162 research outputs found

    Transformation of multiple soybean cultivars by infecting cotyledonary-node with Agrobacterium tumefaciens

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    Transformation of four soybean cultivars (Nannong88-1, Nannong18-6, Yu23 and Nannong 87C-38) by infecting cotyledonary-node with Agrobacterium tumefaciens strain EHA105 harboring pBI121containing GFP reporter gene was conducted. The results indicated that the addition of thiol compounds (L-cysteine, dithiothreitol and sodium thiosulfate) in co-cultivation period increased the transformation efficiency of all four soybean cultivars, with Nannong 88-1 most increased up to 2.20%. Detection of GFP expression in the rooted plants was an effective selection system for the confirmationof soybean transformation. And most GFP-positive plants were confirmed to be positive by Southern blot analysis, which showed that transformation of cotyledonary-node explants mediated byAgrobacterium delivered T-DNA with one or two copies into soybean genome. In our study, the combination of Nannong88-1 with EHA105 is the optimum selection for explant and bacterial inoculum in soybean transformation, which could be applied in future functional study of soybean genes

    Characterization of a novel curled-cotyledons mutant in soybean [Glycine max (L.) Merr.]

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    Cotyledons that affect the plant development are important part of soybean. We describe a recessive soybean mutant, designated as curled-cotyledons mutant which is derived from sodiumazide (NaN3) and 60Coγ ray mutagenized seeds of the ‘Nannong 94-16’ cultivar. The curled-cotyledons mutant has defective morphology in cotyledons development, compared to the wild-type plants. Additionally, it also has other aberrant agronomic character, such as longer growth period, and smaller plants. In the mutant, the embryo sac becomes smaller and bulbous, and ultrastructure of developing cotyledons exhibits larger vacuole, some organelles degradation, and membranous multilamellar appear at different stages. Protein and amino acid contents in seeds of mutant are higher than those of the wild type, especially methionine and cysteine. These results suggest that the curled-cotyledons mutant is a novel cotyledon development mutant, which could serve as a basic material to study seed composition and cotyledon development in soybean.Keywords: Soybean, mutant, curled-cotyledons, gene

    The mechanism of word crowding

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    AbstractWord reading speed in peripheral vision is slower when words are in close proximity of other words (Chung, 2004). This word crowding effect could arise as a consequence of interaction of low-level letter features between words, or the interaction between high-level holistic representations of words. We evaluated these two hypotheses by examining how word crowding changes for five configurations of flanking words: the control condition – flanking words were oriented upright; scrambled – letters in each flanking word were scrambled in order; horizontal-flip – each flanking word was the left–right mirror-image of the original; letter-flip – each letter of the flanking word was the left–right mirror-image of the original; and vertical-flip – each flanking word was the up–down mirror-image of the original. The low-level letter feature interaction hypothesis predicts similar word crowding effect for all the different flanker configurations, while the high-level holistic representation hypothesis predicts less word crowding effect for all the alternative flanker conditions, compared with the control condition. We found that oral reading speed for words flanked above and below by other words, measured at 10° eccentricity in the nasal field, showed the same dependence on the vertical separation between the target and its flanking words, for the various flanker configurations. The result was also similar when we rotated the flanking words by 90° to disrupt the periodic vertical pattern, which presumably is the main structure in words. The remarkably similar word crowding effect irrespective of the flanker configurations suggests that word crowding arises as a consequence of interactions of low-level letter features

    Computational identification of putative cytochrome P450 genes in soybean (Glycine max) using expressed sequence tags (ESTs)

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    Cytochrome P450 is a group of monooxygenase that exists as a gene superfamily and plays an important role in metabolizing physiologically important compounds in plants. However, to date only a limited number of P450s have been identified and characterized in soybean (Glycine max.). In this work, a computational study of expressed sequence tags (ESTs) of soybean was performed by data mining methods and bio-informatics tools and as a result 78 putative P450 genes were identified, including 57 new ones. These genes were classified into five clans and 20 families by sequence similarities and among those 57 new families, 18 new subfamilies were found which have not been observed previously in soybean. This work may provide a basis for further functional dissection of P450 genes in soybean and other legumes.Key words: Expressed sequence tags (ESTs), in silico, soybean (Glycine max.), P450

    Identification of Two bZIP Transcription Factors Interacting with the Promoter of Soybean Rubisco Activase Gene (GmRCAα)

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    Rubisco activase (RCA), a key photosynthetic protein, catalyses the activation of Rubisco and thus plays an important role in photosynthesis. Although the RCA gene has been characterized in a variety of species, the molecular mechanism regulating its transcription remains unclear. Our previous studies on RCA gene expression in soybean suggested that expression of this gene is regulated by trans-acting factors. In the present study, we verified activity of the GmRCAα promoter in both soybean and Arabidopsis and used a yeast one-hybrid (Y1H) system for screening a leaf cDNA expression library to identify transcription factors (TFs) interacting with the GmRCAα promoter. Four basic leucine zipper (bZIP) TFs, GmbZIP04g, GmbZIP07g, GmbZIP1 and GmbZIP71, were isolated, and GmbZIP04g and GmbZIP07g were confirmed as able to bind to a 21-nt G-box-containing sequence. Additionally, the expression patterns of GmbZIP04g, GmbZIp07g and GmRCAα were analysed in response to abiotic stresses and during a 24-h period. Our study will help to advance elucidation of the network regulating GmRCAα transcription

    GmNAC5, a NAC Transcription Factor, Is a Transient Response Regulator Induced by Abiotic Stress in Soybean

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    GmNAC5 is a member of NAM subfamily belonging to NAC transcription factors in soybean (Glycine max (L.) Merr.). Studies on NAC transcription factors have shown that this family functioned in the regulation of shoot apical meristem (SAM), hormone signalling, and stress responses. In this study, we examined the expression levels of GmNAC5. GmNAC5 was highly expressed in the roots and immature seeds, especially strongly in immature seeds of 40 days after flowering. In addition, we found that GmNAC5 was induced by mechanical wounding, high salinity, and cold treatments but was not induced by abscisic acid (ABA). The subcellular localization assay suggested that GmNAC5 was targeted at nucleus. Together, it was suggested that GmNAC5 might be involved in seed development and abiotic stress responses in soybean
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