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Leguminous Plants (leguminous + plant)

Distribution by Scientific Domains

Life Sciences	58%
Earth and Environmental Science	16%
Chemistry	16%

Selected Abstracts

Somatic Embryogenesis in Leguminous Plants

PLANT BIOLOGY, Issue 2 2000
P. Lakshmanan
Abstract: This review examines recent advances in the induction and development of somatic embryos in leguminous plants. Emphasis has been given to identify the current trends and successful strategies for the establishment of somatic embryogenic systems, particularly in the economically important species. It appears that, in legumes, somatic embryogenesis can be realized relatively easily especially in young meristematic tissues such as immature embryos and developing leaves. In the majority of the species examined, chlorophenoxyacetic acids remained the most active inductive compounds; however, the new generation growth regulators such as thidiazuron are emerging as successful alternatives for high-frequency direct regeneration of somatic embryos, even from well differentiated explant tissues. Low-frequency embryo production, poor germination and conversion of somatic embryos into plantlets and somaclonal variation are the major impediments limiting the utility of somatic embryogenesis for biotechnological applications in legumes. These limitations, however, may be considerably reduced in the near future, as more newly developed growth regulators with specific morphogenic targets become available for experimentation. From the published data, it is apparent that more effort should be given to develop repetitive embryogenic systems with high frequency of germination and regeneration, since such systems will find immediate application in mass propagation and other crop improvement programmes. As our understanding of various morphogenic processes, including growth and differentiation of zygotic embryos, is fast expanding, it is conceivable that development of highly efficient somatic embryogenic systems with practical application can be anticipated, at least for the important leguminous crops, in the foreseeable future. [source]

Cloning and characterization of small RNAs from Medicago truncatula reveals four novel legume-specific microRNA families

NEW PHYTOLOGIST, Issue 1 2009
Guru Jagadeeswaran
Summary ,,MicroRNAs (miRNAs) and small-interfering RNAs (siRNAs) have emerged as important regulators of gene expression in higher eukaryotes. Recent studies indicate that genomes in higher plants encode lineage-specific and species-specific miRNAs in addition to the well-conserved miRNAs. Leguminous plants are grown throughout the world for food and forage production. To date the lack of genomic sequence data has prevented systematic examination of small RNAs in leguminous plants. Medicago truncatula, a diploid plant with a near-completely sequenced genome has recently emerged as an important model legume. ,,We sequenced a small RNA library generated from M. truncatula to identify not only conserved miRNAs but also novel small RNAs, if any. ,,Eight novel small RNAs were identified, of which four (miR1507, miR2118, miR2119 and miR2199) are annotated as legume-specific miRNAs because these are conserved in related legumes. Three novel transcripts encoding TIR-NBS-LRR proteins are validated as targets for one of the novel miRNA, miR2118. Small RNA sequence analysis coupled with the small RNA blot analysis, confirmed the expression of around 20 conserved miRNA families in M. truncatula. Fifteen transcripts have been validated as targets for conserved miRNAs. We also characterized Tas3-siRNA biogenesis in M. truncatula and validated three auxin response factor (ARF) transcripts that are targeted by tasiRNAs. ,,These findings indicate that M. truncatula and possibly other related legumes have complex mechanisms of gene regulation involving specific and common small RNAs operating post-transcriptionally. [source]

Anticlastogenic, antitoxic and sorption effects of humic substances on the mutagen maleic hydrazide tested in leguminous plants

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2004
G. Ferrara
Summary The potential anticlastogenic and antitoxic effects of a soil humic acid (HA), a peat HA and a peat fulvic acid (FA) on the mutagen maleic hydrazide (MH) have been investigated in two legume species, Vicia faba and Pisum sativum. Both HAs and FA were tested at two different concentrations, 20 and 200 mg l,1, either alone or after 24-hour interaction with 10 mg l,1 of MH before addition to the legume seeds. Anticlastogenicity, i.e. an antimutagenic action defined as the capacity for minimizing chromosome breakages, was evaluated by counting both micronuclei (MN) and aberrant anatelophases (AAT) in root-tip cells. Length and dry weight of the seedling primary root were measured to test the antitoxic activity of HA and FA on MH. The possible occurrence and extent of adsorption or desorption of MH onto or from HA were also investigated. The two species responded differently to the anticlastogenic tests, with V. faba showing a greater number of MN and AAT anomalies than P. sativum. Peat HA and FA exhibited anticlastogenic and antitoxic activities of similar intensity and greater than those of soil HA. The adsorption capacity of both HAs for MH was small, thus suggesting that adsorption is not a major mechanism responsible for the reduction of clastogenicity and antitoxicity of MH by HA. [source]

Late prehistoric soil fertility, irrigation management, and agricultural production in northwest coastal Peru

GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 1 2004
Lee Nordt
The Pampa de Chaparrí (Pampa) in hyperarid northwest coastal Peru is an ideal area to study late prehispanic agricultural technology and production because irrigation canals and furrowed fields have been preserved since abandonment approximately 500 years ago. We collected 55 samples for soil characterization, fertility, and micromorphic analyses and compared these results to a noncultivated control soil previously sampled in an adjacent valley. Natural soil fertility levels for maize, cotton, and bean production were generally high during late prehispanic cultivation in the Pampa. Maintaining adequate nitrogren levels for production, however, would have required external inputs from livestock manure, guano, or leguminous plants. The management of low soil salinity levels was possible because of rapidly permeable soils and irrigation waters low in salt. Based on available water capacity and climate conditions, the Blaney-Criddle Equation yields evapotranspiration rates indicating that irrigation frequency was necessary in a range of every 10,16 days during the growing season. © 2004 Wiley Periodicals, Inc. [source]

Characterisation of the leaf meals, protein concentrates and residues from some tropical leguminous plants

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2006
J Oluwasola Agbede
Abstract Leaf meals (LMs) from freshly harvested leaves of butterfly pea (Centrosema pubescens), devil bean (Mucuna pruriens), flamboyant flower (Delonix regia), Bauhinia tomentosa, coast wattle (Acacia auriculiformis), quick stick (Glyricidia sepium) and ipil-ipil (Leucaena leucocephala) were analysed for their nutrient and anti-nutritional content. Then, leaf protein concentrates (LPCs) were produced from the leaves by fractionation and characterised along with the fibrous residues. On average, the LM contained 181 g kg,1 dry matter (DM) CP (range: 100,280 g kg,1 DM), 139 g kg,1 DM crude fibre (range: 77,230 g kg,1 DM) and 133 g kg,1 DM ether extract (range: 86,165 g kg,1 DM) while the gross energy averaged 17.0 MJ kg,1. On average, leaf protein fractionation enhanced the CP, ether extract and the gross energy in the LPC by 39.5%, 33.5% and 22.0%, respectively, while the crude fibre of the LMs was reduced by 41%, on average, in the LPCs. Fractionation reduced the mineral content of the leaves generally. The mean phytin content varied from 0.36 g kg,1 in LPCs to 0.86 g kg,1 in leaf meal, while the mean phytin-P content varied from 0.10 g kg,1 in LPCs to 0.24 g kg,1 in leaf meal. The total phenol levels in the LMs were reduced by 33.7% in the LPCs, on average. These results suggest that, while the LPCs from these plants could be used as protein supplements in non-ruminant feeds in regions where there is an acute shortage of plant protein, the LMs or LPC fibrous residues could be fed to ruminant animals. Copyright © 2006 Society of Chemical Industry [source]

Cloning and characterization of small RNAs from Medicago truncatula reveals four novel legume-specific microRNA families

Estradiol-antagonistic activity of phenolic compounds from leguminous plants,

PHYTOTHERAPY RESEARCH, Issue 3 2008
B. Pinto
Abstract Natural flavonoids are currently receiving much attention because of their estrogenic and antiestrogenic properties. Six isoflavones (isoprunetin, isoprunetin 7- O - , - d -glucopyranoside, isoprunetin 4,,7-di- O - , - d -glucopyranoside, genistein, genistein 7-O- , - d -glucopyranoside, daidzein), four flavones (luteolin, luteolin 7-O- , - d -glucopyranoside, luteolin 4,-O- , - d -glucopyranoside, licoflavone C), isolated from Genista morisii and G. ephedroides (two Leguminosae plants of the Mediterranean area) together with two structurally related pterocarpans, bitucarpin A and erybraedyn C, isolated from Bituminaria bituminosa (Leguminosae), were tested for the antagonist activity by a yeast based estrogen receptor assay (Saccharomyces cerevisiae RMY326 ER-ERE). Most compounds inhibited the estradiol-induced transcriptional activity in a concentration dependent manner. In particular, for the flavone luteolin 77% inhibition of the induced , -galactosidase activity was observed. Interestingly, licoflavone C exhibited a dose-dependent antagonistic activity at concentrations up to 10,4 m, but stimulated , -galactosidase expression at higher concentrations resulting in a U-shaped-like dose-response curve. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Somatic Embryogenesis in Leguminous Plants

Relationship between boron and calcium in the N2 -fixing legume,rhizobia symbiosis

PLANT CELL & ENVIRONMENT, Issue 11 2003
M. REDONDO-NIETO
ABSTRACT Because boron (B) and calcium (Ca2+) seem to have a strong effect on legume nodulation and nitrogen fixation, rhizobial symbiosis with leguminous plants, grown under varying concentrations of both nutrients, was investigated. The study of early pre-infection events included the capacity of root exudates to induce nod genes, and the degree of adsorption of bacteria to the root surface. Both phenomena were inhibited by B deficiency, and increased by addition of Ca2+, resulting in an increase of the number of nodules. The infection and invasion steps were investigated by fluorescence microscopy in pea nodules harbouring a Rhizobium leguminosarum strain that constitutively expresses green fluorescent protein. High Ca2+ enhanced cell and tissue invasion by Rhizobium, which was highly inhibited after B deficiency. This was combined with an increased B concentration in nodules of plants grown on B-free medium and supplemented with high Ca2+ concentrations, and that can be attributed to an increased B import to the nodules. Histological examination of indeterminate (pea) and determinate (bean) nodules showed an altered nodule anatomy at low B content of the tissue. The moderate increase in nodular B due to additional Ca2+ was not sufficient to prevent the abnormal cell wall structure and the aberrant distribution of pectin polysaccharides in B-deficient treatments. Overall results indicate that the development of the symbiosis depends of the concentration of B and Ca2+, and that both nutrients are essential for nodule structure and function. [source]

Efficient transposition of the Tnt1 tobacco retrotransposon in the model legume Medicago truncatula

THE PLANT JOURNAL, Issue 1 2003
Isabelle D'Erfurth
Summary The tobacco element, Tnt1, is one of the few active retrotransposons in plants. Its transposition is activated during protoplast culture in tobacco and tissue culture in the heterologous host Arabidopsis thaliana. Here, we report its transposition in the R108 line of Medicago truncatula during the early steps of the in vitro transformation,regeneration process. Two hundred and twenty-five primary transformants containing Tnt1 were obtained. Among them, 11.2% contained only transposed copies of the element, indicating that Tnt1 transposed very early and efficiently during the in vitro transformation process, possibly even before the T-DNA integration. The average number of insertions per transgenic line was estimated to be about 15. These insertions were stable in the progeny and could be separated by segregation. Inspection of the sequences flanking the insertion sites revealed that Tnt1 had no insertion site specificity and often inserted in genes (one out of three insertions). Thus, our work demonstrates the functioning of an efficient transposable element in leguminous plants. These results indicate that Tnt1 can be used as a powerful tool for insertion mutagenesis in M. truncatula. [source]

Key amino acid residues required for aryl migration catalysed by the cytochrome P450 2-hydroxyisoflavanone synthase

THE PLANT JOURNAL, Issue 5 2002
Yuji Sawada
Summary Isoflavonoids are distributed predominantly in leguminous plants, and play pivotal roles in the interaction of host plants with biological environments. Isoflavones in the diet also have beneficial effects on human health as phytoestrogens. The isoflavonoid skeleton is constructed by the CYP93C subfamily of cytochrome P450s in plant cells. The reaction consists of hydroxylation of the flavanone molecule at C-2 and an intramolecular 1,2-aryl migration from C-2 to C-3 to yield 2-hydroxyisoflavanone. In this study, with the aid of alignment of amino acid sequences of CYP93 family P450s and a computer-generated putative stereo structure of the protein, candidates for key amino acid residues in CYP93C2 responsible for the unique aryl migration in 2-hydroxyisoflavanone synthase reaction were identified. Microsomes of recombinant yeast cells expressing mutant proteins of CYP93C2 were prepared, and their catalytic activities tested. The reaction with the mutant in which Ser 310 in the centre of the I-helix was converted to Thr yielded increased formation of 3-hydroxyflavanone, a by-product of the 2-hydroxyisoflavanone synthase reaction, in addition to the major isoflavonoid product. More dramatically, the mutant in which Lys 375 in the end of ,-sheet 1,4 was replaced with Thr produced only 3-hydroxyflavanone and did not yield the isoflavonoid any longer. The roles of these amino acid residues in the catalysis and evolution of isoflavonoid biosynthesis are discussed. [source]

Structural, Functional and Calorimetric Investigation of MosA, a Dihydrodipicolinate Synthase from Sinorhizobium meliloti L5,30, does not Support Involvement in Rhizopine Biosynthesis

CHEMBIOCHEM, Issue 10 2008
Christopher P. Phenix Dr.
Abstract MosA is an enzyme from Sinorhizobium meliloti L5,30, a beneficial soil bacterium that forms a symbiotic relationship with leguminous plants. MosA was proposed to catalyze the conversion of scyllo -inosamine to 3- O -methyl- scyllo -inosamine (compounds known as rhizopines), despite the MosA sequence showing a strong resemblance to dihydrodipicolinate synthase (DHDPS) sequences rather than to methyltransferases. Our laboratory has already shown that MosA is an efficient catalyst of the DHDPS reaction. Here we report the structure of MosA, solved to 1.95 Å resolution, which resembles previously reported DHDPS structures. In this structure Lys161 forms a Schiff base adduct with pyruvate, consistent with the DHDPS mechanism. We have synthesized both known rhizopines and investigated their ability to interact with MosA in the presence and absence of methyl donors. No MosA-catalyzed methyltransferase activity is observed in the presence of scyllo -inosamine and S -adenosylmethionine (SAM). 2-Oxobutyrate can form a Schiff base with MosA, acting as a competitive inhibitor of MosA-catalyzed dihydrodipicolinate synthesis. It can be trapped on the enzyme by reaction with sodium borohydride, but does not act as a methyl donor. The presence of rhizopines does not affect the kinetics of dihydrodipicolinate synthesis. Isothermal titration calorimetry (ITC) shows no apparent interaction of MosA with rhizopines and SAM. Similar experiments with pyruvate as titrant demonstrate that the reversible Schiff base formation is largely entropically driven. This is the first use of ITC to study Schiff base formation between an enzyme and its substrate. [source]