean [Glycine max (L.) Merrill. cv. Jack] using immature zygotic cotyledons was investigated to identify important factors that affected transformation efficiency and resulted in the production of transgenic soybean somatic embryos. The factors evaluated were initial immature zygotic cotyledon size, Agrobacterium concentration during inoculation and co-culture and the selection regime. Our results showed that 8- to 10-mm zygotic cotyledons exhibited a higher transformation rate, as indicated by transient GUS gene expression, whereas the smaller zygotic cotyledons, at less than 5 mm, died shortly after co-cultivation. However, the smaller zygotic cotyledon explants were found to have a higher embryogenic potential. Analysis of Agrobacterium and immature cotyledon explant interactions involved two Agrobacterium concentrations for the inoculation phase and three co-culture regimes. No differences in explant survival or somatic embyogenic potential were observed between the two Agrobacterium concentrations tested. Analysis of co-culture regimes revealed that the shorter co-culture times resulted in higher explant survival and higher somatic embryo production on the explants, whereas the co-culture time of 4 days severely reduced survival of the cotyledon explants and lowered their embryogenic potential. Analysis of selection regimes revealed that direct placement of cotyledon explants on hygromycin 25 mg/l was detrimental to explant survival, whereas 10 mg/l gave continued growth and subsequent somatic embryo development and plant regeneration. The overall transformation frequency in these experiments, from initial explant to whole plant, was 0.03 %. Three fertile soybean plants were obtained during the course of these experiments. Enzymatic GUS assays and Southern blot hybridizations confirmed the integration of T-DNA and expression of the GUS-intron gene in the three primary transformants. Analysis of 48 progeny revealed that three copies of the transgene were inherited as a single Mendelian locus. Received: 6 December 1999 / Revised: 11 February 2000 / Accepted: 14 March 2000     

Comparative phytochemical profiling of different soybean (Glycine max (L.) Merr) genotypes using GC–MS

This study aimed to estimate the proximate, phenolic and flavonoids contents and phytochemicals present in seeds of twenty four soybeans (Glycine max (L.) Merr) genotypes to explore their nutritional and medicinal values. Crude protein composition ranged between 35.63 and 43.13% in Argentinian and USA (Clark) genotypes, respectively. Total phenolic content varied from 1.15 to 1.77?mg?GAE/g, whereas flavonoids varied from 0.68 to 2.13?mg?QE/g. The GC–MS analysis resulted identification of 88 compounds categorized into aldehydes (5), ketones (13), alcohols (5), carboxylic acids (7), esters (13), alkanes (2), heterocyclic compounds (19), phenolic compound (9), sugar moiety (7) ether (4) and amide (3), one Alkene and one fatty acid ester. Indonesian genotypes (Ijen and Indo-1) had the highest phenolic compounds than others genotype having antioxidant activities, while the Australian genotype contains the maximum in esters compounds. The major phytocompounds identified in majority of genotypes were Phenol, 2,6-dimethoxy-, 2-Methoxy-4-vinylphenol, 3,5-Dimethoxyacetophenone, 1,2-cyclopentanedione and Hexadecanoic acid, methyl ester. The presence of phytochemicals with strong pharmacological actions like antimicrobial and antioxidants activities could be considered as sources of quality raw materials for food and pharmaceutical industries. This study further set a platform for isolating and understanding the characteristics of each compound for it pharmacological properties.     

Expression of recombinant human IFN-γ protein in soybean (Glycine max L.)

Plant Cell, Tissue and Organ Culture (PCTOC) - Globular androgenic haploid embryos of TV21 and TV19 cultivars of Camellia ssp., obtained on embryo induction medium (EIM), Murashige and Skoog medium...     

Effect of γFe2O3 nanoparticles on photosynthetic characteristic of soybean (Glycine max (L.) Merr.): foliar spray versus soil amendment

There is an urgent need to address comprehensive biosafety issues associated with the use of Fe₂O₃ nanoparticles (IONPs). The present study was performed to investigate the effect of 6-nm IONPs and citrate-coated IONPs (IONPs-Cit) on photosynthetic characteristics and root elongation during germination of Glycine max (L) Merr. Plant physiological performance was assessed after foliar and soil IONPs fertilization. No adverse impacts at any growth stage of the soybeans were observed after application of IONPs. The Fe₂O₃ nanoparticles produced a significant positive effect on root elongation, particularly when compared to the bulk counterpart (IOBKs) suspensions of concentrations greater than 500 mg L^?1. Furthermore, IONPs-Cit significantly enhanced photosynthetic parameters when sprayed foliarly at the eight-trifoliate leaf stage (P < 0.05). The increases in photosynthetic rates following spraying were attributed to increases in stomatal opening rather than increased CO₂ uptake activity at the chloroplast level. We observed more pronounced positive effects of IONPs via foliar application than by soil treatment. This study concluded that IONPs coated with citric acid at IONPs to citrate molar ratio of 1:3 can markedly improve the effectiveness of insoluble iron oxide for Fe foliar fertilization.     

渗透调节对冷敏感大豆[Glycine max(L.)Merr.]种子膜类脂组成和脂肪酸含量的影响

选用冷敏感的大豆[Gzycine max（L.）Merr．]品种“中黄22”为试材,运用薄层层析法和气相色谱法研究了渗控增强大豆种子活力过程中膜类脂的组成及变化规律,揭示生物膜类脂在抗吸胀冷害中的作用。结果表明,用33％（W／V）的PEG6000处理种子,随着渗控时间的延长,种子的发芽指数、活力指数和根干重都逐渐增加,在渗控72h时,大豆种子中不饱和磷脂如PC、PE的比例增加,各极性脂的脂肪酸组成也发生了变化,PC、PE和PI中饱和脂肪酸16：0的含量显著下降,而不饱和脂肪酸18：2明显上升,使它们的不饱和指数大大提高,并与渗控时间呈正相关。由以上结果可证明,经PEG渗控处理后,提高了冷敏感大豆膜的流动性,为防止吸胀冷害,保持膜系统的完整性和生物膜正常的代谢提供了前提条件。     

Epigenetics’ Role in the Common Bean (Phaseolus vulgaris L.) and Soybean (Glycine max (L.) Merr.) Nodulation: a Review

Plant Molecular Biology Reporter - Nitrogen-fixing bacteria establish symbiosis with legumes for the biological nitrogen fixation process in specific root structures called nodules. Among these...     

Identification of genomic regions determining flower and pod numbers development in soybean （Glycine max L.）

Flower and pod numbers per plant are important agronomic traits underlying soybean yield.So far quantitative trait loci (QTL) detected for flower and pod-related traits have mainly focused on the final stage,and might therefore have ignored genetic effects expressed during a specific developmental stage.Here,dynamic expressions of QTL for flower and pod numbers were identified using 152 recombinant inbred lines (RILs) and a linkage map of 306 markers.Wide genetic variation was found among RILs;17 unconditional and 18 conditional QTL were detected for the two traits at different developmental stages over two years.Some QTL were detected only at one stage and others across two or more stages,indicating that soybean flower and pod numbers development may be governed by time-dependent gene expression.Three main QTL (qfn-Chr18-2,qfn-Chr20-1,and qfn-Chr19) were detected for flower number,and two main QTL (qpn-Chr11 and qpn-Chr20) were detected for pod number.The phenotypic variation explained by them ranged from 6.1% to 34.7%.The markers linked to these QTL could be used in marker-assisted selection for increasing soybean flower and pod numbers,with the ultimate aim of increasing soybean yield.Comparison of the QTL regions for flower and pod numbers traits with the related genes reported previously showed that seven and four related genes were located in the QTL regions of qfn-Chr11 and qfn-Chr19,respectively.Tbese results provide a basis for fine mapping and cloning of flower and pod development-related genes.     

大豆(Glycine max(L.)Merr.)致敏蛋白Gly m Bd 30K检测方法及低致敏优异种质鉴定

Gly m Bd 30K蛋白是大豆中主要的免疫显性过敏原之一,会引起人和牲畜腹泻和肠道炎症等过敏反应.因此,发掘低Gly m Bd 30K蛋白含量优异种质对于培育优质大豆品种具有重要意义.为了获得致敏蛋白Gly m Bd 30K低含量的优异种质,根据Gly m Bd 30K蛋白的190-379aa多肽序列制备多克隆抗体...