WorldWideScience

Sample records for model legume species

  1. The pgip family in soybean and three other legume species: evidence for a birth-and-death model of evolution.

    Science.gov (United States)

    Kalunke, Raviraj M; Cenci, Alberto; Volpi, Chiara; O'Sullivan, Donal M; Sella, Luca; Favaron, Francesco; Cervone, Felice; De Lorenzo, Giulia; D'Ovidio, Renato

    2014-07-18

    Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat (LRR) plant cell wall glycoproteins involved in plant immunity. They are typically encoded by gene families with a small number of gene copies whose evolutionary origin has been poorly investigated. Here we report the complete characterization of the full complement of the pgip family in soybean (Glycine max [L.] Merr.) and the characterization of the genomic region surrounding the pgip family in four legume species. BAC clone and genome sequence analyses showed that the soybean genome contains two pgip loci. Each locus is composed of three clustered genes that are induced following infection with the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, and remnant sequences of pgip genes. The analyzed homeologous soybean genomic regions (about 126 Kb) that include the pgip loci are strongly conserved and this conservation extends also to the genomes of the legume species Phaseolus vulgaris L., Medicago truncatula Gaertn. and Cicer arietinum L., each containing a single pgip locus. Maximum likelihood-based gene trees suggest that the genes within the pgip clusters have independently undergone tandem duplication in each species. The paleopolyploid soybean genome contains two pgip loci comprised in large and highly conserved duplicated regions, which are also conserved in bean, M. truncatula and C. arietinum. The genomic features of these legume pgip families suggest that the forces driving the evolution of pgip genes follow the birth-and-death model, similar to that proposed for the evolution of resistance (R) genes of NBS-LRR-type.

  2. LegumeIP: an integrative database for comparative genomics and transcriptomics of model legumes.

    Science.gov (United States)

    Li, Jun; Dai, Xinbin; Liu, Tingsong; Zhao, Patrick Xuechun

    2012-01-01

    Legumes play a vital role in maintaining the nitrogen cycle of the biosphere. They conduct symbiotic nitrogen fixation through endosymbiotic relationships with bacteria in root nodules. However, this and other characteristics of legumes, including mycorrhization, compound leaf development and profuse secondary metabolism, are absent in the typical model plant Arabidopsis thaliana. We present LegumeIP (http://plantgrn.noble.org/LegumeIP/), an integrative database for comparative genomics and transcriptomics of model legumes, for studying gene function and genome evolution in legumes. LegumeIP compiles gene and gene family information, syntenic and phylogenetic context and tissue-specific transcriptomic profiles. The database holds the genomic sequences of three model legumes, Medicago truncatula, Glycine max and Lotus japonicus plus two reference plant species, A. thaliana and Populus trichocarpa, with annotations based on UniProt, InterProScan, Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes databases. LegumeIP also contains large-scale microarray and RNA-Seq-based gene expression data. Our new database is capable of systematic synteny analysis across M. truncatula, G. max, L. japonicas and A. thaliana, as well as construction and phylogenetic analysis of gene families across the five hosted species. Finally, LegumeIP provides comprehensive search and visualization tools that enable flexible queries based on gene annotation, gene family, synteny and relative gene expression.

  3. Modelling the impact of climatic conditions and plant species on the nitrogen release from mulch of legumes at the soil surface

    Science.gov (United States)

    Gaudinat, Germain; Lorin, Mathieu; Valantin-morison, Muriel; Garnier, Patricia

    2015-04-01

    Cover crops provide multiple services to the agro ecosystem. Among them, the use of legumes as cover crop is one of the solutions for limiting the use of herbicides, mineral fertilizers, and insecticides. However, the dynamic of mineralization is difficult to understand because of the difficulty of measuring nitrogen release from mulch in field. Indeed, residues are degraded at the soil surface as mulch, while the nitrogen uptake by the main crop occurred simultaneously in the soil. This work aims to study the dynamics of nitrogen mineralization from legume residues through i) the use of a model able to describe the physical and biological dynamic of mulch and ii) a data set from a field experiment of intercropping systems "oilseed rape-legumes" from different species (grass pea, lentil, Berseem clover, field pea, vetch). The objective of the simulations is to identify the variations of expected quantities of nitrogen from different legumes. The soil-plant model of mulch decomposition PASTIS-Mulch was used to determine the nitrogen supply from mulch available for rapeseed. These simulation results were compared to the data collected in the experimental field of Grignon (France). We performed analyzes of biochemical and physical characteristics of legume residues and monitored the evolution of mulches (moisture, density, cover surface, biomass) in fields. PASTIS simulations of soil temperature, soil moisture, mulch humidity and mulch decomposition were close to the experimental results. The PASTIS model was suitable to simulate the dynamic of legume mulches in the case of "rape - legume" associations. The model simulated nitrogen restitution of aerial and root parts. We found a more rapid nitrogen release by grass pea than other species. Vetch released less nitrogen than the other species. The scenarios for climate conditions were : i) a freezing in December that causes the destruction of plants, or a destruction by herbicide in March, ii) a strong or a weak rainy

  4. Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland

    DEFF Research Database (Denmark)

    Pirhofer-Walzl, Karin; Høgh Jensen, Henning; Eriksen, Jørgen

    2012-01-01

    Legumes play a crucial role in nitrogen supply to grass-legume mixtures for ruminant fodder. To quantify N transfer from legumes to neighbouring plants in multi-species grasslands we established a grass-legume-herb mixture on a loamy-sandy site in Denmark. White clover (Trifolium repens L.), red...... amounts of N from legumes than dicotyledonous plants which generally have taproots. Slurry application mainly increased N transfer from legumes to grasses. During the growing season the three legumes transferred approximately 40 kg N ha-1 to neighbouring plants. Below-ground N transfer from legumes...

  5. Traits affecting early season nitrogen uptake in nine legume species

    Directory of Open Access Journals (Sweden)

    Elana Dayoub

    2017-02-01

    Full Text Available Legume crops are known to have low soil N uptake early in their life cycle, which can weaken their ability to compete with other species, such as weeds or other crops in intercropping systems. However, there is limited knowledge on the main traits involved in soil N uptake during early growth and for a range of species. The objective of this research was to identify the main traits explaining the variability among legume species in soil N uptake and to study the effect of the soil mineral N supply on the legume strategy for the use of available N sources during early growth. Nine legume species were grown in rhizotrons with or without N supply. Root expansion, shoot and root biomass, nodule establishment, N2 fixation and mineral soil N uptake were measured. A large interspecific variability was observed for all traits affecting soil N uptake. Root lateral expansion and early biomass in relation to seed mass were the major traits influencing soil N uptake regardless of the level of soil N availability. Fenugreek, lentil, alfalfa, and common vetch could be considered weak competitors for soil N due to their low plant biomass and low lateral root expansion. Conversely, peanut, pea, chickpea and soybean had a greater soil N uptake. Faba bean was separated from other species having a higher nodule biomass, a higher N2 fixation and a lower seed reserve depletion. Faba bean was able to simultaneously fix N2 and take up soil N. This work has identified traits of seed mass, shoot and root biomass, root lateral expansion, N2 fixation and seed reserve depletion that allowing classification of legume species regarding their soil N uptake ability during early growth.

  6. Unexpectedly Diverse Mesorhizobium Strains and Rhizobium leguminosarum Nodulate Native Legume Genera of New Zealand, while Introduced Legume Weeds Are Nodulated by Bradyrhizobium Species

    Science.gov (United States)

    Weir, Bevan S.; Turner, Susan J.; Silvester, Warwick B.; Park, Duck-Chul; Young, John M.

    2004-01-01

    The New Zealand native legume flora are represented by four genera, Sophora, Carmichaelia, Clianthus, and Montigena. The adventive flora of New Zealand contains several legume species introduced in the 19th century and now established as serious invasive weeds. Until now, nothing has been reported on the identification of the associated rhizobia of native or introduced legumes in New Zealand. The success of the introduced species may be due, at least in part, to the nature of their rhizobial symbioses. This study set out to address this issue by identifying rhizobial strains isolated from species of the four native legume genera and from the introduced weeds: Acacia spp. (wattles), Cytisus scoparius (broom), and Ulex europaeus (gorse). The identities of the isolates and their relationship to known rhizobia were established by comparative analysis of 16S ribosomal DNA, atpD, glnII, and recA gene sequences. Maximum-likelihood analysis of the resultant data partitioned the bacteria into three genera. Most isolates from native legumes aligned with the genus Mesorhizobium, either as members of named species or as putative novel species. The widespread distribution of strains from individual native legume genera across Mesorhizobium spp. contrasts with previous reports implying that bacterial species are specific to limited numbers of legume genera. In addition, four isolates were identified as Rhizobium leguminosarum. In contrast, all sequences from isolates from introduced weeds aligned with Bradyrhizobium species but formed clusters distinct from existing named species. These results show that native legume genera and these introduced legume genera do not have the same rhizobial populations. PMID:15466541

  7. Legume Information System (LegumeInfo.org): a key component of a set of federated data resources for the legume family

    Science.gov (United States)

    The Legume Information System (LIS), at http://legumeinfo.org, is a genomic data portal (GDP) for the legume family. LIS provides access to genetic and genomic information for major crop and model legumes. With more than two-dozen domesticated legume species, there are numerous specialists working o...

  8. Weed inhibition by sowing legume species in early succession of abandoned fields on Loess Plateau, China

    Science.gov (United States)

    Li, Jin-Hua; Xu, Dang-Hui; Wang, Gang

    2008-01-01

    A major constraint on vegetation succession on abandoned land is dominance by early successional species. Our aim was to inhibit weeds and alter the initial vegetation succession by the introduction of legume species ( Medicago sativa, Melilotus suaveolens, and Astragalus adsurgens) into abandoned fields on the Loess Plateau, China. Results from our study showed that the addition of legume species strongly affected the dominance pattern of the abandoned-field vegetation. The number of naturally colonizing species was inhibited by the introduction of legume species in the first two growing seasons. The strongest effect on weed inhibition appeared by sowing Melilotus suaveolens. Vegetation cover and above-ground biomass increased after introduction of legume species and the number of naturally colonizing plant species showed a positive correlation with above-ground biomass. Later successional species like Stipa breviflora and Astragalus polycladus appeared three years following the introduction of Melilotus suaveolens, indicating that the course of old-field succession may be accelerated by introducing legume species such as Melilotus suaveolens, at least temporarily.

  9. Small RNA pathways and diversity in model legumes: lessons from genomics.

    Directory of Open Access Journals (Sweden)

    Pilar eBustos-Sanmamed

    2013-07-01

    Full Text Available Small non coding RNAs (smRNA participate in the regulation of development, cell differentiation, adaptation to environmental constraints and defense responses in plants. They negatively regulate gene expression by degrading specific mRNA targets, repressing their translation or modifying chromatin conformation through homologous interaction with target loci. MicroRNAs (miRNA and short-interfering RNAs (siRNA are generated from long double stranded RNA (dsRNA that are cleaved into 20- to 24-nucleotide dsRNAs by RNase III proteins called DICERs (DCL. One strand of the duplex is then loaded onto effective complexes containing different ARGONAUTE (AGO proteins. In this review, we explored smRNA diversity in model legumes and compiled available data from miRBAse, the miRNA database, and from 22 reports of smRNA deep sequencing or miRNA identification genome-wide in Medicago truncatula, Glycine max and Lotus japonicus. In addition to conserved miRNAs present in other plant species, 229, 179 and 35 novel miRNA families were identified respectively in these 3 legumes, among which several seems legume-specific. New potential functions of several miRNAs in the legume-specific nodulation process are discussed. Furthermore, a new category of siRNA, the phased siRNAs, which seems to mainly regulate disease-resistance genes, was recently discovered in legumes. Despite that the genome sequence of model legumes are not yet fully completed, further analysis was performed by database mining of gene families and protein characteristics of DCLs and AGOs in these genomes. Although most components of the smRNA pathways are conserved, identifiable homologs of key smRNA players from non-legumes could not yet be detected in M. truncatula available genomic and expressed sequence databases. In addition, an important gene diversification was observed in the three legumes. Functional significance of these variant isoforms may reflect peculiarities of smRNA biogenesis in

  10. Genotype delimitation in the Nod-independent model legume Aeschynomene evenia.

    Science.gov (United States)

    Arrighi, Jean-François; Cartieaux, Fabienne; Chaintreuil, Clémence; Brown, Spencer; Boursot, Marc; Giraud, Eric

    2013-01-01

    Research on the nitrogen-fixing symbiosis has been so far focused on two model legumes, Medicago truncatula and Lotus japonicus, which use a sophisticated infection process involving infection thread formation. However, in 25% of the legumes, the bacterial entry occurs more simply in an intercellular fashion. Among them, some semi-aquatic Aeschynomene species present the distinctive feature to form nitrogen-fixing nodules on both roots and stems following elicitation by photosynthetic bradyrhizobia that do not produce Nod factors. This interaction is believed to represent a living testimony of the ancestral state of the rhizobium-legume symbiosis. To decipher the molecular mechanisms of this unique Nod-independent nitrogen-fixing symbiosis, we previously identified A. evenia C. Wright as an appropriate model legume, because it displays all the requisites for molecular and genetic approaches. To advance the use of this new model legume species, here we characterized the intraspecific diversity found in A. evenia. For this, the accessions available in germplasm banks were collected and subjected to morphological investigations, genotyping with RAPD and SSR markers, molecular phylogenies using ITS and single nuclear gene sequences, and cross-compatibility tests. These combined analyses revealed an important intraspecific differentiation that led us to propose a new taxonomic classification for A. evenia comprising two subspecies and four varieties. The A. evenia ssp. evenia contains var. evenia and var. pauciciliata whereas A. evenia ssp. serrulata comprises var. serrulata and var. major. This study provides information to exploit efficiently the diversity encountered in A. evenia and proposes subsp. evenia as the most appropriate subspecies for future projects aimed at identifying plant determinants of the Nod-independent symbiotic process.

  11. Genotype delimitation in the Nod-independent model legume Aeschynomene evenia.

    Directory of Open Access Journals (Sweden)

    Jean-François Arrighi

    Full Text Available Research on the nitrogen-fixing symbiosis has been so far focused on two model legumes, Medicago truncatula and Lotus japonicus, which use a sophisticated infection process involving infection thread formation. However, in 25% of the legumes, the bacterial entry occurs more simply in an intercellular fashion. Among them, some semi-aquatic Aeschynomene species present the distinctive feature to form nitrogen-fixing nodules on both roots and stems following elicitation by photosynthetic bradyrhizobia that do not produce Nod factors. This interaction is believed to represent a living testimony of the ancestral state of the rhizobium-legume symbiosis. To decipher the molecular mechanisms of this unique Nod-independent nitrogen-fixing symbiosis, we previously identified A. evenia C. Wright as an appropriate model legume, because it displays all the requisites for molecular and genetic approaches. To advance the use of this new model legume species, here we characterized the intraspecific diversity found in A. evenia. For this, the accessions available in germplasm banks were collected and subjected to morphological investigations, genotyping with RAPD and SSR markers, molecular phylogenies using ITS and single nuclear gene sequences, and cross-compatibility tests. These combined analyses revealed an important intraspecific differentiation that led us to propose a new taxonomic classification for A. evenia comprising two subspecies and four varieties. The A. evenia ssp. evenia contains var. evenia and var. pauciciliata whereas A. evenia ssp. serrulata comprises var. serrulata and var. major. This study provides information to exploit efficiently the diversity encountered in A. evenia and proposes subsp. evenia as the most appropriate subspecies for future projects aimed at identifying plant determinants of the Nod-independent symbiotic process.

  12. Leaf morphology in Cowpea [Vigna unguiculata (L. Walp]: QTL analysis, physical mapping and identifying a candidate gene using synteny with model legume species

    Directory of Open Access Journals (Sweden)

    Pottorff Marti

    2012-06-01

    legumes.

  13. A Conserved Potential Development Framework Applies to Shoots of Legume Species with Contrasting Morphogenetic Strategies

    Science.gov (United States)

    Faverjon, Lucas; Escobar-Gutiérrez, Abraham J.; Litrico, Isabelle; Louarn, Gaëtan

    2017-01-01

    A great variety of legume species are used for forage production and grown in multi-species grasslands. Despite their close phylogenetic relationship, they display a broad range of morphologies that markedly affect their competitive abilities and persistence in mixtures. Little is yet known about the component traits that control the deployment of plant architecture in most of these species. During the present study, we compared the patterns of shoot organogenesis and shoot organ growth in contrasting forage species belonging to the four morphogenetic groups previously identified in herbaceous legumes (i.e., stolon-formers, rhizome-formers, crown-formers tolerant to defoliation and crown-formers intolerant to defoliation). To achieve this, three greenhouse experiments were carried out using plant species from each group (namely alfalfa, birdsfoot trefoil, sainfoin, kura clover, red clover, and white clover) which were grown at low density under non-limiting water and soil nutrient availability. The potential morphogenesis of shoots characterized under these conditions showed that all the species shared a number of common morphogenetic features. All complied with a generalized classification of shoot axes into three types (main axis, primary and secondary axes). A common quantitative framework for vegetative growth and development involved: (i) the regular development of all shoot axes in thermal time and a deterministic branching pattern in the absence of stress; (ii) a temporal coordination of organ growth at the phytomer level that was highly conserved irrespective of phytomer position, and (iii) an identical allometry determining the surface area of all the leaves. The species differed in their architecture as a consequence of the values taken by component traits of morphogenesis. Assessing the relationships between the traits studied showed that these species were distinct from each other along two main PCA axes which explained 68% of total variance: the first

  14. IDENTIFICATION AND OCCURRENCE OF FUSARIUM SPECIES ON SEEDS OF COMMON WETCH, WHITE LUPINE AND SOME WILD LEGUMES

    Directory of Open Access Journals (Sweden)

    Tihomir Miličević

    2013-06-01

    Full Text Available The presence and occurrence of Fusarium species was examined on the seeds of cultivated legumes – common vetch (Vicia sativa, white lupine (Lupinus albus, and wild legumes: bird’s-foot trefoil (Lotus corniculatus, wild alfalfa (Medicago sativa, black locust (Robinia pseudoacacia, honey locust (Gleditsia triacanthos, sweet clover (Melilotus officinalis, bird vetch (Vicia cracca and meadow vetchling (Lathyrus pratensis. Thirteen Fusarium species were identified - F. verticillioides, F. acuminatum, F. avenaceum, F. tricinctum F. oxysporum, F. scirpi, F. semitectum, F. culmorum, F. proliferatum, F. pseudograminearum, F. sporotrichioides, F. sambucinum and F. heterosporum. Species F. verticillioides and F. proliferatum were determined on seeds of the cultivated legumes (common vetch and white lupine. Other 11 Fusarium species were determined on seeds of wild legumes (bird’s-foot trefoil, wild alfalfa, sweet clover and bird vetch among which the most prevalent were species F. avenaceum and F. acuminatum.

  15. Cupriavidus necator isolates are able to fix nitrogen in symbiosis with different legume species.

    Science.gov (United States)

    da Silva, Krisle; Florentino, Ligiane Aparecida; da Silva, Karina Barroso; de Brandt, Evie; Vandamme, Peter; de Souza Moreira, Fatima Maria

    2012-05-01

    The aim of the present study was to identify a collection of 35 Cupriavidus isolates at the species level and to examine their capacity to nodulate and fix N(2). These isolates were previously obtained from the root nodules of two promiscuous trap species, Phaseolus vulgaris and Leucaena leucocephala, inoculated with soil samples collected near Sesbania virgata plants growing in Minas Gerais (Brazil) pastures. Phenotypic and genotypic methods applied for this study were SDS-PAGE of whole-cell proteins, and 16S rRNA and gyrB gene sequencing. To confirm the ability to nodulate and fix N(2), the presence of the nodC and nifH genes was also determined, and an experiment was carried out with two representative isolates in order to authenticate them as legume nodule symbionts. All 35 isolates belonged to the betaproteobacterium Cupriavidus necator, they possessed the nodC and nifH genes, and two representative isolates were able to nodulate five different promiscuous legume species: Mimosa caesalpiniaefolia, L. leucocephala, Macroptilium atropurpureum, P. vulgaris and Vigna unguiculata. This is the first study to demonstrate that C. necator can nodulate legume species. Copyright © 2012 Elsevier GmbH. All rights reserved.

  16. Tuberous legumes: preliminary evaluation of tropical Australian and introduced species as fuel crops

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, E.C.

    1981-04-01

    The evaluation of native and introduced legumes with starch-storing roots or tubers was undertaken to test whether plants traditionally collected as food by Australian aborigines might have a role in the development of crops for liquid fuel production (by fermentation of carbohydrates to ethanol). Tuberous-rooted legumes from overseas were planted at the Commonwealth Scientific and Industrial Research Organization, division of Tropical Crops and Pastures, Kimberley Research Station, Western Australia (15/sup 0/39'S, 128/sup 0/42'E) in December 1974, March 1978 and February 1979. Roots from the latter plantings were harvested in June 1979. Native plant material was collected during visits to aboriginal communities in the Kimberleys between April and June 1979. The native and introduced specimens were analyzed for fermentable carbohydrate and protein content. Several native plants appear more promising than introduced species as liquid fuel crops.

  17. Aeschynomene evenia, a model plant for studying the molecular genetics of the nod-independent rhizobium-legume symbiosis.

    Science.gov (United States)

    Arrighi, Jean-François; Cartieaux, Fabienne; Brown, Spencer C; Rodier-Goud, Marguerite; Boursot, Marc; Fardoux, Joel; Patrel, Delphine; Gully, Djamel; Fabre, Sandrine; Chaintreuil, Clémence; Giraud, Eric

    2012-07-01

    Research on the nitrogen-fixing symbiosis has been focused, thus far, on two model legumes, Medicago truncatula and Lotus japonicus, which use a sophisticated infection process involving infection thread formation. However, in 25% of the legumes, the bacterial entry occurs more simply in an intercellular fashion. Among them, some Aeschynomene spp. are nodulated by photosynthetic Bradyrhizobium spp. that do not produce Nod factors. This interaction is believed to represent a living testimony of the ancestral state of the rhizobium-legume symbiosis. To decipher the mechanisms of this Nod-independent process, we propose Aeschynomene evenia as a model legume because it presents all the characteristics required for genetic and molecular analysis. It is a short-perennial and autogamous species, with a diploid and relatively small genome (2n=20; 460 Mb/1C). A. evenia 'IRFL6945' is nodulated by the well-characterized photosynthetic Bradyrhizobium sp. strain ORS278 and is efficiently transformed by Agrobacterium rhizogenes. Aeschynomene evenia is genetically homozygous but polymorphic accessions were found. A manual hybridization procedure has been set up, allowing directed crosses. Therefore, it should be relatively straightforward to unravel the molecular determinants of the Nod-independent process in A. evenia. This should shed new light on the evolution of rhizobium-legume symbiosis and could have important agronomic implications.

  18. Terminal Bacteroid Differentiation Is Associated With Variable Morphological Changes in Legume Species Belonging to the Inverted Repeat-Lacking Clade.

    Science.gov (United States)

    Montiel, Jesús; Szűcs, Attila; Boboescu, Iulian Z; Gherman, Vasile D; Kondorosi, Éva; Kereszt, Attila

    2016-03-01

    Medicago and closely related legume species from the inverted repeat-lacking clade (IRLC) impose terminal differentiation onto their bacterial endosymbionts, manifested in genome endoreduplication, cell enlargement, and loss of cell-division capacity. Nodule-specific cysteine-rich (NCR) secreted host peptides are plant effectors of this process. As bacteroids in other IRLC legumes, such as Cicer arietinum and Glycyrrhiza lepidota, were reported not to display features of terminal differentiation, we investigated the fate of bacteroids in species from these genera as well as in four other species representing distinct genera of the phylogenetic tree for this clade. Bacteroids in all tested legumes proved to be larger in size and DNA content than cultured cells; however, the degree of cell elongation was rather variable in the different species. In addition, the reproductive ability of the bacteroids isolated from these legumes was remarkably reduced. In all IRLC species with available sequence data, the existence of NCR genes was found. These results indicate that IRLC legumes provoke terminal differentiation of their endosymbionts with different morphotypes, probably with the help of NCR peptides.

  19. Unique and conserved features of floral evocation in legumes.

    Science.gov (United States)

    Liew, Lim Chee; Singh, Mohan B; Bhalla, Prem L

    2014-08-01

    Legumes, with their unique ability to fix atmospheric nitrogen, play a vital role in ensuring future food security and mitigating the effects of climate change because they use less fossil energy and produce less greenhouse gases compared with N-fertilized systems. Grain legumes are second only to cereal crops as a source of human and animal food, and they contribute approximately one third of the protein consumed by the human population. The productivity of seed crops, such as grain legumes, is dependent on flowering. Despite the genetic variation and importance of flowering in legume production, studies of the molecular pathways that control flowering in legumes are limited. Recent advances in genomics have revealed that legume flowering pathways are divergent from those of such model species as Arabidopsis thaliana. Here, we discuss the current understanding of flowering time regulation in legumes and highlight the unique and conserved features of floral evocation in legumes.

  20. Unique and conserved features of floral evocation in legumes

    Institute of Scientific and Technical Information of China (English)

    Lim Chee Liew; Mohan B.Singh; Prem L.Bhalla

    2014-01-01

    Legumes, with their unique ability to fix atmo-spheric nitrogen, play a vital role in ensuring future food security and mitigating the effects of climate change because they use less fossil energy and produce less greenhouse gases compared with N-fertilized systems. Grain legumes are second only to cereal crops as a source of human and animal food, and they contribute approximately one third of the protein consumed by the human population. The productivity of seed crops, such as grain legumes, is dependent on flowering. Despite the genetic variation and importance of flowering in legume production, studies of the molecular pathways that control flowering in legumes are limited. Recent advances in genomics have revealed that legume flowering pathways are divergent from those of such model species as Arabidopsis thaliana. Here, we discuss the current understanding of flowering time regulation in legumes and highlight the unique and conserved features of floral evocation in legumes.

  1. Evemphyron sinense, a new genus and species infesting legume seedpods in China (Coleoptera, Attelabidae, Rhynchitinae)

    Science.gov (United States)

    Lv, Xiangyang; Alonso-Zarazaga, Miguel A.; Xiao, Zhishu; Wang, Zhiliang; Zhang, Runzhi

    2016-01-01

    Abstract A new genus Evemphyron Alonso-Zarazaga, Lv & Wang, gen. n., belonging to Attelabidae Rhynchitinae, is described. Its single species, Evemphyron sinense Alonso-Zarazaga, Lv & Wang, sp. n., was reared from larvae found inside seed pods of the legume Callerya dielsiana (Fabaceae, Millettieae) in Sichuan Province (China). The species is figured and placed in the Deporaini because of the presence of minute labial palpi, the strongly crescentic apex of the postmentum, and the apodemes of male IX sternite and female VIII sternite curved sinistro-anterially near their cephalic end. It shows 3-segmented labial palpi and male sex patches on the procoxae, characters that suggest a basal position in the tribe. PMID:27408602

  2. Revegetation of lagoon ash using the legume species Acacia auriculiformis and Leucaena leucocephala

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, K.C.; Wong, J.P.K.; Zhang, Z.Q.; Wong, J.W.C.; Wong, M.H. [Hong Kong Baptist University, Hong Kong (China). Inst. of Natural Resources and Waste Management

    2000-07-01

    This paper describes a greenhouse study conducted to evaluate the potential use of two legume species, Acacia auriculiformis and Leucaena leucocephala for growth on ameliorated lagoon ash with or without nitrogen fixing bacteria inoculation. Even though amendments of 30% (w/w) vermiculite or with sewage sludge compost were added to improve the chemical and physical limitations of lagoon ash, significant suppressions in biomass and plant nutrient content were found with ameliorated lagoon ash in comparison to an agricultural soil. The high proportion of clay-sized ({lt} 53{mu}m) ash particles limited root growth. In addition, heavy metal toxicity was a possible factor contributing to poor seeding growth. Higher plant productivity resulted from the sewage sludge compost-amended lagoon ash than with vermiculite due to a greater contribution of plant nutrients in the compost. Both species showed potential to establish on amended lagoon ash, with Acacia auriculiformis being the best adapted.

  3. Background and History of the Lotus japonicus Model Legume System

    DEFF Research Database (Denmark)

    2014-01-01

    , focusing on endosymbiosis. Several important discoveries have been made, and the Lotus community has contributed novel results, promoting our understanding of plant biology as well as our understanding of properties and characteristics typical for plants belonging to the legume family. Progress has been...

  4. Phylogenetic diversity of Rhizobium strains nodulating diverse legume species growing in Ethiopia.

    Science.gov (United States)

    Degefu, Tulu; Wolde-meskel, Endalkachew; Frostegård, Åsa

    2013-06-01

    The taxonomic diversity of thirty-seven Rhizobium strains, isolated from nodules of leguminous trees and herbs growing in Ethiopia, was studied using multilocus sequence analyses (MLSA) of six core and two symbiosis-related genes. Phylogenetic analysis based on the 16S rRNA gene grouped them into five clusters related to nine Rhizobium reference species (99-100% sequence similarity). In addition, two test strains occupied their own independent branches on the phylogenetic tree (AC86a2 along with R. tibeticum; 99.1% similarity and AC100b along with R. multihospitium; 99.5% similarity). One strain from Milletia ferruginea was closely related (>99%) to the genus Shinella, further corroborating earlier findings that nitrogen-fixing bacteria are distributed among phylogenetically unrelated taxa. Sequence analyses of five housekeeping genes also separated the strains into five well-supported clusters, three of which grouped with previously studied Ethiopian common bean rhizobia. Three of the five clusters could potentially be described into new species. Based on the nifH genes, most of the test strains from crop legumes were closely related to several strains of Ethiopian common bean rhizobia and other symbionts of bean plants (R. etli and R. gallicum sv. phaseoli). The grouping of the test strains based on the symbiosis-related genes was not in agreement with the housekeeping genes, signifying differences in their evolutionary history. Our earlier studies revealing a large diversity of Mesorhizobium and Ensifer microsymbionts isolated from Ethiopian legumes, together with the results from the present analysis of Rhizobium strains, suggest that this region might be a potential hotspot for rhizobial biodiversity.

  5. Legume phylogeny and classification in the 21st century: Progress, prospects and lessons for other species-rich clades

    NARCIS (Netherlands)

    Bruneau, A.; Doyle, J.J.; Herendeen, P.; Hughes, C.; Kenicer, G.; Lewis, G.; Mackinder, B.A.; Pennington, R.T.; Sanderson, M.J.; Wojciechowski, M.F.; Boatwright, S.; Brown, G.; Cardoso, D.; Crips, M.; Egan, A.; Fortunato, R.; Hawkins, J.; Kajita, T.; Klitgaard, B.B.; Koenen, E.; Lavin, M.; Luckow, M.; Marazzi, B.; McMahon, M.M.; Miller, J.T.; Murphy, D.J.; Ohashi, H.; Queiroz, de L.P.; Rico, L.; Särkinen, T.; Schrire, B.; Simon, M.F.; Souza, E.R.; Steele, K.; Torke, B.M.; Wieringa, J.J.; Wijk, B.E.

    2013-01-01

    The Leguminosae, the third-largest angiosperm family, has a global distribution and high ecological and economic importance. We examine how the legume systematic research community might join forces to produce a comprehensive phylogenetic estimate for the ca. 751 genera and ca. 19,500 species of

  6. Legume phylogeny and classification in the 21st century: Progress, prospects and lessons for other species-rich clades

    NARCIS (Netherlands)

    Bruneau, A.; Doyle, J.J.; Herendeen, P.; Hughes, C.; Kenicer, G.; Lewis, G.; Mackinder, B.A.; Pennington, R.T.; Sanderson, M.J.; Wojciechowski, M.F.; Boatwright, S.; Brown, G.; Cardoso, D.; Crips, M.; Egan, A.; Fortunato, R.; Hawkins, J.; Kajita, T.; Klitgaard, B.B.; Koenen, E.; Lavin, M.; Luckow, M.; Marazzi, B.; McMahon, M.M.; Miller, J.T.; Murphy, D.J.; Ohashi, H.; Queiroz, de L.P.; Rico, L.; Särkinen, T.; Schrire, B.; Simon, M.F.; Souza, E.R.; Steele, K.; Torke, B.M.; Wieringa, J.J.; Wijk, B.E.

    2013-01-01

    The Leguminosae, the third-largest angiosperm family, has a global distribution and high ecological and economic importance. We examine how the legume systematic research community might join forces to produce a comprehensive phylogenetic estimate for the ca. 751 genera and ca. 19,500 species of leg

  7. Tannin containing legumes as a model for nutraceuticals against digestive parasites in livestock.

    Science.gov (United States)

    Hoste, H; Torres-Acosta, J F J; Sandoval-Castro, C A; Mueller-Harvey, I; Sotiraki, S; Louvandini, H; Thamsborg, S M; Terrill, T H

    2015-08-15

    Parasitic infections with gastrointestinal nematodes (GINs) still represent a worldwide major pathological threat associated with the outdoor production of various livestock species. Because of the widespread resistance to synthetic chemical anthelmintics, there is a strong impetus to explore novel approaches for a more integrated management of these infections. The use of nutraceuticals in the control of GINs is one of the alternatives which has been widely studied for 20 years. The objectives of this review are: (i) to define and illustrate the concept of 'nutraceutical' in the context of veterinary parasitology based on data obtained on the most studied models to control GINs in small ruminants, the tannin-containing legumes (Fabaceae); (ii) to illustrate how the 'nutraceutical concept' could be expanded to other plants, other livestock production systems and other GI parasitic diseases, and (iii) to explain how this concept is opening up new research fields for better understanding the interactions between the host, the digestive parasites and the environment.

  8. Rhizobium vignae sp. nov., a symbiotic bacterium isolated from multiple legume species.

    Science.gov (United States)

    Ren, Da Wei; Chen, Wen Feng; Sui, Xin Hua; Wang, En Tao; Chen, Wen Xin

    2011-03-01

    A group of rhizobial strains isolated from nodules of multiple legume species grown in different geographical regions of China had identical 16S rRNA genes. Phylogenetic analysis based on the 16S rRNA gene sequences showed that the novel strains formed a subclade in the genus Rhizobium together with Rhizobium galegae, Rhizobium huautlense and Rhizobium alkalisoli, with 99.8  % gene sequence similarity between the strains. The DNA-DNA relatedness values between the representative strain CCBAU 05176(T) and R. galegae ATCC 43677(T), R. huautlense S02(T) and R. alkalisoli CCBAU 01393(T) were 22.6  %, 8.9  % and 15.9  %, respectively. The novel strains were distinguished from recognized species of the genus Rhizobium by using a polyphasic approach, including PCR-based restriction fragment length polymorphism analysis (RFLP) of the 16S-23S intergenic spacer (IGS), phenotypic and physiological tests, sequence comparisons of housekeeping genes and cellular fatty acid profiles. Therefore, it is suggested that this group of strains represents a novel species for which the name Rhizobium vignae sp. nov. is proposed. The type strain is CCBAU 05176(T) (=HAMBI 3039(T)=LMG 25447(T)).

  9. Towards a better understanding of the role of reactive oxygen species in legume root nodules

    NARCIS (Netherlands)

    Ramos Escribano, J.

    2004-01-01

    Biological N2 fixation is carried out exclusively by prokaryotes, either in the free-living form or in mutualistic symbioses with green algae, legumes and actinorhizal plants. The most agronomica1ly relevant symbiosis is, by fàr, that formed between soil rhizobia and legume roots. In addition, the

  10. Towards a better understanding of the role of reactive oxygen species in legume root nodules

    NARCIS (Netherlands)

    Ramos Escribano, J.

    2004-01-01

    Biological N2 fixation is carried out exclusively by prokaryotes, either in the free-living form or in mutualistic symbioses with green algae, legumes and actinorhizal plants. The most agronomica1ly relevant symbiosis is, by fàr, that formed between soil rhizobia and legume roots. In addition, the i

  11. Revegetation of lagoon ash using the legume species Acacia auriculiformis and Leucaena leucocephala.

    Science.gov (United States)

    Cheung, K C; Wong, J P; Zhang, Z Q; Wong, J W; Wong, M H

    2000-07-01

    A greenhouse study was conducted to evaluate the potential use of two legume species, Acacia auriculiformis and Leucaena leucocephala for growth on ameliorated lagoon ash with or without nitrogen (N(2))-fixing bacteria inoculation. Even though amendments of 30% (w/w) vermiculite or with sewage sludge compost were added to improve the chemical and physical limitations of lagoon ash, significant suppressions in biomass and plant nutrient content were found with ameliorated lagoon ash in comparison to an agricultural soil. The high proportion of clay-sized (<53 microm) ash particles limited root growth. In addition, heavy metal toxicity was a possible factor contributing to poor seedling growth. Higher plant productivity resulted from the sewage sludge compost-amended lagoon ash than with vermiculite due to a greater contribution of plant nutrients in the compost. Nodulation was inhibited in ameliorated lagoon ash but not in agricultural soil. High pH and electrical conductivity and elevated toxic metals may be important parameters that limit bacterial activity. Both species showed potential to establish on amended lagoon ash, with Acacia auriculiformis being the best adapted.

  12. Legume and Lotus japonicus Databases

    DEFF Research Database (Denmark)

    Hirakawa, Hideki; Mun, Terry; Sato, Shusei

    2014-01-01

    Since the genome sequence of Lotus japonicus, a model plant of family Fabaceae, was determined in 2008 (Sato et al. 2008), the genomes of other members of the Fabaceae family, soybean (Glycine max) (Schmutz et al. 2010) and Medicago truncatula (Young et al. 2011), have been sequenced. In this sec....... In this section, we introduce representative, publicly accessible online resources related to plant materials, integrated databases containing legume genome information, and databases for genome sequence and derived marker information of legume species including L. japonicus...

  13. The Proteome of Seed Development in the Model Legume Lotus japonicus

    DEFF Research Database (Denmark)

    Dam, Svend; Laursen, Brian S.; Ornfelt, Jane H.

    2009-01-01

    We have characterized the development of seeds in the model legume Lotus japonicus. Like soybean (Glycine max) and pea (Pisum sativum), Lotus develops straight seed pods and each pod contains approximately 20 seeds that reach maturity within 40 days. Histological sections show the characteristic...

  14. Production Performance of Root Systems of Four Forage Legume Species and Their Development Characteristics in Loess Plateau,China

    Institute of Scientific and Technical Information of China (English)

    Zhang; Jianquan; Zhang; Jiyu; Wang; Yanrong; Xie; Wengang; Li; Juncheng

    2014-01-01

    Production performance of four forage legumes species of Medicago sativa,Onobrychis viciifolia,Lotus corniculatus and Galega officinalis were determined,including plant height,above-ground biomass per unit area,tillers per unit area,fertile tillers per unit area,shoot /leaf ratio and fresh /dry matter weight ratio,and the distribution characteristics of their root systems in 0- 100 cm soil layers with 10 cm interval were studied. Results showed that the average aboveground fresh biomass(4 a and 5 a) of four forage legumes species successively were L. corniculatus > M. sativa > O. viciifolia > G. officinalis. The average plant heights in two years successively were O. viciifolia > M. sativa > G. officinalis > L. corniculatus. Tillers per unit area of four forage legume species in two years successively were M. sativa > L. corniculatus > O. viciifolia > G. officinalis. Fertile tillers per unit area in two years were O. viciifolia > M. sativa > L. corniculatus > G. officinalis. Average shoot /leaf ratio in two years were G. officinalis > M. sativa > O. viciifolia > L. corniculatus. Average moisture contents of four forage legume species in two years successively were G. officinalis > L. corniculatus > M. sativa = O. viciifolia. The distribution characteristics of root systems of four forage legumes species in 0- 100 cm soil layers were as follows: the root weights of M. sativa in 0- 40 cm soil layers accounted for about 98. 3% of total root weight,that of O. viciifolia in 0- 30 cm soil layers was 85. 8%,that of L. corniculatus in 0- 10 cm soil layers was 80%,and that of G. officinalis in 0- 40 cm soil layers was 81. 4%. The results suggested that L. corniculatus was suited to plant in slighter degraded pasture to control water and soil erosion in early stage,G. officinalis with strong lateral roots was adapted to degraded grassland in the Loess Plateau where soil nutrient was poor,while O. viciifolia and M. sativa with potentially strong main root were fit for water

  15. Legume genomes: more than peas in a pod.

    Science.gov (United States)

    Young, Nevin Dale; Mudge, Joann; Ellis, T H Noel

    2003-04-01

    A growing array of sequence-based tools is helping to reveal the organization, evolution and syntenic relationships of legume genomes. The results indicate that legumes form a coherent taxonomic group with frequent and widespread macro- and microsynteny. This is good news for two model legume systems, Medicago truncatula and Lotus japonicus. Indeed, both models have recently been used to clone and characterize genes for nodulation-related receptors that were originally described in legumes with more complex genomes. Studies of legume genomes have also provided insight into genome size, gene clustering, genome duplications and repetitive elements. To understand legume genomes better, it will be necessary to develop tools for studying under-represented taxa beyond the relatively small group of economically important species that have been examined so far.

  16. Reactive Oxygen Species and Nitric Oxide Control Early Steps of the Legume – Rhizobium Symbiotic Interaction

    Science.gov (United States)

    Damiani, Isabelle; Pauly, Nicolas; Puppo, Alain; Brouquisse, Renaud; Boscari, Alexandre

    2016-01-01

    The symbiotic interaction between legumes and nitrogen-fixing rhizobium bacteria leads to the formation of a new organ, the nodule. Early steps of the interaction are characterized by the production of bacterial Nod factors, the reorientation of root-hair tip growth, the formation of an infection thread (IT) in the root hair, and the induction of cell division in inner cortical cells of the root, leading to a nodule primordium formation. Reactive oxygen species (ROS) and nitric oxide (NO) have been detected in early steps of the interaction. ROS/NO are determinant signals to arbitrate the specificity of this mutualistic association and modifications in their content impair the development of the symbiotic association. The decrease of ROS level prevents root hair curling and ITs formation, and that of NO conducts to delayed nodule formation. In root hairs, NADPH oxidases were shown to produce ROS which could be involved in the hair tip growth process. The use of enzyme inhibitors suggests that nitrate reductase and NO synthase-like enzymes are the main route for NO production during the early steps of the interaction. Transcriptomic analyses point to the involvement of ROS and NO in the success of the infection process, the induction of early nodulin gene expression, and the repression of plant defense, thereby favoring the establishment of the symbiosis. The occurrence of an interplay between ROS and NO was further supported by the finding of both S-sulfenylated and S-nitrosylated proteins during early symbiotic interaction, linking ROS/NO production to a redox-based regulation of the symbiotic process. PMID:27092165

  17. Reactive oxygen species and nitric oxide control early steps of the legume – Rhizobium symbiotic interaction

    Directory of Open Access Journals (Sweden)

    Isabelle eDamiani

    2016-04-01

    Full Text Available The symbiotic interaction between legumes and nitrogen-fixing rhizobium bacteria leads to the formation of a new organ, the nodule. Early steps of the interaction are characterized by the production of bacterial Nod factors, the reorientation of root-hair tip growth, the formation of an infection thread in the root hair, and the induction of cell division in inner cortical cells of the root, leading to a nodule primordium formation. Reactive oxygen species (ROS and nitric oxide (NO have been detected in early steps of the interaction. ROS/NO are determinant signals to arbitrate the specificity of this mutualistic association and modifications in their content impair the development of the symbiotic association. The decrease of ROS level prevents root hair curling and infection threads formation, and that of NO conducts to delayed nodule formation. In root hairs, NADPH oxidases were shown to produce ROS which could be involved in the hair tip growth process. The use of enzyme inhibitors suggests that nitrate reductase and NO synthase-like enzymes are the main route for NO production during the early steps of the interaction. Transcriptomic analyses point to the involvement of ROS and NO in the success of the infection process, the induction of early nodulin gene expression, and the repression of plant defense, thereby favoring the establishment of the symbiosis. The occurrence of an interplay between ROS and NO was further supported by the finding of both S-sulfenylated and S-nitrosylated proteins during early symbiotic interaction, linking ROS/NO production to a redox-based regulation of the symbiotic process.

  18. N2-fixation and residual N effect of four legume species and four companion grass species

    DEFF Research Database (Denmark)

    Rasmussen, Jim; Søegaard, Karen; Pirhofer-Walzl, Karin

    2012-01-01

    and climatic conditions. We conducted a field experiment on a sandy soil at two nitrogen levels with seven two-species forage mixtures: alfalfa, bird's-foot trefoil, red clover, or white clover in mixture with perennial ryegrass, and white clover in mixture with meadow fescue, timothy, or hybrid ryegrass. We...... found high N2-fixation of more than 300 kg N ha−1 from both red clover and alfalfa even when the two mixtures received 300 kg total-N ha−1 in cattle slurry. The addition of cattle slurry N fertilizer lowered N2-fixation for white clover and red clover as expected, but for bird's-foot trefoil and alfalfa...... no changes in the proportion of N derived from N2-fixation was observed. We conclude that the competition for available soil N from perennial ryegrass in mixture was an important factor for the proportion of N in alfalfa, white clover, and bird's-foot trefoil obtained from N2-fixation. White clover had...

  19. The evolutionary dynamics of ancient and recent polyploidy in the African semiaquatic species of the legume genus Aeschynomene.

    Science.gov (United States)

    Chaintreuil, Clémence; Gully, Djamel; Hervouet, Catherine; Tittabutr, Panlada; Randriambanona, Herizo; Brown, Spencer C; Lewis, Gwilym P; Bourge, Mickaël; Cartieaux, Fabienne; Boursot, Marc; Ramanankierana, Heriniaina; D'Hont, Angélique; Teaumroong, Neung; Giraud, Eric; Arrighi, Jean-François

    2016-08-01

    The legume genus Aeschynomene is notable in the ability of certain semiaquatic species to develop nitrogen-fixing stem nodules. These species are distributed in two clades. In the first clade, all the species are characterized by the use of a unique Nod-independent symbiotic process. In the second clade, the species use a Nod-dependent symbiotic process and some of them display a profuse stem nodulation as exemplified in the African Aeschynomene afraspera. To facilitate the molecular analysis of the symbiotic characteristics of such legumes, we took an integrated molecular and cytogenetic approach to track occurrences of polyploidy events and to analyze their impact on the evolution of the African species of Aeschynomene. Our results revealed two rounds of polyploidy: a paleopolyploid event predating the African group and two neopolyploid speciations, along with significant chromosomal variations. Hence, we found that A. afraspera (8x) has inherited the contrasted genomic properties and the stem-nodulation habit of its parental lineages (4x). This study reveals a comprehensive picture of African Aeschynomene diversification. It notably evidences a history that is distinct from the diploid Nod-independent clade, providing clues for the identification of the specific determinants of the Nod-dependent and Nod-independent symbiotic processes, and for comparative analysis of stem nodulation.

  20. Genomic survey, gene expression analysis and structural modeling suggest diverse roles of DNA methyltransferases in legumes.

    Directory of Open Access Journals (Sweden)

    Rohini Garg

    Full Text Available DNA methylation plays a crucial role in development through inheritable gene silencing. Plants possess three types of DNA methyltransferases (MTases, namely Methyltransferase (MET, Chromomethylase (CMT and Domains Rearranged Methyltransferase (DRM, which maintain methylation at CG, CHG and CHH sites. DNA MTases have not been studied in legumes so far. Here, we report the identification and analysis of putative DNA MTases in five legumes, including chickpea, soybean, pigeonpea, Medicago and Lotus. MTases in legumes could be classified in known MET, CMT, DRM and DNA nucleotide methyltransferases (DNMT2 subfamilies based on their domain organization. First three MTases represent DNA MTases, whereas DNMT2 represents a transfer RNA (tRNA MTase. Structural comparison of all the MTases in plants with known MTases in mammalian and plant systems have been reported to assign structural features in context of biological functions of these proteins. The structure analysis clearly specified regions crucial for protein-protein interactions and regions important for nucleosome binding in various domains of CMT and MET proteins. In addition, structural model of DRM suggested that circular permutation of motifs does not have any effect on overall structure of DNA methyltransferase domain. These results provide valuable insights into role of various domains in molecular recognition and should facilitate mechanistic understanding of their function in mediating specific methylation patterns. Further, the comprehensive gene expression analyses of MTases in legumes provided evidence of their role in various developmental processes throughout the plant life cycle and response to various abiotic stresses. Overall, our study will be very helpful in establishing the specific functions of DNA MTases in legumes.

  1. An expression database for roots of the model legume Medicago truncatula under salt stress

    Directory of Open Access Journals (Sweden)

    Dong Jiangli

    2009-11-01

    Full Text Available Abstract Background Medicago truncatula is a model legume whose genome is currently being sequenced by an international consortium. Abiotic stresses such as salt stress limit plant growth and crop productivity, including those of legumes. We anticipate that studies on M. truncatula will shed light on other economically important legumes across the world. Here, we report the development of a database called MtED that contains gene expression profiles of the roots of M. truncatula based on time-course salt stress experiments using the Affymetrix Medicago GeneChip. Our hope is that MtED will provide information to assist in improving abiotic stress resistance in legumes. Description The results of our microarray experiment with roots of M. truncatula under 180 mM sodium chloride were deposited in the MtED database. Additionally, sequence and annotation information regarding microarray probe sets were included. MtED provides functional category analysis based on Gene and GeneBins Ontology, and other Web-based tools for querying and retrieving query results, browsing pathways and transcription factor families, showing metabolic maps, and comparing and visualizing expression profiles. Utilities like mapping probe sets to genome of M. truncatula and In-Silico PCR were implemented by BLAT software suite, which were also available through MtED database. Conclusion MtED was built in the PHP script language and as a MySQL relational database system on a Linux server. It has an integrated Web interface, which facilitates ready examination and interpretation of the results of microarray experiments. It is intended to help in selecting gene markers to improve abiotic stress resistance in legumes. MtED is available at http://bioinformatics.cau.edu.cn/MtED/.

  2. Genomic survey, gene expression analysis and structural modeling suggest diverse roles of DNA methyltransferases in legumes.

    Science.gov (United States)

    Garg, Rohini; Kumari, Romika; Tiwari, Sneha; Goyal, Shweta

    2014-01-01

    DNA methylation plays a crucial role in development through inheritable gene silencing. Plants possess three types of DNA methyltransferases (MTases), namely Methyltransferase (MET), Chromomethylase (CMT) and Domains Rearranged Methyltransferase (DRM), which maintain methylation at CG, CHG and CHH sites. DNA MTases have not been studied in legumes so far. Here, we report the identification and analysis of putative DNA MTases in five legumes, including chickpea, soybean, pigeonpea, Medicago and Lotus. MTases in legumes could be classified in known MET, CMT, DRM and DNA nucleotide methyltransferases (DNMT2) subfamilies based on their domain organization. First three MTases represent DNA MTases, whereas DNMT2 represents a transfer RNA (tRNA) MTase. Structural comparison of all the MTases in plants with known MTases in mammalian and plant systems have been reported to assign structural features in context of biological functions of these proteins. The structure analysis clearly specified regions crucial for protein-protein interactions and regions important for nucleosome binding in various domains of CMT and MET proteins. In addition, structural model of DRM suggested that circular permutation of motifs does not have any effect on overall structure of DNA methyltransferase domain. These results provide valuable insights into role of various domains in molecular recognition and should facilitate mechanistic understanding of their function in mediating specific methylation patterns. Further, the comprehensive gene expression analyses of MTases in legumes provided evidence of their role in various developmental processes throughout the plant life cycle and response to various abiotic stresses. Overall, our study will be very helpful in establishing the specific functions of DNA MTases in legumes.

  3. Identification of conserved microRNAs and their targets in the model legume Lotus japonicus.

    Science.gov (United States)

    Hu, Jihong; Zhang, Hongyuan; Ding, Yi

    2013-04-15

    MicroRNAs (miRNAs) are a new class of non-protein coding small RNAs that regulate gene expression at the post-transcriptional level in plants and animals. Although thousands of miRNAs were identified in many plant species, only 3 miRNAs have been reported in Lotus Japonicus, a model legume plant. In this study, 80 potential miRNA candidates were identified in 28 ESTs and 52 GSSs of L. japonicus using a homology-based computational analysis. A total of 735 miRNA targets were predicted and some of them encoded transcription factors as well as genes that function in stress response, signal transduction, methylation and others. Quantitative real-time PCR (qRT-PCR) analysis indicated that miR156a, miR160a and miR399a participated in seed germination of L. japonicus. GO and KEGG analysis suggested that the predicted miRNAs might target genes involved in lipid, nitrogen, starch sucrose metabolism and signal transduction.

  4. Differences in Crenate Broomrape Parasitism Dynamics on Three Legume Crops Using a Thermal Time Model

    Science.gov (United States)

    Pérez-de-Luque, Alejandro; Flores, Fernando; Rubiales, Diego

    2016-01-01

    Root parasitic weeds are a major limiting production factor in a number of crops, and control is difficult. Genetic resistance and chemical control lead the fight, but without unequivocal success. Models that help to describe and even predict the evolution of parasitism underground are a valuable tool for herbicide applications, and even could help in breeding programs. Legumes are heavily affected by Orobanche crenata (crenate broomrape) in the Mediterranean basin. This work presents a descriptive model based on thermal time and correlating growing degree days (GDD) with the different developmental stages of the parasite. The model was developed in three different legume crops (faba bean, grass pea and lentil) attacked by crenate broomrape. The developmental stages of the parasite strongly correlated with the GDD and differences were found depending on the host crop. PMID:28018421

  5. The molecular genetic linkage map of the model legume Medicago truncatula: an essential tool for comparative legume genomics and the isolation of agronomically important genes

    Directory of Open Access Journals (Sweden)

    Ané Jean-Michel

    2002-01-01

    Full Text Available Abstract Background The legume Medicago truncatula has emerged as a model plant for the molecular and genetic dissection of various plant processes involved in rhizobial, mycorrhizal and pathogenic plant-microbe interactions. Aiming to develop essential tools for such genetic approaches, we have established the first genetic map of this species. Two parental homozygous lines were selected from the cultivar Jemalong and from the Algerian natural population (DZA315 on the basis of their molecular and phenotypic polymorphism. Results An F2 segregating population of 124 individuals between these two lines was obtained using an efficient manual crossing technique established for M. truncatula and was used to construct a genetic map. This map spans 1225 cM (average 470 kb/cM and comprises 289 markers including RAPD, AFLP, known genes and isoenzymes arranged in 8 linkage groups (2n = 16. Markers are uniformly distributed throughout the map and segregation distortion is limited to only 3 linkage groups. By mapping a number of common markers, the eight linkage groups are shown to be homologous to those of diploid alfalfa (M. sativa, implying a good level of macrosynteny between the two genomes. Using this M. truncatula map and the derived F3 populations, we were able to map the Mtsym6 symbiotic gene on linkage group 8 and the SPC gene, responsible for the direction of pod coiling, on linkage group 7. Conclusions These results demonstrate that Medicago truncatula is amenable to diploid genetic analysis and they open the way to map-based cloning of symbiotic or other agronomically-important genes using this model plant.

  6. Proteome analysis of pod and seed development in the model legume Lotus japonicus

    DEFF Research Database (Denmark)

    Nautrup-Pedersen, G.; Dam, S.; Laursen, B. S.;

    2010-01-01

    Legume pods serve important functions during seed development and are themselves sources of food and feed. Compared to seeds, the metabolism and development of pods are not well-defined. The present characterization of pods from the model legume Lotus japonicus, together with the detailed analyses...... seed proteins, including 263 proteins distinguishing the pod. The complete data set is publicly available at http://www.cbs.dtu.dk/cgi-bin/lotus/db.cgi , where spots in a reference map are linked to experimental data, such as matched peptides, quantification values, and gene accessions. Identified pod...... of the pod and seed proteomes in five developmental stages, paves the way for comparative pathway analysis and provides new metabolic information. Proteins were analyzed by two-dimensional gel electrophoresis and tandem-mass spectrometry. These analyses lead to the identification of 604 pod proteins and 965...

  7. The proteome of seed development in the model legume Lotus japonicus.

    Science.gov (United States)

    Dam, Svend; Laursen, Brian S; Ornfelt, Jane H; Jochimsen, Bjarne; Staerfeldt, Hans Henrik; Friis, Carsten; Nielsen, Kasper; Goffard, Nicolas; Besenbacher, Søren; Krusell, Lene; Sato, Shusei; Tabata, Satoshi; Thøgersen, Ida B; Enghild, Jan J; Stougaard, Jens

    2009-03-01

    We have characterized the development of seeds in the model legume Lotus japonicus. Like soybean (Glycine max) and pea (Pisum sativum), Lotus develops straight seed pods and each pod contains approximately 20 seeds that reach maturity within 40 days. Histological sections show the characteristic three developmental phases of legume seeds and the presence of embryo, endosperm, and seed coat in desiccated seeds. Furthermore, protein, oil, starch, phytic acid, and ash contents were determined, and this indicates that the composition of mature Lotus seed is more similar to soybean than to pea. In a first attempt to determine the seed proteome, both a two-dimensional polyacrylamide gel electrophoresis approach and a gel-based liquid chromatography-mass spectrometry approach were used. Globulins were analyzed by two-dimensional polyacrylamide gel electrophoresis, and five legumins, LLP1 to LLP5, and two convicilins, LCP1 and LCP2, were identified by matrix-assisted laser desorption ionization quadrupole/time-of-flight mass spectrometry. For two distinct developmental phases, seed filling and desiccation, a gel-based liquid chromatography-mass spectrometry approach was used, and 665 and 181 unique proteins corresponding to gene accession numbers were identified for the two phases, respectively. All of the proteome data, including the experimental data and mass spectrometry spectra peaks, were collected in a database that is available to the scientific community via a Web interface (http://www.cbs.dtu.dk/cgi-bin/lotus/db.cgi). This database establishes the basis for relating physiology, biochemistry, and regulation of seed development in Lotus. Together with a new Web interface (http://bioinfoserver.rsbs.anu.edu.au/utils/PathExpress4legumes/) collecting all protein identifications for Lotus, Medicago, and soybean seed proteomes, this database is a valuable resource for comparative seed proteomics and pathway analysis within and beyond the legume family.

  8. Quantitative trait locus analysis of symbiotic nitrogen fixation activity in the model legume Lotus japonicus.

    Science.gov (United States)

    Tominaga, Akiyoshi; Gondo, Takahiro; Akashi, Ryo; Zheng, Shao-Hui; Arima, Susumu; Suzuki, Akihiro

    2012-05-01

    Many legumes form nitrogen-fixing root nodules. An elevation of nitrogen fixation in such legumes would have significant implications for plant growth and biomass production in agriculture. To identify the genetic basis for the regulation of nitrogen fixation, quantitative trait locus (QTL) analysis was conducted with recombinant inbred lines derived from the cross Miyakojima MG-20 × Gifu B-129 in the model legume Lotus japonicus. This population was inoculated with Mesorhizobium loti MAFF303099 and grown for 14 days in pods containing vermiculite. Phenotypic data were collected for acetylene reduction activity (ARA) per plant (ARA/P), ARA per nodule weight (ARA/NW), ARA per nodule number (ARA/NN), NN per plant, NW per plant, stem length (SL), SL without inoculation (SLbac-), shoot dry weight without inoculation (SWbac-), root length without inoculation (RLbac-), and root dry weight (RWbac-), and finally 34 QTLs were identified. ARA/P, ARA/NN, NW, and SL showed strong correlations and QTL co-localization, suggesting that several plant characteristics important for symbiotic nitrogen fixation are controlled by the same locus. QTLs for ARA/P, ARA/NN, NW, and SL, co-localized around marker TM0832 on chromosome 4, were also co-localized with previously reported QTLs for seed mass. This is the first report of QTL analysis for symbiotic nitrogen fixation activity traits.

  9. Proteome analysis of pod and seed development in the model legume Lotus japonicus.

    Science.gov (United States)

    Nautrup-Pedersen, Gitte; Dam, Svend; Laursen, Brian S; Siegumfeldt, Astrid L; Nielsen, Kasper; Goffard, Nicolas; Stærfeldt, Hans Henrik; Friis, Carsten; Sato, Shusei; Tabata, Satoshi; Lorentzen, Andrea; Roepstorff, Peter; Stougaard, Jens

    2010-11-01

    Legume pods serve important functions during seed development and are themselves sources of food and feed. Compared to seeds, the metabolism and development of pods are not well-defined. The present characterization of pods from the model legume Lotus japonicus, together with the detailed analyses of the pod and seed proteomes in five developmental stages, paves the way for comparative pathway analysis and provides new metabolic information. Proteins were analyzed by two-dimensional gel electrophoresis and tandem-mass spectrometry. These analyses lead to the identification of 604 pod proteins and 965 seed proteins, including 263 proteins distinguishing the pod. The complete data set is publicly available at http://www.cbs.dtu.dk/cgi-bin/lotus/db.cgi , where spots in a reference map are linked to experimental data, such as matched peptides, quantification values, and gene accessions. Identified pod proteins represented enzymes from 85 different metabolic pathways, including storage globulins and a late embryogenesis abundant protein. In contrast to seed maturation, pod maturation was associated with decreasing total protein content, especially proteins involved in protein biosynthesis and photosynthesis. Proteins detected only in pods included three enzymes participating in the urea cycle and four in nitrogen and amino group metabolism, highlighting the importance of nitrogen metabolism during pod development. Additionally, five legume seed proteins previously unassigned in the glutamate metabolism pathway were identified.

  10. Identification of nutrient and physical seed trait QTL in the model legume Lotus japonicus.

    Science.gov (United States)

    Klein, Melinda A; Grusak, Michael A

    2009-08-01

    Legume seeds have the potential to provide a significant portion of essential micronutrients to the human diet. To identify the genetic basis for seed nutrient density, quantitative trait locus (QTL) analysis was conducted with the Miyakojima MG-20 x Gifu B-129 recombinant inbred population from the model legume Lotus japonicus. This population was grown to seed under greenhouse conditions in 2006 and 2007. Phenotypic data were collected for seed calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P), sulfur (S), and zinc (Zn) concentrations and content. Data for physical seed traits (average seed mass and seed-pod allocation values) were also collected. Based on these phenotypic data, QTL analyses identified 103 QTL linked to 55 different molecular markers. Transgressive segregation, identified within this recombinant inbred population for both seed nutrient and physical traits, suggests new allelic combinations are available for agronomic trait improvement. QTL co-localization was also seen, suggesting that common transport processes might contribute to seed nutrient loading. Identification of loci involved in seed mineral density can be an important first step in identifying the genetic factors and, consequently, the physiological processes involved in mineral distribution to developing seeds. Longer term research efforts will focus on facilitating agronomic breeding efforts through ortholog identification in related crop legumes.

  11. LegumeIP 2.0--a platform for the study of gene function and genome evolution in legumes.

    Science.gov (United States)

    Li, Jun; Dai, Xinbin; Zhuang, Zhaohong; Zhao, Patrick X

    2016-01-04

    The LegumeIP 2.0 database hosts large-scale genomics and transcriptomics data and provides integrative bioinformatics tools for the study of gene function and evolution in legumes. Our recent updates in LegumeIP 2.0 include gene and protein sequences, gene models and annotations, syntenic regions, protein families and phylogenetic trees for six legume species: Medicago truncatula, Glycine max (soybean), Lotus japonicus, Phaseolus vulgaris (common bean), Cicer arietinum (chickpea) and Cajanus cajan (pigeon pea) and two outgroup reference species: Arabidopsis thaliana and Poplar trichocarpa. Moreover, the LegumeIP 2.0 features the following new data resources and bioinformatics tools: (i) an integrative gene expression atlas for four model legumes that include 550 array hybridizations from M. truncatula, 962 gene expression profiles of G. max, 276 array hybridizations from L. japonicas and 56 RNA-Seq-based gene expression profiles for C. arietinum. These datasets were manually curated and hierarchically organized based on Experimental Ontology and Plant Ontology so that users can browse, search, and retrieve data for their selected experiments. (ii) New functions/analytical tools to query, mine and visualize large-scale gene sequences, annotations and transcriptome profiles. Users may select a subset of expression experiments and visualize and compare expression profiles for multiple genes. The LegumeIP 2.0 database is freely available to the public at http://plantgrn.noble.org/LegumeIP/.

  12. To feed or not to feed: plant factors located in the epidermis, mesophyll, and sieve elements influence pea aphid's ability to feed on legume species.

    Directory of Open Access Journals (Sweden)

    Alexander Schwarzkopf

    Full Text Available The pea aphid (Acyrthosiphon pisum Harris, a legume specialist, encompasses at least 11 genetically distinct sympatric host races. Each host race shows a preference for a certain legume species. Six pea aphid clones from three host races were used to localize plant factors influencing aphid probing and feeding behavior on four legume species. Aphid performance was tested by measuring survival and growth. The location of plant factors influencing aphid probing and feeding was determined using the electrical penetration graph (EPG technique. Every aphid clone performed best on the plant species from which it was originally collected, as well as on Vicia faba. On other plant species, clones showed intermediate or poor performance. The most important plant factors influencing aphid probing and feeding behavior were localized in the epidermis and sieve elements. Repetitive puncturing of sieve elements might be relevant for establishing phloem feeding, since feeding periods appear nearly exclusively after these repetitive sieve element punctures. A combination of plant factors influences the behavior of pea aphid host races on different legume species and likely contributes to the maintenance of these races.

  13. Phenolic antioxidants in some Vigna species of legumes and their distinct inhibitory effects on α-glucosidase and pancreatic lipase activities.

    Science.gov (United States)

    Sreerama, Yadahally N; Takahashi, Yoko; Yamaki, Kohji

    2012-09-01

    Phenolic extracts of 4 Vigna species of legumes (mung bean, moth bean, and black and red varieties of adzuki beans) were evaluated for phenolic contents, antioxidant activities, and inhibitory properties against α-glucosidase and pancreatic lipase. Results showed that adzuki bean varieties contain higher phenolic indexes than mung bean and moth beans. Adzuki bean (black) variety was found to be the most active 2,2'-diphenyl-1-picrylhydrazyl and superoxide anion scavenger. However, the hydrogen peroxide scavenging and metal chelating abilities were significantly higher in adzuki bean (red) variety. Mung bean exhibited least antioxidant activities in all the methods tested. Phenolic extracts from these legumes also showed distinct variations in the inhibition of enzymes associated with hyperglycemia and hyperlipidemia. Inhibitory activities of all the extracts against lipase were found to be more potent than α-glucosidase. Although, α-glucosidase inhibitory activity was superior in the black variety of adzuki bean (IC(50,) 26.28 mg/mL), both adzuki bean varieties (black and red) along with moth bean showed strong inhibitory activities on lipase with no significant difference in their IC(50) values (7.32 to 9.85 mg/mL). These results suggest that Vigna species of legumes are potential source of antioxidant phenolics and also great sources of strong natural inhibitors for α-glucosidase and lipase activities. This information may help for effective utilization of these legumes as functional food ingredients for promoting health. Practical Application:  Vigna species of legumes are good sources of phenolic antioxidants and strong natural inhibitors of enzymes associated with diabetes and obesity. Therefore, utilization of these legumes in the development of functional foods with increased therapeutic value would be a significant step toward health promotion and wellness.

  14. Tannin containing legumes as a model for nutraceuticals against digestive parasites in livestock

    DEFF Research Database (Denmark)

    Hoste, H.; Torres-Acosta, J. F. J.; Sandoval-Castro, C. A.

    2015-01-01

    approaches for a more integrated management of these infections. The use of nutraceuticals in the control of GINs is one of the alternatives which has been widely studied for 20 years. The objectives of this review are: (i) to define and illustrate the concept of 'nutraceutical' in the context of veterinary...... parasitology based on data obtained on the most studied models to control GINs in small ruminants, the tannin-containing legumes (Fabaceae); (ii) to illustrate how the 'nutraceutical concept' could be expanded to other plants, other livestock production systems and other GI parasitic diseases, and (iii...

  15. Beneficial effects of legumes on parameters of the metabolic syndrome: a systematic review of trials in animal models.

    Science.gov (United States)

    Martínez, Rosario; López-Jurado, María; Wanden-Berghe, Carmina; Sanz-Valero, Javier; Porres, Jesús María; Kapravelou, Garyfallia

    2016-08-01

    Legume consumption plays a pivotal role in the prevention and treatment of the metabolic syndrome (MetS). This systematic review aimed to highlight the beneficial effects of legume interventions for the prevention and/or improvement of parameters related to the MetS and the implicated metabolic pathways so far reported. The methodology involved a search in four electronic databases (Medline, Web of Science, Scopus, Cochrane Library) from January 2007 to December 2014, considering as descriptors 'Metabolic Syndrome' and 'Fabaceae' and adequately adjusting the equation in each one of them. In total, forty-one studies were finally included. The majority of the studies described a regulating effect on glucose and lipid metabolism due to legume administration, whereas effects on blood pressure and renal parameters are not fully described. Regarding the metabolic pathways involved, they include the up-regulation of genes related to β-oxidation and acetyl-CoA degradation and the down-regulation of glycolytic and lipogenesis genes, as well as those associated with the acetyl-CoA synthesis. The ameliorating effects of legume consumption on the alterations associated with the MetS are clearly reported and coincide with changes in the expression of protein and genes involved in lipid and glucose metabolism. More research needs to be conducted including more legume species that are highly consumed as part of a healthy dietary pattern.

  16. Legume-rhizobia signal exchange: promiscuity and environmental effects.

    Science.gov (United States)

    Lira, Mario A; Nascimento, Luciana R S; Fracetto, Giselle G M

    2015-01-01

    Although signal exchange between legumes and their rhizobia is among the best-known examples of this biological process, most of the more characterized data comes from just a few legume species and environmental stresses. Although a relative wealth of information is available for some model legumes and some of the major pulses such as soybean, little is known about tropical legumes. This relative disparity in current knowledge is also apparent in the research on the effects of environmental stress on signal exchange; cool-climate stresses, such as low-soil temperature, comprise a relatively large body of research, whereas high-temperature stresses and drought are not nearly as well understood. Both tropical legumes and their environmental stress-induced effects are increasingly important due to global population growth (the demand for protein), climate change (increasing temperatures and more extreme climate behavior), and urbanization (and thus heavy metals). This knowledge gap for both legumes and their environmental stresses is compounded because whereas most temperate legume-rhizobia symbioses are relatively specific and cultivated under relatively stable environments, the converse is true for tropical legumes, which tend to be promiscuous, and grow in highly variable conditions. This review will clarify some of this missing information and highlight fields in which further research would benefit our current knowledge.

  17. Seasonal and Species Variation of the Hepatotoxin Indospicine in Australian Indigofera Legumes As Measured by UPLC-MS/MS.

    Science.gov (United States)

    Tan, Eddie T T; Materne, Christopher M; Silcock, Richard G; D'Arcy, Bruce R; Al Jassim, Rafat; Fletcher, Mary T

    2016-08-31

    Livestock industries have maintained a keen interest in pasture legumes because of the high protein content and nutritive value. Leguminous Indigofera plant species have been considered as having high feeding values to be utilized as pasture, but the occurrence of the toxic constituent indospicine in some species has restricted this utility. Indospicine has caused both primary and secondary hepatotoxicosis and also reproductive losses, but has only previously been determined in a small number of Indigofera species. This paper validates a high-throughput ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to determine the indospicine content of various Indigofera species found in Australian pasture. Twelve species of Indigofera together with Indigastrum parviflorum plants were collected and analyzed. Of the 84 samples analyzed, *I. spicata (the asterisk indicates a naturalized species) contained the highest indospicine level (1003 ± 328 mg/kg DM, n = 4) followed by I. linnaei (755 ± 490 mg/kg DM, n = 51). Indospicine was not detected in 9 of the remaining 11 species and at only low levels (<10 mg/kg DM) in 2 of 8 I. colutea specimens and in 1 of 5 I. linifolia specimens. Indospicine concentrations were below quantitation levels for other Indigofera spp. (I. adesmiifolia, I. georgei, I. hirsuta, I. leucotricha, *I. oblongifolia, I. australis, and I. trita) and Indigastrum parviflorum. One of the more significant findings to emerge from this study is that the indospicine content of I. linnaei is highly variable (from 159 to 2128 mg/kg DM, n = 51) and differs across both regions and seasons. Its first regrowth after spring rain has a higher (p < 0.01) indospicine content than growth following more substantial summer rain. The species collected include the predominant Indigofera in Australia pasture, and of these, only *I. spicata and I. linnaei contain high enough levels of indospicine to pose a potential toxic threat to grazing

  18. How many peas in a pod? Legume genes responsible for mutualistic symbioses underground.

    Science.gov (United States)

    Kouchi, Hiroshi; Imaizumi-Anraku, Haruko; Hayashi, Makoto; Hakoyama, Tsuneo; Nakagawa, Tomomi; Umehara, Yosuke; Suganuma, Norio; Kawaguchi, Masayoshi

    2010-09-01

    The nitrogen-fixing symbiosis between legume plants and Rhizobium bacteria is the most prominent plant-microbe endosymbiotic system and, together with mycorrhizal fungi, has critical importance in agriculture. The introduction of two model legume species, Lotus japonicus and Medicago truncatula, has enabled us to identify a number of host legume genes required for symbiosis. A total of 26 genes have so far been cloned from various symbiotic mutants of these model legumes, which are involved in recognition of rhizobial nodulation signals, early symbiotic signaling cascades, infection and nodulation processes, and regulation of nitrogen fixation. These accomplishments during the past decade provide important clues to understanding not only the molecular mechanisms underlying plant-microbe endosymbiotic associations but also the evolutionary aspects of nitrogen-fixing symbiosis between legume plants and Rhizobium bacteria. In this review we survey recent progress in molecular genetic studies using these model legumes.

  19. From embryo sac to oil and protein bodies: embryo development in the model legume Medicago truncatula.

    Science.gov (United States)

    Wang, Xin-Ding; Song, Youhong; Sheahan, Michael B; Garg, Manohar L; Rose, Ray J

    2012-01-01

    • The cell and developmental biology of zygotic embryogenesis in the model legume Medicago truncatula has received little attention. We studied M. truncatula embryogenesis from embryo sac until cotyledon maturation, including oil and protein body biogenesis. • We characterized embryo development using light and electron microscopy, measurement of protein and lipid fatty acid accumulation and by profiling the expression of key seed storage genes. • Embryo sac development in M. truncatula is of the Polygonum type. A distinctive multicellular hypophysis and suspensor develops before the globular stage and by the early cotyledon stage, the procambium connects the developing apical meristems. In the storage parenchyma of cotyledons, ovoid oil bodies surround protein bodies and the plasma membrane. Four major lipid fatty acids accumulate as cotyledons develop, paralleling the expression of OLEOSIN and the storage protein genes, VICILIN and LEGUMIN. • Zygotic embryogenesis in M. truncatula features the development of a distinctive multicellular hypophysis and an endopolyploid suspensor with basal transfer cell. A clear procambial connection between the apical meristems is evident and there is a characteristic arrangement of oil bodies in the cotyledons and radicle. Our data help link embryogenesis to the genetic regulation of oil and protein body biogenesis in legume seed.

  20. Quantitative trait locus analysis of multiple agronomic traits in the model legume Lotus japonicus.

    Science.gov (United States)

    Gondo, Takahiro; Sato, Shusei; Okumura, Kenji; Tabata, Satoshi; Akashi, Ryo; Isobe, Sachiko

    2007-07-01

    The first quantitative trait locus (QTL) analysis of multiple agronomic traits in the model legume Lotus japonicus was performed with a population of recombinant inbred lines derived from Miyakojima MG-20 x Gifu B-129. Thirteen agronomic traits were evaluated in 2004 and 2005: traits of vegetative parts (plant height, stem thickness, leaf length, leaf width, plant regrowth, plant shape, and stem color), flowering traits (flowering time and degree), and pod and seed traits (pod length, pod width, seeds per pod, and seed mass). A total of 40 QTLs were detected that explained 5%-69% of total variation. The QTL that explained the most variation was that for stem color, which was detected in the same region of chromosome 2 in both years. Some QTLs were colocated, especially those for pod and seed traits. Seed mass QTLs were located at 5 locations that mapped to the corresponding genomic positions of equivalent QTLs in soybean, pea, chickpea, and mung bean. This study provides fundamental information for breeding of agronomically important legume crops.

  1. Phytoremediation of oil contaminated soil by some arid legume tree species

    Directory of Open Access Journals (Sweden)

    Anil Vyas

    2010-07-01

    Full Text Available Petroleum contamination of soil is a serious problem throughout the world. Phytoremediationis a promising technology for the clean up of petroleum contaminated soil. In the present work therhizosphere of Prosopis cineraria (L. Druce, Acacia senegal (L. Willd. and Acacia nilotica (L. Willd. Ex.Del. plants were tested for their abilities to stimulate the microbial degradation of soil pollutants in desertsoil contaminated with 2.5-2.6% crude petroleum oil. The results showed that the roots of the threedifferent plants were density associated with total bacteria, fungi and oil-degrading microorganisms, thisis confirmed from the (R+/S+ ratios which ranged from 55.2-250.8 (for total bacteria, 20-131.3 (forfungi and 95.7-296.1 (for oil degraders. Percentages of oil-degraders were higher in the rhizospheresoil of P. cineraria (65.5% as compared to the rhizosphere soil of A. senegal and A. nilotica plants (22.5% and 20.2 % respectively. The results of the biodegradation of oil and its fractions showed that greatreduction (26 % of total petroleum hydrocarbons (TPHs was observed in the rhizosphere soil of P.cineraria as compared to 15.6 % and 12.8 % reduction in rhizosphere soil of A. senegal and A. niloticarespectively. It was observed also that in the polluted non-cultivated soil the TPHs were reduced by 8.2 -10.5 % as a result of biostimulation process only (addition of nutrients.The results also showed that P.cineraria rhizosphere was able to reduce more of the saturated (43.0 % and more of the aromatics(25.7 % fractions, compared to (35.2 % and 7.9 % for A. senegal and (31.2 % and 4.1 % for A.nilotica rhizospheres. It is of interest to find that 5.3 % of the hardly degradable fraction resins weredegraded in rhizosphere soil of P. cineraria. The present results clearly demonstrated that P. cineraria provided successful phytoremediation process of a contaminated desert soil as compared to the othertwo legume trees.

  2. Protein contamination on Klason lignin contents in tropical grasses and legumes

    Directory of Open Access Journals (Sweden)

    Edenio Detmann

    2014-12-01

    Full Text Available The objective of this work was to evaluate the extent of protein contamination on Klason lignin (KL in tropical grasses and legumes, and to propose an equation to estimate the protein-free content of Klason lignin (KLp. Five grass (30 samples and 12 legume species (31 samples were evaluated. Legumes had higher KL contents. Protein contamination was significant in both grasses and legumes, but greater in legume samples. The model to predict KLp was based on KL and crude protein (CP contents, as follows: KLp = 0.8807KL - 0.0938KL x D - 0.00338CP (R2=0.935, in which D=0, for grasses, and D=1 for legumes.

  3. An experimental and modelling exploration of the host-sanction hypothesis in legume-rhizobia mutualism.

    Science.gov (United States)

    Marco, Diana E; Carbajal, Juan P; Cannas, Sergio; Pérez-Arnedo, Rebeca; Hidalgo-Perea, Angeles; Olivares, José; Ruiz-Sainz, José E; Sanjuán, Juan

    2009-08-07

    Despite the importance of mutualism as a key ecological process, its persistence in nature is difficult to explain since the existence of exploitative, "cheating" partners that could erode the interaction is common. By analogy with the proposed policing strategy stabilizing intraspecific cooperation, host sanctions against non-N(2) fixing, cheating symbionts have been proposed as a force stabilizing mutualism in legume-Rhizobium symbiosis. Following this proposal, penalizations would include decreased nodular rhizobial viability and/or early nodule senescence in nodules occupied by cheating rhizobia. In this work, we analyse the stability of Rhizobium-legume symbiosis when non-fixing, cheating strains are present, using an experimental and modelling approach. We used split-root experiments with soybean plants inoculated with two rhizobial strains, a cooperative, normal N(2) fixing strain and an isogenic non-fixing, "perfect" cheating mutant derivative that lacks nitrogenase activity but has the same nodulation abilities inoculated to split-root plants. We found no experimental evidence of functioning plant host sanctions to cheater rhizobia based on nodular rhizobia viability and nodule senescence and maturity molecular markers. Based on these experiments, we developed a population dynamic model with and without the inclusion of plant host sanctions. We show that plant populations persist in spite of the presence of cheating rhizobia without the need of incorporating any sanction against the cheater populations in the model, under the realistic assumption that plants can at least get some amount of fixed N(2) from the effectively mutualistic rhizobia occupying some nodules. Inclusion of plant sanctions leads to the unrealistic effect of ultimate extinction of cheater strains in soil. Our simulation results are in agreement with increasing experimental evidence and theoretical work showing that mutualisms can persist in presence of cheating partners.

  4. A transient decrease in reactive oxygen species in roots leads to root hair deformation in the legume-rhizobia symbiosis.

    Science.gov (United States)

    Lohar, Dasharath Prasad; Haridas, Sajeet; Gantt, J Stephen; VandenBosch, Kathryn A

    2007-01-01

    * A possible role for reactive oxygen species (ROS) in root hair deformation in response to Nod factor (NF) was investigated using Medicago truncatula nodulation mutants, and an inhibitor and precursors of ROS. * In wild-type roots, ROS efflux transiently decreased approximately 1 h after NF treatment. Transcript accumulation of two NADPH oxidase homologs, respiratory burst oxidase homolog 2 (MtRBOH2) and MtRBOH3, also transiently decreased at 1 h. However, in the nonnodulating mutant Nod factor perception (nfp), transcript accumulation did not change. * Exogenous application of ROS prevented root hair swelling and branching induced by NF. When accumulation of ROS was prevented by diphenylene iodonium (DPI), NF did not induce root hair branching. Root treatment with DPI alone reduced ROS efflux and induced root hair tip swelling. Transient treatment of roots with DPI mimicked NF treatment and resulted in root hair branching in the absence of NF. A transient DPI treatment did not induce root hair branching in the nonlegumes Arabidopsis thaliana and tomato (Lycopersicon esculentum). * The results suggest a role for the transient reduction of ROS accumulation in governing NF-induced root hair deformation in legumes.

  5. Using mycorrhiza-defective mutant genotypes of non-legume plant species to study the formation and functioning of arbuscular mycorrhiza: a review.

    Science.gov (United States)

    Watts-Williams, Stephanie J; Cavagnaro, Timothy R

    2015-11-01

    A significant challenge facing the study of arbuscular mycorrhiza is the establishment of suitable non-mycorrhizal treatments that can be compared with mycorrhizal treatments. A number of options are available, including soil disinfection or sterilisation, comparison of constitutively mycorrhizal and non-mycorrhizal plant species, comparison of plants grown in soils with different inoculum potential and the comparison of mycorrhiza-defective mutant genotypes with their mycorrhizal wild-type progenitors. Each option has its inherent advantages and limitations. Here, the potential to use mycorrhiza-defective mutant and wild-type genotype plant pairs as tools to study the functioning of mycorrhiza is reviewed. The emphasis of this review is placed on non-legume plant species, as mycorrhiza-defective plant genotypes in legumes have recently been extensively reviewed. It is concluded that non-legume mycorrhiza-defective mutant and wild-type pairs are useful tools in the study of mycorrhiza. However, the mutant genotypes should be well characterised and, ideally, meet a number of key criteria. The generation of more mycorrhiza-defective mutant genotypes in agronomically important plant species would be of benefit, as would be more research using these genotype pairs, especially under field conditions.

  6. Differential Effects of Legume Species on the Recovery of Soil Microbial Communities, and Carbon and Nitrogen Contents, in Abandoned Fields of the Loess Plateau, China

    Science.gov (United States)

    Li, Jin Hua; Jiao, Shu Mei; Gao, Rong Qing; Bardgett, Richard D.

    2012-12-01

    Plant-soil interactions are known to influence a wide range of ecosystem-level functions. Moreover, the recovery of these functions is of importance for the successful restoration of soils that have been degraded through intensive and/or inappropriate land use. Here, we assessed the effect of planting treatments commonly used to accelerate rates of grassland restoration, namely introduction of different legume species Medicago sativa, Astragalus adsurgens, Melilotus suaveolens, on the recovery of soil microbial communities and carbon and nitrogen contents in abandoned fields of the Loess Plateau, China. The results showed effects were species-specific, and either positive, neutral or negative depending on the measure and time-scale. All legumes increased basal respiration and metabolic quotient and had a positive effect on activity and functional diversity of the soil microbial community, measured using Biolog EcoPlate. However, soil under Astragalus adsurgens had the highest activity and functional diversity relative to the other treatments. Soil carbon and nitrogen content and microbial biomass were effectively restored in 3-5 years by introducing Medicago sativa and Astragalus adsurgens into early abandoned fields. Soil carbon and nitrogen content were retarded in 3-5 years and microbial biomass was retarded in the fifth year by introducing Melilotus suaveolens. Overall, the restoration practices of planting legumes can significantly affect soil carbon and nitrogen contents, and the biomass, activity, and functional diversity of soil microbial community. Therefore, we propose certain legume species could be used to accelerate ecological restoration of degraded soils, hence assist in the protection and preservation of the environment.

  7. Genetic Mapping of a Major Resistance Gene to Pea Aphid (Acyrthosipon pisum in the Model Legume Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Lars G. Kamphuis

    2016-07-01

    Full Text Available Resistance to the Australian pea aphid (PA; Acyrthosiphon pisum biotype in cultivar Jester of the model legume Medicago truncatula is mediated by a single dominant gene and is phloem-mediated. The genetic map position for this resistance gene, APR (Acyrthosiphon pisum resistance, is provided and shows that APR maps 39 centiMorgans (cM distal of the A. kondoi resistance (AKR locus, which mediates resistance to a closely related species of the same genus bluegreen aphid (A. kondoi. The APR region on chromosome 3 is dense in classical nucleotide binding site leucine-rich repeats (NLRs and overlaps with the region harbouring the RAP1 gene which confers resistance to a European PA biotype in the accession Jemalong A17. Further screening of a core collection of M. truncatula accessions identified seven lines with strong resistance to PA. Allelism experiments showed that the single dominant resistance to PA in M. truncatula accessions SA10481 and SA1516 are allelic to SA10733, the donor of the APR locus in cultivar Jester. While it remains unclear whether there are multiple PA resistance genes in an R-gene cluster or the resistance loci identified in the other M. truncatula accessions are allelic to APR, the introgression of APR into current M. truncatula cultivars will provide more durable resistance to PA.

  8. Food legume production in China

    Directory of Open Access Journals (Sweden)

    Ling Li

    2017-04-01

    Full Text Available Food legumes comprise all legumes grown for human food in China as either dry grains or vegetables, except for soybean and groundnut. China has a vast territory with complex ecological conditions. Rotation, intercropping, and mixed cropping involving pulses are normal cropping systems in China. Whether indigenous or introduced crops, pulses have played an important role in Chinese cropping systems and made an important contribution to food resources for humans since ancient times. The six major food legume species (pea, faba bean, common bean, mung bean, adzuki bean, and cowpea are the most well-known pulses in China, as well as those with more local distributions; runner bean, lima bean, chickpea, lentil, grass pea, lupine, rice bean, black gram, hyacinth bean, pigeon pea, velvet bean, winged bean, guar bean, sword bean, and jack bean. China has remained the world's leading producer of peas, faba beans, mung beans, and adzuki beans in recent decades, as documented by FAO statistics and China Agriculture Statistical Reports. The demand for food legumes as a healthy food will markedly increase with the improvement of living standards in China. Since China officially joined the World Trade Organization (WTO in 2001, imports of pea from Canada and Australia have rapidly increased, resulting in reduced prices for dry pea and other food legumes. With reduced profits for food legume crops, their sowing area and total production has decreased within China. At the same time, the rising consumer demand for vegetable food legumes as a healthy food has led to attractive market prices and sharp production increases in China. Vegetable food legumes have reduced growing duration and enable flexibility in cropping systems. In the future, production of dry food legumes will range from stable to slowly decreasing, while production of vegetable food legumes will continue to increase.

  9. Microsatellite diversity and broad scale geographic structure in a model legume: building a set of nested core collection for studying naturally occurring variation in Medicago truncatula

    DEFF Research Database (Denmark)

    Ronfort, Joelle; Bataillon, Thomas; Santoni, Sylvain

    2006-01-01

    scheme. Conclusion The stratification inferred is discussed considering potential historical events like expansion, refuge history and admixture between neighbouring groups. Information on the allelic richness and the inferred population structure are used to build a nested core-collection. The set......Abstract               Acknowledgements References   Background Exploiting genetic diversity requires previous knowledge of the extent and structure of the variation occurring in a species. Such knowledge can in turn be used to build a core-collection, i.e. a subset of accessions that aim...... at representing the genetic diversity of this species with a minimum of repetitiveness. We investigate the patterns of genetic diversity and population structure in a collection of 346 inbred lines representing the breadth of naturally occurring diversity in the Legume plant model Medicago truncatula using 13...

  10. Physical and Chemical Properties of Starch from Major Legume Species in Gansu%甘肃主要杂豆淀粉理化特性分析

    Institute of Scientific and Technical Information of China (English)

    郭神旺; 王充; 单玉琳; 罗勤贵; 张国权

    2012-01-01

    In this work,physical and chemical properties of starches extracted by wet-grinding method from four major species of legume in Gansu province including pea(Pisum sativum L.),colored pea(Pisum sativum L.),white bean(Phaseolus vulgaris L.),Lathyrum hirsativa(Lathyrus sativus L.) were analyzed and compared with those of corn,potato and mung bean starches.Starch granules from these legume species under investigation were kidney-shaped with obvious birefringence in X-shape and cross-shape.Meanwhile,some starch granules revealed obvious umbilical points.The average size of starch particles was 21 — 29 μ m,and Lathyrum hirsativa starch particles revealed the largest size,but colored pea revealed the smallest size.The crystal type of legume starch granules was type C,so was mung bean starch.Compared with corn starch and potato starch,the contents of amylose in starches from the four legume species showed a considerable increase,and were ranked in descending order as follows: colored pea starch,white bean starch,pea starch and Lathyrum hirsativa starch.These legume starches displayed increases in swelling capacity and solubility with increasing temperature,which belonged to restricted type expansion starch.Their starting pasting temperature varied in the range of 72.6 — 78.8 ℃.Moreover,good hot paste and cold paste stability and high paste transparency were observed,while the retrogradation rate was fast and the freeze-thaw stability was poor.In conclusion,the properties of these legume starches were similar to those of mung bean starch.The legume starches tested in this study could tolerate heat treatment,but was not suitable for the production of frozen foods.%以甘肃产三角豌豆、白豌豆、小白芸豆、麻豌豆为材料,采用湿磨法提取淀粉,以玉米、马铃薯及绿豆淀粉为对照,对杂豆淀粉的理化特性进行分析。结果表明:参试杂豆淀粉颗粒多呈卵圆形,偏光十字较明显,多呈"X"形和斜十字形,部分

  11. Jasmonate Signalling and Defence Responses in the Model Legume Medicago truncatula-A Focus on Responses to Fusarium Wilt Disease.

    Science.gov (United States)

    Thatcher, Louise F; Gao, Ling-Ling; Singh, Karam B

    2016-02-05

    Jasmonate (JA)-mediated defences play important roles in host responses to pathogen attack, in particular to necrotrophic fungal pathogens that kill host cells in order to extract nutrients and live off the dead plant tissue. The root-infecting fungal pathogen Fusarium oxysporum initiates a necrotrophic growth phase towards the later stages of its lifecycle and is responsible for devastating Fusarium wilt disease on numerous legume crops worldwide. Here we describe the use of the model legume Medicago truncatula to study legume-F. oxysporum interactions and compare and contrast this against knowledge from other model pathosystems, in particular Arabidopsis thaliana-F. oxysporum interactions. We describe publically-available genomic, transcriptomic and genetic (mutant) resources developed in M. truncatula that enable dissection of host jasmonate responses and apply aspects of these herein during the M. truncatula--F. oxysporum interaction. Our initial results suggest not all components of JA-responses observed in M. truncatula are shared with Arabidopsis in response to F. oxysporum infection.

  12. Oil body biogenesis and biotechnology in legume seeds.

    Science.gov (United States)

    Song, Youhong; Wang, Xin-Ding; Rose, Ray J

    2017-09-02

    The seeds of many legume species including soybean, Pongamia pinnata and the model legume Medicago truncatula store considerable oil, apart from protein, in their cotyledons. However, as a group, legume storage strategies are quite variable and provide opportunities for better understanding of carbon partitioning into different storage products. Legumes with their ability to fix nitrogen can also increase the sustainability of agricultural systems. This review integrates the cell biology, biochemistry and molecular biology of oil body biogenesis before considering biotechnology strategies to enhance oil body biosynthesis. Cellular aspects of packaging triacylglycerol (TAG) into oil bodies are emphasized. Enhancing seed oil content has successfully focused on the up-regulation of the TAG biosynthesis pathways using overexpression of enzymes such as diacylglycerol acyltransferase1 and transcription factors such as WRINKLE1 and LEAFY COTYLEDON1. While these strategies are central, decreasing carbon flow into other storage products and maximizing the packaging of oil bodies into the cytoplasm are other strategies that need further examination. Overall there is much potential for integrating carbon partitioning, up-regulation of fatty acid and TAG synthesis and oil body packaging, for enhancing oil levels. In addition to the potential for integrated strategies to improving oil yields, the capacity to modify fatty acid composition and use of oil bodies as platforms for the production of recombinant proteins in seed of transgenic legumes provide other opportunities for legume biotechnology.

  13. A comparative analysis of transcriptomic, biochemical, and physiological responses to elevated ozone identifies species-specific mechanisms of resilience in legume crops.

    Science.gov (United States)

    Yendrek, Craig R; Koester, Robert P; Ainsworth, Elizabeth A

    2015-12-01

    Current concentrations of tropospheric ozone ([O3]) pollution negatively impact plant metabolism, which can result in decreased crop yields. Interspecific variation in the physiological response of plants to elevated [O3] exists; however, the underlying cellular responses explaining species-specific differences are largely unknown. Here, a physiological screen has been performed on multiple varieties of legume species. Three varieties of garden pea (Pisum sativum L.) were resilient to elevated [O3]. Garden pea showed no change in photosynthetic capacity or leaf longevity when exposed to elevated [O3], in contrast to varieties of soybean (Glycine max (L.) Merr.) and common bean (Phaseolus vulgaris L.). Global transcriptomic and targeted biochemical analyses were then done to examine the mechanistic differences in legume responses to elevated [O3]. In all three species, there was an O3-mediated reduction in specific leaf weight and total non-structural carbohydrate content, as well as increased abundance of respiration-related transcripts. Differences specific to garden pea included a pronounced increase in the abundance of GLUTATHIONE REDUCTASE transcript, as well as greater contents of foliar glutathione, apoplastic ascorbate, and sucrose in elevated [O3]. These results suggest that garden pea may have had greater capacity for detoxification, which prevented net losses in CO2 fixation in an elevated [O3] environment.

  14. Peroxiredoxins and NADPH-dependent thioredoxin systems in the model legume Lotus japonicus.

    Science.gov (United States)

    Tovar-Méndez, Alejandro; Matamoros, Manuel A; Bustos-Sanmamed, Pilar; Dietz, Karl-Josef; Cejudo, Francisco Javier; Rouhier, Nicolas; Sato, Shusei; Tabata, Satoshi; Becana, Manuel

    2011-07-01

    Peroxiredoxins (Prxs), thioredoxins (Trxs), and NADPH-thioredoxin reductases (NTRs) constitute central elements of the thiol-disulfide redox regulatory network of plant cells. This study provides a comprehensive survey of this network in the model legume Lotus japonicus. The aims were to identify and characterize these gene families and to assess whether the NTR-Trx systems are operative in nodules. Quantitative reverse transcription-polymerase chain reaction and immunological and proteomic approaches were used for expression profiling. We identified seven Prx, 14 Trx, and three NTR functional genes. The PrxQ1 gene was found to be transcribed in two alternative spliced variants and to be expressed at high levels in leaves, stems, petals, pods, and seeds and at low levels in roots and nodules. The 1CPrx gene showed very high expression in the seed embryos and low expression in vegetative tissues and was induced by nitric oxide and cytokinins. In sharp contrast, cytokinins down-regulated all other Prx genes, except PrxQ1, in roots and nodules, but only 2CPrxA and PrxQ1 in leaves. Gene-specific changes in Prx expression were also observed in response to ethylene, abscisic acid, and auxins. Nodules contain significant mRNA and protein amounts of cytosolic PrxIIB, Trxh1, and NTRA and of plastidic NTRC. Likewise, they express cytosolic Trxh3, Trxh4, Trxh8, and Trxh9, mitochondrial PrxIIF and Trxo, and plastidic Trxm2, Trxm4, and ferredoxin-Trx reductase. These findings reveal a complex regulation of Prxs that is dependent on the isoform, tissue, and signaling molecule and support that redox NTR-Trx systems are functional in the cytosol, mitochondria, and plastids of nodules.

  15. The efficiency of nitrogen fixation of the model legume Medicago truncatula (Jemalong A17) is low compared to Medicago sativa.

    Science.gov (United States)

    Sulieman, Saad; Schulze, Joachim

    2010-06-15

    Medicago truncatula (Gaertn.) (barrel medic) serves as a model legume in plant biology. Numerous studies have addressed molecular aspects of the biology of M. truncatula, while comparatively little is known about the efficiency of N(2) fixation at the whole plant level. The objective of the present study was to compare the efficiency of N(2) fixation of M. truncatula to the genetically closely related Medicago sativa (L.) (alfalfa). The relative growth of both species relying exclusively on N(2) fixation versus nitrate nutrition, H(2) evolution, nitrogen assimilation, the concentration of amino acids and organic acids in nodules, and (15)N(2) uptake and distribution were studied. M. truncatula showed much lower efficiency of N(2) fixation. Nodule-specific activity was several-fold lower when compared to M. sativa, partially as a result of a lower electron allocation to N(2) versus H(+). M. truncatula or M. sativa plants grown solely on N(2) fixation as a nitrogen source reached about 30% or 80% of growth, respectively, when compared to plants supplied with sufficient nitrate. Moreover, M. truncatula had low %N in shoots and a lower allocation of (15)N to shoots during 1h (15)N(2) labeling period. Amino acid concentration was about 20% higher in M. sativa nodules, largely as a result of more asparagine, while the organic acid concentration was about double in M. sativa, coinciding with a six-fold higher concentration of malate. Total soluble protein in nodules was about three times lower in M. truncatula and the pattern of enzyme activity in that fraction was strongly different. Sucrose cleaving enzymes displayed higher activity in M. truncatula nodules, while the activity of phosphoenolpyruvate carboxylase (PEPC) was much lower. It is concluded that the low efficiency of the M. truncatula symbiotic system is related to a low capacity of organic acid formation and limited nitrogen export from nodules.

  16. Bounding species distribution models

    Directory of Open Access Journals (Sweden)

    Thomas J. STOHLGREN, Catherine S. JARNEVICH, Wayne E. ESAIAS,Jeffrey T. MORISETTE

    2011-10-01

    Full Text Available Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for “clamping” model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART and maximum entropy (Maxent models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5: 642–647, 2011].

  17. Bounding Species Distribution Models

    Science.gov (United States)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  18. Effects of species diversity on functional trait of legume forage%物种多样性对豆科牧草功能特征的影响

    Institute of Scientific and Technical Information of China (English)

    张灵菲; 魏斌; 郝敏; 葛庆征; 傅华; 张卫国; 江小雷

    2012-01-01

    利用室外盆栽实验方法就物种多样性对豆科牧草功能特征及生产力的影响进行了研究。结果表明,物种多样性对豆科牧草比叶面积、株高有促进作用,二者呈显著正相关关系;对相对生长率、根深、叶干物质含量和单位叶面积根量4个功能特征有负面影响,4个变量均随物种多样性的增加而显著下降(P〈0.05)。豆科牧草的地上、地下生产力都随着物种多样性的增加而下降。研究结果说明。随着物种多样性的增加,种间竞争作用导致豆科牧草的比叶面积和株高增加,而导致相对生长率、根深、叶干物质含量和单位叶面积根量4个与生产力密切相关的功能特征值减小,进而限制混播群落中豆科牧草的生产力。%A pot experiment was used to determine the effects of species diversity on functional traits of legume forages by measuring the relative growth rate, specific leaf area, leaf dry mass content, plant height, root depth and root mass per unit leaf area, and productivity. The results of this study indicated that the species diversity had a positive effect on specific leaf area and plant height, and a negative effect on relative growth rate, root depth, leaf dry mass content, and root mass per unit leaf area. The productivity, aboveground and belowground biomass of legume forage decreased as the species diversity increased. These results suggested that the increasing interspecific competition caused by the increase of species diversity increased the specific leaf area and plant height, but restricted other four functional traits and the productivity of legume forages.

  19. Explaining coexistence of nitrogen fixing and non-fixing rhizobia in legume-rhizobia mutualism using mathematical modeling.

    Science.gov (United States)

    Moyano, G; Marco, D; Knopoff, D; Torres, G; Turner, C

    2017-10-01

    In the mutualism established between legumes and soil bacteria known as rhizobia, bacteria from soil infect plants roots and reproduce inside root nodules where they fix atmospheric N2 for plant nutrition, receiving carbohydrates in exchange. Host-plant sanctions against non N2 fixing, cheating bacterial symbionts have been proposed to act in the legume-Rhizobium symbiosis, to preserve the mutualistic relationship. Sanctions include decreased rhizobial survival in nodules occupied by cheating rhizobia. Previously, a simple population model experimentally based showed that the coexistence of fixing and cheating rhizobia strains commonly found in field conditions is possible, and that the inclusion of sanctions leads to the extinction of cheating strains in soil. Here, we extend the previous model to include other factors that could complicate the sanction scenario, like horizontal transmission of symbiotic plasmids, turning non-nodulating strains into nodulating rhizobia, and competition between fixing and cheating strains for nodulation. In agreement with previous results, we show that plant populations persist even in the presence of cheating rhizobia without incorporating any sanction against the cheater populations in the model, under the realistic assumption that plants can at least get some amount of fixed N2 from the effectively mutualistic rhizobia occupying some nodules. Inclusion of plant sanctions leads to the unrealistic extinction of cheater strains in soil. Our results agree with increasing experimental evidence and theoretical work showing that mutualisms can persist in presence of cheating partners. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Jasmonate Signalling and Defence Responses in the Model Legume Medicago truncatula—A Focus on Responses to Fusarium Wilt Disease

    Science.gov (United States)

    Thatcher, Louise F.; Gao, Ling-Ling; Singh, Karam B.

    2016-01-01

    Jasmonate (JA)-mediated defences play important roles in host responses to pathogen attack, in particular to necrotrophic fungal pathogens that kill host cells in order to extract nutrients and live off the dead plant tissue. The root-infecting fungal pathogen Fusarium oxysporum initiates a necrotrophic growth phase towards the later stages of its lifecycle and is responsible for devastating Fusarium wilt disease on numerous legume crops worldwide. Here we describe the use of the model legume Medicago truncatula to study legume–F. oxysporum interactions and compare and contrast this against knowledge from other model pathosystems, in particular Arabidopsis thaliana–F. oxysporum interactions. We describe publically-available genomic, transcriptomic and genetic (mutant) resources developed in M. truncatula that enable dissection of host jasmonate responses and apply aspects of these herein during the M. truncatula-–F. oxysporum interaction. Our initial results suggest not all components of JA-responses observed in M. truncatula are shared with Arabidopsis in response to F. oxysporum infection. PMID:27135231

  1. Jasmonate Signalling and Defence Responses in the Model Legume Medicago truncatula—A Focus on Responses to Fusarium Wilt Disease

    Directory of Open Access Journals (Sweden)

    Louise F. Thatcher

    2016-02-01

    Full Text Available Jasmonate (JA-mediated defences play important roles in host responses to pathogen attack, in particular to necrotrophic fungal pathogens that kill host cells in order to extract nutrients and live off the dead plant tissue. The root-infecting fungal pathogen Fusarium oxysporum initiates a necrotrophic growth phase towards the later stages of its lifecycle and is responsible for devastating Fusarium wilt disease on numerous legume crops worldwide. Here we describe the use of the model legume Medicago truncatula to study legume–F. oxysporum interactions and compare and contrast this against knowledge from other model pathosystems, in particular Arabidopsis thaliana–F. oxysporum interactions. We describe publically-available genomic, transcriptomic and genetic (mutant resources developed in M. truncatula that enable dissection of host jasmonate responses and apply aspects of these herein during the M. truncatula-–F. oxysporum interaction. Our initial results suggest not all components of JA-responses observed in M. truncatula are shared with Arabidopsis in response to F. oxysporum infection.

  2. The Proteome of Seed Development in the Model Legume Lotus japonicus

    DEFF Research Database (Denmark)

    Dam, Svend; Laursen, Brian S.; Ornfelt, Jane H.

    2009-01-01

    three developmental phases of legume seeds and the presence of embryo, endosperm, and seed coat in desiccated seeds. Furthermore, protein, oil, starch, phytic acid, and ash contents were determined, and this indicates that the composition of mature Lotus seed is more similar to soybean than to pea....... In a first attempt to determine the seed proteome, both a two-dimensional polyacrylamide gel electrophoresis approach and a gel-based liquid chromatography-mass spectrometry approach were used. Globulins were analyzed by two-dimensional polyacrylamide gel electrophoresis, and five legumins, LLP1 to LLP5...

  3. Proteomics and Metabolomics: two emerging areas for legume improvement

    Directory of Open Access Journals (Sweden)

    Abirami eRamalingam

    2015-12-01

    Full Text Available The crop legumes such as chickpea, common bean, cowpea, peanut, pigeonpea, soybean, etc. are important source of nutrition and contribute to a significant amount of biological nitrogen fixation (>20 million tons of fixed nitrogen in agriculture. However, the production of legumes is constrained due to abiotic and biotic stresses. It is therefore imperative to understand the molecular mechanisms of plant response to different stresses and identify key candidate genes regulating tolerance which can be deployed in breeding programs. The information obtained from transcriptomics has facilitated the identification of candidate genes for the given trait of interest and utilizing them in crop breeding programs to improve stress tolerance. However, the mechanisms of stress tolerance are complex due to the influence of multi-genes and post-transcriptional regulations. Furthermore, stress conditions greatly affect gene expression which in turn causes modifications in the composition of plant proteomes and metabolomes. Therefore, functional genomics involving various proteomics and metabolomics approaches have been obligatory for understanding plant stress tolerance. These approaches have also been found useful to unravel different pathways related to plant and seed development as well as symbiosis. Proteome and metabolome profiling using high-throughput based systems have been extensively applied in the model legume species Medicago truncatula and Lotus japonicus, as well as in the model crop legume, soybean, to examine stress signalling pathways, cellular and developmental processes and nodule symbiosis. Moreover, the availability of protein reference maps as well as proteomics and metabolomics databases greatly support research and understanding of various biological processes in legumes. Protein-protein interaction techniques, particularly the yeast two-hybrid system have been advantageous for studying symbiosis and stress signalling in legumes. In

  4. Differential effectiveness of novel and old legume-rhizobia mutualisms: implications for invasion by exotic legumes.

    Science.gov (United States)

    Rodríguez-Echeverría, Susana; Fajardo, Susana; Ruiz-Díez, Beatriz; Fernández-Pascual, Mercedes

    2012-09-01

    The degree of specialization in the legume-rhizobium mutualism and the variation in the response to different potential symbionts are crucial factors for understanding the process of invasion by exotic legumes and the consequences for the native resident plants and bacteria. The enhanced novel mutualism hypothesis predicts that exotic invasive legumes would take advantage of native rhizobia present in the invaded soils. However, recent studies have shown that exotic legumes might become invasive by using exotic introduced microsymbionts, and that they could be a source of exotic bacteria for native legumes. To unravel the role of novel and old symbioses in the progress of invasion, nodulation and symbiotic effectiveness were analyzed for exotic invasive plants and native co-occurring legumes in a Mediterranean coastal dune ecosystem. Although most of the studied species nodulated with bacteria from distant origins these novel mutualisms were less effective in terms of nodulation, nitrogenase activity and plant growth than the interactions of plants and bacteria from the same origin. The relative effect of exotic bradyrhizobia was strongly positive for exotic invasive legumes and detrimental for native shrubs. We conclude that (1) the studied invasive legumes do not rely on novel mutualisms but rather need the co-introduction of compatible symbionts, and (2) since exotic rhizobia colonize native legumes in invaded areas, the lack of effectiveness of these novel symbiosis demonstrated here suggests that invasion can disrupt native belowground mutualisms and reduce native legumes fitness.

  5. The impact of heating and soaking on the in vitro enzymatic hydrolysis of protein varies in different species of tropical legumes.

    Science.gov (United States)

    Torres, Julieta; Rutherfurd, Shane M; Muñoz, Luz S; Peters, Michael; Montoya, Carlos A

    2016-03-01

    The effects of different thermal (raw, autoclaving or boiling for 5 and 20min) and soaking (with or without) treatments on the degree of hydrolysis (DH) of protein were investigated for selected legumes (Canavalia brasiliensis; Lablab purpureus; pink, red and white colour hulls Vigna unguiculata). Each legume preparation underwent in vitro simulated gastrointestinal tract digestion comprising either pepsin (120min) or pepsin/pancreatin (120/240min) digestion. The DH was determined based on the amount of free amino groups released. Autoclaving for 5min increased the pepsin/pancreatin DH for all the unsoaked and soaked legumes (+20% to 46% units) except Canavalia, while boiling for 5min only increased DH for two soaked legumes (+12% to 28% units). Extending boiling from 5 to 20min increased the DH for three soaked legumes (+5% to 29% units). In conclusion, autoclaving, in general, extensively increased the sequential pepsin/pancreatin DH, while boiling only increased it for selected legumes.

  6. Changes in nutritive value and herbage yield during extended growth intervals in grass-legume mixtures: effects of species, maturity at harvest, and relationships between productivity and components of feed quality

    DEFF Research Database (Denmark)

    Elgersma, Anjo; Søegaard, Karen

    2017-01-01

    There is a lack of information on the effects of companion species in grass–legume mixtures on herbage yield and quality changes during prolonged growth. Such information is relevant for harvest planning and estimation of consequences for feeding value of conserved feed when harvesting is delayed...

  7. How legumes recognize rhizobia.

    Science.gov (United States)

    Via, Virginia Dalla; Zanetti, María Eugenia; Blanco, Flavio

    2016-01-01

    Legume plants have developed the capacity to establish symbiotic interactions with soil bacteria (known as rhizobia) that can convert N2 to molecular forms that are incorporated into the plant metabolism. The first step of this relationship is the recognition of bacteria by the plant, which allows to distinguish potentially harmful species from symbiotic partners. The main molecular determinant of this symbiotic interaction is the Nod Factor, a diffusible lipochitooligosaccharide molecule produced by rhizobia and perceived by LysM receptor kinases; however, other important molecules involved in the specific recognition have emerged over the years. Secreted exopolysaccharides and the lipopolysaccharides present in the bacterial cell wall have been proposed to act as signaling molecules, triggering the expression of specific genes related to the symbiotic process. In this review we will briefly discuss how transcriptomic analysis are helping to understand how multiple signaling pathways, triggered by the perception of different molecules produced by rhizobia, control the genetic programs of root nodule organogenesis and bacterial infection. This knowledge can help to understand how legumes have evolved to recognize and establish complex ecological relationships with particular species and strains of rhizobia, adjusting gene expression in response to identity determinants of bacteria.

  8. Bounding species distribution models

    Institute of Scientific and Technical Information of China (English)

    Thomas J. STOHLGREN; Catherine S. JARNEVICH; Wayne E. ESAIAS; Jeffrey T. MORISETTE

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern.Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development,yet there is no recommended best practice for “clamping” model extrapolations.We relied on two commonly used modeling approaches:classification and regression tree (CART) and maximum entropy (Maxent) models,and we tested a simple alteration of the model extrapolations,bounding extrapolations to the maximum and minimum values of primary environmental predictors,to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States.Findings suggest that multiple models of bounding,and the most conservative bounding of species distribution models,like those presented here,should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5):642-647,2011].

  9. Competition between rhizobia under different environmental conditions affects the nodulation of a legume.

    Science.gov (United States)

    Ji, Zhao Jun; Yan, Hui; Cui, Qing Guo; Wang, En Tao; Chen, Wen Feng; Chen, Wen Xin

    2017-03-01

    Mutualistic symbiosis and nitrogen fixation of legume rhizobia play a key role in ecological environments. Although many different rhizobial species can form nodules with a specific legume, there is often a dominant microsymbiont, which has the highest nodule occupancy rates, and they are often known as the "most favorable rhizobia". Shifts in the most favorable rhizobia for a legume in different geographical regions or soil types are not well understood. Therefore, in order to explore the shift model, an experiment was designed using successive inoculations of rhizobia on one legume. The plants were grown in either sterile vermiculite or a sandy soil. Results showed that, depending on the environment, a legume could select its preferential rhizobial partner in order to establish symbiosis. For perennial legumes, nodulation is a continuous and sequential process. In this study, when the most favorable rhizobial strain was available to infect the plant first, it was dominant in the nodules, regardless of the existence of other rhizobial strains in the rhizosphere. Other rhizobial strains had an opportunity to establish symbiosis with the plant when the most favorable rhizobial strain was not present in the rhizosphere. Nodule occupancy rates of the most favorable rhizobial strain depended on the competitiveness of other rhizobial strains in the rhizosphere and the environmental adaptability of the favorable rhizobial strain (in this case, to mild vermiculite or hostile sandy soil). To produce high nodulation and efficient nitrogen fixation, the most favorable rhizobial strain should be selected and inoculated into the rhizosphere of legume plants under optimum environmental conditions.

  10. The legume manifesto: (Networkers on Fabaceae, unite!

    Directory of Open Access Journals (Sweden)

    Mikić Aleksandar

    2011-01-01

    Full Text Available Legumes have been an important part of cropping systems since the dawn of agriculture. The shift in Europe from draught animals to meat animals coincided with the increasing availability of soybean meal from North and South America, and the Common Agricultural Policy of the European Union promoted the growing of cereals and oilseeds at the expense of other crops so legumes fell out of favour with farmers and decision-makers. Continental concerns about food and feed security, high prices of oil and soybean meal and advances in the application of fundamental molecular genetics to crop species, all mean that now is a good opportunity to promote the return of legumes to European cropping systems by enhancing the efficiency of research and development on this family. Hence we propose the establishment of a Legume Society that will promote information exchange and scientific productivity by uniting the various legume research communities.

  11. Using coloured roots to study root interaction and competition in intercropped legumes and non-legumes

    DEFF Research Database (Denmark)

    Tosti, Giacomo; Thorup-Kristensen, Kristian

    2010-01-01

    if a species with coloured roots can be used to examine the interaction in a legume-non-legume intercropping system; (ii) to verify the importance of initial root growth on the successive root development of mixture component plants; (iii) to test if the root interaction in the shallow layers has consequences...

  12. Quantitative understanding of the performance of upland rice – cover legume cropping systems in West Africa

    NARCIS (Netherlands)

    Akanvou, R.K.

    2001-01-01

    Keywords: upland rice, relay intercropping, modelling, cover crops, improved fallow.Reducing the long fallow period by replacing the natural fallow with fast growing legume species to improve soil fertility, control weeds or to grow additional forage necessitate selection of suitable species for tho

  13. Comprehensive Comparative Genomic and Transcriptomic Analyses of the Legume Genes Controlling the Nodulation Process.

    Science.gov (United States)

    Qiao, Zhenzhen; Pingault, Lise; Nourbakhsh-Rey, Mehrnoush; Libault, Marc

    2016-01-01

    Nitrogen is one of the most essential plant nutrients and one of the major factors limiting crop productivity. Having the goal to perform a more sustainable agriculture, there is a need to maximize biological nitrogen fixation, a feature of legumes. To enhance our understanding of the molecular mechanisms controlling the interaction between legumes and rhizobia, the symbiotic partner fixing and assimilating the atmospheric nitrogen for the plant, researchers took advantage of genetic and genomic resources developed across different legume models (e.g., Medicago truncatula, Lotus japonicus, Glycine max, and Phaseolus vulgaris) to identify key regulatory protein coding genes of the nodulation process. In this study, we are presenting the results of a comprehensive comparative genomic analysis to highlight orthologous and paralogous relationships between the legume genes controlling nodulation. Mining large transcriptomic datasets, we also identified several orthologous and paralogous genes characterized by the induction of their expression during nodulation across legume plant species. This comprehensive study prompts new insights into the evolution of the nodulation process in legume plant and will benefit the scientific community interested in the transfer of functional genomic information between species.

  14. Legume growth-promoting rhizobia: an overview on the Mesorhizobium genus.

    Science.gov (United States)

    Laranjo, Marta; Alexandre, Ana; Oliveira, Solange

    2014-01-20

    The need for sustainable agricultural practices is revitalizing the interest in biological nitrogen fixation and rhizobia-legumes symbioses, particularly those involving economically important legume crops in terms of food and forage. The genus Mesorhizobium includes species with high geographical dispersion and able to nodulate a wide variety of legumes, including important crop species, like chickpea or biserrula. Some cases of legume-mesorhizobia inoculant introduction represent exceptional opportunities to study the rhizobia genomes evolution and the evolutionary relationships among species. Complete genome sequences revealed that mesorhizobia typically harbour chromosomal symbiosis islands. The phylogenies of symbiosis genes, such as nodC, are not congruent with the phylogenies based on core genes, reflecting rhizobial host range, rather than species affiliation. This agrees with studies showing that Mesorhizobium species are able to exchange symbiosis genes through lateral transfer of chromosomal symbiosis islands, thus acquiring the ability to nodulate new hosts. Phylogenetic analyses of the Mesorhizobium genus based on core and accessory genes reveal complex evolutionary relationships and a high genomic plasticity, rendering the Mesorhizobium genus as a good model to investigate rhizobia genome evolution and adaptation to different host plants. Further investigation of symbiosis genes as well as stress response genes will certainly contribute to understand mesorhizobia-legume symbiosis and to develop more effective mesorhizobia inoculants.

  15. Legume proteomics: Progress, prospects, and challenges.

    Science.gov (United States)

    Rathi, Divya; Gayen, Dipak; Gayali, Saurabh; Chakraborty, Subhra; Chakraborty, Niranjan

    2016-01-01

    Legumes are the major sources of food and fodder with strong commercial relevance, and are essential components of agricultural ecosystems owing to their ability to carry out endosymbiotic nitrogen fixation. In recent years, legumes have become one of the major choices of plant research. The legume proteomics is currently represented by more than 100 reference maps and an equal number of stress-responsive proteomes. Among the 48 legumes in the protein databases, most proteomic studies have been accomplished in two model legumes, soybean, and barrel medic. This review highlights recent contributions in the field of legume proteomics to comprehend the defence and regulatory mechanisms during development and adaptation to climatic changes. Here, we attempted to provide a concise overview of the progress in legume proteomics and discuss future developments in three broad perspectives: (i) proteome of organs/tissues; (ii) subcellular compartments; and (iii) spatiotemporal changes in response to stress. Such data mining may aid in discovering potential biomarkers for plant growth, in general, apart from essential components involved in stress tolerance. The prospect of integrating proteome data with genome information from legumes will provide exciting opportunities for plant biologists to achieve long-term goals of crop improvement and sustainable agriculture.

  16. Genome sequence of Ensifer meliloti strain WSM1022; a highly effective microsymbiont of the model legume Medicago truncatula A17.

    Science.gov (United States)

    Terpolilli, Jason; Hill, Yvette; Tian, Rui; Howieson, John; Bräu, Lambert; Goodwin, Lynne; Han, James; Liolios, Konstantinos; Huntemann, Marcel; Pati, Amrita; Woyke, Tanja; Mavromatis, Konstantinos; Markowitz, Victor; Ivanova, Natalia; Kyrpides, Nikos; Reeve, Wayne

    2013-12-20

    Ensifer meliloti WSM1022 is an aerobic, motile, Gram-negative, non-spore-forming rod that can exist as a soil saprophyte or as a legume microsymbiont of Medicago. WSM1022 was isolated in 1987 from a nodule recovered from the roots of the annual Medicago orbicularis growing on the Cyclades Island of Naxos in Greece. WSM1022 is highly effective at fixing nitrogen with M. truncatula and other annual species such as M. tornata and M. littoralis and is also highly effective with the perennial M. sativa (alfalfa or lucerne). In common with other characterized E. meliloti strains, WSM1022 will nodulate but fixes poorly with M. polymorpha and M. sphaerocarpos and does not nodulate M. murex. Here we describe the features of E. meliloti WSM1022, together with genome sequence information and its annotation. The 6,649,661 bp high-quality-draft genome is arranged into 121 scaffolds of 125 contigs containing 6,323 protein-coding genes and 75 RNA-only encoding genes, and is one of 100 rhizobial genomes sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

  17. Effects of fluoride on germination, early growth and antioxidant enzyme activities of legume plant species Prosopis juliflora.

    Science.gov (United States)

    Saini, Poonam; Khan, Suphiya; Baunthiyal, Mamta; Sharma, Vinay

    2013-03-01

    Prosopis juliflora (Mimosoideae) is a fast growing and drought resistant tree of semi-arid region of India where fluoride (F) toxicity is a common problem. In the present investigations this species was fluoride tested to check their capacity as bioindicator plant and its efficiency to accumulate. To achieve this aim, P. juliflora seedlings grown in hydroponic culture containing different concentrations of F were analyzed for germination percentage together with some biochemical parameters viz, antioxidant enzyme activities, total chlorophyll and accumulation of F in different plant parts. After 15 days of treatment, root growth (r = -0.928, p < 0.01), shoot growth (r = -0.976, p < 0.01), vigor index (r = -0.984, p < 0.01) were in decreasing trend with increasing concentration of NaF. Both catalase (3.2 folds) and peroxidase (2.7 folds) enzymes activity increased with increase in F concentration. Plant accumulated larger portion of the F in the roots (1024.63 microg g(-1) d.wt.) followed by shoot (492.30 microg g(-1) d.wt.). As P. juliflora did not show any morphological changes (marginal and tip chlorosis of leaf portions, necrosis and together these features are referred to as leaf "tip-burn") therefore, this species may be used as suitable bioindicator species for potentially F affected areas. Further, higher accumulation of F in roots indicates that P. juliflora is a suitable species for the removal of F in phytoremediation purposes.

  18. Nitrogen Fixing Legumes in the Plant Communities

    Directory of Open Access Journals (Sweden)

    M. A.A. Al-Fredan

    2011-01-01

    Full Text Available Problems statement: Numerous authors have used energetic to explain the ecological success of N-fixing plants. Legume biodiversity assessment, species dynamics, nitrogen fixation monitoring and environment impact assessment of these ecological events in Al-Hassa Oasis, Saudi Arabia are rare and need to be continuous and more frequent. Approach: Thus the objectives of this study were to analyze legume abundance within and outside Al-Hassa Oasis and relate it to the distribution of the different genera. Results: Thirty two legume plant species from 20 genera have been recorded within and outside the Oasis. The largest genera were Cassia (4 species, Indigofera (4 and Acacia (3. Annual herbs were the dominant growth form (34% of species recorded, followed by shrubs (28%, perennial herbs (19% and trees (19%. Eighteen alien plant species were recorded (maybe an underestimated number. The nitrogen fixation of the legume plant species in Al-Hassa Oasis was estimated/analyzing the fixing potentiality of these species and nonfixing reference species (Panicum turgidum using the 15N natural abundance method. Species with great nitrogen fixing capacity in Al-Hassa include: Medicago sativa, Vicia faba, Vicia sativa, Melitotus indicus, Dolicus lablab, Melitotus alba and Cliforia ternate. The mean biological fixation contribution of most of the recorded legume plants were high, varying from 3.9% (Indigofera argentea to 64.6% (Medicago sativa. Conclusion: Al-Hassa Oasis is richer than expected based on its location within the desert zone. This study confirms the importance of the Oasis for national flora conservation in the Kingdom. results showed a good potential for use of the 15N natural abundance methodology for evaluating the nitrogen fixation ability of the legume plants under field conditions as well as for the estimation of %Ndfa.

  19. The glucocorticoid-inducible GVG system causes severe growth defects in both root and shoot of the model legume Lotus japonicus.

    Science.gov (United States)

    Andersen, Stig Uggerhøj; Cvitanich, Cristina; Hougaard, Birgit Kristine; Roussis, Andreas; Grønlund, Mette; Jensen, Dorthe Bødker; Frøkjaer, Line Askou; Jensen, Erik Ostergaard

    2003-12-01

    During the past decade, the legume Lotus japonicus has emerged as an important model system for study of symbiotic nitrogen fixation. Controlled expression of genes involved in symbiosis from an inducible promoter at specific time points would be a valuable tool for investigating gene function in L. japonicus. We have attempted to study the function of the putative transcription factors LjNDX and LjCPP1 by expression from the GVG inducible system. This study showed that the GVG system itself causes growth disturbances in L. japonicus. Shoot internode elongation and root pericycle cell division are affected when the chimeric GVG transcription factor is activated. We suggest that deficient auxin signaling could cause the phenotype observed and conclude that the GVG inducible system is not well suited for use in the model legume L. japonicus.

  20. Establishment of a root proteome reference map for the model legume Medicago truncatula using the expressed sequence tag database for peptide mass fingerprinting

    DEFF Research Database (Denmark)

    Mathesius, U; Keijzers, Guido; Natera, S H

    2001-01-01

    We have established a proteome reference map for Medicago truncatula root proteins using two-dimensional gel electrophoresis combined with peptide mass fingerprinting to aid the dissection of nodulation and root developmental pathways by proteome analysis. M. truncatula has been chosen as a model....... This proteome map will be updated continuously (http://semele.anu.edu.au/2d/2d.html) and will be a powerful tool for investigating the molecular mechanisms of root symbioses in legumes....

  1. Common bean: a legume model on the rise for unraveling responses and adaptations to iron, zinc and phosphate deficiencies.

    Directory of Open Access Journals (Sweden)

    Norma A Castro Guerrero

    2016-05-01

    Full Text Available Common bean (Phaseolus vulgaris was domesticated ~8000 years ago in the Americas and today is a staple food worldwide. Besides caloric intake, common bean is also an important source of protein and micronutrients and it is widely appreciated in developing countries for their affordability (compared to animal protein and its long storage life. As a legume, common bean also has the economic and environmental benefit of associating with nitrogen-fixing bacteria, thus reducing the use of synthetic fertilizers, which is key for sustainable agriculture. Despite significant advances in the plant nutrition field, the mechanisms underlying the adaptation of common bean to low nutrient input remains largely unknown. The recent release of the common bean genome offers, for the first time, the possibility of applying techniques and approaches that have been exclusive to model plants to study the adaptive responses of common bean to challenging environments. In this review, we discuss the hallmarks of common bean domestication and subsequent distribution around the globe. We also discuss recent advances in phosphate, iron, and zinc homeostasis, as these nutrients often limit plant growth, development and yield. In addition, iron and zinc are major targets of crop biofortification to improve human nutrition. Developing common bean varieties able to thrive under nutrient limiting conditions will have a major impact on human nutrition, particularly in countries where dry beans are the main source of carbohydrates, protein and minerals.

  2. Legumes and forage species sole or intercropped with corn in soybean-corn succession in midwestern Brazil

    Directory of Open Access Journals (Sweden)

    Gessí Ceccon

    2013-02-01

    Full Text Available The feasibility of no-tillage in the Cerrado (Savanna-like vegetation of Brazil depends on the production of sufficient above-ground crop residue, which can be increased by corn-forage intercropping. This study evaluated how above-ground crop residue production and yields of soybean and late-season corn in a soybean-corn rotation were influenced by the following crops in the year before soybean: corn (Zea mays L. intercropped with Brachiaria (Urochloa brizantha cv. Marandu, B. decumbens cv. Basilisk, B. ruziziensis, cv. comum., Panicummaximum cv. Tanzânia, sunn hemp (Crotalaria juncea L., pigeon pea [Cajanus cajan (L. Millsp]; sole corn, forage sorghum [Sorghum bicolor (L. Moench (cv. Santa Elisa], and ruzi grass. In March 2005, corn and forage species were planted in alternate rows spaced 0.90 m apart, and sole forage species were planted in rows spaced 0.45 m apart. In October 2005, the forages were killed with glyphosate and soybean was planted. After the soybean harvest in March 2006, sole late-season corn was planted in the entire experimental area. Corn grain and stover yields were unaffected by intercropping. Above-ground crop residue was greater when corn was intercropped with Tanzania grass (10.7 Mg ha-1, Marandu (10.1 Mg ha-1, and Ruzi Grass (9.8 Mg ha-1 than when corn was not intercropped (4.0 Mg ha-1. The intercropped treatments increased the percentage of soil surface covered with crop residue. Soybean and corn grain yields were higher after sole ruzi grass and intercropped ruzi grass than after other crops. The intercropping corn with Brachiaria spp. and corn with Panicum spp. increases above-ground crop residue production and maintains nutrients in the soil without reducing late-season corn yield and the viability of no-till in the midwestern region of Brazil.

  3. Germination Characteristics of Seed Coating for Five Species of Legume%5种豆科植物种子包衣萌发特性的研究

    Institute of Scientific and Technical Information of China (English)

    李志武

    2014-01-01

    通过对草木樨、花棒、杨柴、锦鸡儿、紫穗槐等5种豆科植物进行种子包衣试验,结果显示,种子包衣能明显增加种子的千粒质量,与对照相比,种子包衣后的千粒质量增加98.61%~292.6%;发芽率没有显著差异,出苗率和苗高有显著提高;根长包衣前后没有明显变化。种子包衣是一项保护种子损失的有效技术措施,对荒漠化植被恢复有重大意义。%Seed coating experiments of five species of legume (Melilotus suaveolens ,Hedysarum scoparium ,Hedysa-rum mongolicum ,Caragana sinica & A morpha fruticosa) were conducted .Result shows that :seed coating can sig-nificantly increase 1 000-grain weight of the seed ;compared with CK ,1 000-grain weight increase by 98 .61%-292 .6% ;germination rate has no significant difference .Germination rate & seedling height have significant increa-ses;root length did not change significantly before and after coating .Seed coating ,which is an effective technical measure to protect seed loss ,have great significant desertification recovery for plant .

  4. In-vitro regeneration studies of an important legume, Cicer arietinum: Hurdles and future prospects

    Directory of Open Access Journals (Sweden)

    Pragati Kumari

    2015-06-01

    Full Text Available There are several economically important grain legumes including chickpea that play significant role in nutrition of the rural and urban poor in developing world. Plants are subjected to a large number of stresses that may interfere with the normal growth and development. The model legumes are being developed as experimental systems to study a number of key biological questions using molecular tools including genomics and proteomics. Most of the functional genomics approaches rely upon the highthroughput transformation system useful for studying various gene identification strategies. The difficulty to transform a plant varies from species to species in legumes. There is limited success in exchange of the desirable characters by the classical and modern breeding technologies, in important pulse crop chickpea and biotechnological tools like plant tissue culture and genetic transformation techniques have emerged as a potential supplement. The major bottleneck is requirement of an in vitro manipulation of leguminosae members and the availability of reproducible, efficient and better plant regeneration methods. The regeneration and transformation of legumes particularly chickpea suffers due to recalcitrant nature towards rooting and transplantation of the in vitro regenerated plants. This becomes a limiting factor for the application of this technology towards designated mandate of crop improvement programs. This article discusses the hurdles and strategies for transformation of legumes in general and chickpea in particular.

  5. Estimating variability in grain legume yields across Europe and the Americas

    Science.gov (United States)

    Cernay, Charles; Ben-Ari, Tamara; Pelzer, Elise; Meynard, Jean-Marc; Makowski, David

    2015-01-01

    Grain legume production in Europe has recently come under scrutiny. Although legume crops are often promoted to provide environmental services, European farmers tend to turn to non-legume crops. It is assumed that high variability in legume yields explains this aversion, but so far this hypothesis has not been tested. Here, we estimate the variability of major grain legume and non-legume yields in Europe and the Americas from yield time series over 1961–2013. Results show that grain legume yields are significantly more variable than non-legume yields in Europe. These differences are smaller in the Americas. Our results are robust at the level of the statistical methods. In all regions, crops with high yield variability are allocated to less than 1% of cultivated areas. Although the expansion of grain legumes in Europe may be hindered by high yield variability, some species display risk levels compatible with the development of specialized supply chains. PMID:26054055

  6. Specificity in Legume-Rhizobia Symbioses.

    Science.gov (United States)

    Andrews, Mitchell; Andrews, Morag E

    2017-03-26

    Most species in the Leguminosae (legume family) can fix atmospheric nitrogen (N₂) via symbiotic bacteria (rhizobia) in root nodules. Here, the literature on legume-rhizobia symbioses in field soils was reviewed and genotypically characterised rhizobia related to the taxonomy of the legumes from which they were isolated. The Leguminosae was divided into three sub-families, the Caesalpinioideae, Mimosoideae and Papilionoideae. Bradyrhizobium spp. were the exclusive rhizobial symbionts of species in the Caesalpinioideae, but data are limited. Generally, a range of rhizobia genera nodulated legume species across the two Mimosoideae tribes Ingeae and Mimoseae, but Mimosa spp. show specificity towards Burkholderia in central and southern Brazil, Rhizobium/Ensifer in central Mexico and Cupriavidus in southern Uruguay. These specific symbioses are likely to be at least in part related to the relative occurrence of the potential symbionts in soils of the different regions. Generally, Papilionoideae species were promiscuous in relation to rhizobial symbionts, but specificity for rhizobial genus appears to hold at the tribe level for the Fabeae (Rhizobium), the genus level for Cytisus (Bradyrhizobium), Lupinus (Bradyrhizobium) and the New Zealand native Sophora spp. (Mesorhizobium) and species level for Cicer arietinum (Mesorhizobium), Listia bainesii (Methylobacterium) and Listia angolensis (Microvirga). Specificity for rhizobial species/symbiovar appears to hold for Galega officinalis (Neorhizobium galegeae sv. officinalis), Galega orientalis (Neorhizobium galegeae sv. orientalis), Hedysarum coronarium (Rhizobium sullae), Medicago laciniata (Ensifer meliloti sv. medicaginis), Medicago rigiduloides (Ensifer meliloti sv. rigiduloides) and Trifolium ambiguum (Rhizobium leguminosarum sv. trifolii). Lateral gene transfer of specific symbiosis genes within rhizobial genera is an important mechanism allowing legumes to form symbioses with rhizobia adapted to particular soils

  7. Responses of legumes and grasses to non-, moderate, and dense shade in Missouri, USA. II. Forage quality and its species-level plasticity

    Science.gov (United States)

    Kejia Pang; J.W. Van Sambeek; Nadia E. Navarrete-Tindall; Chung-Ho Lin; Shibu Jose; H. E. Garrett

    2017-01-01

    From a series of shade tolerance screening trials conducted in an outdoor Shade Tolerance Screening Laboratory, 22 forages (16 grasses and 6 legumes) were selected for quality evaluation. The forages were grown under non-shade (100% of full sun, the control), moderate shade (45%), and dense shade (20%) with adequate water and nutrients and free of competition from...

  8. Herbage dry-matter production and forage quality of three legumes and four non-leguminous forbs grown in single-species stands

    DEFF Research Database (Denmark)

    Elgersma, A.; Søegaard, Karen; Jensen, Søren Krogh

    2014-01-01

    ). No common feature was found within the functional groups of non-leguminous forbs and leguminous forbs, other than higher crude protein contents (198–206 g kg−1 DM) in the legumes. DM yield and fibre content were lowest in October. Digestibility declined with higher temperature and increasing fibre content...

  9. A simple model for pollen-parent fecundity distributions in bee-pollinated forage legume polycrosses

    Science.gov (United States)

    Random mating or panmixis is a fundamental assumption in quantitative genetic theory. Random mating is sometimes thought to occur in actual fact although a large body of empirical work shows that this is often not the case in nature. Models have been developed to model many non-random mating phenome...

  10. Water-tolerant legume nodulation.

    Science.gov (United States)

    Capoen, Ward; Goormachtig, Sofie; Holsters, Marcelle

    2010-03-01

    Water-tolerant nodulation is an adaptation of legumes that grow in wet or temporarily flooded habitats. This nodulation mode takes place at lateral root bases via intercellular bacterial invasion in cortical infection pockets. The tropical legume Sesbania rostrata has become a model for the study of the molecular basis of crack entry nodulation compared with root hair curl nodulation. For intercellular invasion, Nodulation Factor (NF) signalling recruits an ethylene-dependent, common Sym gene-independent pathway, leading to local cell death. The NF structure requirements are less stringent than for intracellular invasion in root hairs, which is correlated with a very specific NF-induced calcium spiking signature, presumably necessary for correct gene expression to assemble a functional entry complex in the epidermis.

  11. From model to crop: functional analysis of a STAY-GREEN gene in the model legume Medicago truncatula and effective use of the gene for alfalfa improvement.

    Science.gov (United States)

    Zhou, Chuanen; Han, Lu; Pislariu, Catalina; Nakashima, Jin; Fu, Chunxiang; Jiang, Qingzhen; Quan, Li; Blancaflor, Elison B; Tang, Yuhong; Bouton, Joseph H; Udvardi, Michael; Xia, Guangmin; Wang, Zeng-Yu

    2011-11-01

    Medicago truncatula has been developed into a model legume. Its close relative alfalfa (Medicago sativa) is the most widely grown forage legume crop in the United States. By screening a large population of M. truncatula mutants tagged with the transposable element of tobacco (Nicotiana tabacum) cell type1 (Tnt1), we identified a mutant line (NF2089) that maintained green leaves and showed green anthers, central carpels, mature pods, and seeds during senescence. Genetic and molecular analyses revealed that the mutation was caused by Tnt1 insertion in a STAY-GREEN (MtSGR) gene. Transcript profiling analysis of the mutant showed that loss of the MtSGR function affected the expression of a large number of genes involved in different biological processes. Further analyses revealed that SGR is implicated in nodule development and senescence. MtSGR expression was detected across all nodule developmental zones and was higher in the senescence zone. The number of young nodules on the mutant roots was higher than in the wild type. Expression levels of several nodule senescence markers were reduced in the sgr mutant. Based on the MtSGR sequence, an alfalfa SGR gene (MsSGR) was cloned, and transgenic alfalfa lines were produced by RNA interference. Silencing of MsSGR led to the production of stay-green transgenic alfalfa. This beneficial trait offers the opportunity to produce premium alfalfa hay with a more greenish appearance. In addition, most of the transgenic alfalfa lines retained more than 50% of chlorophylls during senescence and had increased crude protein content. This study illustrates the effective use of knowledge gained from a model system for the genetic improvement of an important commercial crop.

  12. Modelling protection behaviour towards micronutrient deficiencies: Case of iodine biofortified vegetable legumes as health intervention for school-going children

    Science.gov (United States)

    De Steur, Hans; Gellynck, Xavier; Makokha, Anselimo

    2016-01-01

    BACKGROUND/OBJECTIVES Despite successes recorded in combating iodine deficiency, more than 2 billion people are still at risk of iodine deficiency disorders. Rural landlocked and mountainous areas of developing countries are the hardest hit, hence the need to explore and advance novel strategies such as biofortification. SUBJECTS/METHODS We evaluated adoption, purchase, and consumption of iodine biofortified vegetable legumes (IBVL) using the theory of protection motivations (PMT) integrated with an economic valuation technique. A total of 1,200 participants from three land-locked locations in East Africa were recruited via multi-stage cluster sampling, and data were collected using two, slightly distinct, questionnaires incorporating PMT constructs. The survey also elicited preferences for iodine biofortified foods when offered at a premium or discount. Determinants of protection motivations and preferences for iodine biofortified foods were assessed using path analysis modelling and two-limit Tobit regression, respectively. RESULTS Knowledge of iodine, iodine-health link, salt iodization, and biofortification was very low, albeit lower at the household level. Iodine and biofortification were not recognized as nutrient and novel approaches, respectively. On the other hand, severity, fear, occupation, knowledge, iodine status, household composition, and self-efficacy predicted the intention to consume biofortified foods at the household level; only vulnerability, self-efficacy, and location were the most crucial elements at the school level. In addition, results demonstrated a positive willingness-to-pay a premium or acceptance of a lesser discount for biofortification. Furthermore, preference towards iodine biofortified foods was a function of protection motivations, severity, vulnerability, fear, response efficacy, response cost, knowledge, iodine status, gender, age. and household head. CONCLUSIONS Results lend support for prevention of iodine deficiency in

  13. Modelling protection behaviour towards micronutrient deficiencies: case of iodine biofortified vegetable legumes as health intervention for school-going children

    OpenAIRE

    Mogendi, Joseph Birundu; De Steur, Hans; Gellynck, Xavier; Makokha, Anselimo

    2016-01-01

    BACKGROUND/OBJECTIVES: Despite successes recorded in combating iodine deficiency, more than 2 billion people are still at risk of iodine deficiency disorders. Rural landlocked and mountainous areas of developing countries are the hardest hit, hence the need to explore and advance novel strategies such as biofortification. SUBJECTS/METHODS: We evaluated adoption, purchase, and consumption of iodine biofortified vegetable legumes (IBVL) using the theory of protection motivations (PMT) integ...

  14. Comparative genomics and prediction of conditionally dispensable sequences in legume-infecting Fusarium oxysporum formae speciales facilitates identification of candidate effectors.

    Science.gov (United States)

    Williams, Angela H; Sharma, Mamta; Thatcher, Louise F; Azam, Sarwar; Hane, James K; Sperschneider, Jana; Kidd, Brendan N; Anderson, Jonathan P; Ghosh, Raju; Garg, Gagan; Lichtenzveig, Judith; Kistler, H Corby; Shea, Terrance; Young, Sarah; Buck, Sally-Anne G; Kamphuis, Lars G; Saxena, Rachit; Pande, Suresh; Ma, Li-Jun; Varshney, Rajeev K; Singh, Karam B

    2016-03-05

    Soil-borne fungi of the Fusarium oxysporum species complex cause devastating wilt disease on many crops including legumes that supply human dietary protein needs across many parts of the globe. We present and compare draft genome assemblies for three legume-infecting formae speciales (ff. spp.): F. oxysporum f. sp. ciceris (Foc-38-1) and f. sp. pisi (Fop-37622), significant pathogens of chickpea and pea respectively, the world's second and third most important grain legumes, and lastly f. sp. medicaginis (Fom-5190a) for which we developed a model legume pathosystem utilising Medicago truncatula. Focusing on the identification of pathogenicity gene content, we leveraged the reference genomes of Fusarium pathogens F. oxysporum f. sp. lycopersici (tomato-infecting) and F. solani (pea-infecting) and their well-characterised core and dispensable chromosomes to predict genomic organisation in the newly sequenced legume-infecting isolates. Dispensable chromosomes are not essential for growth and in Fusarium species are known to be enriched in host-specificity and pathogenicity-associated genes. Comparative genomics of the publicly available Fusarium species revealed differential patterns of sequence conservation across F. oxysporum formae speciales, with legume-pathogenic formae speciales not exhibiting greater sequence conservation between them relative to non-legume-infecting formae speciales, possibly indicating the lack of a common ancestral source for legume pathogenicity. Combining predicted dispensable gene content with in planta expression in the model legume-infecting isolate, we identified small conserved regions and candidate effectors, four of which shared greatest similarity to proteins from another legume-infecting ff. spp. We demonstrate that distinction of core and potential dispensable genomic regions of novel F. oxysporum genomes is an effective tool to facilitate effector discovery and the identification of gene content possibly linked to host

  15. Rumen degradability of some feed legume seeds

    OpenAIRE

    González, Javier; Andrés, Santiago

    2003-01-01

    International audience; The aim of this work was to determine the effective degradability (ED) of CP for different feed legume seeds and the possible relationship with their physical and chemical characteristics. The ED was measured using nylon bags and rumen outflow rate techniques on three rumen cannulated wethers fed at 40 g DM$\\cdot$kg$^{-0.75}$, with a 2:1 (on DM basis) hay to concentrate diet. Nine seed samples of the following legume species were tested: lupin (Lupinus albus L., cultiv...

  16. Produtividade e valor nutritivo de pastos consorciados com diferentes espécies de leguminosas Productivity and nutritive value of mixed pastures with different legume species

    Directory of Open Access Journals (Sweden)

    Clair Jorge Olivo

    2012-11-01

    , the botanical composition and the structural components were evaluated. Samples from hand-plucking method were collected to analyze neutral detergent fiber (NDF, acid detergent fiber (ADF, crude protein (CP, in vitro dry matter digestibility (IVDMD and in vitro organic matter digestibility (IVOMD. The experimental design used was completely randomized with two treatments, two repetitions in complete split-plot time. The mean values of initial forage mass and stocking rate were similar among PS. Superior results were found for mean of CP in PS2. The use of ryegrass, legumes and spontaneous growing species mixed to EG allow the forage mass to be uniform during the grazing pastures.

  17. Flooding tolerance of forage legumes.

    Science.gov (United States)

    Striker, Gustavo G; Colmer, Timothy D

    2016-06-20

    We review waterlogging and submergence tolerances of forage (pasture) legumes. Growth reductions from waterlogging in perennial species ranged from >50% for Medicago sativa and Trifolium pratense to Lotus corniculatus, L. tenuis, and T. fragiferum For annual species, waterlogging reduced Medicago truncatula by ~50%, whereas Melilotus siculus and T. michelianum were not reduced. Tolerant species have higher root porosity (gas-filled volume in tissues) owing to aerenchyma formation. Plant dry mass (waterlogged relative to control) had a positive (hyperbolic) relationship to root porosity across eight species. Metabolism in hypoxic roots was influenced by internal aeration. Sugars accumulate in M. sativa due to growth inhibition from limited respiration and low energy in roots of low porosity (i.e. 4.5%). In contrast, L. corniculatus, with higher root porosity (i.e. 17.2%) and O2 supply allowing respiration, maintained growth better and sugars did not accumulate. Tolerant legumes form nodules, and internal O2 diffusion along roots can sustain metabolism, including N2 fixation, in submerged nodules. Shoot physiology depends on species tolerance. In M. sativa, photosynthesis soon declines and in the longer term (>10 d) leaves suffer chlorophyll degradation, damage, and N, P, and K deficiencies. In tolerant L corniculatus and L. tenuis, photosynthesis is maintained longer, shoot N is less affected, and shoot P can even increase during waterlogging. Species also differ in tolerance of partial and complete shoot submergence. Gaps in knowledge include anoxia tolerance of roots, N2 fixation during field waterlogging, and identification of traits conferring the ability to recover after water subsides.

  18. Scent glands in legume flowers.

    Science.gov (United States)

    Marinho, C R; Souza, C D; Barros, T C; Teixeira, S P

    2014-01-01

    Scent glands, or osmophores, are predominantly floral secretory structures that secrete volatile substances during anthesis, and therefore act in interactions with pollinators. The Leguminosae family, despite being the third largest angiosperm family, with a wide geographical distribution and diversity of habits, morphology and pollinators, has been ignored with respect to these glands. Thus, we localised and characterised the sites of fragrance production and release in flowers of legumes, in which scent plays an important role in pollination, and also tested whether there are relationships between the structure of the scent gland and the pollinator habit: diurnal or nocturnal. Flowers in pre-anthesis and anthesis of 12 legume species were collected and analysed using immersion in neutral red, olfactory tests and anatomical studies (light and scanning electron microscopy). The main production site of floral scent is the perianth, especially the petals. The scent glands are distributed in a restricted way in Caesalpinia pulcherrima, Anadenanthera peregrina, Inga edulis and Parkia pendula, constituting mesophilic osmophores, and in a diffuse way in Bauhinia rufa, Hymenaea courbaril, Erythrostemon gilliesii, Poincianella pluviosa, Pterodon pubescens, Platycyamus regnellii, Mucuna urens and Tipuana tipu. The glands are comprised of cells of the epidermis and mesophyll that secrete mainly terpenes, nitrogen compounds and phenols. Relationships between the presence of osmophores and type of anthesis (diurnal and nocturnal) and the pollinator were not found. Our data on scent glands in Leguminosae are original and detail the type of diffuse release, which has been very poorly studied.

  19. Mass Spectrometric-Based Selected Reaction Monitoring of Protein Phosphorylation during Symbiotic Signaling in the Model Legume, Medicago truncatula.

    Directory of Open Access Journals (Sweden)

    Lori K Van Ness

    Full Text Available Unlike the major cereal crops corn, rice, and wheat, leguminous plants such as soybean and alfalfa can meet their nitrogen requirement via endosymbiotic associations with soil bacteria. The establishment of this symbiosis is a complex process playing out over several weeks and is facilitated by the exchange of chemical signals between these partners from different kingdoms. Several plant components that are involved in this signaling pathway have been identified, but there is still a great deal of uncertainty regarding the early events in symbiotic signaling, i.e., within the first minutes and hours after the rhizobial signals (Nod factors are perceived at the plant plasma membrane. The presence of several protein kinases in this pathway suggests a mechanism of signal transduction via posttranslational modification of proteins in which phosphate is added to the hydroxyl groups of serine, threonine and tyrosine amino acid side chains. To monitor the phosphorylation dynamics and complement our previous untargeted 'discovery' approach, we report here the results of experiments using a targeted mass spectrometric technique, Selected Reaction Monitoring (SRM that enables the quantification of phosphorylation targets with great sensitivity and precision. Using this approach, we confirm a rapid change in the level of phosphorylation in 4 phosphosites of at least 4 plant phosphoproteins that have not been previously characterized. This detailed analysis reveals aspects of the symbiotic signaling mechanism in legumes that, in the long term, will inform efforts to engineer this nitrogen-fixing symbiosis in important non-legume crops such as rice, wheat and corn.

  20. Mass Spectrometric-Based Selected Reaction Monitoring of Protein Phosphorylation during Symbiotic Signaling in the Model Legume, Medicago truncatula.

    Science.gov (United States)

    Van Ness, Lori K; Jayaraman, Dhileepkumar; Maeda, Junko; Barrett-Wilt, Gregory A; Sussman, Michael R; Ané, Jean-Michel

    2016-01-01

    Unlike the major cereal crops corn, rice, and wheat, leguminous plants such as soybean and alfalfa can meet their nitrogen requirement via endosymbiotic associations with soil bacteria. The establishment of this symbiosis is a complex process playing out over several weeks and is facilitated by the exchange of chemical signals between these partners from different kingdoms. Several plant components that are involved in this signaling pathway have been identified, but there is still a great deal of uncertainty regarding the early events in symbiotic signaling, i.e., within the first minutes and hours after the rhizobial signals (Nod factors) are perceived at the plant plasma membrane. The presence of several protein kinases in this pathway suggests a mechanism of signal transduction via posttranslational modification of proteins in which phosphate is added to the hydroxyl groups of serine, threonine and tyrosine amino acid side chains. To monitor the phosphorylation dynamics and complement our previous untargeted 'discovery' approach, we report here the results of experiments using a targeted mass spectrometric technique, Selected Reaction Monitoring (SRM) that enables the quantification of phosphorylation targets with great sensitivity and precision. Using this approach, we confirm a rapid change in the level of phosphorylation in 4 phosphosites of at least 4 plant phosphoproteins that have not been previously characterized. This detailed analysis reveals aspects of the symbiotic signaling mechanism in legumes that, in the long term, will inform efforts to engineer this nitrogen-fixing symbiosis in important non-legume crops such as rice, wheat and corn.

  1. Productivity and residual benefits of grain legumes to sorghum under semi-arid conditions in south-western Zimbabwe: Unravelling the effects of water and nitrogen using a simulation model

    NARCIS (Netherlands)

    Ncube, B.; Dimes, J.P.; Wijk, van M.T.; Twomlow, S.J.; Giller, K.E.

    2009-01-01

    The APSIM model was used to assess the impact of legumes on sorghum grown in rotation in a nutrient-limited system under dry conditions in south-western Zimbabwe. An experiment was conducted at Lucydale, Matopos Research Station, between 2002 and 2005. The model was used to simulate soil and plant

  2. The abundance and diversity of legume-nodulating rhizobia in 28-year-old plantations of tropical, subtropical, and exotic tree species: a case study from the Forest Reserve of Bandia, Senegal.

    Science.gov (United States)

    Sene, Godar; Thiao, Mansour; Samba-Mbaye, Ramatoulaye; Khasa, Damase; Kane, Aboubacry; Mbaye, Mame Samba; Beaulieu, Marie-Ève; Manga, Anicet; Sylla, Samba Ndao

    2013-01-01

    Several fast-growing and multipurpose tree species have been widely used in West Africa to both reverse the tendency of land degradation and restore soil productivity. Although beneficial effects have been reported on soil stabilization, there still remains a lack of information about their impact on soil microorganisms. Our investigation has been carried out in exotic and native tree plantations of 28 years and aimed to survey and compare the abundance and genetic diversity of natural legume-nodulating rhizobia (LNR). The study of LNR is supported by the phylogenetic analysis which clustered the isolates into three genera: Bradyrhizobium, Mesorhizobium, and Sinorhizobium. The results showed close positive correlations between the sizes of LNR populations estimated both in the dry and rainy seasons and the presence of legume tree hosts. There were significant increases in Rhizobium spp. population densities in response to planting with Acacia spp., and high genetic diversities and richness of genotypes were fittest in these tree plantations. This suggests that enrichment of soil Rhizobium spp. populations is host specific. The results indicated also that species of genera Mesorhizobium and Sinorhizobium were lacking in plantations of non-host species. By contrast, there was a widespread distribution of Bradyrhizobium spp. strains across the tree plantations, with no evident specialization in regard to plantation type. Finally, the study provides information about the LNR communities associated with a range of old tree plantations and some aspects of their relationships to soil factors, which may facilitate the management of man-made forest systems that target ecosystem rehabilitation and preservation of soil biota.

  3. Seed shape in model legumes: approximation by a cardioid reveals differences in ethylene insensitive mutants of Lotus japonicus and Medicago truncatula.

    Science.gov (United States)

    Cervantes, Emilio; Martín, José Javier; Chan, Pick Kuen; Gresshoff, Peter M; Tocino, Ángel

    2012-09-15

    Seed shape in the model legumes Lotus japonicus and Medicago truncatula is described. Based in previous work with Arabidopsis, the outline of the longitudinal sections of seeds is compared with a cardioid curve. L. japonicus seeds adjust well to an unmodified cardioid, whereas accurate adjustment in M. truncatula is obtained by the simple transformation of scaling the vertical axis by a factor equal to the Golden Ratio. Adjustments of seed shape measurements with simple geometrical forms are essential tools for the statistical analysis of variations in seed shape under different conditions or in mutants. The efficiency of the adjustment to a cardioid in the model plants suggests that seed morphology may be related to genome complexity. Seeds of ethylene insensitive mutants present differences in size and shape as well as altered responses to imbibition. The biological implication and meaning of these relationships are discussed.

  4. Responses of photosynthesis and growth to weak light regime in four legume species%四种豆科作物的光合生理和生长发育对弱光的响应

    Institute of Scientific and Technical Information of China (English)

    邹长明; 王允青; 刘英; 张晓红; 唐杉

    2015-01-01

    为了确定豆科作物作为林果行间套种作物的适宜性,于2014年通过田间试验和盆栽试验对4种豆科作物的耐阴能力及其光合生理进行了研究。测定全光和弱光处理(全光的48%)下豆科作物在初花期的叶片光合特征参数、光合色素含量与核酮糖-1,5-二磷酸羧化酶(RuBPCase)活性,监测其生长发育对弱光的响应。结果表明:弱光使供试作物的最大净光合速率、光饱和点、光补偿点、表观量子效率和暗呼吸速率不同程度地向耐阴植物变化;弱光还使供试作物的净光合速率、气孔导度、蒸腾速率、瞬时水分利用效率和RuBPCase活性不同程度地下降,而胞间CO2浓度显著上升;遮阴后,乌豇豆(Vigna cylindrica)和绿豆(Vigna radiata)的叶绿素(Chl) a和Chl b含量显著增加, Chl a/b值显著降低,大猪屎豆(Crotalaria assamica)和望江南(Senna occidentalis)的光合色素含量也有不同程度的变化;弱光使供试作物茎变细,侧枝数减少,生物量和干物质积累效率降低,根冠比降低,根瘤量减少,叶片变小变薄,叶片数减少,叶面积指数降低;弱光胁迫下,大猪屎豆不开花,望江南只开花不结实,而绿豆和乌豇豆开花数减少,花期缩短,种子产量显著降低。根据供试作物的光合特性和生长发育对弱光的响应,得出它们的耐阴能力排序是:乌豇豆>绿豆>望江南>大猪屎豆,其中乌豇豆和绿豆适宜与林果套种,而望江南和大猪屎豆不适宜套种。%Aims In order to determine the adaptability of legumes as the interplanting crops in fruit yards, field and pot experimental treatments with full natural light and weak light (48% of full natural light) regimes were conducted in 2014 to test the shade tolerance and physiological mechanisms of four legume species. Methods The leaf photosynthetic characteristic parameters, photosynthetic pigments contents and the activities of ribulose-1,5-bisphosphate

  5. Objectives and approaches in the breeding of perennial legumes for use in temporary pasturelands

    OpenAIRE

    Naydenova G.; Hristova Ts.; Aleksiev Y.

    2013-01-01

    Legumes are the major element of grassland ecosystem, on which the forage quality depends. Breeding of pasture varieties in perennial legumes firstly aims at achieving tolerance and persistence of the legume component in the pasture. In species having low natural grazing tolerance (lucerne and red clover) it is necessary to conduct breeding for biological, morphological and physiological characteristics, directly related to grazing tolerance. In the species...

  6. Grain legumes and human health

    OpenAIRE

    Lambein, Fernand; Kuo, Yu-Haey; Ikegami, Fumio; Kusama-Eguchi, Kuniko; Enneking, Dirk

    2009-01-01

    Since early civilisation in different continents, grain legumes have been a part of balanced diets together with cereals. In general the seeds from those two plant families give together a good source of essential amino acids and may have given an evolutionary advantage. A sustainable diet for vegetarians may not be possible without the protein-rich legumes. Consumed alone, legumes can be a mixed blessing because of their deficiency of some essential amino acids. This deficiency can be balanc...

  7. A global experimental dataset for assessing grain legume production

    Science.gov (United States)

    Cernay, Charles; Pelzer, Elise; Makowski, David

    2016-09-01

    Grain legume crops are a significant component of the human diet and animal feed and have an important role in the environment, but the global diversity of agricultural legume species is currently underexploited. Experimental assessments of grain legume performances are required, to identify potential species with high yields. Here, we introduce a dataset including results of field experiments published in 173 articles. The selected experiments were carried out over five continents on 39 grain legume species. The dataset includes measurements of grain yield, aerial biomass, crop nitrogen content, residual soil nitrogen content and water use. When available, yields for cereals and oilseeds grown after grain legumes in the crop sequence are also included. The dataset is arranged into a relational database with nine structured tables and 198 standardized attributes. Tillage, fertilization, pest and irrigation management are systematically recorded for each of the 8,581 crop*field site*growing season*treatment combinations. The dataset is freely reusable and easy to update. We anticipate that it will provide valuable information for assessing grain legume production worldwide.

  8. Healthy food trends -- beans and legumes

    Science.gov (United States)

    Healthy food trends - pulses; Healthy eating - beans and legumes; Weight loss - beans and legumes; Healthy diet - beans and legumes; ... My Plate.gov. Beans and Peas Are Unique Foods. Updated January 12, 2016. www.choosemyplate.gov/vegetables- ...

  9. Legume presence reduces the decomposition rate of non-legume roots, role of plant traits?

    Science.gov (United States)

    De Deyn, Gerlinde B.; Saar, Sirgi; Barel, Janna; Semchenko, Marina

    2016-04-01

    Plant litter traits are known to play an important role in the rate of litter decomposition and mineralization, both for aboveground and belowground litter. However also the biotic and abiotic environment in which the litter decomposes plays a significant role in the rate of decomposition. The presence of living plants may accelerate litter decomposition rates via a priming effects. The size of this effect is expected to be related to the traits of the litter. In this study we focus on root litter, given that roots and their link to ecosystem processes have received relatively little attention in trait-based research. To test the effect of a growing legume plant on root decomposition and the role of root traits in this we used dead roots of 7 different grassland species (comprising grasses, a forb and legumes), determined their C, N, P content and quantified litter mass loss after eight weeks of incubation in soil with and without white clover. We expected faster root decomposition with white clover, especially for root litter with low N content. In contrast we found slower decomposition of grass and forb roots which were poor in N (negative priming) in presence of white clover, while decomposition rates of legume roots were not affected by the presence of white clover. Overall we found that root decomposition can be slowed down in the presence of a living plant and that this effect depends on the traits of the decomposing roots, with a pronounced reduction in root litter poor in N and P, but not in the relatively nutrient-rich legume root litters. The negative priming effect of legume plants on non-legume litter decomposition may have resulted from preferential substrate utilisation by soil microbes.

  10. Confronting species distribution model predictions with species functional traits.

    Science.gov (United States)

    Wittmann, Marion E; Barnes, Matthew A; Jerde, Christopher L; Jones, Lisa A; Lodge, David M

    2016-02-01

    Species distribution models are valuable tools in studies of biogeography, ecology, and climate change and have been used to inform conservation and ecosystem management. However, species distribution models typically incorporate only climatic variables and species presence data. Model development or validation rarely considers functional components of species traits or other types of biological data. We implemented a species distribution model (Maxent) to predict global climate habitat suitability for Grass Carp (Ctenopharyngodon idella). We then tested the relationship between the degree of climate habitat suitability predicted by Maxent and the individual growth rates of both wild (N = 17) and stocked (N = 51) Grass Carp populations using correlation analysis. The Grass Carp Maxent model accurately reflected the global occurrence data (AUC = 0.904). Observations of Grass Carp growth rate covered six continents and ranged from 0.19 to 20.1 g day(-1). Species distribution model predictions were correlated (r = 0.5, 95% CI (0.03, 0.79)) with observed growth rates for wild Grass Carp populations but were not correlated (r = -0.26, 95% CI (-0.5, 0.012)) with stocked populations. Further, a review of the literature indicates that the few studies for other species that have previously assessed the relationship between the degree of predicted climate habitat suitability and species functional traits have also discovered significant relationships. Thus, species distribution models may provide inferences beyond just where a species may occur, providing a useful tool to understand the linkage between species distributions and underlying biological mechanisms.

  11. Impact of global climate change and fire on the occurrence and function of understorey legumes in forest ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Reverchon, Frederique; Xu, Zhihong; Blumfield, Timothy J.; Chen, Chengrong; Abdullah, Kadum M. [Griffith Univ., Nathan, QLD (Australia). Environmental Futures Centre and School of Biomolecular and Physical Sciences

    2012-02-15

    The objective of this review was to provide a better understanding of how global climate change and fire influence the occurrence of understorey legumes and thereby biological nitrogen (N) fixation rates in forest ecosystems. Legumes are interesting models since they represent an interface between the soil, plant, and microbial compartments, and are directly linked to nutrient cycles through their ability to fix N. As such, they are likely to be affected by environmental changes. Biological N fixation has been shown to increase under enriched CO{sub 2} conditions, but is constrained by the availability of phosphorus and water. Climate change can also influence the species composition of legumes and their symbionts through warming, altered rainfall patterns, or changes in soil physicochemistry, which could modify the effectiveness of the symbiosis. Additionally, global climate change may increase the occurrence and intensity of forest wildfires thereby further influencing the distribution of legumes. The establishment of leguminous species is generally favored by fire, as is N{sub 2} fixation. This fixed N could therefore replenish the N lost through volatilization during the fire. However, fire may also generate shifts in the associated microbial community which could affect the outcome of the symbiosis. Understorey legumes are important functional species, and even when they cannot reasonably be expected to reestablish the nutrient balance in forest soils, they may be used as indicators to monitor nutrient fluxes and the response of forest ecosystems to changing environmental conditions. This would be helpful to accurately model ecosystem N budgets, and since N is often a limiting factor to plant growth and a major constraint on C storage in ecosystems, would allow us to assess more precisely the potential of these forests for C sequestration. (orig.)

  12. Incorporating Context Dependency of Species Interactions in Species Distribution Models.

    Science.gov (United States)

    Lany, Nina K; Zarnetske, Phoebe L; Gouhier, Tarik C; Menge, Bruce A

    2017-07-01

    Species distribution models typically use correlative approaches that characterize the species-environment relationship using occurrence or abundance data for a single species. However, species distributions are determined by both abiotic conditions and biotic interactions with other species in the community. Therefore, climate change is expected to impact species through direct effects on their physiology and indirect effects propagated through their resources, predators, competitors, or mutualists. Furthermore, the sign and strength of species interactions can change according to abiotic conditions, resulting in context-dependent species interactions that may change across space or with climate change. Here, we incorporated the context dependency of species interactions into a dynamic species distribution model. We developed a multi-species model that uses a time-series of observational survey data to evaluate how abiotic conditions and species interactions affect the dynamics of three rocky intertidal species. The model further distinguishes between the direct effects of abiotic conditions on abundance and the indirect effects propagated through interactions with other species. We apply the model to keystone predation by the sea star Pisaster ochraceus on the mussel Mytilus californianus and the barnacle Balanus glandula in the rocky intertidal zone of the Pacific coast, USA. Our method indicated that biotic interactions between P. ochraceus and B. glandula affected B. glandula dynamics across >1000 km of coastline. Consistent with patterns from keystone predation, the growth rate of B. glandula varied according to the abundance of P. ochraceus in the previous year. The data and the model did not indicate that the strength of keystone predation by P. ochraceus varied with a mean annual upwelling index. Balanus glandula cover increased following years with high phytoplankton abundance measured as mean annual chlorophyll-a. M. californianus exhibited the same

  13. Distribution of native Legumes (Leguminoseae) in frequently burned longleaf pine (Pinaceae)-Wiregrass (Poaceae) ecosystems

    Science.gov (United States)

    Mark J. Hainds; Robert J. Mitchell; Brian J. Palik; Lindsay R. Boring; Dean H. Gjerstad

    1999-01-01

    Legume species distribution and abundance and selected environmental variables were quantified across a complex gradient (varying in both water-holding capacity and fertility) for frequently burned longleaf pine (Pinus palustris)-wiregrass (Aristida stricta) ecosystems. Legumes were present in all months; however, abundance...

  14. Dependência de micorrizas para a nodulação de leguminosas arbóreas tropicais Dependence on arbuscular mycorrhizal fungi for nodulation and growth of tropical woody legume species

    Directory of Open Access Journals (Sweden)

    Ederson da Conceição Jesus

    2005-08-01

    woody legume species P. gonoacantha and P. paniculata was studied. The experiments were carried out under greenhouse conditions, at Embrapa Agrobiologia, Rio de Janeiro. The species were inoculated with specific rhizobia and with the mycorrhizal fungi Gigaspora margarita and Glomus clarum. Both tree species were highly responsive to mycorrhizal inoculation. Only the plants inoculated with both rhizobium and mycorrhizal fungi were nodulated. Plants inoculated with both rhizobia and mycorrhizal fungi presented higher dry matter than those inoculated only with rhizobia. P. gonoacantha plants presented higher shoot phosphorus content when inoculated with mycorrhizal fungi. These results show that mycorrhizal inoculation is needed for nodulation and growth of the tree species studied. We suggest the use of mycorrhizal fungi to select rhizobial strains for legumes which have difficulty to grow in Leonard jars.

  15. Nitrogen transfer from forage legumes to grass in a systematic planting design. [Medicago sativa; Lotus corniculatus; Phalaris arundinacea

    Energy Technology Data Exchange (ETDEWEB)

    Brophy, L.S.; Heichel, G.H.; Russelle, M.P.

    Alfalfa (Medicago sativa L.) is the most important forage legume in the USA, but N transfer from this or other perennial forage species to companion grasses growing in a mixed sward is poorly understood. Furthermore, interplant distances and legume/grass ratios have seldom been controlled in studies of N transfer from legumes to non-legumes. The objectives of this field study were: (i) to determine the amount of N transferred from alfalfa and birdsfoot trefoil (Lotus carniculatus L.) to reed canarygrass (Phalaris arundinacea L.); (ii) to define conditions of distance and species ratio under which N transfer occurs; (iii) to compare the two legumes for N transfer; and (iv) to determine the effect of grass proximity on legume N/sub 2/ fixation. Legumes were interplanted with grass in single-species rows within km/sup 2/ plots on a Typic hapludoll soil labeled with /sup 15/N. Analysis of herbage showed significantly lower /sup 15/N concentration in grass near legumes than in grass grown alone, and significantly lower /sup 15/N concentration in legumes near grass than legumes in monoculture. Calculations using isotope dilution methods showed that grass derived a maximum of 68% of its N from alfalfa and 79% from trefoil. This N represented 13% of the N/sub 2/ fixed by trefoil and 17% of that fixed by alfalfa. The results indicated that N transfer occurred over a distance of 20 cm with maximum N transfer in areas of high legume/grass ratio. At third harvest, N derived from symbiosis was significantly higher (95% in alfalfa, 92% in trefoil) for legumes grown in mixture with grass than for legumes grown in monoculture (86% in alfalfa, 80% in trefoil). These results indicate that significant N transfer occurred, and that the amount of N transferred was dependent on interspecies distance and legume/grass ratio.

  16. Biological fixation and nitrogen transfer by three legume species in mango and soursop organic orchards;Fixacao biologica e transferencia de nitrogenio por leguminosas em pomar organico de mangueira e gravioleira

    Energy Technology Data Exchange (ETDEWEB)

    Paulino, Gleicia Miranda; Barroso, Deborah Guerra, E-mail: gleiciamiranda@yahoo.com.b, E-mail: deborah@uenf.b [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacazes, RJ (Brazil). Dept. de Fitotecnia; Alves, Bruno Jose Rodrigues; Urquiaga, Segundo; Espindola, Jose Antonio Azevedo, E-mail: bruno@cnpab.embrapa.b, E-mail: urquiaga@cnpab.embrapa.b, E-mail: jose@cnpab.embrapa.b [EMBRAPA Agrobiologia, Seropedica, RJ (Brazil)

    2009-12-15

    The objective of this work was to evaluate the biological nitrogen fixation (BNF) and the N transfer derived from BNF of the legume species - Gliricidia sepium (gliricidia), Crotalaria juncea (sunnhemp) and Cajanus cajan (pigeon pea) - for an intercropped organic orchard with mango and soursop, through the {sup 15}N natural abundance method. The following inter cropping systems were evaluated: mango and soursop with gliricidia; mango and soursop with sunnhemp; mango and soursop with pigeon pea; and mango and soursop as control. Gliricidia showed the highest BNF potential (80%) , followed by sunnhemp (64.5%) and pigeon pea (45%). After two sunnhemp prunes, 149.5 kg ha{sup -1} of N per year were supplied, with 96.5 kg derived from BNF. After three annual prunes, gliricidia supplied 56.4 and 80.3 kg ha{sup -1} of N per year, with 45 and 64 kg derived from BNF, in two consecutive years. The quantity of N supplied to the system was higher than the mango and soursop requirements. Variations in the natural abundance of {sup 15}N were found only in soursop leaves. Gliricidia and sunnhemp were prominent in N transfer, with approximately 22.5 and 40% respectively. Green manuring using gliricidia permits fractioning of the N supply, which is an advantage in N obtention by the fruit trees (author)

  17. Rhizobium calliandrae sp. nov., Rhizobium mayense sp. nov. and Rhizobium jaguaris sp. nov., rhizobial species nodulating the medicinal legume Calliandra grandiflora

    National Research Council Canada - National Science Library

    Rincón-Rosales, Reiner; Villalobos-Escobedo, José M; Rogel, Marco A; Martinez, Julio; Ormeño-Orrillo, Ernesto; Martínez-Romero, Esperanza

    2013-01-01

    ...) and 16S rRNA gene sequence analysis. Most isolates corresponded to members of the genus Rhizobium and those not related to species with validly published names were further characterized by recA, atpD, rpoB and nifH gene phylogenies...

  18. Transcriptome Sequencing of Lima Bean (Phaseolus lunatus to Identify Putative Positive Selection in Phaseolus and Legumes

    Directory of Open Access Journals (Sweden)

    Fengqi Li

    2015-07-01

    Full Text Available The identification of genes under positive selection is a central goal of evolutionary biology. Many legume species, including Phaseolus vulgaris (common bean and Phaseolus lunatus (lima bean, have important ecological and economic value. In this study, we sequenced and assembled the transcriptome of one Phaseolus species, lima bean. A comparison with the genomes of six other legume species, including the common bean, Medicago, lotus, soybean, chickpea, and pigeonpea, revealed 15 and 4 orthologous groups with signatures of positive selection among the two Phaseolus species and among the seven legume species, respectively. Characterization of these positively selected genes using Non redundant (nr annotation, gene ontology (GO classification, GO term enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG pathway analyses revealed that these genes are mostly involved in thylakoids, photosynthesis and metabolism. This study identified genes that may be related to the divergence of the Phaseolus and legume species. These detected genes are particularly good candidates for subsequent functional studies.

  19. Elevated CO₂ mitigates drought and temperature-induced oxidative stress differently in grasses and legumes.

    Science.gov (United States)

    AbdElgawad, Hamada; Farfan-Vignolo, Evelyn Roxana; de Vos, Dirk; Asard, Han

    2015-02-01

    Increasing atmospheric CO2 will affect plant growth, including mitigation of stress impact. Such effects vary considerably between species-groups. Grasses (Lolium perenne, Poa pratensis) and legumes (Medicago lupulina, Lotus corniculatus) were subjected to drought, elevated temperature and elevated CO2. Drought inhibited plant growth, photosynthesis and stomatal conductance, and induced osmolytes and antioxidants in all species. In contrast, oxidative damage was more strongly induced in the legumes than in the grasses. Warming generally exacerbated drought effects, whereas elevated CO2 reduced stress impact. In the grasses, photosynthesis and chlorophyll levels were more protected by CO2 than in the legumes. Oxidative stress parameters (lipid peroxidation, H2O2 levels), on the other hand, were generally more reduced in the legumes. This is consistent with changes in molecular antioxidants, which were reduced by elevated CO2 in the grasses, but not in the legumes. Antioxidant enzymes decreased similarly in both species-groups. The ascorbate-glutathione cycle was little affected by drought and CO2. Overall, elevated CO2 reduced drought effects in grasses and legumes, and this mitigation was stronger in the legumes. This is possibly explained by stronger reduction in H2O2 generation (photorespiration and NADPH oxidase), and a higher availability of molecular antioxidants. The grass/legume-specificity was supported by principal component analysis.

  20. Potential of legume-based grassland-livestock systems in Europe: a review.

    Science.gov (United States)

    Lüscher, A; Mueller-Harvey, I; Soussana, J F; Rees, R M; Peyraud, J L

    2014-06-01

    European grassland-based livestock production systems face the challenge of producing more meat and milk to meet increasing world demands and to achieve this using fewer resources. Legumes offer great potential for achieving these objectives. They have numerous features that can act together at different stages in the soil-plant-animal-atmosphere system, and these are most effective in mixed swards with a legume proportion of 30-50%. The resulting benefits include reduced dependence on fossil energy and industrial N-fertilizer, lower quantities of harmful emissions to the environment (greenhouse gases and nitrate), lower production costs, higher productivity and increased protein self-sufficiency. Some legume species offer opportunities for improving animal health with less medication, due to the presence of bioactive secondary metabolites. In addition, legumes may offer an adaptation option to rising atmospheric CO2 concentrations and climate change. Legumes generate these benefits at the level of the managed land-area unit and also at the level of the final product unit. However, legumes suffer from some limitations, and suggestions are made for future research to exploit more fully the opportunities that legumes can offer. In conclusion, the development of legume-based grassland-livestock systems undoubtedly constitutes one of the pillars for more sustainable and competitive ruminant production systems, and it can be expected that forage legumes will become more important in the future.

  1. Mechanistic action of gibberellins in legume nodulation.

    Science.gov (United States)

    Hayashi, Satomi; Gresshoff, Peter M; Ferguson, Brett J

    2014-10-01

    Legume plants are capable of entering into a symbiotic relationship with rhizobia bacteria. This results in the formation of novel organs on their roots, called nodules, in which the bacteria capture atmospheric nitrogen and provide it as ammonium to the host plant. Complex molecular and physiological changes are involved in the formation and establishment of such nodules. Several phytohormones are known to play key roles in this process. Gibberellins (gibberellic acids; GAs), a class of phytohormones known to be involved in a wide range of biological processes (i.e., cell elongation, germination) are reported to be involved in the formation and maturation of legume nodules, highlighted by recent transcriptional analyses of early soybean symbiotic steps. Here, we summarize what is currently known about GAs in legume nodulation and propose a model of GA action during nodule development. Results from a wide range of studies, including GA application, mutant phenotyping, and gene expression studies, indicate that GAs are required at different stages, with an optimum, tightly regulated level being key to achieve successful nodulation. Gibberellic acids appear to be required at two distinct stages of nodulation: (i) early stages of rhizobia infection and nodule primordium establishment; and (ii) later stages of nodule maturation.

  2. Mechanistic action of gibberellins in legume nodulation

    Institute of Scientific and Technical Information of China (English)

    Satomi Hayashi; Peter MGresshoff; Brett J.Ferguson

    2014-01-01

    Legume plants are capable of entering into a symbiotic relationship with rhizobia bacteria. This results in the formation of novel organs on their roots, cal ed nodules, in which the bacteria capture atmospheric nitrogen and provide it as ammonium to the host plant. Complex molecular and physiological changes are involved in the formation and establishment of such nodules. Several phytohormones are known to play key roles in this process. Gibberel ins (gibberel ic acids;GAs), a class of phytohormones known to be involved in a wide range of biological processes (i.e., cellelongation, germination) are reported to be involved in the formation and maturation of legume nodules, highlighted by recent tran-scriptional analyses of early soybean symbiotic steps. Here, we summarize what is currently known about GAs in legume nodulation and propose a model of GA action during nodule development. Results from a wide range of studies, including GA application, mutant phenotyping, and gene expression studies, indicate that GAs are required at different stages, with an optimum, tightly regulated level being key to achieve successful nodulation. Gibberel ic acids appear to be required at two distinct stages of nodulation:(i) early stages of rhizobia infection and nodule primordium establishment;and (i ) later stages of nodule maturation.

  3. Rhizobium calliandrae sp. nov., Rhizobium mayense sp. nov. and Rhizobium jaguaris sp. nov., rhizobial species nodulating the medicinal legume Calliandra grandiflora.

    Science.gov (United States)

    Rincón-Rosales, Reiner; Villalobos-Escobedo, José M; Rogel, Marco A; Martinez, Julio; Ormeño-Orrillo, Ernesto; Martínez-Romero, Esperanza

    2013-09-01

    Calliandra grandiflora has been used as a medicinal plant for thousands of years in Mexico. Rhizobial strains were obtained from root nodules of C. grandiflora collected from different geographical regions in Chiapas and characterized by BOX-PCR, amplified rDNA restriction analysis (ARDRA) and 16S rRNA gene sequence analysis. Most isolates corresponded to members of the genus Rhizobium and those not related to species with validly published names were further characterized by recA, atpD, rpoB and nifH gene phylogenies, phenotypic and DNA-DNA hybridization analyses. Three novel related species of the genus Rhizobium within the 'Rhizobium tropici group' share the same symbiovar that may be named sv. calliandrae. The names proposed for the three novel species are Rhizobium calliandrae sp. nov. (type strain, CCGE524(T) =ATCC BAA-2435(T) =CIP 110456(T) =LBP2-1(T)), Rhizobium mayense sp. nov. (type strain, CCGE526(T) =ATCC BAA-2446(T) = CIP 110454(T) =NSJP1-1(T)) and Rhizobium jaguaris sp. nov. (type strain, CCGE525(T) =ATCC BAA-2445(T) =CIP 110453(T) =SJP1-2(T)).

  4. Modelling biological invasions: species traits, species interactions, and habitat heterogeneity.

    Science.gov (United States)

    Cannas, Sergio A; Marco, Diana E; Páez, Sergio A

    2003-05-01

    In this paper we explore the integration of different factors to understand, predict and control ecological invasions, through a general cellular automaton model especially developed. The model includes life history traits of several species in a modular structure interacting multiple cellular automata. We performed simulations using field values corresponding to the exotic Gleditsia triacanthos and native co-dominant trees in a montane area. Presence of G. triacanthos juvenile bank was a determinant condition for invasion success. Main parameters influencing invasion velocity were mean seed dispersal distance and minimum reproductive age. Seed production had a small influence on the invasion velocity. Velocities predicted by the model agreed well with estimations from field data. Values of population density predicted matched field values closely. The modular structure of the model, the explicit interaction between the invader and the native species, and the simplicity of parameters and transition rules are novel features of the model.

  5. Testing a pollen-parent fecundity distribution model on seed-parent fecundity distributions in bee-pollinated forage legume polycrosses

    Science.gov (United States)

    Random mating (i.e., panmixis) is a fundamental assumption in quantitative genetics. In outcrossing bee-pollinated perennial forage legume polycrosses, mating is assumed by default to follow theoretical random mating. This assumption informs breeders of expected inbreeding estimates based on polycro...

  6. Symbiotic specificity of tropical tree rhizobia for host legumes

    NARCIS (Netherlands)

    Bala, A.; Giller, K.E.

    2001-01-01

    The host range and specificity is reported of a genetically diverse group of rhizobia isolated from nodules of Calliandra calothyrsus, Gliricidia sepium, Leucaena leucocephala and Sesbania sesban. Nodule number and nitrogen content was measured in seedlings of herbaceous and woody legume species aft

  7. Novel associations between rhizobial populations and legume species within the genera Lathyrus and Oxytropis grown in the temperate region of China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Fifty rhizobial isolates of Lathyrus and Oxytropis collected from northern regions of China were studied in their genotypic characterization based upon analyses of ARDRA, 16S-23S IGS PCR-RFLP, TP-RAPD, MLEE, sequences of 16S rDNA gene and housekeeping genes of atpD, recA and glnII. The results demonstrated that most of the Lathyrus rhizobia belonged to Rhizobium and most of the Oxytropis rhizobia belonged to Sinorhizobium. A novel group of Rhizobium sp. I and S. meliloti were identified as the main microsymbionts respectively associated with Lathyrus and Oxytropis species in the collection area, which were new associations between rhizobia and the mentioned hosts. This study also provides new evidence for biogeography of rhizobia.

  8. Novel associations between rhizobial populations and legume species within the genera Lathyrus and Oxytropis grown in the temperate region of China

    Institute of Scientific and Technical Information of China (English)

    SUI XinHua; HAN LiLi; WANG EnTao; JIANG Feng; LIU YiHai; CHEN WenXin

    2009-01-01

    Fifty rhizobial isolates of Lathyrus and Oxytropis collected from northern regions of China were studied in their genotypic characterization based upon analyses of ARDRA, 16S-23S IGS PCR-RFLP, TP-RAPD, MLEE, sequences of 16S rDNA gene and housekeeping genes of atpD, recA and glnll. The results demonstrated that most of the Lathyrus rhizobia belonged to Rhizobium and most of the Oxytropis rhizobia belonged to Sinorhizobium. A novel group of Rhizobium sp. I and S. meliloti were identified as the main microsymbionts respectively associated with Lathyrus and Oxytropis species in the collection area, which were new associations between rhizobia and the mentioned hosts. This study also provides new evidence for biogeography of rhizobia.

  9. MtVRN2 is a Polycomb VRN2-like gene which represses the transition to flowering in the model legume Medicago truncatula.

    Science.gov (United States)

    Jaudal, Mauren; Zhang, Lulu; Che, Chong; Hurley, Daniel G; Thomson, Geoffrey; Wen, Jiangqi; Mysore, Kirankumar S; Putterill, Joanna

    2016-04-01

    Optimising the timing of flowering contributes to successful sexual reproduction and yield in agricultural plants. FLOWERING LOCUS T (FT) genes, first identified in Arabidopsis thaliana (Arabidopsis), promote flowering universally, but the upstream flowering regulatory pathways can differ markedly among plants. Flowering in the model legume, Medicago truncatula (Medicago) is accelerated by winter cold (vernalisation) followed by long day (LD) photoperiods leading to elevated expression of the floral activator, FT-like gene FTa1. However, Medicago, like some other plants, lacks the activator CONSTANS (CO) and the repressor FLOWERING LOCUS C (FLC) genes which directly regulate FT and are key to LD and vernalisation responses in Arabidopsis. Conversely, Medicago has a VERNALISATION2-LIKE VEFS-box gene (MtVRN2). In Arabidopsis AtVRN2 is a key member of a Polycomb complex involved in stable repression of Arabidopsis FLC after vernalisation. VRN2-like genes have been identified in other eudicot plants, but their function has never been reported. We show that Mtvrn2 mutants bypass the need for vernalisation for early flowering in LD conditions in Medicago. Investigation of the underlying mechanism by transcriptome analysis reveals that Mtvrn2 mutants precociously express FTa1 and other suites of genes including floral homeotic genes. Double-mutant analysis indicates that early flowering is dependent on functional FTa1. The broad significance of our study is that we have demonstrated a function for a VRN2-like VEFS gene beyond the Brassicaceae. In particular, MtVRN2 represses the transition to flowering in Medicago by regulating the onset of expression of the potent floral activator, FTa1.

  10. Alley cropping of legumes with grasses as forages : Effect of different grass species and row spacing of gliricidia on the growth and biomass production of forages

    Directory of Open Access Journals (Sweden)

    Siti Yuhaeni

    1998-12-01

    Full Text Available A study to evaluate the effect of different grass species and row spacing of gliricidia (Gliricidia sepium on the growth and biomass production of forages in an alley cropping system was conducted in two different agroclimatical zones i.e. Bogor, located at 500 m a .s .l . with an average annual rainfall of 3,112 nun/year and Sukabumi located at 900 m a .s .l . with an average annual rainfall of 1,402 mm/year . Both locations have low N, P, and K content and the soil is classified as acidic. The experimental design used was a split plot design with 3 replicates . The main plots were different grass species i.e. king grass (Pennisetum purpureum x P. typhoides and elephant grass (P. purpureum. The sub plots were the row spacing of gliricidia at 2, 3, 4, 6 m (1 hedgerows and 4 m (2 hedgerows. The results indicated that the growth and biomass production of grasses were significantly affected (P<0 .05 by the treatments in Bogor. The highest biomass productions was obtained from the 2 m row spacing which gave the highest dry matter production of grasses (1 .65 kg/hill and gliricidia (0 .086 kg/tree . In Sukabumi the growth and biomass production of grasses and gliricidia were also significantly affected by the treatments . The highest dry matter production was obtained with 2 m row spacing (dry matter of grasses and gliricidia were 1 .12 kg/hill and 0 .026 kg/tree, respectively . The result further indicated that biomass production of forages increased with the increase in gliricidia population. The alley cropping system wich is suitable for Bogor was the 2 m row spacing of gliricidia intercropped with either king or elephant grass and for Sukabumi 2 and 4 m (2 rows of gliricidia row spacing intercropped with king or elephant grass .

  11. Reproductive Strategies in Mediterranean Legumes: Trade-Offs between Phenology, Seed Size and Vigor within and between Wild and Domesticated Lupinus Species Collected along Aridity Gradients

    Science.gov (United States)

    Berger, Jens D.; Shrestha, Damber; Ludwig, Christiane

    2017-01-01

    To investigate wild and domesticated Mediterranean annual reproductive strategies, common garden comparisons of Old World lupins collected along aridity gradients were initiated. These are excellent candidates for ecophysiology, being widely distributed across contrasting environments, having distinct domestication histories, from ancient Lupinus albus to recently domesticated Lupinus angustifolius and Lupinus luteus, facilitating the study of both natural and human selection. Strong trade-offs between seed size, early vigor and phenology were observed: vigor increasing, and flowering becoming earlier with increasing seed size. Despite large specific differences in all these traits, natural and human selection have operated in very similar ways in all 3 species. In wild material, as collection environments became drier and hotter, phenology became earlier, while seed size, early vigor and reproductive investment increased. Wild and domesticated germplasm separated along similar lines. Within similar habitats, domesticated material was consistently earlier, with larger seeds, greater early vigor and higher reproductive investment than wild, suggesting selection for both early establishment and timely maturity/drought escape in both domesticated and wild low rainfall ecotypes. Species differences reflected their distribution. Small and soft-seeded, low vigor L. luteus had a late, rainfall-responsive phenology specifically adapted to long season environments, and a narrow coastal distribution. L. angustifolius was much more conservative; more hard-seeded, flowering and maturing much earlier, with a wide Mediterranean distribution. L. albus flowered earlier but matured much later, with longer reproductive phases supporting much larger seed sizes and early vigor than either L. luteus or L. angustifolius. This ruderal/competitive combination appears to give L. albus a broad adaptive capacity, reflected in its relatively wider Mediterranean/North African distribution

  12. Legume adaptation to sulfur deficiency revealed by comparing nutrient allocation and seed traits in Medicago truncatula.

    Science.gov (United States)

    Zuber, Hélène; Poignavent, Germain; Le Signor, Christine; Aimé, Delphine; Vieren, Eric; Tadla, Charlène; Lugan, Raphaël; Belghazi, Maya; Labas, Valérie; Santoni, Anne-Lise; Wipf, Daniel; Buitink, Julia; Avice, Jean-Christophe; Salon, Christophe; Gallardo, Karine

    2013-12-01

    Reductions in sulfur dioxide emissions and the use of sulfur-free mineral fertilizers are decreasing soil sulfur levels and threaten the adequate fertilization of most crops. To provide knowledge regarding legume adaptation to sulfur restriction, we subjected Medicago truncatula, a model legume species, to sulfur deficiency at various developmental stages, and compared the yield, nutrient allocation and seed traits. This comparative analysis revealed that sulfur deficiency at the mid-vegetative stage decreased yield and altered the allocation of nitrogen and carbon to seeds, leading to reduced levels of major oligosaccharides in mature seeds, whose germination was dramatically affected. In contrast, during the reproductive period, sulfur deficiency had little influence on yield and nutrient allocation, but the seeds germinated slowly and were characterized by low levels of a biotinylated protein, a putative indicator of germination vigor that has not been previously related to sulfur nutrition. Significantly, plants deprived of sulfur at an intermediary stage (flowering) adapted well by remobilizing nutrients from source organs to seeds, ensuring adequate quantities of carbon and nitrogen in seeds. This efficient remobilization of photosynthates may be explained by vacuolar sulfate efflux to maintain leaf metabolism throughout reproductive growth, as suggested by transcript and metabolite profiling. The seeds from these plants, deprived of sulfur at the floral transition, contained normal levels of major oligosaccharides but their germination was delayed, consistent with low levels of sucrose and the glycolytic enzymes required to restart seed metabolism during imbibition. Overall, our findings provide an integrative view of the legume response to sulfur deficiency.

  13. Distribution of native legumes (Leguminoseae) in frequently burned longleaf pine (Pinaceae)-wiregrass (Poaceae) ecosystems.

    Science.gov (United States)

    Hainds, M J; Mitchell, R J; Palik, B J; Boring, L R; Gjerstad, D H

    1999-11-01

    Legume species distribution and abundance and selected environmental variables were quantified across a complex gradient (varying in both water-holding capacity and fertility) for frequently burned longleaf pine (Pinus palustris)-wiregrass (Aristida stricta) ecosystems. Legumes were present in all months; however, abundance peaked in June and was minimal after killing frosts in October. Legume species were prominent in the flora (43 species encountered) ubiquitous (94% of 2-m(2) subplots had at least one legume species), and abundant (nearly 120 000 stems/ha). Although most species were widely distributed throughout the gradient, Lespedeza angustifolia was distinctly associated with the more hydric end of the gradient, while both Petalostemon pinnatum and Galactia microphylla were located in the more xeric extreme. The percentage variation in species that could be accounted for by environmental variation was low (27%). Of the variation that could be accounted for, a number of environmental variables were important, including soil moisture, pine basal area (i.e., light), and bivalent base cations (e.g., Ca(2+)). Although gradients in resource availability among sites did not affect the distribution of species or abundance of legumes strongly, variation in resources are likely to regulate N(2)-fixation rates of the various native legume species, and thereby affect ecological functions such as maintenance of N capital and productivity.

  14. Performance of organic grain legumes in Tuscany

    Directory of Open Access Journals (Sweden)

    Valentina Moschini

    2014-03-01

    Full Text Available In 2005-2007 growing season, few varieties of field bean, high protein pea and white lupin were compared in an organic farm of Central Italy (Mugello area, Tuscany, to evaluate their agronomic performance in terms of grain yield, nutritional quality and competitive ability against weeds. The experiment was performed under rain-fed conditions. Furthermore, grain legumes features were compared between two different sowing seasons (autumnal vs late-winter for two years, in order to get information on the best time of sowing of these species, and the stability of yields of different genotypes in those climatic and soil conditions. These legumes could be an alternative protein source to external soybean, a high-risk alimentary source of genetically modified organisms, in the organic livestock sector. The main findings indicate that higher yields in grain and crude protein were obtained with the pea species and in particular with cultivars Hardy (4.0 t/ha grain yield; 626 kg/ha crude protein yield and Classic (3.1 t/ha grain yield; 557 kg/ha crude protein yield; followed by field bean cv. Chiaro di Torre Lama (2.9 t/ha grain yield; 624 kg/ha crude protein yield and cv. Vesuvio (2.5 t/ha grain yield; 549 kg/ha crude protein yield. Furthermore the field bean is interesting for the stability of yield in both years despite climatic conditions rather different. The white lupin has showed the lower yield but the best values of grain quality, with higher values in lupin Multitalia for dry matter, crude protein and ether extract and in lupin Luxe also for crude fibre, respect to the other legumes analysed. Among lupin varieties, lupin Multitalia showed the best yield results for the pedo-climatic conditions of Mugello area (0.9 t/ha lupin Multitalia; 0.2 t/ha lupin Luxe. The total yield of organic grain legumes, in the experimental site, is resulted higher with an autumnal seeding respect to the late-winter seeding (2.8 t/ha vs 1.9 t/ha.

  15. CAROTENOID CLEAVAGE DIOXYGENASE 7 modulates plant growth, reproduction, senescence, and determinate nodulation in the model legume Lotus japonicas

    NARCIS (Netherlands)

    Liu, J.; Novero, M.; Charnikhova, T.; Ferrandino, A.; Schubert, A.; Ruyter-Spira, C.P.; Biofante, P.; Lovisolo, C.; Bouwmeester, H.J.

    2013-01-01

    Strigolactones (SLs) are newly identified hormones that regulate multiple aspects of plant development, infection by parasitic weeds, and mutualistic symbiosis in the roots. In this study, the role of SLs was studied for the first time in the model plant Lotus japonicus using transgenic lines silenc

  16. Comparative sequence analysis of nitrogen fixation-related genes in six legumes

    Directory of Open Access Journals (Sweden)

    Dong Hyun eKim

    2013-08-01

    Full Text Available Legumes play an important role as food and forage crops in international agriculture especially in developing countries. Legumes have a unique biological process called nitrogen fixation (NF by which they convert atmospheric nitrogen to ammonia. Although legume genomes have undergone polyploidization, duplication and divergence, NF-related genes, because of their essential functional role for legumes, might have remained conserved. To understand the relationship of divergence and evolutionary processes in legumes, this study analyzes orthologs and paralogs for selected 20 NF-related genes by using comparative genomic approaches in six legumes i.e. Medicago truncatula (Mt, Cicer arietinum, Lotus japonicus, Cajanus cajan (Cc, Phaseolus vulgaris (Pv and Glycine max (Gm. Subsequently, sequence distances, numbers of synonymous substitutions per synonymous site (Ks and nonsynonymous substitutions per nonsynonymous site (Ka between orthologs and paralogs were calculated and compared across legumes. These analyses suggest the closest relationship between Gm and Cc and the farthest distance between Mt and Pv in 6 legumes. Ks proportional plots clearly showed ancient genome duplication in all legumes, whole genome duplication event in Gm and also speciation pattern in different legumes. This study also reported some interesting observations e.g. no peak at Ks 0.4 in Gm-Gm, location of two independent genes next to each other in Mt and low Ks values for outparalogs for three genes as compared to other 12 genes. In summary, this study underlines the importance of NF-related genes and provides important insights in genome organization and evolutionary aspects of six legume species analyzed.

  17. Pseudoabsence generation strategies for species distribution models.

    Directory of Open Access Journals (Sweden)

    Brice B Hanberry

    Full Text Available BACKGROUND: Species distribution models require selection of species, study extent and spatial unit, statistical methods, variables, and assessment metrics. If absence data are not available, another important consideration is pseudoabsence generation. Different strategies for pseudoabsence generation can produce varying spatial representation of species. METHODOLOGY: We considered model outcomes from four different strategies for generating pseudoabsences. We generating pseudoabsences randomly by 1 selection from the entire study extent, 2 a two-step process of selection first from the entire study extent, followed by selection for pseudoabsences from areas with predicted probability <25%, 3 selection from plots surveyed without detection of species presence, 4 a two-step process of selection first for pseudoabsences from plots surveyed without detection of species presence, followed by selection for pseudoabsences from the areas with predicted probability <25%. We used Random Forests as our statistical method and sixteen predictor variables to model tree species with at least 150 records from Forest Inventory and Analysis surveys in the Laurentian Mixed Forest province of Minnesota. CONCLUSIONS: Pseudoabsence generation strategy completely affected the area predicted as present for species distribution models and may be one of the most influential determinants of models. All the pseudoabsence strategies produced mean AUC values of at least 0.87. More importantly than accuracy metrics, the two-step strategies over-predicted species presence, due to too much environmental distance between the pseudoabsences and recorded presences, whereas models based on random pseudoabsences under-predicted species presence, due to too little environmental distance between the pseudoabsences and recorded presences. Models using pseudoabsences from surveyed plots produced a balance between areas with high and low predicted probabilities and the strongest

  18. Phytoremediation of heavy and transition metals aided by legume-rhizobia symbiosis.

    Science.gov (United States)

    Hao, X; Taghavi, S; Xie, P; Orbach, M J; Alwathnani, H A; Rensing, C; Wei, G

    2014-01-01

    Legumes are important for nitrogen cycling in the environment and agriculture due to the ability of nitrogen fixation by rhizobia. In this review, we introduce an important and potential role of legume-rhizobia symbiosis in aiding phytoremediation of some metal contaminated soils as various legumes have been found to be the dominant plant species in metal contaminated areas. Resistant rhizobia used for phytoremediation could act on metals directly by chelation, precipitation, transformation, biosorption and accumulation. Moreover, the plant growth promoting (PGP) traits of rhizobia including nitrogen fixation, phosphorus solubilization, phytohormone synthesis, siderophore release, and production of ACC deaminase and the volatile compounds of acetoin and 2, 3-butanediol may facilitate legume growth while lessening metal toxicity. The benefits of using legumes inoculated with naturally resistant rhizobia or recombinant rhizobia with enhanced resistance, as well as co-inoculation with other plant growth promoting bacteria (PGPB) are discussed. However, the legume-rhizobia symbiosis appears to be sensitive to metals, and the effect of metal toxicity on the interaction between legumes and rhizobia is not clear. Therefore, to obtain the maximum benefits from legumes assisted by rhizobia for phytoremediation of metals, it is critical to have a good understanding of interactions between PGP traits, the symbiotic plant-rhizobia relationship and metals.

  19. Biodiversity effects of elevated CO{sub 2} in species-rich model communities from the semi-arid Negev of Israel

    Energy Technology Data Exchange (ETDEWEB)

    Grunzweig, J.M. [Weismann Inst. Sci., Dept. Environm. Sci. and Energy Res., Rehovot (Israel); Korner, C. [Univ. Basel, Inst. Bot., Basel (Switzerland)

    2002-10-01

    Species-specific responses to atmospheric CO2 enrichment may affect biodiversity, which in turn may alter ecosystem functioning. Here we have explored biodiversity effects in model assemblages of semi-arid grassland of the northern Negev, Israel, at 280 ppm (pre-industrial era), 440 ppm (early 21st century) and 600 ppm CO{sub 2} (mid to late 21st century). Thirty-two mostly annual species were grown together in large containers (ca 400 kg each) on native soil and under a dynamic simulation of the Negev winter climate, CO{sub 2} enrichment increased concentrations of total non-structural carbohydrates and C/N ratios, and reduced specific leaf area and nitrogen concentrations in leaves of all species. In contrast to these uniform CO{sub 2} effects on leaf quality. biomass and reproductive output remained unchanged in most species, and varied greatly among the few responsive ones ( - 80 to + 145%). Biomass was significantly increased at elevated CO2 in Onobrychis crista-galli (one of the six legume species) and was reduced in Biscutella didyma (Brassicaceae). Seed yield increased in three out of six legumes and in the root hemiparasite Parentucellia flaviflora. and decreased in the grass Aegilops peregrina. Fruit dry matter tended to be reduced in two Brassicaceae. Onobrychis, the largest and most responsive species present, was the most 'mesic' legume, and might have profited most from the higher soil moisture induced by CO{sub 2} enrichment. The significant CO{sub 2} response of only 5-6 out of 32 species, in particular their altered seed yield, suggests a potential shift in biodiversity. In a future CO{sub 2}-enriched atmosphere. 'mesic' legumes and root hemiparasites might be favored. while some Brassicaceae and grasses might decline. As indicated by significant 280- vs 440-ppm differences. reductions in leaf nitrogen concentration of grasses and legumes are likely to be under way right now, and may negatively affect grazers. Altered seed

  20. Finessing atlas data for species distribution models

    NARCIS (Netherlands)

    Niamir, A.; Skidmore, A.K.; Toxopeus, A.G.; Munoz, A.R.; Real, R.

    2011-01-01

    Aim The spatial resolution of species atlases and therefore resulting model predictions are often too coarse for local applications. Collecting distribution data at a finer resolution for large numbers of species requires a comprehensive sampling effort, making it impractical and expensive. This stu

  1. Finessing atlas data for species distribution models

    NARCIS (Netherlands)

    Niamir, A.; Skidmore, A.K.; Toxopeus, A.G.; Munoz, A.R.; Real, R.

    2011-01-01

    Aim The spatial resolution of species atlases and therefore resulting model predictions are often too coarse for local applications. Collecting distribution data at a finer resolution for large numbers of species requires a comprehensive sampling effort, making it impractical and expensive. This

  2. THE POSSIBILITY OF LEGUMES PRODUCTION

    Directory of Open Access Journals (Sweden)

    Glinushkin A.P.

    2013-10-01

    Full Text Available Primary receptacles improve profitability legumes are limiting demonstrations and acts of plant diseases and pests. Pathogens are 25-50% lower yield of soybean, chickpea, beans, peas. Pests focally up to 87% of viable seeds sown reduce the number of plants per 1 ha. Only effective protection against disease and estimates of crop production can increase the average profitability of legume crops by 15-30%. Livestock is very important, but in the Southern Urals requires real support for its production with a positive balance (in the calculations with a deviation of 5%. The most important resource in our opinion may be a reduction in price of fodder. Thus, legumes are sought for animal protein. Soybeans, chickpeas, beans, peas universal culture and the possibility of their use in the food balance for a healthy diet of ordinary people engaged in recreational and other sports niche expands further improve the profitability of their production. Regulation of the balance of the distribution of food and feed produced grain legumes allows fine regulation of the cost of fodder for a particular type of livestock activities. Phytosanitary capabilities , the balance of influence of legumes on arable land, also requires a fine regulation of these processes. Obtaining long-term public support for this production is unlikely in the WTO because actual search for ways to improve the profitability of production of agricultural technologies. In our view, a comprehensive approach taking into account the capacity of local markets for crop production. Such activity can act as a guaranteed quality of agro-technology and animal products from local resources specific zonal conditions of production.

  3. The First Attested Extraction of Ancient DNA in Legumes (Fabaceae).

    Science.gov (United States)

    Mikić, Aleksandar M

    2015-01-01

    Ancient DNA (aDNA) is any DNA extracted from ancient specimens, important for diverse evolutionary researches. The major obstacles in aDNA studies are mutations, contamination and fragmentation. Its studies may be crucial for crop history if integrated with human aDNA research and historical linguistics, both general and relating to agriculture. Legumes (Fabaceae) are one of the richest end economically most important plant families, not only from Neolithic onwards, since they were used as food by Neanderthals and Paleolithic modern man. The idea of extracting and analyzing legume aDNA was considered beneficial for both basic science and applied research, with an emphasis on genetic resources and plant breeding. The first reported successful and attested extraction of the legume aDNA was done from the sample of charred seeds of pea (Pisum sativum) and bitter vetch (Vicia ervilia) from Hissar, southeast Serbia, dated to 1,350-1,000 Before Christ. A modified version of cetyltrimethylammonium bromide (CTAB) method and the commercial kit for DNA extraction QIAGEN DNAesy yielded several ng μl(-1) of aDNA of both species and, after the whole genome amplification and with a fragment of nuclear ribosomal DNA gene 26S rDNA, resulted in the detection of the aDNA among the PCR products. A comparative analysis of four informative chloroplast DNA regions (trnSG, trnK, matK, and rbcL) among the modern wild and cultivated pea taxa demonstrated not only that the extracted aDNA was genuine, on the basis of mutation rate, but also that the ancient Hissar pea was most likely an early domesticated crop, related to the modern wild pea of a neighboring region. It is anticipated that this premier extraction of legume aDNA may provide taxonomists with the answers to diverse questions, such as leaf development in legumes, as well as with novel data on the single steps in domesticating legume crops worldwide.

  4. Species ages in neutral biodiversity models.

    Science.gov (United States)

    Chisholm, Ryan A; O'Dwyer, James P

    2014-05-01

    Biogeography seeks to understand the mechanisms that drive biodiversity across long temporal and large spatial scales. Theoretical models of biogeography can be tested by comparing their predictions of quantities such as species ages against empirical estimates. It has previously been claimed that the neutral theory of biodiversity and biogeography predicts species ages that are unrealistically long. Any improved theory of biodiversity must rectify this problem, but first it is necessary to quantify the problem precisely. Here we provide analytical expressions for species ages in neutral biodiversity communities. We analyse a spatially implicit metacommunity model and solve for both the zero-sum and non-zero-sum cases. We explain why our new expressions are, in the context of biodiversity, usually more appropriate than those previously imported from neutral molecular evolution. Because of the time symmetry of the spatially implicit neutral model, our expressions also lead directly to formulas for species persistence times and species lifetimes. We use our new expressions to estimate species ages of forest trees under a neutral model and find that they are about an order of magnitude shorter than those predicted previously but still unrealistically long. In light of our results, we discuss different models of biogeography that may solve the problem of species ages.

  5. Legumes are different: Leaf nitrogen, photosynthesis, and water use efficiency.

    Science.gov (United States)

    Adams, Mark Andrew; Turnbull, Tarryn L; Sprent, Janet I; Buchmann, Nina

    2016-04-12

    Using robust, pairwise comparisons and a global dataset, we show that nitrogen concentration per unit leaf mass for nitrogen-fixing plants (N2FP; mainly legumes plus some actinorhizal species) in nonagricultural ecosystems is universally greater (43-100%) than that for other plants (OP). This difference is maintained across Koppen climate zones and growth forms and strongest in the wet tropics and within deciduous angiosperms. N2FP mostly show a similar advantage over OP in nitrogen per leaf area (Narea), even in arid climates, despite diazotrophy being sensitive to drought. We also show that, for most N2FP, carbon fixation by photosynthesis (Asat) and stomatal conductance (gs) are not related to Narea-in distinct challenge to current theories that place the leaf nitrogen-Asat relationship at the center of explanations of plant fitness and competitive ability. Among N2FP, only forbs displayed an Narea-gs relationship similar to that for OP, whereas intrinsic water use efficiency (WUEi; Asat/gs) was positively related to Narea for woody N2FP. Enhanced foliar nitrogen (relative to OP) contributes strongly to other evolutionarily advantageous attributes of legumes, such as seed nitrogen and herbivore defense. These alternate explanations of clear differences in leaf N between N2FP and OP have significant implications (e.g., for global models of carbon fluxes based on relationships between leaf N and Asat). Combined, greater WUE and leaf nitrogen-in a variety of forms-enhance fitness and survival of genomes of N2FP, particularly in arid and semiarid climates.

  6. From Model to Crop: Functional Analysis of a STAY-GREEN Gene in the Model Legume Medicago truncatula and Effective Use of the Gene for Alfalfa Improvement1[W][OA

    Science.gov (United States)

    Zhou, Chuanen; Han, Lu; Pislariu, Catalina; Nakashima, Jin; Fu, Chunxiang; Jiang, Qingzhen; Quan, Li; Blancaflor, Elison B.; Tang, Yuhong; Bouton, Joseph H.; Udvardi, Michael; Xia, Guangmin; Wang, Zeng-Yu

    2011-01-01

    Medicago truncatula has been developed into a model legume. Its close relative alfalfa (Medicago sativa) is the most widely grown forage legume crop in the United States. By screening a large population of M. truncatula mutants tagged with the transposable element of tobacco (Nicotiana tabacum) cell type1 (Tnt1), we identified a mutant line (NF2089) that maintained green leaves and showed green anthers, central carpels, mature pods, and seeds during senescence. Genetic and molecular analyses revealed that the mutation was caused by Tnt1 insertion in a STAY-GREEN (MtSGR) gene. Transcript profiling analysis of the mutant showed that loss of the MtSGR function affected the expression of a large number of genes involved in different biological processes. Further analyses revealed that SGR is implicated in nodule development and senescence. MtSGR expression was detected across all nodule developmental zones and was higher in the senescence zone. The number of young nodules on the mutant roots was higher than in the wild type. Expression levels of several nodule senescence markers were reduced in the sgr mutant. Based on the MtSGR sequence, an alfalfa SGR gene (MsSGR) was cloned, and transgenic alfalfa lines were produced by RNA interference. Silencing of MsSGR led to the production of stay-green transgenic alfalfa. This beneficial trait offers the opportunity to produce premium alfalfa hay with a more greenish appearance. In addition, most of the transgenic alfalfa lines retained more than 50% of chlorophylls during senescence and had increased crude protein content. This study illustrates the effective use of knowledge gained from a model system for the genetic improvement of an important commercial crop. PMID:21957014

  7. Wide distribution range of rhizobial symbionts associated with pantropical sea-dispersed legumes.

    Science.gov (United States)

    Bamba, Masaru; Nakata, Sayuri; Aoki, Seishiro; Takayama, Koji; Núñez-Farfán, Juan; Ito, Motomi; Miya, Masaki; Kajita, Tadashi

    2016-12-01

    To understand the geographic distributions of rhizobia that associated with widely distributed wild legumes, 66 nodules obtained from 41 individuals including three sea-dispersed legumes (Vigna marina, Vigna luteola, and Canavalia rosea) distributed across the tropical and subtropical coastal regions of the world were studied. Partial sequences of 16S rRNA and nodC genes extracted from the nodules showed that only Bradyrhizobium and Sinorhizobium were associated with the pantropical legumes, and some of the symbiont strains were widely distributed over the Pacific. Horizontal gene transfer of nodulation genes were observed within the Bradyrhizobium and Sinorhizobium lineages. BLAST searches in GenBank also identified records of these strains from various legumes across the world, including crop species. However, one of the rhizobial strains was not found in GenBank, which implies the strain may have adapted to the littoral environment. Our results suggested that some rhizobia, which associate with the widespread sea-dispersed legume, distribute across a broad geographic range. By establishing symbiotic relationships with widely distributed rhizobia, the pantropical legumes may also be able to extend their range much further than other legume species.

  8. Interaction between a tannin-containing legume and endophyte-infected tall fescue seed on lambs’ feeding behavior and physiology

    Science.gov (United States)

    It was hypothesized that a tannin-rich legume like sainfoin reduces the negative post-ingestive effects of ergot alkaloids in tall fescue. Thirty-two 4-month-old lambs were individually penned and randomly assigned to a 2X2 factorial arrangement with two legume species (1-sainfoin [SAN; ' 3% condens...

  9. A Single Species Model with Impulsive Diffusion

    Institute of Scientific and Technical Information of China (English)

    Jing Hui; Lan-sun Chen

    2005-01-01

    In most models of population dynamics, diffusion between patches is assumed to be continuous or discrete, but in practice many species diffuse only during a single period. In this paper we propose a single species model with impulsive diffusion between two patches, which provides a more natural description of population dynamics. By using the discrete dynamical system generated by a monotone, concave map for the population,we prove that the map alwayshas a globally stable positive fixed point. This means that a single species system with impulsive diffusion always has a globally stable positive periodic solution. This result is further substantiated by numerical simulation. Under impulsive diffusion the single species survives in the two patches.

  10. BEHAVIOR ANALYSIS OF TREE LEGUME SPECIES INTRODUCED IN TROPICAL GRASS PASTURES ANÁLISE DO COMPORTAMENTO DE ESPÉCIES LEGUMINOSAS ARBÓREAS INTRODUZIDAS EM PASTAGENS DE GRAMÍNEAS TROPICAIS

    Directory of Open Access Journals (Sweden)

    Janaina Ribeiro Costa

    2007-09-01

    Full Text Available

    The objective of this study was to analyze the behavior of sixteen tree legume species introduced in tropical grass pastures, without seedling protection and in the presence of animals, in three municipalities of Rio de Janeiro State, Brazil. A multivariate factor analysis method was used with sixteen variables related to seven experimental units in the municipalities and ten variables related to leguminous species. The first rotative factor (F1, which explained the highest percentage of the observed variance (62.7%, showed that the Fazenda Santo Antônio experimental unit, in the Itatiaia municipality, presented the highest values for Ca+Mg, N, and Mg, and the lowest value for P (soil sample collected at the beginning of experimental period, while the opposite was observed for Sipa I unit, in the Seropédica municipality. The F1 factor also showed that the species Jurema branca (Mimosa artemisiana and Jurema preta (Mimosa tenuiflora presented the highest values for diameter growth rate of stem and crown, and the lowest percentage of pastured seedlings, while Leucena (Leucaena leucocephala showed the inverse behavior. Results indicate that M. artemisiana and M. tenuiflora present better potential for introduction in tropical grass pastures without seedling protection and without animal exclusion.

    KEY-WORDS: Tree seedling; factor analysis; communality, mimosa; Leucaena.

    O objetivo deste trabalho foi analisar o comportamento de dezesseis espécies leguminosas arbóreas introduzidas em pastagens de gramíneas tropicais, sem proteção das mudas e na presença de animais, em três municípios do estado do Rio de Janeiro. Para isso, utilizou-se a técnica multivariada da análise de fatores, considerando-se dezesseis variáveis relativas a sete unidades experimentais nos municípios e dez vari

  11. Complex interactions between a legume and two grasses in a subalpine meadow.

    Science.gov (United States)

    Marty, Charles; Pornon, André; Escaravage, Nathalie; Winterton, Peter; Lamaze, Thierry

    2009-10-01

    Interactions between plants are a complex combination of positive and negative interactions, with the net outcome depending on environmental contexts. The more frequent association of Trifolium alpinum (legume) with Festuca eskia than with Nardus stricta (grasses) in many Pyrenean subalpine meadows suggests a differential ability to use nitrogen (N) derived from N(2) fixation. In the field, we investigated the interactions between the legume and grasses and, in the glasshouse, the transfer of (15)N from the legume to the grasses. In one grass-Trifolium mixture, the legume had a strong positive effect on the biomass and N content of the grass as compared to pure grass stands. When both grasses grew together with the legume, only Festuca benefited from the presence of Trifolium but, surprisingly, the benefit decreased with increasing Trifolium abundance. Leaf labeling experiments with (15)N-NH(4)(+) revealed a higher transfer of (15)N from Trifolium to Festuca than to Nardus, suggesting a more direct N pathway between the two species. This more direct pathway could prevent Nardus from benefiting from the legume N in the three-species mixtures. Thus, the positive interactions between N-fixers and nonfixers appear to be largely species-specific and to depend strongly on the species in the plant assemblage.

  12. Legumes are valuable sources of tocopherols.

    Science.gov (United States)

    Boschin, Giovanna; Arnoldi, Anna

    2011-08-01

    Grain legumes contain numerous phytochemicals useful for their nutritional or nutraceutical properties, such as tocopherols, involved in the prevention of cardiovascular disease and eye pathologies. In this work, tocopherols were quantified in soybean, chickpea, lentil, pea, common bean, broad bean, and three lupin species. In all samples, the gamma congener was the most abundant tocopherol, followed by minor quantities of alpha-tocopherol (with the exception of common bean lacking in this congener) and delta-tocopherol (with the exception of Lupinus angustifolius and Lupinus mutabilis). Beta-tocopherol and tocotrienols were never detected. Some samples of soybean, pea, white lupin and chickpea contained over 10mg/100g seeds of total tocopherols. In order to estimate the nutritional value, the vitamin E activity was calculated. Chickpea, soybean and, to a lesser extent, lupin, broad bean and pea may contribute in a relevant way to the daily intake of this vitamin.

  13. Ensilage of tropical grasses mixed with legumes and molasses.

    Science.gov (United States)

    Tjandraatmadja, M; Norton, B W; Mac Rae, I C

    1994-01-01

    The effects of adding two legumes, Gliricidia sepium and Leucaena leucocephala, cv. Cunningham, and molasses on the fermentation characteristics of silages made from two tropical grasses (Pangola grass, Digitaria decumbens, and Setaria sphacelata cv. Kazungula) were investigated. Pangola grass silages contained significantly higher contents of water-soluble carbohydrates and lactic acid than did setaria silages after 100 days fermentation, but there were no significant differences between the two silages in populations of lactic acid bacteria and contents of total N and NH3-N. Addition of either species of legume had no significant effect on fermentation acids and NH3-N contents, and numbers of lactic acid bacteria. Addition of both legumes reduced NH3-N production in the silages by 59% after 5 days' fermentation. Numbers of lactic acid bacteria were not significantly affected by the different treatments. Enterococcus faecalis represented 60% of the lactic acid bacteria isolated from the treated herbages prior to ensiling. By 100 days of fermentation, only lactobacilli were isolated: 82% homo-fermenters and 18% hetero-fermenters. Lactobacillus mesenteroides subsp. dextranicum was found only in the silage supplemented with 33% (w/w) legume. It was concluded that the low quality of tropical grasses used as feeds for ruminants may be significantly improved by ensiling these grasses with small amounts of molasses and with high-protein tree leaves.

  14. Species Tree Inference Using a Mixture Model.

    Science.gov (United States)

    Ullah, Ikram; Parviainen, Pekka; Lagergren, Jens

    2015-09-01

    Species tree reconstruction has been a subject of substantial research due to its central role across biology and medicine. A species tree is often reconstructed using a set of gene trees or by directly using sequence data. In either of these cases, one of the main confounding phenomena is the discordance between a species tree and a gene tree due to evolutionary events such as duplications and losses. Probabilistic methods can resolve the discordance by coestimating gene trees and the species tree but this approach poses a scalability problem for larger data sets. We present MixTreEM-DLRS: A two-phase approach for reconstructing a species tree in the presence of gene duplications and losses. In the first phase, MixTreEM, a novel structural expectation maximization algorithm based on a mixture model is used to reconstruct a set of candidate species trees, given sequence data for monocopy gene families from the genomes under study. In the second phase, PrIME-DLRS, a method based on the DLRS model (Åkerborg O, Sennblad B, Arvestad L, Lagergren J. 2009. Simultaneous Bayesian gene tree reconstruction and reconciliation analysis. Proc Natl Acad Sci U S A. 106(14):5714-5719), is used for selecting the best species tree. PrIME-DLRS can handle multicopy gene families since DLRS, apart from modeling sequence evolution, models gene duplication and loss using a gene evolution model (Arvestad L, Lagergren J, Sennblad B. 2009. The gene evolution model and computing its associated probabilities. J ACM. 56(2):1-44). We evaluate MixTreEM-DLRS using synthetic and biological data, and compare its performance with a recent genome-scale species tree reconstruction method PHYLDOG (Boussau B, Szöllősi GJ, Duret L, Gouy M, Tannier E, Daubin V. 2013. Genome-scale coestimation of species and gene trees. Genome Res. 23(2):323-330) as well as with a fast parsimony-based algorithm Duptree (Wehe A, Bansal MS, Burleigh JG, Eulenstein O. 2008. Duptree: a program for large-scale phylogenetic

  15. The use of legume and herb forage species to create high performance pastures for sheep and cattle grazing systems Uso de leguminosas e forrageiras herbáceas para criar pastos de alto desempenho para sistema de pastejo de ovinos e bovinos

    Directory of Open Access Journals (Sweden)

    Peter David Kemp

    2010-07-01

    Full Text Available Sheep and cattle farmers need pastoral systems that are more productive and environmentally sustainable. The role that high feeding value herb and legume forage species can play in the farms of the future is highlighted. It is shown that species such as chicory (Cichorium intybus, plantain (Plantago lanceolata, red clover (Trifolium pratense and white clover (T.repens can provide live weight gains in lambs that are 70% greater than those from perennial ryegrass (Lolium perenne based pastures. A case for replicated experiments that examine the value of whole technology packages based on herb and legume species, rather than component research, is made.Produtores de ovinos e bovinos necessitam de sistemas pastoris mais produtivos e ambientalmente sustentáveis. As espécies forrageiras herbáceas e leguminosas de alto valor nutricional podem ter um papel destacado no futuro desses produtores. Foi demonstrado que espécies tais como a chicória (Cichorium intybus, plantago (Plantago lanceolata, trevo vermelho (Trifolium pratense e trevo-branco (T. repens podem fornecer um ganho de peso 70% maior em carneiros quando comparado com pastagens de azevém (Lolium perenne. Mais que um componente de pesquisa, este é um caso para repetidos experimentos que examinem o valor de todos os pacotes tecnológicos baseados em espécies herbáceas e leguminosas.

  16. Diversity and biogeographical patterns of legumes (Leguminosae) indigenous to southern Africa.

    Science.gov (United States)

    Trytsman, Marike; Westfall, Robert H; Breytenbach, Philippus J J; Calitz, Frikkie J; van Wyk, Abraham E

    2016-01-01

    The principal aim of this study was to establish biogeographical patterns in the legume flora of southern Africa so as to facilitate the selection of species with agricultural potential. Plant collection data from the National Herbarium, South Africa, were analysed to establish the diversity and areas covered by legumes (Leguminosae/Fabaceae) indigenous to South Africa, Lesotho and Swaziland. A total of 27,322 records from 1,619 quarter degree grid cells, representing 1,580 species, 122 genera and 24 tribes were included in the analyses. Agglomerative hierarchical clustering was applied to the presence or absence of legume species in quarter degree grid cells, the resultant natural biogeographical regions (choria) being referred to as leguminochoria. The description of the 16 uniquely formed leguminochoria focuses on defining the associated bioregions and biomes, as well as on the key climate and soil properties. Legume species with a high occurrence in a leguminochorion are listed as key species. The dominant growth form of key species, species richness and range within each leguminochorion is discussed. Floristic links between the leguminochoria are established, by examining and comparing key species common to clusters, using a vegetation classification program. Soil pH and mean annual minimum temperature were found to be the main drivers for distinguishing among legume assemblages. This is the first time that distribution data for legumes has been used to identify biogeographical areas covered by leguminochoria on the subcontinent. One potential application of the results of this study is to assist in the selection of legumes for pasture breeding and soil conservation programs, especially in arid and semi-arid environments.

  17. Breeding Food Legumes for Resistance to Storage Insect Pests: Potential and Limitations

    OpenAIRE

    2011-01-01

    Storage insect pests cause significant losses of food legumes particularly in the Tropics and the Sub-tropics. The most important species of storage insect pests of food legumes include Callosobruchus chinensis , C. maculatus , C. analis , Acanthoscelides obtectus , Bruchus incarnatus , B. rufimanus , B. dentipes , B. quinqueguttatus , B. emarginatus , B. ervi , B. lentis and B. pisorum . Effective post-harvest insect pest control measures should constitute part of the overall crop husbandry ...

  18. Grain legumes in organic cropping systems

    OpenAIRE

    Hauggaard-Nielsen, Dr. Henrik

    2002-01-01

    Grain legumes are valuable protein and energy sources in animal feeds and in human diets low in meat. Furthermore, grain legumes strongly benefit the cropping system, via biological fixation of atmospheric N2 - a fundamental process for maintaining soil fertility in organic farming systems. Other positive effects in the crop rotations are recycled N-rich crop residues and the break-crop effect in cereals-rich rotations. However, yield variability in grain legumes is well known and related to...

  19. [Genetic diversity of rhizobia isolated from shrubby and herbaceous legumes in Shenmu arid area, Shaanxi, China].

    Science.gov (United States)

    Nie, Gang; Chen, Wei-Min; Wei, Ge-Hong

    2014-06-01

    Legume, with a strong resistance to the adverse environmental conditions, is one of pioneer plants in the desert region and plays an important role in the protection of the ecological environment. In this study, the symbiosis of rhizobia associating with shrubby and herbaceous legumes in Shenmu area, Shaanxi, China was characterized by the 16S rRNA PCR-RFLP and sequence analysis of involved genes. A total of 55 strains were isolated and purified, including 30 strains from the shrubby legume Amorpha fruticosa and Caragana microphylla, and 25 strains from herbaceous plants Astragalus adsurgens, Medicago sativa and Astragalus melilotoides. Results showed that there were 11 16S rRNA genotypes. The strains isolated from herbaceous legumes belonged to five genus including Mesorhizobium, Ensifer, Rhizobium, Phyllobacterium and Agrobacterium, which were very close related to M. huakuii, M. mediterraneum, M. robiniae, E. fredii, E. meliloti, R. indigoferae, R. radiobacter, P. ifriqiyense and Ag. tumefaciens through the phylogenetic analysis. The strains isolated from shrubby legumes belonged to Mesorhizobium, and they were very close related to M. huakuii and M. mediterraneum which were shared simultaneously by shrubby and herbaceous legumes. All of these indicated the choice of rhizobia by the two types of legumes in the arid area was different, and it might depend on the species of host plant and environmental factors.

  20. Exploitation of the nutritional and functional characteristics of traditional Italian legumes: the potential of sourdough fermentation.

    Science.gov (United States)

    Curiel, José Antonio; Coda, Rossana; Centomani, Isabella; Summo, Carmine; Gobbetti, Marco; Rizzello, Carlo Giuseppe

    2015-03-02

    This study aimed at evaluating the composition of nineteen traditional Italian legumes and at investigating the potential of the sourdough fermentation with selected lactic acid bacteria to improve the nutritional and functional features. Traditional Italian legumes, all with product certifications and belonging to Phaseolus vulgaris, Cicer arietinum, Lathyrus sativus, Lens culinaris and Pisum sativum species, were used in this study. Seeds were milled, and flours were analyzed for proximate composition and subjected to sourdough fermentation at 30°C for 24h. Lactobacillus plantarum C48 and Lactobacillus brevis AM7 were used as selected starters. Compared to control doughs, without bacterial inoculum, the concentrations of free amino acids (FAA), soluble fibres, and total phenols increased for all legume sourdoughs. Raffinose decreased of up to ca. 64%. During sourdough fermentation, the level of GABA markedly increased and reached values up to 624mg/kg. Condensed tannins decreased. At the same time, almost all legume sourdoughs showed increases of the antioxidant and phytase activities. As shown by PCA analysis based on data of total FAA, GABA, raffinose, soluble/insoluble dietary fibre, condensed tannins and antioxidant and phytase activities, all legume sourdoughs were clearly differentiated from control doughs. The traditional Italian legumes are bio-diverse, and all showed high levels of nutritional elements and suitability for optimal sourdough fermentation. Legume flours subjected to sourdough fermentation would be suitable to be used alone or better in mixture with cereals, and as gluten-free ingredients for making novel and healthy foods.

  1. Avaliação de espécies leguminosas na formação de cafezais no segmento da agricultura familiar no Acre Evaluation of legume species for coffee plants formation in the segment of family farms in Acre

    Directory of Open Access Journals (Sweden)

    Celso Luis Bergo

    2006-03-01

    Full Text Available Leguminosas quando consorciadas com o café e usadas como adubação verde podem contribuir fornecendo nitrogênio e proteção ao solo pela adição de matéria orgânica. O trabalho foi conduzido com o objetivo de avaliar o efeito do uso de leguminosas no sistema de produção de café, no segmento de agricultura familiar, visando promover a implantação e a manutenção dos cafezais de forma técnica e economicamente sustentável. O experimento foi conduzido no período de novembro de 2000 a abril de 2003, em delineamento experimental de blocos ao acaso em esquema de parcelas subdivididas, com quatro repetições. Os tratamentos utilizados nas parcelas foram as leguminosas (Stizolobium atterrimum, Cajanus cajan, Canavalia endiformis e Flemingia congesta e a testemunha (sem leguminosa e, nas subparcelas, duas doses de N (0 e 22 g de N por cova. A Flemingia congesta e a Mucuna aterrima foram as leguminosas que mais influenciaram positivamente a produtividade dos cafeeiros, independente da adubação nitrogenada. Em relação à testemunha, o aumento em produção foi de 109% quando utilizou-se a Flemingia congesta e 52% com a Mucuna aterrima. A Flemingia congesta foi também a leguminosa que melhor controlou as invasoras, dado o volume de fitomassa produzida e a possibilidade de 2 cortes durante um período de doze meses, evidenciando o potencial desta leguminosa na formação de novos cafezais no Acre. Por outro lado, a Canavalia ensiformis, leguminosa que é normalmente utilizada nas entrelinhas dos cafeeiros pelos cafeicultores, do Acre e de outras regiões produtoras, neste trabalho influenciou negativamente a altura das plantas, diâmetro da copa e crescimento dos cafeeiros.Legumes, when associated with coffee crop and used as green manure can contribute with nitrogen and protect the soil by addition of organic matter. The effect of the use legume species in the coffee production system of family farms, was evaluated in order to promote

  2. Simplifying biochemical models with intermediate species

    DEFF Research Database (Denmark)

    Feliu, Elisenda; Wiuf, Carsten

    2013-01-01

    canonical model that characterizes crucial dynamical properties, such as mono- and multistationarity and stability of steady states, of all models in the class. We show that if the core model does not have conservation laws, then the introduction of intermediates does not change the steady...... techniques, we study systematically the effects of intermediate, or transient, species in biochemical systems and provide a simple, yet rigorous mathematical classification of all models obtained from a core model by including intermediates. Main examples include enzymatic and post-translational modification...... systems, where intermediates often are considered insignificant and neglected in a model, or they are not included because we are unaware of their existence. All possible models obtained from the core model are classified into a finite number of classes. Each class is defined by a mathematically simple...

  3. Applications of species distribution modeling to paleobiology

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Fløjgaard, Camilla; A. Marske, Katharine

    2011-01-01

    Species distribution modeling (SDM: statistical and/or mechanistic approaches to the assessment of range determinants and prediction of species occurrence) offers new possibilities for estimating and studying past organism distributions. SDM complements fossil and genetic evidence by providing (i...... the role of Pleistocene glacial refugia in biogeography and evolution, especially in Europe, but also in many other regions. SDM-based approaches are also beginning to contribute to a suite of other research questions, such as historical constraints on current distributions and diversity patterns, the end...

  4. Competition Experiments for Legume Infection Identify Burkholderia phymatum as a Highly Competitive β-Rhizobium

    Science.gov (United States)

    Lardi, Martina; de Campos, Samanta Bolzan; Purtschert, Gabriela; Eberl, Leo; Pessi, Gabriella

    2017-01-01

    Members of the genus Burkholderia (β-proteobacteria) have only recently been shown to be able to establish a nitrogen-fixing symbiosis with several legumes, which is why they are also referred to as β-rhizobia. Therefore, very little is known about the competitiveness of these species to nodulate different legume host plants. In this study, we tested the competitiveness of several Burkholderia type strains (B. diazotrophica, B. mimosarum, B. phymatum, B. sabiae, B. symbiotica and B. tuberum) to nodulate four legumes (Phaseolus vulgaris, Macroptilium atropurpureum, Vigna unguiculata and Mimosa pudica) under our closely defined growth conditions. The assessment of nodule occupancy of these species on different legume host plants revealed that B. phymatum was the most competitive strain in the three papilionoid legumes (bean, cowpea and siratro), while B. mimosarum outcompeted the other strains in mimosa. The analysis of phenotypes known to play a role in nodulation competitiveness (motility, exopolysaccharide production) and additional in vitro competition assays among β-rhizobial strains suggested that B. phymatum has the potential to be a very competitive legume symbiont. PMID:28861050

  5. Competition Experiments for Legume Infection Identify Burkholderia phymatum as a Highly Competitive β-Rhizobium

    Directory of Open Access Journals (Sweden)

    Martina Lardi

    2017-08-01

    Full Text Available Members of the genus Burkholderia (β-proteobacteria have only recently been shown to be able to establish a nitrogen-fixing symbiosis with several legumes, which is why they are also referred to as β-rhizobia. Therefore, very little is known about the competitiveness of these species to nodulate different legume host plants. In this study, we tested the competitiveness of several Burkholderia type strains (B. diazotrophica, B. mimosarum, B. phymatum, B. sabiae, B. symbiotica and B. tuberum to nodulate four legumes (Phaseolus vulgaris, Macroptilium atropurpureum, Vigna unguiculata and Mimosa pudica under our closely defined growth conditions. The assessment of nodule occupancy of these species on different legume host plants revealed that B. phymatum was the most competitive strain in the three papilionoid legumes (bean, cowpea and siratro, while B. mimosarum outcompeted the other strains in mimosa. The analysis of phenotypes known to play a role in nodulation competitiveness (motility, exopolysaccharide production and additional in vitro competition assays among β-rhizobial strains suggested that B. phymatum has the potential to be a very competitive legume symbiont.

  6. Utilization of summer legumes as bioenergy feedstocks

    Science.gov (United States)

    Sunn hemp (Crotolaria juncea), is a fast growing, high biomass yielding tropical legume that may be a possible southeastern bioenergy crop. When comparing this legume to a commonly grown summer legume—cowpeas (Vigna unguiculata), sunn hemp was superior in biomass yield and subsequent energy yield. S...

  7. Cycling of grain legume residue nitrogen

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1995-01-01

    Symbiotic nitrogen fixation by legumes is the main input of nitrogen in ecological agriculture. The cycling of N-15-labelled mature pea (Pisum sativum L.) residues was studied during three years in small field plots and lysimeters. The residual organic labelled N declined rapidly during the initial...... management methods in order to conserve grain legume residue N sources within the soil-plant system....

  8. A comparison of different legume seeds as protein supplement to optimise the use of low quality forages by ruminants

    DEFF Research Database (Denmark)

    Yánez-Ruiz, David R; Martin-Garcia, Antonio I; Weisbjerg, Martin Riis;

    2009-01-01

    The potential of different legume seeds species, including recently new developed varieties (Vicia faba: a commercial variety and varieties Alameda, Palacio and Baraka; Lupinus angustifolius; Pisum sativum and Cicer arietinum: varieties Fardon and Zegr ) as protein supplements to low quality...

  9. Geochemical Characterization of Copper Tailings after Legume Revegetation

    Directory of Open Access Journals (Sweden)

    Justine Perry T. Domingo

    2014-12-01

    Full Text Available Knowledge on the geochemistry of mine tailings is important in understanding the challenges in establishing vegetation cover on tailings dumps and mined out areas. In this study, the mineralogy and trace element composition of copper tailings were examined. Two legume species, Calopogonium mucunoides and Centrosema molle, were utilized to investigate the possible effects of these plants in the geochemical development of mine tailings into soil-like material. The initial mineralogical and chemical analysis of the tailings samples indicated poor conditions for plant growth—minimal levels of major nutrients and organic matter as well as elevated copper concentrations. Despite these conditions, the two legume species exhibited good growth rates. Both legumes have likewise signif icantly reduced heavy metal concentrations in the tailings, indicating the possibility of metal hyperaccumulation in the plant tissue. The mineral composition has been retained even after revegetation; nevertheless, breakdown of primary minerals and subsequent formation of clay minerals were detected. These results provide insights on the transformation of toxic materials into habitable substrates for sustained plant growth.

  10. Therapeutic Potential of Temperate Forage Legumes: A Review.

    Science.gov (United States)

    Cornara, Laura; Xiao, Jianbo; Burlando, Bruno

    2016-07-29

    The discovery of bioactive molecules from botanical sources is an expanding field, preferentially oriented to plants having a tradition of use in medicine and providing high yields and availability. Temperate forage legumes are Fabaceae species that include worldwide-important crops. These plants possess therapeutic virtues that have not only been used in veterinary and folk medicine, but have also attracted the interest of official medicine. We have examined here Medicago sativa (alfalfa), Trifolium pratense and T. repens (clovers), Melilotus albus and M. officinalis (sweet clovers), Lotus corniculatus (birdsfoot trefoil), Onobrychis viciifolia (sainfoin), Lespedeza capitata (roundhead lespedeza), and Galega officinalis (goat's rue). The phytochemical complexes of these species contain secondary metabolites whose pharmacological potentials deserve investigation. Major classes of compounds include alkaloids and amines, cyanogenic glycosides, flavonoids, coumarins, condensed tannins, and saponins. Some of these phytochemicals have been related to antihypercholesterolemia, antidiabetic, antimenopause, anti-inflammatory, antiedema, anthelmintic, and kidney protective effects. Two widely prescribed drugs have been developed starting from temperate forage legumes, namely, the antithrombotic warfarin, inspired from sweet clover's coumarin, and the antidiabetic metformin, a derivative of sainfoin's guanidine. Available evidence suggests that temperate forage legumes are a potentially important resource for the extraction of active principles to be used as nutraceuticals and pharmaceuticals.

  11. Soil macrofauna in wooded pasture with legume trees

    Directory of Open Access Journals (Sweden)

    Lusimar Lamarte Gonzaga Galindo da Silva

    2015-07-01

    Full Text Available Grasslands afforestation aims at adding different soil uses in a way they become profitable for their owners. As such handling aims at minimizing impacts, the current study had as its goal the use of soil macrofauna in order to evaluate legume afforestation effects on the soil, regardless the depth. Thus, nitrogen fixing species were inserted onto grassland areas and the macrofauna collection was performed 6 years after their planting in the 0-10cm, 10-20cm and 20.30cm layers, in winter and summer. Leguminous influence was different between depths and times of the year. It mostly favors communities under "Mimosa" Genus treetops. Besides, the effects from climatic seasonal variations on invertebrates were mitigated by the implementation of such legume trees

  12. Symbiosis within Symbiosis: Evolving Nitrogen-Fixing Legume Symbionts.

    Science.gov (United States)

    Remigi, Philippe; Zhu, Jun; Young, J Peter W; Masson-Boivin, Catherine

    2016-01-01

    Bacterial accessory genes are genomic symbionts with an evolutionary history and future that is different from that of their hosts. Packages of accessory genes move from strain to strain and confer important adaptations, such as interaction with eukaryotes. The ability to fix nitrogen with legumes is a remarkable example of a complex trait spread by horizontal transfer of a few key symbiotic genes, converting soil bacteria into legume symbionts. Rhizobia belong to hundreds of species restricted to a dozen genera of the Alphaproteobacteria and Betaproteobacteria, suggesting infrequent successful transfer between genera but frequent successful transfer within genera. Here we review the genetic and environmental conditions and selective forces that have shaped evolution of this complex symbiotic trait. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Cooking Has Variable Effects on the Fermentability in the Large Intestine of the Fraction of Meats, Grain Legumes, and Insects That Is Resistant to Digestion in the Small Intestine in an in Vitro Model of the Pig's Gastrointestinal Tract.

    Science.gov (United States)

    Poelaert, Christine; Despret, Xavier; Sindic, Marianne; Beckers, Yves; Francis, Frédéric; Portetelle, Daniel; Soyeurt, Hélène; Théwis, André; Bindelle, Jérôme

    2017-01-18

    This study aimed to evaluate the fermentation in the large intestine of indigestible dietary protein sources from animal, insect, and plant origin using an in vitro model of the pig's gastrointestinal tract. Protein sources were used raw and after a cooking treatment. Results showed that the category of the ingredient (meats, insects, or grain legumes) exerts a stronger impact on enzymatic digestibility, fermentation patterns, and bacterial metabolites such as short-chain fatty acids (SCFA) and hydrogen sulfide (H2S) than the cooking treatment. The digestibility and the fermentation characteristics of insects were more affected by the cooking procedure than the other categories. Per gram of consumed food, ingredients from animal origin, namely, meats and insects, were associated with fewer fermentation end-products (gas, H2S, SCFA) than ingredients from plant origin, which is related to their higher small intestinal digestibility.

  14. Evaluation of nutritional value some forage species available in Iran ...

    African Journals Online (AJOL)

    Novin

    2012-07-17

    Jul 17, 2012 ... between gas production parameters and CP content of forage species. The study shows that these ..... Legume, grass and legume-grass mixture quality standards. Quality standard1 ..... Temperature effects on anatomy and ...

  15. How can model comparison help improving species distribution models?

    Science.gov (United States)

    Gritti, Emmanuel Stephan; Gaucherel, Cédric; Crespo-Perez, Maria-Veronica; Chuine, Isabelle

    2013-01-01

    Today, more than ever, robust projections of potential species range shifts are needed to anticipate and mitigate the impacts of climate change on biodiversity and ecosystem services. Such projections are so far provided almost exclusively by correlative species distribution models (correlative SDMs). However, concerns regarding the reliability of their predictive power are growing and several authors call for the development of process-based SDMs. Still, each of these methods presents strengths and weakness which have to be estimated if they are to be reliably used by decision makers. In this study we compare projections of three different SDMs (STASH, LPJ and PHENOFIT) that lie in the continuum between correlative models and process-based models for the current distribution of three major European tree species, Fagussylvatica L., Quercusrobur L. and Pinussylvestris L. We compare the consistency of the model simulations using an innovative comparison map profile method, integrating local and multi-scale comparisons. The three models simulate relatively accurately the current distribution of the three species. The process-based model performs almost as well as the correlative model, although parameters of the former are not fitted to the observed species distributions. According to our simulations, species range limits are triggered, at the European scale, by establishment and survival through processes primarily related to phenology and resistance to abiotic stress rather than to growth efficiency. The accuracy of projections of the hybrid and process-based model could however be improved by integrating a more realistic representation of the species resistance to water stress for instance, advocating for pursuing efforts to understand and formulate explicitly the impact of climatic conditions and variations on these processes.

  16. Improvement of native grassland by legumes introduction and tillage techniques

    OpenAIRE

    Syamsu Bahar; S. Hardjosoewignjo; I Kismono; O Haridjaja

    1999-01-01

    A factorial design using three species of legumes (Siratro, Centro and Stylo) and three different of tillage techniques (no-tillage, minimum tillage and total tillage) was applied in this experiment. The results showed that there was no interaction between species and tillage techniques. There was significant reductions on bulk density from 1.23±0.03 g/cm3 (no-tillage) to 1.07±0.02 g/cm3 (minimum tillage) and 1.05±0.03 g/cm3 (total tillage). Also reductions on penetration resistance from 17.4...

  17. The first attested extraction of ancient DNA in legumes (Fabaceae

    Directory of Open Access Journals (Sweden)

    Aleksandar M. Mikić

    2015-11-01

    Full Text Available Ancient DNA (aDNA is any DNA extracted from ancient specimens, important for diverse evolutionary researches. The major obstacles in aDNA studies are mutations, contamination and fragmentation. Its studies may be crucial for crop history if integrated with human aDNA research and historical linguistics, both general and relating to agriculture. Legumes (Fabaceae are one of the richest end economically most important plant families, not only from Neolithic onwards, since they were used as food by Neanderthals and Paleolithic modern man. The idea of extracting and analysing legume aDNA was considered beneficial for both basic science and applied research, with an emphasis on genetic resources and plant breeding. The first reported successful and attested extraction of the legume aDNA was done from the sample of charred seeds of pea (Pisum sativum and bitter vetch (Vicia ervilia from Hissar, southeast Serbia, dated to 1,350 - 1,000 Before Christ. A modified version of cetyltrimethylammonium bromide (CTAB method and the commercial kit for DNA extraction QIAGEN DNAesy yielded several ng μl-1 of aDNA of both species and, after the whole genome amplification and with a fragment of nuclear ribosomal DNA gene 26S rDNA, resulted in the detection of the aDNA among the PCR products. A comparative analysis of four informative chloroplast DNA regions (trnSG, trnK, matK and rbcL among the modern wild and cultivated pea taxa demonstrated not only that the extracted aDNA was genuine, on the basis of mutation rate, but also that the ancient Hissar pea was most likely an early domesticated crop, related to the modern wild pea of a neighbouring region. It is anticipated that this premier extraction of legume aDNA may provide taxonomists with the answers to diverse questions, such as leaf development in legumes, as well as with novel data on the single steps in domesticating legume crops worldwide.

  18. NUTRITIONAL AND HEALTH IMPLICATIONS OF LEGUMES

    Directory of Open Access Journals (Sweden)

    Mebrahtom Gebrelibanos*, Dinka Tesfaye, Y. Raghavendra and Biruk Sintayeyu

    2013-04-01

    Full Text Available ABSTRACT: Legumes are plants in the family Fabaceae characterized by seeds in pods that are often edible though sometimes poisonous. The nutrient content (protein, carbohydrate and micronutrients of legumes contribute to address under-nutrition, especially protein-calorie malnutrition among children and nursing mothers in developing countries where supplementing cereal-based diets with legumes is suggested as one of the best solutions to protein calorie malnutrition. Anti-nutritional factors, in legumes, may limit their biological value and acceptance as a regular food item, yet they are readily removable and recent research has shown potential health benefits of some of these compounds; and hence, manipulation of processing conditions may be required to remove or reduce only those unwanted components. Moreover, legumes play a role in prevention, improvement and/or treatment of disease conditions such as, diabetes mellitus, cardiovascular diseases, cancer diseases (e.g breast and prostate cancers and lowers blood cholesterol level. Most of these disease conditions are associated with over-nutrition and obesity and are considered as diseases of the rich. It is, therefore, claimed that including legumes in a health-promoting diet is important in meeting the major dietary recommendations to improve the nutritional status of undernourished as well as over-nourished individuals, and to reduce risk of chronic diseases such as cardiovascular disease, diabetes mellitus and cancer. In this review, some of the scientific viewpoints that attempt to justify the nutritional contributions, anti-nutritional considerations and health implications of legumes are discussed.

  19. Impact of thermal processing on legume allergens.

    Science.gov (United States)

    Verma, Alok Kumar; Kumar, Sandeep; Das, Mukul; Dwivedi, Premendra D

    2012-12-01

    Food induced allergic manifestations are reported from several parts of the world. Food proteins exert their allergenic potential by absorption through the gastrointestinal tract and can even induce life threatening anaphylaxis reactions. Among all food allergens, legume allergens play an important role in induction of allergy because legumes are a major source of protein for vegetarians. Most of the legumes are cooked either by boiling, roasting or frying before consumption, which can be considered a form of thermal treatment. Thermal processing may also include autoclaving, microwave heating, blanching, pasteurization, canning, or steaming. Thermal processing of legumes may reduce, eliminate or enhance the allergenic potential of a respective legume. In most of the cases, minimization of allergenic potential on thermal treatment has generally been reported. Thus, thermal processing can be considered an important tool by indirectly prevent allergenicity in susceptible individuals, thereby reducing treatment costs and reducing industry/office/school absence in case of working population/school going children. The present review attempts to explore various possibilities of reducing or eliminating allergenicity of leguminous food using different methods of thermal processing. Further, this review summarizes different methods of food processing, major legumes and their predominant allergenic proteins, thermal treatment and its relation with antigenicity, effect of thermal processing on legume allergens; also suggests a path that may be taken for future research to reduce the allergenicity using conventional/nonconventional methods.

  20. Highly productive forage legume stands show no positive biodiversity effect on yield and N2-fixation

    DEFF Research Database (Denmark)

    Dhamala, Nawa Raj; Eriksen, Jørgen; Carlsson, Georg

    2017-01-01

    derived most (around 85%) of their N from atmospheric N fixation (%Ndfa). However, no positive effect of species diversity was found in any of the mixtures. Species composition of the forage legume mixtures affected the amount of N from N fixation by affecting DM production and N accumulation...

  1. [Genetic diversity of rhizobia isolated from common legumes in the Karst area. Northwest Guangxi].

    Science.gov (United States)

    Liu, Lu; He, Xun-yang; Xie, Qiang; Wang, Ke-lin

    2015-12-01

    Legumes, with a strong resistance to the adverse environmental conditions, are pioneer plants in degraded habitats, and play an important role in ecosystem restoration. In this study, the nodulation characteristics of 24 legumes were surveyed in the Karst area of Northwest Guangxi. A total of 39 nodule samples were collected from 15 legumes, the DNA was extracted and the 16S rDNA and nifH gene were amplified. A phylogenetic tree was then constructed to analyze the genetic diversity of rhizobia. The results showed that 15 legumes were nodulated, of which 14 belonged to the Papilionoideae, one to the Mimosaceae, and none to the Caesalpinoideae. No nodules were found on some legumes that were reported as nodulated, which might result from soil water stress in Karst. BLAST result and phylogenetic analyse indicated that most of the legumes were associated with rhizobia that belonged to the genus Bradyrhizobium, with the exception of two samples from Callerya nitida that were associated with the genus Mesorhizobium. In the phylogenetic tree, the sequences obtained from the same plot or the sequences from the same host species clustered together in most cases. This finding suggested that host selection and the ecological environment are the major factors that influence the genotype of rhizobia.

  2. Unveiling common responses of Medicago truncatula to appropriate and inappropriate rust species

    Directory of Open Access Journals (Sweden)

    Maria Carlota eVaz Patto

    2014-11-01

    Full Text Available Little is known about the nature of effective defense mechanisms in legumes to pathogens of remotely related plant species. Some rust species are among pathogens with broad host range causing dramatic losses in various crop plants. To understand and compare the different host and nonhost resistance responses of legume species against rusts, we characterized the reaction of the model legume Medicago truncatula to one appropriate (Uromyces striatus and two inappropriate (U. viciae-fabae and U. lupinicolus rusts. We found that similar pre and post-haustorial mechanisms of resistance appear to be operative in M. truncatula against appropriate and inappropriate rust fungus. The appropriate U. striatus germinated better on M. truncatula accessions then the inappropriate U. viciae-fabae and U. lupinicolus, but once germinated, germ tubes of the three rusts had a similar level of success in finding stomata and forming an appressoria over a stoma. However responses to different inappropriate rust species also showed some specificity, suggesting a combination of non specific and specific responses underlying this legume nonhost resistance to rust fungi. Further genetic and expression analysis studies will contribute to the development of the necessary molecular tools to use the present information on host and nonhost resistance mechanisms to breed for broad-spectrum resistance to rust in legume species.

  3. Compound leaf development in model plant species.

    Science.gov (United States)

    Bar, Maya; Ori, Naomi

    2015-02-01

    Plant leaves develop in accordance with a common basic program, which is flexibly adjusted to the species, developmental stage and environment. Two key stages of leaf development are morphogenesis and differentiation. In the case of compound leaves, the morphogenesis stage is prolonged as compared to simple leaves, allowing for the initiation of leaflets. Here, we review recent advances in the understanding of how plant hormones and transcriptional regulators modulate compound leaf development, yielding a substantial diversity of leaf forms, focusing on four model compound leaf organisms: cardamine (Cardamine hirsuta), tomato (Solanum lycopersicum), medicago (Medicago truncatula) and pea (Pisum sativum).

  4. Beneficial Effects of Temperate Forage Legumes that Contain Condensed Tannins

    Directory of Open Access Journals (Sweden)

    Jennifer W. MacAdam

    2015-07-01

    Full Text Available The two temperate forage legumes containing condensed tannins (CT that promote ruminant production are birdsfoot trefoil (Lotus corniculatus L.; BFT and sainfoin (Onobrychis viciifolia Scop.; SF. Both are well-adapted to the cool-temperate climate and alkaline soils of the Mountain West USA. Condensed tannins comprise a diverse family of bioactive chemicals with multiple beneficial functions for ruminants, including suppression of internal parasites and enteric methane. Birdsfoot trefoil contains 10 to 40 g·CT·kg−1 dry matter (DM, while SF contains 30 to 80 g·CT·kg−1 DM. Our studies have focused on these two plant species and have demonstrated consistently elevated rates of gain for beef calves grazing both BFT and SF. Novel results from our BFT research include carcass dressing percentages and consumer sensory evaluations equivalent to feedlot-finished steers and significantly greater than grass-finished steers, but with omega-3 fatty acid concentrations equal to grass-finished beef. We have further demonstrated that ruminants fed BFT or SF will consume more endophyte-infected tall fescue (Schedonorus arundinaceus (Schreb. Dumort. forage or seed than ruminants fed a non-CT forage legume. There is great potential value for sustainable livestock production in the use of highly digestible, nitrogen-fixing legumes containing tannins demonstrated to improve ruminant productivity.

  5. Conditions Affecting Shelf-Life of Inoculated Legume Seed

    Directory of Open Access Journals (Sweden)

    Greg Gemell

    2012-02-01

    Full Text Available Microbial inoculants are becoming more available as sustainable alternatives to fertilizers and other agrichemicals in broad-acre cropping. However, with the exception of legume inoculants little is understood about effective delivery and survival of the inoculum. Legume inoculants are applied to both seed and soil but seed inoculation is the most economical technique. Large quantities of pasture seed in Australia are inoculated by commercial seed coating companies, but the long-term survival of seed-applied inoculum is variable and monitoring of viability requires specialist microbiology skills and facilities. The aim of our research was to define optimum storage conditions for survival of rhizobia on legume seed and evaluate water activity as a means of monitoring shelf-life. The relationship between survival and water activity varied according to seed species, inoculum preparation, coating ingredients, initial water activity and time suggesting that storage conditions would need to be defined for each different combination. Although drying seeds after coating significantly reduced viable numbers of rhizobia, survival of rhizobia on dried commercially coated lucerne seed after 11 weeks was less variable than seeds that had not been dried. The highest numbers were maintained when seeds remained dry with water activities of between 0.47 and 0.38. The quality of inoculated seed could be improved by reducing the death rate of inoculum during preparation and providing optimum storage conditions for long-term survival.

  6. Molecular phylogeny and evolution of alcohol dehydrogenase (Adh genes in legumes

    Directory of Open Access Journals (Sweden)

    Ochiai Toshinori

    2005-04-01

    Full Text Available Abstract Background Nuclear genes determine the vast range of phenotypes that are responsible for the adaptive abilities of organisms in nature. Nevertheless, the evolutionary processes that generate the structures and functions of nuclear genes are only now be coming understood. The aim of our study is to isolate the alcohol dehydrogenase (Adh genes in two distantly related legumes, and use these sequences to examine the molecular evolutionary history of this nuclear gene. Results We isolated the expressed Adh genes from two species of legumes, Sophora flavescens Ait. and Wisteria floribunda DC., by a RT-PCR based approach and found a new Adh locus in addition to homologues of the Adh genes found previously in legumes. To examine the evolution of these genes, we compared the species and gene trees and found gene duplication of the Adh loci in the legumes occurred as an ancient event. Conclusion This is the first report revealing that some legume species have at least two Adh gene loci belonging to separate clades. Phylogenetic analyses suggest that these genes resulted from relatively ancient duplication events.

  7. Molecular phylogeny and evolution of alcohol dehydrogenase (Adh) genes in legumes

    Science.gov (United States)

    Fukuda, Tatsuya; Yokoyama, Jun; Nakamura, Toru; Song, In-Ja; Ito, Takuro; Ochiai, Toshinori; Kanno, Akira; Kameya, Toshiaki; Maki, Masayuki

    2005-01-01

    Background Nuclear genes determine the vast range of phenotypes that are responsible for the adaptive abilities of organisms in nature. Nevertheless, the evolutionary processes that generate the structures and functions of nuclear genes are only now be coming understood. The aim of our study is to isolate the alcohol dehydrogenase (Adh) genes in two distantly related legumes, and use these sequences to examine the molecular evolutionary history of this nuclear gene. Results We isolated the expressed Adh genes from two species of legumes, Sophora flavescens Ait. and Wisteria floribunda DC., by a RT-PCR based approach and found a new Adh locus in addition to homologues of the Adh genes found previously in legumes. To examine the evolution of these genes, we compared the species and gene trees and found gene duplication of the Adh loci in the legumes occurred as an ancient event. Conclusion This is the first report revealing that some legume species have at least two Adh gene loci belonging to separate clades. Phylogenetic analyses suggest that these genes resulted from relatively ancient duplication events. PMID:15836788

  8. Molecular mechanisms controlling legume autoregulation of nodulation

    National Research Council Canada - National Science Library

    Dugald E. Reid; Brett J. Ferguson; Satomi Hayashi; Yu-Hsiang Lin; Peter M. Gresshoff

    2011-01-01

    .... • Scope Understanding how legume plants maintain control of nodulation to balance the nitrogen gains with their energy needs and developmental costs will assist in increasing their productivity and relative advantage...

  9. Biological Potential of Sixteen Legumes in China

    Directory of Open Access Journals (Sweden)

    Guixing Ren

    2011-10-01

    Full Text Available Phenolic acids have been identified in a variety of legumes including lima bean, broad bean, common bean, pea, jack bean, goa bean, adzuki bean, hyacinth bean, chicking vetch, garbanzo bean, dral, cow bean, rice bean, mung bean and soybean. The present study was carried out with the following aims: (1 to identify and quantify the individual phenolic acid and determine the total phenolic content (TPC; (2 to assess their antioxidant activity, inhibition activities of α-glucosidase, tyrosinase, and formation of advanced glycation endproducts; and (3 to investigate correlations among the phytochemicals and biological activity. Common bean possesses the highest antioxidant activity and advanced glycation endproducts formation inhibition activity. Adzuki bean has the highest α-glucosidase inhibition activity, and mung bean has the highest tyrosinase inhibition activity. There are significant differences in phytochemical content and functional activities among the bean species investigated. Selecting beans can help treat diseases such as dermatological hyperpigmentation illness, type 2 diabetes and associated cardiovascular diseases.

  10. Pollen structure and function in caesalpinioid legumes.

    Science.gov (United States)

    Banks, Hannah; Rudall, Paula J

    2016-03-01

    A diverse range of pollen morphologies occurs within the large, paraphyletic legume subfamily Caesalpinioideae, especially among early-branching lineages. Previous studies have hypothesized an association between surface ornamentation and pollination syndrome or other aspects of pollen function such as desiccation tolerance and adaptations to accommodate volume changes. We reviewed caesalpinioid pollen morphology using light microscopy, scanning and transmission electron microscopy, in combination with a literature survey of pollination vectors. Pollen structural diversity is greatest in the early-branching tribes Cercideae and Detarieae, whereas Cassieae and Caesalpinieae are relatively low in pollen diversity. Functional structures to counter desiccation include opercula (lids) covering apertures and reduced aperture size. Structures preventing wall rupture during dehydration and rehydration include different forms of colpi (syncolpi, parasyncolpi, pseudocolpi), striate supratectal ornamentation, and columellate or granular wall structures that resist tensile or compressive forces respectively. Specialized aperture structures (Zwischenkörper) may be advantageous for efficient germination of the pollen tube. In Detarieae and Cercideae in particular, there is potential to utilize pollen characters to estimate pollination systems where these are unknown. Supratectal verrucae and gemmae have apparently evolved iteratively in Cercideae and Detarieae. At the species level, there is a potential correlation between striate/verrucate patterns and vertebrate pollination. © 2016 Botanical Society of America.

  11. Production of resistant starch by enzymatic debranching in legume flours.

    Science.gov (United States)

    Morales-Medina, Rocío; Del Mar Muñío, María; Guadix, Emilia M; Guadix, Antonio

    2014-01-30

    Resistant starch (RS) was produced by enzymatic hydrolysis of flours from five different legumes: lentil, chickpea, faba bean, kidney bean and red kidney bean. Each legume was firstly treated thermally, then hydrolyzed with pullulanase for 24h at 50°C and pH 5 and lyophilized. At the end of each hydrolysis reaction, the RS amount ranged from 4.7% for red kidney beans to 7.5% for chickpeas. With respect to the curves of RS against hydrolysis time, a linear increase was observed initially and a plateau was generally achieved by the end of reaction. These curves were successfully modeled by a kinetic equation including three parameters: initial RS, RS at long operation time and a kinetic constant (k). Furthermore, the relative increase in hydrolysis, calculated using the kinetic parameters, was successfully correlated to the percentage of amylose.

  12. Nutrient and nonnutrient components of legumes, and its chemopreventive activity: a review.

    Science.gov (United States)

    Sánchez-Chino, Xariss; Jiménez-Martínez, Cristian; Dávila-Ortiz, Gloria; Álvarez-González, Isela; Madrigal-Bujaidar, Eduardo

    2015-01-01

    Legumes in combination with other products are the staple food for a large part of the world population, especially the low-income fragment, because their seeds provide valuable amounts of carbohydrates, fiber, and proteins, and have an important composition of essential amino acids, the sulphured amino acids being the limiting ones. Furthermore, legumes also have nonnutritional compounds that may decrease the absorption of nutrients or produce toxic effects; however, it has been reported that depending on the dose, these nonnutritional compounds also have different bioactivities as antioxidant, hypolipidemic, hypoglycemic, and anticarcinogenic agents, which have been proven in scientific studies. It has been observed that in countries with a high consumption of legumes, the incidence of colorectal cancer is lower. Some studies have shown that legume seeds are an alternative chemopreventive therapy against various cancers especially colon; this was verified in various animal models of induced by azoxymethane, a colon specific carcinogenic compound, in which a diet was supplemented with different concentrations of beans, lentils, chickpeas, or soybeans, mostly. These studies have proven the anticancer activity of legumes in early stages of carcinogenesis. Therefore, it is important to review the information available to elucidate the chemopreventive mechanisms of action of legume compounds.

  13. Improving species distribution models: the value of data on abundance

    National Research Council Canada - National Science Library

    Howard, Christine; Stephens, Philip A; Pearce‐Higgins, James W; Gregory, Richard D; Willis, Stephen G; McPherson, Jana

    2014-01-01

    Species distribution models (SDMs) are important tools for forecasting the potential impacts of future environmental changes but debate remains over the most robust modelling approaches for making projections...

  14. Impact of rhizobial populations and their host legumes on microbial activity in soils of arid regions in Tunisia

    Energy Technology Data Exchange (ETDEWEB)

    Fterich, A.; Mahdhi, M.; Mars, M.

    2009-07-01

    Nitrogen fixing legumes and their microsymbionts are a fundamental contributor to soil fertility and prevent their degradation in arid and semi arid ecosystems. In Tunisia, few data are available on the contribution of these legumes in microbial activity in the arid soil. In this objective, a study was undertaken on five leguminous species from different arid regions to evaluate their ability to regenerate microbiological processes of the soil: Genista saharea, Genista microcephala, Acacia tortilis sspr raddiana, Retama raetam and Prosopis stephaniana. (Author)

  15. Redox Changes during the Legume-Rhizobium Symbiosis

    Institute of Scientific and Technical Information of China (English)

    Christine Chang; Isabelle Damiani; Alain Puppo; Pierre Frendol

    2009-01-01

    Reactive Oxygen Species (ROS) are continuously produced as a result of aerobic metabolism or in response to biotic and abiotic stresses.ROS are not only toxic by-products of aerobic metabolism,but are also signaling molecules involved in plant growth and environmental adaptation.Antioxidants can protect the cell from oxidative damage by scav-enging the ROS.Thus,they play an important role in optimizing cell function by regulating cellular redox state and mod-ifying gene expression.This article aims to review recent studies highlighting the role of redox signals in establishing and maintaining symbiosis between rhizobia and legumes.

  16. Legume Diversity Patterns in West Central Africa

    NARCIS (Netherlands)

    Estrella, de la M.; Mateo, M.A.; Wieringa, J.J.; Mackinder, B.; Munoz, J.

    2012-01-01

    Objectives - Species Distribution Models (SDMs) are used to produce predictions of potential Leguminosae diversity in West Central Africa. Those predictions are evaluated subsequently using expert opinion. The established methodology of combining all SDMs is refined to assess species diversity withi

  17. Solubilisation of inorganic phosphates by inoculant strains from tropical legumes

    Directory of Open Access Journals (Sweden)

    Leandro Marciano Marra

    2011-10-01

    Full Text Available Microbial solubilisation of low soluble inorganic phosphates is an important process contributing for the phosphorus available to plants in tropical soils. This study evaluates the ability of inoculant strains for tropical legumes to solubilise inorganic phosphates of low solubility that are found in tropical soils. Seven strains of Leguminosae nodulating bacteria (LNB were compared with one another and with a non-nodulating positive control, Burkholderia cepacia (LMG 1222T. Four of the strains are used as inoculants for cowpeas (Vigna unguiculata (Bradyrhizobium sp. UFLA 03-84; Bradyrhizobium elkani INPA 03-11B and Bradyrhizobium japonicum BR3267 or for common beans (Phaseolus vulgaris (Rhizobium tropici CIAT 899T. Rhizobium etli UFLA 02-100 and Rhizobium leguminosarum 316C10a are also efficient nodulators of beans and Cupriavidus taiwanensis LMG 19424T nodulates on Mimosa pudica. Two experiments, with solid and liquid media, were performed to determine whether the strains were able to solubilise CaHPO4, Al(H2PO43 or FePO4.2H2O. On solid GELP medium none of the strains dissolved FePO4.2H2O, but LMG 1222, UFLA 03-84 and CIAT 899 solubilised CaHPO4 particularly well. These strains, along with LMG 19424 and BR 3267, were also able to increase the solubility of Al(H2PO43. In liquid GELP medium, LMG 1222 solubilised all phosphate sources, but no legume nodulating strain could increase the solubility of Al(H2PO43. The strains CIAT 899 and UFLA 02-100 were the only legume nodulating bacteria able to solubilise the other phosphate sources in liquid media, dissolving both CaHPO4 and FePO4.2H2O. There was a negative correlation between the pH of the culture medium and the concentration of soluble phosphate when the phosphorus source was CaHPO4 or FePO4.2H2O. The contribution of these strains to increasing the phosphorus nutrition of legumes and non-legume plant species should be investigated further by in vivo experiments.

  18. Effects of Plant Age and Rock Phosphate on Quality and Nutrient Release of Legume Residue

    Institute of Scientific and Technical Information of China (English)

    I. ABARCHI; ZHANG Zhan-Yu; B. VANLAUWE; GUO Xiang-Ping; WANG Wei-Mu; B. T. I. ONG'OR; D. TIMBELY

    2009-01-01

    An incubation experiment was carried out on plateau and slope fields to investigate the effect of plant age and rock phosphate (RP) on the organic resource (OR) quality and available N and P release of the legume residues, including standing biomass and surface litter. The legumes, Mueuna pruriens (L.) and Lablab purpureus (L.), were treated with or without Togn rock phosphate (RP) and were sampled at 12, 18, 24 and 30 weeks after planting. Results showed that the application of RP significantly affected the P content of the legume residues on the plateau field for the first 18 weeks, but not the other OR quality parameters, nor their N mineralization, or P release parameters. Although application of RPled to higher P contents in both legumes on the plateau field, the P contents were still far below those observed on the slope field. For both species, the biomass age appeared to have a major impact on their N, P, and polyphenol contents, but not on the lignin content. At 24 weeks, both legume N and P contents dropped to about half their values at 12 weeks of age. Residue age also significantly affected N mineralization both with and without RP addition and the net Olsen-P with RP addition. The younger residues generally led to higher N mineralization and net Olsen-P content than the older residues. The best immediate responses to herbaceous legume addition were expected from younger materials, but often at the cost of the total biomass produced and the possibility to produce seeds. The production of seeds, however, could be potentially implemented on a small area of legumes, thus invariably allowing for maturity and seed production.

  19. Influence of legume crops on content of organic carbon in sandy soil

    Directory of Open Access Journals (Sweden)

    Hajduk Edmund

    2015-06-01

    Full Text Available The paper presents the results of a 3-year field experiment designed to evaluate the content of organic carbon in brown soil (Haplic Cambisol Dystric developed from a light loamy sand under legumes cultivation. Experimental factors were: species of legume crop (colorful-blooming pea (Pisum sativum, chickling vetch (Lathyrus sativus, narrow-leafed lupin (Lupinus angustifolius, methods of legumes tillage (legumes in pure culture and in mixture with naked oats and mineral N fertilization (0, 30, 60, 90 kg N·ha−1. Cultivation of legumes on sandy soil did not result in an increase of organic carbon content in the soil after harvest as compared to the initial situation, i.e. 7.39 vs. 7.76 g·kg−1 dry matter (DM, on average, respectively. However, there was the beneficial effect of this group of plants on soil abundance in organic matter, the manifestation of which was higher content of organic carbon in soils after legume harvest as compared to soils with oats grown (7.21 g·kg−1 DM, on average. Among experimental crops, cultivation of pea exerted the most positive action to organic carbon content (7.58 g·kg−1, after harvest, on average, whereas narrow-leaved lupin had the least effect on organic carbon content (7.23 g·kg−1, on average. Pure culture and greater intensity of legume cultivation associated with the use of higher doses of mineral nitrogen caused less reduction in organic carbon content in soils after harvest.

  20. Legumes mitigate ecological consequences of a topographic gradient in a northern Mongolian steppe.

    Science.gov (United States)

    Casper, Brenda B; Goldman, Robert; Lkhagva, Ariuntsetseg; Helliker, Brent R; Plante, Alain F; Spence, Laura A; Liancourt, Pierre; Boldgiv, Bazartseren; Petraitis, Peter S

    2012-05-01

    Topography should create spatial variation in water and nutrients and play an especially important role in the ecology of water-limited systems. We use stable isotopes to discern how plants respond both to ecological gradients associated with elevation and to neighboring legumes on a south-facing slope in the semi-arid, historically grazed steppe of northern Mongolia. Out of three target species, Potentilla acaulis, Potentilla sericea, and Festuca lenensis, when >30 cm from a legume, all showed a decrease in leaf δ(15)N with increasing elevation. This, together with measures of soil δ(15)N, suggests greater N processing at the moister, more productive, lower elevation, and more N fixation at the upper elevation, where cover of legumes and lichens and plant-available nitrate were greater. Total soil N was greater at the lower elevation, but not lichen biomass or root colonization by AMF. Leaf δ(13)C values for P. acaulis and F. lenensis are consistent with increasing water stress with elevation; δ(13)C values indicated the greatest intrinsic water use efficiency for P. sericea, which is more abundant at the upper elevation. Nearby legumes (<10 cm) moderate the effect of elevation on leaf δ(15)N, confirming legumes' meaningful input of N, and affect leaf δ(13)C for two species, suggesting an influence on the efficiency of carbon fixation. Variation in leaf %N and %C as a function of elevation and proximity to a legume differs among species. Apparently, most N input is at upper elevations, pointing to the possible importance of grazers, in addition to hydrological processes, as transporters of N throughout this landscape.

  1. CO2-adapted legumes ameliorate but do not prevent the negative effect of elevated CO2 on nitrogen fixation

    Science.gov (United States)

    Newton, P.; Bowatte, S.; Lieffering, M.; Li, F.

    2015-12-01

    The response of biological nitrogen fixation (BNF) to climate and elevated CO2 (eCO2) is a key uncertainty in modelling C cycle projections. In addition, as BNF provides 50% of the nitrogen (N) input to agricultural production and as ecosystem responses to eCO2 are strongly influenced by N availability then the eCO2 impact on BNF is central to modelling legume-based system responses to climate change. Greater photoassimilate production under eCO2 should lead to enhanced BNF and this response is a feature of ecosystem models thus providing the N inputs necessary to provide continuing stimulation of NPP. FACE experiments provide a 'realistic' environment for eCO2 studies; however, even if run for multiple years, they still may not capture adaptation to eCO2 particularly in ecosystems dominated by perennial species. We tested the effect of eCO2 on BNF and the potential importance of adaption by growing legumes that had been exposed to high or ambient CO2 concentrations at a natural CO2 spring in a long-running (16 year) FACE experiment on grassland. BNF was significantly lower under eCO2 but the reduction was less marked where plants had originated in a high CO2 environment. An ecosystem model run with reduced BNF proved a better fit to the experimental data for the FACE experiment than where BNF was enhanced or unchanged under eCO2.

  2. Nyala and Bushbuck I: A Competing Species Model.

    Science.gov (United States)

    Fay, Temple H.; Greeff, Johanna C.

    1999-01-01

    Introduces a model of differential equations for students--a very real overpopulation problem is occurring in the Ndumu Game Reserve in KwaZulu-Natal, South Africa, where one species of antelope, the Nyala, is crowding out another species, the Bushbuck. Constructs a competing species model to mathematically describe what is occurring in Ndumu.…

  3. Nyala and Bushbuck I: A Competing Species Model.

    Science.gov (United States)

    Fay, Temple H.; Greeff, Johanna C.

    1999-01-01

    Introduces a model of differential equations for students--a very real overpopulation problem is occurring in the Ndumu Game Reserve in KwaZulu-Natal, South Africa, where one species of antelope, the Nyala, is crowding out another species, the Bushbuck. Constructs a competing species model to mathematically describe what is occurring in Ndumu.…

  4. Predicting fish species distribution in estuaries: Influence of species' ecology in model accuracy

    Science.gov (United States)

    França, Susana; Cabral, Henrique N.

    2016-10-01

    Current threats to biodiversity, combined with limited data availability, have made for species distribution models (SDMs) to be increasingly used due to their ability to predict species' potential distribution, by relating species occurrence with environmental estimates. Often used in ecology, conservation biology and environmental management, SDMs have been informing conservation strategies, and thus it is becoming crucial to understand how trustworthy their predictions are. Uncertainty in model predictions is expected, but knowing the origin of prediction errors may help reducing it. Indeed, uncertainty may be related not only with data quality and the modelling algorithm used, but also with species ecological characteristics. To investigate whether the performance of SDM's may vary with species' ecological characteristics, distribution models for 21 fish species occurring in estuaries from the Portuguese coast were examined. These models were built at two distinct spatial resolutions and seven environmental explanatory variables were used as predictors. SDMs' accuracy was assessed with the area under the curve (AUC) of receiver operating characteristics (ROC) plots, sensitivity and specificity. Relationships between each measure of accuracy and species ecological characteristics were then examined. SDMs of the fish species presented small differences between the considered scales, and predictors as latitude, temperature and salinity were often selected at both scales. Measures of model accuracy presented differences between species and scales, but generally higher accuracy was obtained at smaller spatial scales. Among the ecological traits tested, species feeding mode and estuarine use functional groups were the most influential on the performance of distribution models. Habitat tolerance (number of habitat types frequented), species abundance, body size and spawning period also showed some effect. This analyses will contribute to distinguish, based on species

  5. Mutualism and adaptive divergence: co-invasion of a heterogeneous grassland by an exotic legume-rhizobium symbiosis.

    Directory of Open Access Journals (Sweden)

    Stephanie S Porter

    Full Text Available Species interactions play a critical role in biological invasions. For example, exotic plant and microbe mutualists can facilitate each other's spread as they co-invade novel ranges. Environmental context may influence the effect of mutualisms on invasions in heterogeneous environments, however these effects are poorly understood. We examined the mutualism between the legume, Medicago polymorpha, and the rhizobium, Ensifer medicae, which have both invaded California grasslands. Many of these invaded grasslands are composed of a patchwork of harsh serpentine and relatively benign non-serpentine soils. We grew legume genotypes collected from serpentine or non-serpentine soil in both types of soil in combination with rhizobium genotypes from serpentine or non-serpentine soils and in the absence of rhizobia. Legumes invested more strongly in the mutualism in the home soil type and trends in fitness suggested that this ecotypic divergence was adaptive. Serpentine legumes had greater allocation to symbiotic root nodules in serpentine soil than did non-serpentine legumes and non-serpentine legumes had greater allocation to nodules in non-serpentine soil than did serpentine legumes. Therefore, this invasive legume has undergone the rapid evolution of divergence for soil-specific investment in the mutualism. Contrary to theoretical expectations, the mutualism was less beneficial for legumes grown on the stressful serpentine soil than on the non-serpentine soil, possibly due to the inhibitory effects of serpentine on the benefits derived from the interaction. The soil-specific ability to allocate to a robust microbial mutualism may be a critical, and previously overlooked, adaptation for plants adapting to heterogeneous environments during invasion.

  6. Exploring socio-ecological niches for legumes in western Kenya smallholder farming systems

    NARCIS (Netherlands)

    Ojiem, J.O.

    2006-01-01

    Keywords: adaptability, agro-ecosystems, biophysical and socio-economic heterogeneity, economic benefits, N2-fixation, productivity.This thesis explores the potential of using herbaceous and grain legume species to improve soil fertility and farm productivity in the heterogeneous s

  7. Exploring socio-ecological niches for legumes in western Kenya smallholder farming systems

    NARCIS (Netherlands)

    Ojiem, J.O.

    2006-01-01

    Keywords: adaptability, agro-ecosystems, biophysical and socio-economic heterogeneity, economic benefits, N2-fixation, productivity.This thesis explores the potential of using herbaceous and grain legume species to improve soil fertility and farm productivity in the heterogeneous

  8. Nodulation of tree legumes and the ecology of their native rhizobial populations in tropical soils

    NARCIS (Netherlands)

    Bala, A.; Murphy, P.J.; Osunde, A.O.; Giller, K.E.

    2003-01-01

    A legume introduced into a new area will only form nodules and fix nitrogen if compatible rhizobia are present in the soil. Using 25 (60 in the case of Sesbania sesban) soils sampled from tropical areas of Africa, Asia and Latin America, we examined the nodulation of four agroforestry tree species (

  9. A gene-based map of the Nod factor-independent Aeschynomene evenia sheds new light on the evolution of nodulation and legume genomes.

    Science.gov (United States)

    Chaintreuil, Clémence; Rivallan, Ronan; Bertioli, David J; Klopp, Christophe; Gouzy, Jérôme; Courtois, Brigitte; Leleux, Philippe; Martin, Guillaume; Rami, Jean-François; Gully, Djamel; Parrinello, Hugues; Séverac, Dany; Patrel, Delphine; Fardoux, Joël; Ribière, William; Boursot, Marc; Cartieaux, Fabienne; Czernic, Pierre; Ratet, Pascal; Mournet, Pierre; Giraud, Eric; Arrighi, Jean-François

    2016-08-01

    Aeschynomene evenia has emerged as a new model legume for the deciphering of the molecular mechanisms of an alternative symbiotic process that is independent of the Nod factors. Whereas most of the research on nitrogen-fixing symbiosis, legume genetics and genomics has so far focused on Galegoid and Phaseolid legumes, A. evenia falls in the more basal and understudied Dalbergioid clade along with peanut (Arachis hypogaea). To provide insights into the symbiotic genes content and the structure of the A. evenia genome, we established a gene-based genetic map for this species. Firstly, an RNAseq analysis was performed on the two parental lines selected to generate a F2 mapping population. The transcriptomic data were used to develop molecular markers and they allowed the identification of most symbiotic genes. The resulting map comprised 364 markers arranged in 10 linkage groups (2n = 20). A comparative analysis with the sequenced genomes of Arachis duranensis and A. ipaensis, the diploid ancestors of peanut, indicated blocks of conserved macrosynteny. Altogether, these results provided important clues regarding the evolution of symbiotic genes in a Nod factor-independent context. They provide a basis for a genome sequencing project and pave the way for forward genetic analysis of symbiosis in A. evenia.

  10. Annual legumes for improving soil fertility in the smallholder maize ...

    African Journals Online (AJOL)

    In addition to providing food, these crops are widely recognised to help maintain soil fertility. ... Most of our knowledge about the soil fertility benefits from annual legumes has ... Smallholder farmers already rotate grain legumes with maize.

  11. Experiences of soil fertility management through legume based ...

    African Journals Online (AJOL)

    Mo

    either sandy soils or sandy loam soils to compare soil rehabilitation benefits of ... to incorporate the legume crop residues in order to maximize the residual nitrogen benefit to the cereal crop. ... different legume technologies either in rotation or.

  12. Determination of Phytoestrogen Content in Fresh-Cut Legume Forage

    Directory of Open Access Journals (Sweden)

    Pavlína Hloucalová

    2016-07-01

    Full Text Available The aim of the study was to determine phytoestrogen content in fresh-cut legume forage. This issue has been much discussed in recent years in connection with the health and safety of feedstuffs and thus livestock health. The experiments were carried out on two experimental plots at Troubsko and Vatín, Czech Republic during June and July in 2015. Samples were collected of the four forage legume species perennial red clover (variety “Amos”, alfalfa (variety “Holyně”, and annuals Persian clover and Alexandrian clover. Forage was sampled twice at regular three to four day intervals leading up to harvest and a third time on the day of harvest. Fresh and wilted material was analyzed using liquid chromatography–mass spectrometry (LC-MS. Higher levels ( p < 0.05 of isoflavones biochanin A (3.697 mg·g −1 of dry weight and formononetin (4.315 mg·g −1 of dry weight were found in red clover than in other species. The highest isoflavone content was detected in red clover, reaching 1.001% of dry matter ( p < 0.05, representing a risk for occurrence of reproduction problems and inhibited secretion of animal estrogen. The phytoestrogen content was particularly increased in wilted forage. Significant isoflavone reduction was observed over three to four day intervals leading up to harvest.

  13. Improvement of native grassland by legumes introduction and tillage techniques

    Directory of Open Access Journals (Sweden)

    Syamsu Bahar

    1999-10-01

    Full Text Available A factorial design using three species of legumes (Siratro, Centro and Stylo and three different of tillage techniques (no-tillage, minimum tillage and total tillage was applied in this experiment. The results showed that there was no interaction between species and tillage techniques. There was significant reductions on bulk density from 1.23±0.03 g/cm3 (no-tillage to 1.07±0.02 g/cm3 (minimum tillage and 1.05±0.03 g/cm3 (total tillage. Also reductions on penetration resistance from 17.47±3.84 kg/cm2 (no-tillage to 3.31±0.43 kg/cm2 (minimum tillage and 3.19±0.45 kg/cm2 (total tillage. Otherwise significant increasing on aeration porosity from 12.80±0.80% vol. (no-tillage to 21.70±0.95% vol. (minimum tillage and 20.70±0.35% vol. (total tillage. Total tillage gives increased dry matter yield. Also both total tillage and minimum tillage give yields with a higher percentage of legumes compared with no-tillage. It was concluded that total tillage and minimum tillage could be used for improving native grassland.

  14. Tolerance of herbaceous summer legumes of temporary waterlogging

    Directory of Open Access Journals (Sweden)

    Elsa M. Ciotti

    2014-09-01

    Full Text Available A greenhouse study to evaluate adaptation of 4 herbaceous summer legumes to temporary waterlogging was conducted.  Species evaluated were Desmanthus virgatus and Aeschynomene americana in their vegetative stage, and Macroptilium lathyroides and M. atropurpureum in both vegetative and reproductive stages.  The experimental design was randomized blocks with 5 replications and treatments were:  T0, control; T1, saturation by capillary movement placing pots in buckets of 5 L with 10 cm of permanent water; and T2, flooding, placing pots in buckets of 10 L and a layer of water 5 cm above the soil.  The duration of the water treatments was 7 days. Waterlogging did not affect shoot or root biomass production nor nodulation in A. americana, whereas D. virgatus had its highest dry matter production in saturated soil (T1.  In M. lathyroides flooding tolerance was more evident in the reproductive than in the vegetative stage, probably due to more production of adventitious roots and formation of aerenchymatic tissue.  Macroptilium atropurpureum showed adaptation to temporary flooding.  Survival and quick recovery of these species would confirm their potential as forages for temporarily waterlogged soils.Keywords: Forage legumes, flooding, Aeschynomene americana, Desmanthus virgatus, Macroptilium lathyroides, Northeast Argentina.DOI: 10.17138/TGFT(2278-286

  15. Tolerance of herbaceous summer legumes of temporary waterlogging

    Directory of Open Access Journals (Sweden)

    Elsa M. Ciotti

    2014-09-01

    Full Text Available A greenhouse study to evaluate adaptation of 4 herbaceous summer legumes to temporary waterlogging was conducted.  Species evaluated were Desmanthus virgatus and Aeschynomene americana in their vegetative stage, and Macroptilium lathyroides and M. atropurpureum in both vegetative and reproductive stages.  The experimental design was randomized blocks with 5 replications and treatments were:  T0, control; T1, saturation by capillary movement placing pots in buckets of 5 L with 10 cm of permanent water; and T2, flooding, placing pots in buckets of 10 L and a layer of water 5 cm above the soil.  The duration of the water treatments was 7 days. Waterlogging did not affect shoot or root biomass production nor nodulation in A. americana, whereas D. virgatus had its highest dry matter production in saturated soil (T1.  In M. lathyroides flooding tolerance was more evident in the reproductive than in the vegetative stage, probably due to more production of adventitious roots and formation of aerenchymatic tissue.  Macroptilium atropurpureum showed adaptation to temporary flooding.  Survival and quick recovery of these species would confirm their potential as forages for temporarily waterlogged soils.Keywords: Forage legumes, flooding, Aeschynomene americana, Desmanthus virgatus, Macroptilium lathyroides, Northeast Argentina.DOI: 10.17138/TGFT(2278-286

  16. Grain legume protein quality: a hot subject

    Directory of Open Access Journals (Sweden)

    Vaz Patto, Maria Carlota

    2016-06-01

    Full Text Available Grain legumes, also called pulses, play a key role in the nutritional improvement of food and feed. These legumes are important sources of protein as well as other nutritional compounds. Today, protein is one of the most sought after ingredients in the market and grain legumes represent one of the most sustainable protein sources. However, not all grain legume proteins are nutritionally equal. Their quality varies and depends on their amino acid composition and digestibility. In this article, we review concepts related to grain legume protein quality and discuss challenges regarding their genetic improvement. A comprehensive database of grain legume amino acid profiles and protein digestibility is needed to address the matter of protein quality in grain legume breeding. This database will be enhanced by quantitative information on digestibility-reducing bioactive compounds and the development of reliable screening tools. The achievement of higher protein quality grain legume varieties, better adjusted to animal and human requirements, will cut dietary protein content, associated costs and nitrogen excretion, thus reducing the environmental impact.Las leguminosas grano tienen un alto potencial en alimentación humana y animal siendo una importante fuente de proteínas así como de otros compuestos beneficiosos para la nutrición y salud. La proteína es uno de los ingredientes más demandados y las leguminosas grano son una delas fuentes más sostenible de proteína. Sin embargo, no todas las leguminosas grano son igual de nutritivas, variando la calidad con la composición de aminoácidos y su digestibilidad. En este artículo revisaremos los conceptos de calidad de la proteína y discutiremos las posibilidades de mejora genética. Para abordar con éxito la mejora de la calidad de la proteína será de gran ayuda disponer de bases de datos con los perfiles de aminoácidos y de digestibilidad, así como de información cuantitativa sobre los

  17. Responses of Legumes to Phosphorus Deficiency

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Phosphorus deficiency is a universal problem in most world soils. Furthermore, of all nutrients, shortage of phosphorus has the biggest impact on legumes, therefore, lots of studies were carried out for identifying responses of legumes to shortage of phosphorus. They concluded that to maintain improved growth under phosphorus deficiency conditions plants develop two major mechanisms: (i) Phosphorus acquisition (root morphology, root exudation and phosphorus uptake mechanisms), (ii) Phosphorus utilization (internal mechanisms associated with better use of absorbed phosphorus at cellular level). The aim of this brief review is to elucidate root morphological changes and rhizophere acidification to phosphorus deficiency.

  18. Legume crops phylogeny and genetic diversity for science and breeding

    Science.gov (United States)

    Economically, legumes (Fabaceae) represent the second most important family of crop plants after the grass family, Poaceae. Grain legumes account for 27% of world crop production and provide 33% of the dietary protein consumed by humans, while pasture and forage legumes provide vital part of animal ...

  19. The chickpea genomic web resource: visualization and analysis of the desi-type Cicer arietinum nuclear genome for comparative exploration of legumes.

    Science.gov (United States)

    Misra, Gopal; Priya, Piyush; Bandhiwal, Nitesh; Bareja, Neha; Jain, Mukesh; Bhatia, Sabhyata; Chattopadhyay, Debasis; Tyagi, Akhilesh K; Yadav, Gitanjali

    2014-12-18

    Availability of the draft nuclear genome sequences of small-seeded desi-type legume crop Cicer arietinum has provided an opportunity for investigating unique chickpea genomic features and evaluation of their biological significance. The increasing number of legume genome sequences also presents a challenge for developing reliable and information-driven bioinformatics applications suitable for comparative exploration of this important class of crop plants. The Chickpea Genomic Web Resource (CGWR) is an implementation of a suite of web-based applications dedicated to chickpea genome visualization and comparative analysis, based on next generation sequencing and assembly of Cicer arietinum desi-type genotype ICC4958. CGWR has been designed and configured for mapping, scanning and browsing the significant chickpea genomic features in view of the important existing and potential roles played by the various legume genome projects in mutant mapping and cloning. It also enables comparative informatics of ICC4958 DNA sequence analysis with other wild and cultivated genotypes of chickpea, various other leguminous species as well as several non-leguminous model plants, to enable investigations into evolutionary processes that shape legume genomes. CGWR is an online database offering a comprehensive visual and functional genomic analysis of the chickpea genome, along with customized maps and gene-clustering options. It is also the only plant based web resource supporting display and analysis of nucleosome positioning patterns in the genome. The usefulness of CGWR has been demonstrated with discoveries of biological significance made using this server. The CGWR is compatible with all available operating systems and browsers, and is available freely under the open source license at http://www.nipgr.res.in/CGWR/home.php.

  20. Evolution of species from Darwin theory: A simple model

    Science.gov (United States)

    Moret, M. A.; Pereira, H. B. B.; Monteiro, S. L.; Galeão, A. C.

    2012-04-01

    Evolution of species is a complex phenomenon. Some theoretical models take into account evolution of species, like the Bak-Sneppen model that obtain punctuated equilibrium from self-organized criticality and the Penna model for biological aging that consists in a bit-string model subjected to aging, reproduction and death. In this work we propose a simple model to study different scenarios used to simulate the evolution of species. This model is based on Darwin's ideas of evolution. The present findings show that punctuated equilibria and stasis seem to be obtained directly from the mutation, selection of parents and the genetic crossover, and are very close to the fossil data analysis.

  1. A simple model for skewed species-lifetime distributions

    KAUST Repository

    Murase, Yohsuke

    2010-06-11

    A simple model of a biological community assembly is studied. Communities are assembled by successive migrations and extinctions of species. In the model, species are interacting with each other. The intensity of the interaction between each pair of species is denoted by an interaction coefficient. At each time step, a new species is introduced to the system with randomly assigned interaction coefficients. If the sum of the coefficients, which we call the fitness of a species, is negative, the species goes extinct. The species-lifetime distribution is found to be well characterized by a stretched exponential function with an exponent close to 1/2. This profile agrees not only with more realistic population dynamics models but also with fossil records. We also find that an age-independent and inversely diversity-dependent mortality, which is confirmed in the simulation, is a key mechanism accounting for the distribution. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

  2. LEGUMES UTILISED IN TRADITIONAL FOODS IN IRAQ

    Directory of Open Access Journals (Sweden)

    Dalaram S. Ismael

    2014-02-01

    Full Text Available Iraq is famous in the traditional food from legumes, especially chickpea, lentil, and beans are fresh and dry seeds and as well as for peas, beans and the seeds of faba, cowpea and chickpeas boiled with salt eaten in the form of Lablabe, or make soup from fresh cowpea, fresh faba bean, fresh fasoulia, as well as lentil soup (shorbat adas and different kinds of salad. Turshi, pickled vegetables and fresh pea, fresh fasoulia in the cuisine of many Balkan and Middle East countries. It is a traditional appetizer, meze. Chickpea is eaten on form falafel . The cuisine of Iraq reflects this rich inheritance as well as strong influence from the culinary traditions of neighbouring Persia, Turkey and the Syria region area. Meals begin with appetizers and salads known as Mezza. Some popular dishes include kebab (often marinated with garlic, lemon and spices, then grilled. It can be challenging to help people adjust their diet to meet their nutrient needs and promote weight loss, while at the same time still keeping them satiated. Nutrient rich legumes can be a valuable part of such a diet. They contain soluble fibre and protein and are low glycemic index, all of which may help promote satiety. Legumes are one of the most sustainable sources of protein in the world. Legumes are also significant sources of resistant starch, which is fermented by colonic bacteria to short chain fatty acids.

  3. Grain legume genetic resources for allele mining

    Science.gov (United States)

    Sequencing capacities for higher throughput at significantly lower costs have enabled larger scale genotyping of plant genetic resources. One challenge to sequencing the USDA grain legume collections of pea, chickpea and lentil core accessions is the amount of heterogeneity in the landrace accessio...

  4. Utilization of summer legumes as bioenergy feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Keri B.; Bauer, Philip J.; Ro, Kyoung S. [United States Department of Agriculture, ARS, Coastal Plains Soil, Water, and Plant Research Center, 2611 W. Lucas St. Florence, SC 29501 (United States)

    2010-12-15

    Sunn hemp (Crotolaria juncea), is a fast growing, high biomass yielding tropical legume that may be a possible southeastern bioenergy crop. When comparing this legume to a commonly grown summer legume - cowpeas (Vigna unguiculata), sunn hemp was superior in biomass yield (kg ha{sup -1}) and subsequent energy yield (GJ ha{sup -1}). In one year of the study after 12 weeks of growth, sunn hemp had 10.7 Mg ha{sup -1} of biomass with an energy content of 19.0 Mg ha{sup -1}. This resulted in an energy yield of 204 GJ ha{sup -1}. The energy content was 6% greater than that of cowpeas. Eventhough sunn hemp had a greater amount of ash, plant mineral concentrations were lower in some cases of minerals (K, Ca, Mg, S) known to reduce thermochemical conversion process efficiency. Pyrolytic degradation of both legumes revealed that sunn hemp began to degrade at higher temperatures as well as release greater amounts of volatile matter at a faster rate. (author)

  5. NPR1 protein regulates pathogenic and symbiotic interactions between Rhizobium and legumes and non-legumes.

    Directory of Open Access Journals (Sweden)

    Smadar Peleg-Grossman

    Full Text Available BACKGROUND: Legumes are unique in their ability to establish symbiotic interaction with rhizobacteria from Rhizobium genus, which provide them with available nitrogen. Nodulation factors (NFs produced by Rhizobium initiate legume root hair deformation and curling that entrap the bacteria, and allow it to grow inside the plant. In contrast, legumes and non-legumes activate defense responses when inoculated with pathogenic bacteria. One major defense pathway is mediated by salicylic acid (SA. SA is sensed and transduced to downstream defense components by a redox-regulated protein called NPR1. METHODOLOGY/PRINCIPAL FINDINGS: We used Arabidopsis mutants in SA defense pathway to test the role of NPR1 in symbiotic interactions. Inoculation of Sinorhizobium meliloti or purified NF on Medicago truncatula or nim1/npr1 A. thaliana mutants induced root hair deformation and transcription of early and late nodulins. Application of S. meliloti or NF on M. truncatula or A. thaliana roots also induced a strong oxidative burst that lasted much longer than in plants inoculated with pathogenic or mutualistic bacteria. Transient overexpression of NPR1 in M. truncatula suppressed root hair curling, while inhibition of NPR1 expression by RNAi accelerated curling. CONCLUSIONS/SIGNIFICANCE: We show that, while NPR1 has a positive effect on pathogen resistance, it has a negative effect on symbiotic interactions, by inhibiting root hair deformation and nodulin expression. Our results also show that basic plant responses to Rhizobium inoculation are conserved in legumes and non-legumes.

  6. Anti-inflammatory effects of phytochemicals from fruits, vegetables, and food legumes: A review.

    Science.gov (United States)

    Zhu, Fengmei; Du, Bin; Xu, Baojun

    2017-06-12

    Inflammation is the first biological response of the immune system to infection, injury or irritation. Evidence suggests that the anti-inflammatory effect is mediated through the regulation of various inflammatory cytokines, such as nitric oxide, interleukins, tumor necrosis factor alpha-α, interferon gamma-γ as well as noncytokine mediator, prostaglandin E2. Fruits, vegetables, and food legumes contain high levels of phytochemicals that show anti-inflammatory effect, but their mechanisms of actions have not been completely identified. The aim of this paper was to summarize the recent investigations and findings regarding in vitro and animal model studies on the anti-inflammatory effects of fruits, vegetables, and food legumes. Specific cytokines released for specific type of physiological event might shed some light on the specific use of each source of phytochemicals that can benefit to counter the inflammatory response. As natural modulators of proinflammatory gene expressions, phytochemical from fruits, vegetables, and food legumes could be incorporated into novel bioactive anti-inflammatory formulations of various nutraceuticals and pharmaceuticals. Finally, these phytochemicals are discussed as the natural promotion strategy for the improvement of human health status. The phenolics and triterpenoids in fruits and vegetables showed higher anti-inflammatory activity than other compounds. In food legumes, lectins and peptides had anti-inflammatory activity in most cases. However, there are lack of human study data on the anti-inflammatory activity of phytochemicals from fruits, vegetables, and food legumes.

  7. Determinism of carbon and nitrogen reserve accumulation in legume seeds.

    Science.gov (United States)

    Munier-Jolain, Nathalie; Larmure, Annabelle; Salon, Christophe

    2008-10-01

    In legume plants, the determination of individual seed weight is a complex phenomenon that depends on two main factors. The first one corresponds to the number of cotyledon cells, which determines the potential seed weight as the cotyledon cell number is related to seed growth rate during seed filling. Since cell divisions take place between flowering and the beginning of seed filling, any stress occurring before the beginning of seed filling can affect individual seed growth rate (C and N reserve accumulation in seeds), and thus individual seed weights. The second factor concerns carbon and nitrogen supply to the growing seed to support reserve accumulation. Grain legume species produce protein-rich seeds involving high requirement of nitrogen. Since seed growth rate as determined by cotyledon cell number is hardly affected by photoassimilate availability during the filling period, a reduction of photosynthetic activity caused by nitrogen remobilization in leaves (e.g., remobilization of essential proteins involved in photosynthesis) can lead to shorten the duration of the filling period, and by that can provoke a limitation of individual seed weights. Accordingly, any biotic or abiotic stress during seed filling causing a decrease in photosynthetic activity should lead to a reduction of the duration of seed filling.

  8. Standardized mapping of nodulation patterns in legume roots.

    Science.gov (United States)

    Remmler, Lauren; Clairmont, Lindsey; Rolland-Lagan, Anne-Gaëlle; Guinel, Frédérique Catherine

    2014-05-01

    Optimizing nodulation in legumes is a target for crop improvement, and the spatial control of nodulation is just beginning to be unravelled. However, there is currently no method for standard phenotyping of nodulation patterns. Here we present a method and software for the quantitative analysis of nodulation phenotypes. Roots of nodulated peas (Pisum sativum), wild-type and two mutants, were photographed. Data from the photographs were extracted using custom image and data analysis software. The software makes it possible to extract each nodule's position along primary and lateral roots, and to represent the nodulated root system in a standardized way independent of the way roots are arranged in the soil. A wide variety of nodulation and root variables are calculated, and average spatial nodulation patterns can be computed from multiple samples. Standardized spatial analysis of nodulation patterns opens the way for comparative analyses among genotypes of a single legume species, as here in pea. This approach could also be used to compare nodulation patterns among crops, among plants grown under different environmental conditions, or among plants exposed to different pharmacological treatments. The proposed method should therefore prove useful for studies on nodule organogenesis and nodule physiology and for optimizing nodulation in crops. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  9. Impacts of Species Misidentification on Species Distribution Modeling with Presence-Only Data

    Directory of Open Access Journals (Sweden)

    Hugo Costa

    2015-11-01

    Full Text Available Spatial records of species are commonly misidentified, which can change the predicted distribution of a species obtained from a species distribution model (SDM. Experiments were undertaken to predict the distribution of real and simulated species using MaxEnt and presence-only data “contaminated” with varying rates of misidentification error. Additionally, the difference between the niche of the target and contaminating species was varied. The results show that species misidentification errors may act to contract or expand the predicted distribution of a species while shifting the predicted distribution towards that of the contaminating species. Furthermore the magnitude of the effects was positively related to the ecological distance between the species’ niches and the size of the error rates. Critically, the magnitude of the effects was substantial even when using small error rates, smaller than common average rates reported in the literature, which may go unnoticed while using a standard evaluation method, such as the area under the receiver operating characteristic curve. Finally, the effects outlined were shown to impact negatively on practical applications that use SDMs to identify priority areas, commonly selected for various purposes such as management. The results highlight that species misidentification should not be neglected in species distribution modeling.

  10. Missing in action: Species competition is a neglected predictor variable in species distribution modelling.

    Science.gov (United States)

    Mpakairi, Kudzai Shaun; Ndaimani, Henry; Tagwireyi, Paradzayi; Gara, Tawanda Winmore; Zvidzai, Mark; Madhlamoto, Daphine

    2017-01-01

    The central role of species competition in shaping community structure in ecosystems is well appreciated amongst ecologists. However species competition is a consistently missing variable in Species Distribution Modelling (SDM). This study presents results of our attempt to incorporate species competition in SDMs. We used a suit of predictor variables including Soil Adjusted Vegetation Index (SAVI), as well as distance from roads, settlements and water, fire frequency and distance from the nearest herbivore sighting (of selected herbivores) to model individual habitat preferences of five grazer species (buffalo, warthog, waterbuck, wildebeest and zebra) with the Ensemble SDM algorithm for Gonarezhou National Park, Zimbabwe. Our results showed that distance from the nearest animal sighting (a proxy for competition among grazers) was the best predictor of the potential distribution of buffalo, wildebeest and zebra but the second best predictor for warthog and waterbuck. Our findings provide evidence to that competition is an important predictor of grazer species' potential distribution. These findings suggest that species distribution modelling that neglects species competition may be inadequate in explaining the potential distribution of species. Therefore our findings encourage the inclusion of competition in SDM as well as potentially igniting discussions that may lead to improving the predictive power of future SDM efforts.

  11. Historical Species Distribution Models Predict Species Limits in Western Plethodon Salamanders.

    Science.gov (United States)

    Pelletier, Tara A; Crisafulli, Charlie; Wagner, Steve; Zellmer, Amanda J; Carstens, Bryan C

    2015-11-01

    Allopatry is commonly used to predict boundaries in species delimitation investigations under the assumption that currently allopatric distributions are indicative of reproductive isolation; however, species ranges are known to change over time. Incorporating a temporal perspective of geographic distributions should improve species delimitation; to explore this, we investigate three species of western Plethodon salamanders that have shifted their ranges since the end of the Pleistocene. We generate species distribution models (SDM) of the current range, hindcast these models onto a climatic model 21 Ka, and use three molecular approaches to delimit species in an integrated fashion. In contrast to expectations based on the current distribution, we detect no independent lineages in species with allopatric and patchy distributions (Plethodon vandykei and Plethodon larselli). The SDMs indicate that probable habitat is more expansive than their current range, especially during the last glacial maximum (LGM) (21 Ka). However, with a contiguous distribution, two independent lineages were detected in Plethodon idahoensis, possibly due to isolation in multiple glacial refugia. Results indicate that historical SDMs are a better predictor of species boundaries than current distributions, and strongly imply that researchers should incorporate SDM and hindcasting into their investigations and the development of species hypotheses. © The Author(s) 2014. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Models of reactive oxygen species in cancer

    OpenAIRE

    Lu, Weiqin; Ogasawara, Marcia A.; Huang, Peng

    2007-01-01

    Increased generation of reactive oxygen species (ROS) has been observed in cancer, degenerative diseases, and other pathological conditions. ROS can stimulate cell proliferation, promote genetic instability, and induce adaptive responses that enable cancer cells to maintain their malignant phenotypes. However, when cellular redox balance is severely disturbed, high levels of ROS may cause various damages leading to cell death. The studies of ROS effects on biological systems, their underlying...

  13. Projecting future expansion of invasive species: comparing and improving methodologies for species distribution modeling.

    Science.gov (United States)

    Mainali, Kumar P; Warren, Dan L; Dhileepan, Kunjithapatham; McConnachie, Andrew; Strathie, Lorraine; Hassan, Gul; Karki, Debendra; Shrestha, Bharat B; Parmesan, Camille

    2015-12-01

    Modeling the distributions of species, especially of invasive species in non-native ranges, involves multiple challenges. Here, we developed some novel approaches to species distribution modeling aimed at reducing the influences of such challenges and improving the realism of projections. We estimated species-environment relationships for Parthenium hysterophorus L. (Asteraceae) with four modeling methods run with multiple scenarios of (i) sources of occurrences and geographically isolated background ranges for absences, (ii) approaches to drawing background (absence) points, and (iii) alternate sets of predictor variables. We further tested various quantitative metrics of model evaluation against biological insight. Model projections were very sensitive to the choice of training dataset. Model accuracy was much improved using a global dataset for model training, rather than restricting data input to the species' native range. AUC score was a poor metric for model evaluation and, if used alone, was not a useful criterion for assessing model performance. Projections away from the sampled space (i.e., into areas of potential future invasion) were very different depending on the modeling methods used, raising questions about the reliability of ensemble projections. Generalized linear models gave very unrealistic projections far away from the training region. Models that efficiently fit the dominant pattern, but exclude highly local patterns in the dataset and capture interactions as they appear in data (e.g., boosted regression trees), improved generalization of the models. Biological knowledge of the species and its distribution was important in refining choices about the best set of projections. A post hoc test conducted on a new Parthenium dataset from Nepal validated excellent predictive performance of our 'best' model. We showed that vast stretches of currently uninvaded geographic areas on multiple continents harbor highly suitable habitats for parthenium

  14. Symbiotic effectiveness of rhizobial mutualists varies in interactions with native Australian legume genera.

    Directory of Open Access Journals (Sweden)

    Peter H Thrall

    Full Text Available BACKGROUND AND OBJECTIVES: Interactions between plants and beneficial soil organisms (e.g. rhizobial bacteria, mycorrhizal fungi are models for investigating the ecological impacts of such associations in plant communities, and the evolution and maintenance of variation in mutualisms (e.g. host specificity and the level of benefits provided. With relatively few exceptions, variation in symbiotic effectiveness across wild host species is largely unexplored. METHODS: We evaluated these associations using representatives of several legume genera which commonly co-occur in natural ecosystems in south-eastern Australia and an extensive set of rhizobial strains isolated from these hosts. These strains had been previously assigned to specific phylotypes on the basis of molecular analyses. In the first of two inoculation experiments, the growth responses of each host species was evaluated with rhizobial strains isolated from that species. The second experiment assessed performance across genera and the extent of host specificity using a subset of these strains. RESULTS: While host growth responses to their own (sympatric isolates varied considerably, rhizobial phylotype was a significant predictor of symbiotic performance, indicating that bacterial species designations on the basis of molecular markers have ecological importance. Hosts responded in qualitatively different ways to sympatric and allopatric strains of rhizobia, ranging from species with a clear preference for their own strains, to those that were broad generalists, through to species that grew significantly better with allopatric strains. CONCLUSION: Theory has focused on trade-offs between the provision of benefits and symbiont competitive ability that might explain the persistence of less beneficial strains. However, differences in performance among co-occurring host species could also drive such patterns. Our results thus highlight the likely importance of plant community structure in

  15. Establishment of the Lotus japonicus Gene Expression Atlas (LjGEA) and its use to explore legume seed maturation.

    Science.gov (United States)

    Verdier, Jerome; Torres-Jerez, Ivone; Wang, Mingyi; Andriankaja, Andry; Allen, Stacy N; He, Ji; Tang, Yuhong; Murray, Jeremy D; Udvardi, Michael K

    2013-04-01

    Lotus japonicus is a model species for legume genomics. To accelerate legume functional genomics, we developed a Lotus japonicus Gene Expression Atlas (LjGEA), which provides a global view of gene expression in all organ systems of this species, including roots, nodules, stems, petioles, leaves, flowers, pods and seeds. Time-series data covering multiple stages of developing pod and seed are included in the LjGEA. In addition, previously published L. japonicus Affymetrix data are included in the database, making it a 'one-stop shop' for transcriptome analysis of this species. The LjGEA web server (http://ljgea.noble.org/) enables flexible, multi-faceted analyses of the transcriptome. Transcript data may be accessed using the Affymetrix probe identification number, DNA sequence, gene name, functional description in natural language, and GO and KEGG annotation terms. Genes may be discovered through co-expression or differential expression analysis. Users may select a subset of experiments and visualize and compare expression profiles of multiple genes simultaneously. Data may be downloaded in a tabular form compatible with common analytical and visualization software. To illustrate the power of LjGEA, we explored the transcriptome of developing seeds. Genes represented by 36 474 probe sets were expressed at some stage during seed development, and almost half of these genes displayed differential expression during development. Among the latter were 624 transcription factor genes, some of which are orthologs of transcription factor genes that are known to regulate seed development in other species, while most are novel and represent attractive targets for reverse genetics approaches to determine their roles in this important organ.

  16. Modeling considerations for using expression data from multiple species.

    Science.gov (United States)

    Siewert, Elizabeth; Kechris, Katerina J

    2013-10-15

    Although genome-wide expression data sets from multiple species are now more commonly generated, there have been few studies on how to best integrate this type of correlated data into models. Starting with a single-species, linear regression model that predicts transcription factor binding sites as a case study, we investigated how best to take into account the correlated expression data when extending this model to multiple species. Using a multivariate regression model, we accounted for the phylogenetic relationships among the species in two ways: (i) a repeated-measures model, where the error term is constrained; and (ii) a Bayesian hierarchical model, where the prior distributions of the regression coefficients are constrained. We show that both multiple-species models improve predictive performance over the single-species model. When compared with each other, the repeated-measures model outperformed the Bayesian model. We suggest a possible explanation for the better performance of the model with the constrained error term. Copyright © 2013 John Wiley & Sons, Ltd.

  17. Selection for cheating across disparate environments in the legume-rhizobium mutualism.

    Science.gov (United States)

    Porter, Stephanie S; Simms, Ellen L

    2014-09-01

    The primary dilemma in evolutionarily stable mutualisms is that natural selection for cheating could overwhelm selection for cooperation. Cheating need not entail parasitism; selection favours cheating as a quantitative trait whenever less-cooperative partners are more fit than more-cooperative partners. Mutualisms might be stabilised by mechanisms that direct benefits to more-cooperative individuals, which counter selection for cheating; however, empirical evidence that natural selection favours cheating in mutualisms is sparse. We measured selection on cheating in single-partner pairings of wild legume and rhizobium lineages, which prevented legume choice. Across contrasting environments, selection consistently favoured cheating by rhizobia, but did not favour legumes that provided less benefit to rhizobium partners. This is the first simultaneous measurement of selection on cheating across both host and symbiont lineages from a natural population. We empirically confirm selection for cheating as a source of antagonistic coevolutionary pressure in mutualism and a biological dilemma for models of cooperation.

  18. Predicting weed problems in maize cropping by species distribution modelling

    Directory of Open Access Journals (Sweden)

    Bürger, Jana

    2014-02-01

    Full Text Available Increasing maize cultivation and changed cropping practices promote the selection of typical maize weeds that may also profit strongly from climate change. Predicting potential weed problems is of high interest for plant production. Within the project KLIFF, experiments were combined with species distribution modelling for this task in the region of Lower Saxony, Germany. For our study, we modelled ecological and damage niches of nine weed species that are significant and wide spread in maize cropping in a number of European countries. Species distribution models describe the ecological niche of a species, these are the environmental conditions under which a species can maintain a vital population. It is also possible to estimate a damage niche, i.e. the conditions under which a species causes damage in agricultural crops. For this, we combined occurrence data of European national data bases with high resolution climate, soil and land use data. Models were also projected to simulated climate conditions for the time horizon 2070 - 2100 in order to estimate climate change effects. Modelling results indicate favourable conditions for typical maize weed occurrence virtually all over the study region, but only a few species are important in maize cropping. This is in good accordance with the findings of an earlier maize weed monitoring. Reaction to changing climate conditions is species-specific, for some species neutral (E. crus-galli, other species may gain (Polygonum persicaria or loose (Viola arvensis large areas of suitable habitats. All species with damage potential under present conditions will remain important in maize cropping, some more species will gain regional importance (Calystegia sepium, Setara viridis.

  19. Legume consumption and its association with fasting glucose, insulin resistance and type 2 diabetes in the Indian Migration Study.

    Science.gov (United States)

    Dhillon, Preet K; Bowen, Liza; Kinra, Sanjay; Bharathi, Ankalmadugu Venkatsubbareddy; Agrawal, Sutapa; Prabhakaran, Dorairaj; Reddy, Kolli Srinath; Ebrahim, Shah

    2016-11-01

    Legume consumption is associated with lower fasting glucose (FG) and insulin levels in nutrition trials and lower CVD mortality in large-scale epidemiological studies. In India, legumes are widely consumed in various preparations, yet no epidemiological study has evaluated the association of legumes with FG levels, insulin resistance and diabetes risk. The present study aimed to fill this gap. Fasting blood samples, in-person interviews to obtain information on demographic/socio-economic factors, physical activity, alcohol and tobacco use, and anthropometric measurements were collected. Dietary intakes were assessed by an interviewer-administered, validated, semi-quantitative FFQ. Lucknow, Nagpur, Hyderabad and Bangalore, India. Men and women (n 6367) aged 15-76 years - urban residents, urban migrants and their rural siblings. In multivariate random-effects models adjusted for age, BMI, total energy intake, macronutrients, physical activity and rural/migration status, daily legume consumption was not associated with FG (P-for-trend=0·78), insulin resistance (homeostasis model assessment score; P-for-trend=0·73) or the prevalence of type 2 diabetes mellitus (P-for-trend=0·41). Stratified analyses by vegetarian diet and migration status did not change the findings. Inverse associations between legumes and FG emerged for participants with lower BMI and higher carbohydrate, protein, fat and sugar intakes. Although legumes are essential in traditional Indian diets, as well as in prudent and Mediterranean diets in the West, we did not find an association between legumes and markers of glycaemic control, insulin resistance or diabetes, except for subgroups based on BMI and macronutrient intake. The ubiquitous presence and complexity of legume preparations in Indian diets may contribute to these findings.

  20. Five (or so) challenges for species distribution modelling

    DEFF Research Database (Denmark)

    Bastos Araujo, Miguel; Guisan, Antoine

    2006-01-01

    Species distribution modelling is central to both fundamental and applied research in biogeography. Despite widespread use of models, there are still important conceptual ambiguities as well as biotic and algorithmic uncertainties that need to be investigated in order to increase confidence...... in model results. We identify and discuss five areas of enquiry that are of high importance for species distribution modelling: (1) clarification of the niche concept; (2) improved designs for sampling data for building models; (3) improved parameterization; (4) improved model selection and predictor...

  1. Cyclin-like F-box protein plays a role in growth and development of the three model species Medicago truncatula, Lotus japonicus, and Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Boycheva I

    2015-08-01

    Full Text Available Irina Boycheva,1 Valya Vassileva,2 Miglena Revalska,1 Grigor Zehirov,2 Anelia Iantcheva1 1Department of Functional Genetics Legumes, 2AgroBioInstitute, Department of Plant Stress Molecular Biology, Institute of Plant Physiology and Genetics, Sofia, Bulgaria Abstract: In eukaryotes, F-box proteins are one of the main components of the SCF complex that belongs to the family of ubiquitin E3 ligases, which catalyze protein ubiquitination and maintain the balance between protein synthesis and degradation. In the present study, we clarified the role and function of the gene encoding cyclin-like F-box protein from Medicago truncatula using transgenic plants of the model species M. truncatula, Lotus japonicas, and Arabidopsis thaliana generated by Agrobacterium-mediated transformation. Morphological and transcriptional analyses combined with flow cytometry and histochemistry demonstrated the participation of this protein in many aspects of plant growth and development, including processes of indirect somatic embryogenesis and symbiotic nodulation. The cyclin-like F-box gene showed expression in all plant organs and tissues comprised of actively dividing cells. The observed variations in root and hypocotyl growth, leaf and silique development, ploidy levels, and leaf parameters in the obtained transgenic lines demonstrated the effects of this gene on organ development. Furthermore, knockdown of cyclin-like F-box led to accumulation of higher levels of the G2/M transition-specific gene cyclin B1:1 (CYCB1:1, suggesting its possible role in cell cycle control. Together, the collected data suggest a similar role of the cyclin-like F-box protein in the three model species, providing evidence for the functional conservation of the studied gene. Keywords: cyclin-like F-box, model legumes, Arabidopsis thaliana, plant growth, plant development, cell cycle

  2. Legume Lectins: Proteins with Diverse Applications

    Science.gov (United States)

    Lagarda-Diaz, Irlanda; Guzman-Partida, Ana Maria; Vazquez-Moreno, Luz

    2017-01-01

    Lectins are a diverse class of proteins distributed extensively in nature. Among these proteins; legume lectins display a variety of interesting features including antimicrobial; insecticidal and antitumor activities. Because lectins recognize and bind to specific glycoconjugates present on the surface of cells and intracellular structures; they can serve as potential target molecules for developing practical applications in the fields of food; agriculture; health and pharmaceutical research. This review presents the current knowledge of the main structural characteristics of legume lectins and the relationship of structure to the exhibited specificities; provides an overview of their particular antimicrobial; insecticidal and antitumor biological activities and describes possible applications based on the pattern of recognized glyco-targets. PMID:28604616

  3. Theoretical biology: Comparing models of species abundance - Brief Communications Arising

    NARCIS (Netherlands)

    Chave, J.; Alonso, D.; Etienne, R.S.

    2006-01-01

    Ecologists are struggling to explain how so many tropical tree species can coexist in tropical forests, and several empirical studies have demonstrated that negative density dependence is an important mechanism of tree-species coexistence1, 2. Volkov et al.3 compare a model incorporating negative de

  4. Comparing the performance of species distribution models of

    NARCIS (Netherlands)

    Valle , M.; van Katwijk, M.M.; de Jong, D.J.; Bouma, T.; Schipper, A.M.; Chust, G.; Benito, B.M.; Garmendia, J.M.; Borja, A.

    2013-01-01

    Intertidal seagrasses show high variability in their extent and location, with local extinctions and (re-)colonizations being inherent in their population dynamics. Suitable habitats are identified usually using Species Distribution Models (SDM), based upon the overall distribution of the species;

  5. Late Embryogenesis Abundant (LEA proteins in legumes

    Directory of Open Access Journals (Sweden)

    Marina eBattaglia

    2013-06-01

    Full Text Available Plants are exposed to different external conditions that affect growth, development, and productivity. Water deficit is one of these adverse conditions caused by drought, salinity, and extreme temperatures. Plants have developed different responses to prevent, ameliorate or repair the damage inflicted by these stressful environments. One of these responses is the activation of a set of genes encoding a group of hydrophilic proteins that typically accumulate to high levels during seed dehydration, at the last stage of embryogenesis, hence named Late Embryogenesis Abundant (LEA proteins. LEA proteins also accumulate in response to water limitation in vegetative tissues, and have been classified in seven groups based on their amino acid sequence similarity and on the presence of distinctive conserved motifs. These proteins are widely distributed in the plant kingdom, from ferns to angiosperms, suggesting a relevant role in the plant response to this unfavorable environmental condition. In this review, we analyzed the LEA proteins from those legumes whose complete genomes have been sequenced such as Phaseolus vulgaris, Glycine max, Medicago truncatula, Lotus japonicus, Cajanus cajan and Cicer arietinum. Considering their distinctive motifs, LEA proteins from the different groups were identified, and their sequence analysis allowed the recognition of novel legume specific motifs. Moreover, we compile their transcript accumulation patterns based on publicly available data. In spite of the limited information on these proteins in legumes, the analysis and data compiled here confirms the high correlation between their accumulation and water deficit, reinforcing their functional relevance under this detrimental conditions.

  6. Molecular mechanisms controlling legume autoregulation of nodulation.

    Science.gov (United States)

    Reid, Dugald E; Ferguson, Brett J; Hayashi, Satomi; Lin, Yu-Hsiang; Gresshoff, Peter M

    2011-10-01

    High input costs and environmental pressures to reduce nitrogen use in agriculture have increased the competitive advantage of legume crops. The symbiotic relationship that legumes form with nitrogen-fixing soil bacteria in root nodules is central to this advantage. Understanding how legume plants maintain control of nodulation to balance the nitrogen gains with their energy needs and developmental costs will assist in increasing their productivity and relative advantage. For this reason, the regulation of nodulation has been extensively studied since the first mutants exhibiting increased nodulation were isolated almost three decades ago. Nodulation is regulated primarily via a systemic mechanism known as the autoregulation of nodulation (AON), which is controlled by a CLAVATA1-like receptor kinase. Multiple components sharing homology with the CLAVATA signalling pathway that maintains control of the shoot apical meristem in arabidopsis have now been identified in AON. This includes the recent identification of several CLE peptides capable of activating nodule inhibition responses, a low molecular weight shoot signal and a role for CLAVATA2 in AON. Efforts are now being focused on directly identifying the interactions of these components and to identify the form that long-distance transport molecules take.

  7. Legume NADPH Oxidases Have Crucial Roles at Different Stages of Nodulation

    Directory of Open Access Journals (Sweden)

    Jesús Montiel

    2016-05-01

    Full Text Available Plant NADPH oxidases, formerly known as respiratory burst oxidase homologues (RBOHs, are plasma membrane enzymes dedicated to reactive oxygen species (ROS production. These oxidases are implicated in a wide variety of processes, ranging from tissue and organ growth and development to signaling pathways in response to abiotic and biotic stimuli. Research on the roles of RBOHs in the plant’s response to biotic stresses has mainly focused on plant-pathogen interactions; nonetheless, recent findings have shown that these oxidases are also involved in the legume-rhizobia symbiosis. The legume-rhizobia symbiosis leads to the formation of the root nodule, where rhizobia reduce atmospheric nitrogen to ammonia. A complex signaling and developmental pathway in the legume root hair and root facilitate rhizobial entrance and nodule organogenesis, respectively. Interestingly, several reports demonstrate that RBOH-mediated ROS production displays versatile roles at different stages of nodulation. The evidence collected to date indicates that ROS act as signaling molecules that regulate rhizobial invasion and also function in nodule senescence. This review summarizes discoveries that support the key and versatile roles of various RBOH members in the legume-rhizobia symbiosis.

  8. Self-reseeding annual legumes for cover cropping in rainfed managed olive orchards

    Energy Technology Data Exchange (ETDEWEB)

    Ângelo Rodrigues, M.; Ferreira, I. Q.; Freitas, S.L.; Pires, J.M.; Arrobas, M.P.

    2015-07-01

    Given the environmental impact of nitrogen (N)-fertilizer manufacture and use, the sustainable management of agro-systems should be sought by growing N-fixing legumes. In this work, eleven self-reseeding annual legumes were grown in pure stands as mulching cover crops in a rainfed olive orchard managed without grazing animals. Dry matter yield, N content in above-ground biomass, groundcover percentage and persistence of the sown species were assessed during four growing seasons. All covers provided enough soil protection over the year, with living plants during the autumn/winter period and a mulch of dead residues during the summer. The legumes overcame a false break observed in the third year recovering the dominance of the covers in the fourth growing season. This means that the seed bank established in previous seasons ensured the persistence of the sown legume even when a gap in seed production occurred. The early-maturing cultivars produced less biomass and fixed less N (approx. 50 kg N/ha/yr present in the above-ground biomass) than the late-maturing ones, but would compete less for water since the growing cycle finished earlier in the spring. They seem best suited to being grown in dry farmed olive orchards with low N demand in drought prone regions. (Author)

  9. Breeding Food Legumes for Resistance to Storage Insect Pests: Potential and Limitations

    Directory of Open Access Journals (Sweden)

    Kifle Dagne

    2011-08-01

    Full Text Available Storage insect pests cause significant losses of food legumes particularly in the Tropics and the Sub-tropics. The most important species of storage insect pests of food legumes include Callosobruchus chinensis, C. maculatus, C. analis, Acanthoscelides obtectus, Bruchus incarnatus, B. rufimanus, B. dentipes, B. quinqueguttatus, B. emarginatus, B. ervi, B. lentis and B. pisorum. Effective post-harvest insect pest control measures should constitute part of the overall crop husbandry practices for preserving the quality of produce. Storage insect pests are commonly controlled using chemical insecticides which, however, bear many drawbacks related to high cost, environmental pollution and food safety risks. Breeding legume crops to improve their resistance against storage insect pests, although having technical limitations, is the best way of overcoming these disadvantages in an environment-friendly manner. In this paper, we present the findings of our extensive reviews on the potential of breeding resistant varieties of food legumes against storage insect pests along with the major technical limitations one would likely encounter and the prospective ways of tackling them.

  10. Legume NADPH Oxidases Have Crucial Roles at Different Stages of Nodulation

    Science.gov (United States)

    Montiel, Jesús; Arthikala, Manoj-Kumar; Cárdenas, Luis; Quinto, Carmen

    2016-01-01

    Plant NADPH oxidases, formerly known as respiratory burst oxidase homologues (RBOHs), are plasma membrane enzymes dedicated to reactive oxygen species (ROS) production. These oxidases are implicated in a wide variety of processes, ranging from tissue and organ growth and development to signaling pathways in response to abiotic and biotic stimuli. Research on the roles of RBOHs in the plant’s response to biotic stresses has mainly focused on plant-pathogen interactions; nonetheless, recent findings have shown that these oxidases are also involved in the legume-rhizobia symbiosis. The legume-rhizobia symbiosis leads to the formation of the root nodule, where rhizobia reduce atmospheric nitrogen to ammonia. A complex signaling and developmental pathway in the legume root hair and root facilitate rhizobial entrance and nodule organogenesis, respectively. Interestingly, several reports demonstrate that RBOH-mediated ROS production displays versatile roles at different stages of nodulation. The evidence collected to date indicates that ROS act as signaling molecules that regulate rhizobial invasion and also function in nodule senescence. This review summarizes discoveries that support the key and versatile roles of various RBOH members in the legume-rhizobia symbiosis. PMID:27213330

  11. THE NUTRITIONAL COMPOSITION AND ACCEPTABILITY OF CACTI (Opuntia ficus indica-LEGUME MIXED SILAGE

    Directory of Open Access Journals (Sweden)

    J. GUSHA

    2013-03-01

    Full Text Available The potential of making silage using dry browse legume hay (Acacia angustissima, Leucaena leucocephala, Calliandra callothrysus and Macroptilium Atropurpureum mixed with fresh cactus (Opuntia ficus-indica for winter supplementation of veld grass was evaluated using the proximate, tannins and the pH analyses. Chemical analysis revealed that N values were significantly increased (P<0.05. The N levels were 3.72, 4.5, 4.05, and 2.5% DM for A. angustissima, L. leucocephala, C. callothrysus and M. atropurpureum respectively, which were higher when compared to silage made from cereals. The NDF and ADF values were slightly higher than those reported in literature for cereal silages. The DM level of cactus –browse silage was very good (41%DM considering that cactus normally have less than 10% DM. The silage pH was within the reported range, ranging from 3.97 to 4.11 on a pH meter. This was a good indicator of silage quality considering that low pH inhibit undesirable microbial activities. The tannins levels were lower in the silages but significantly different (P<0.05 between browse legume species. Ensiling lowered the tannin levels in the silage compared to the individual browse legume tannin levels. This study concluded that purely on compositional laboratory analysis, the legumes and cactus can be used to make silage which can be used by farmers during dry season.

  12. Legume NADPH Oxidases Have Crucial Roles at Different Stages of Nodulation.

    Science.gov (United States)

    Montiel, Jesús; Arthikala, Manoj-Kumar; Cárdenas, Luis; Quinto, Carmen

    2016-05-18

    Plant NADPH oxidases, formerly known as respiratory burst oxidase homologues (RBOHs), are plasma membrane enzymes dedicated to reactive oxygen species (ROS) production. These oxidases are implicated in a wide variety of processes, ranging from tissue and organ growth and development to signaling pathways in response to abiotic and biotic stimuli. Research on the roles of RBOHs in the plant's response to biotic stresses has mainly focused on plant-pathogen interactions; nonetheless, recent findings have shown that these oxidases are also involved in the legume-rhizobia symbiosis. The legume-rhizobia symbiosis leads to the formation of the root nodule, where rhizobia reduce atmospheric nitrogen to ammonia. A complex signaling and developmental pathway in the legume root hair and root facilitate rhizobial entrance and nodule organogenesis, respectively. Interestingly, several reports demonstrate that RBOH-mediated ROS production displays versatile roles at different stages of nodulation. The evidence collected to date indicates that ROS act as signaling molecules that regulate rhizobial invasion and also function in nodule senescence. This review summarizes discoveries that support the key and versatile roles of various RBOH members in the legume-rhizobia symbiosis.

  13. Mineral composition of legumes forages cultivated under different levels of shade

    Directory of Open Access Journals (Sweden)

    João Carlos de Carvalho Almeida

    2015-02-01

    Full Text Available The objective of this study was to evaluate the composition of calcium, phosphorus and potassium, and the leaf: stem ratio of four tropical forage legumes: Calopogonium mucunoides (calopo, Pueraria phaseoloides (puero, Macrotyloma axillare (archer and Neonotonia wightii (perennial soybean, under different levels of artificial shade (0, 30, 50 and 70% in the summer and autumn seasons of 2006 and 2007, respectively. The experimental design was a randomized complete block in factorial 4x4 design with four replications. Was used SNK test at 5% probability to evaluate the effect of the legume species and regression analysis to test the effect of the level of shading. There was a trend of increase in the concentration of 3 independent minerals examined the season. In contrast, there was a reduction in the leaf: stem ratio and a slight increase in specific leaf area archer, perennial soybean and puero (R2 ? 40%, which suggests small effect of shading on the morphology of leaves of 3 forage legumes, which in turn have little effect concentrating minerals, besides these finding is confirmed the annual calopo behavior, which prevents their use as legume forage for the autumn season.

  14. GLOBAL ATTRACTIVITY IN A PERIODIC DELAY SINGLE SPECIES MODEL

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, we establish the existence of a positive periodic solution for a periodic delay single species population growth model, and obtain sufficient conditions for the periodic solution to be globally attractive.

  15. The Combined Use of Correlative and Mechanistic Species Distribution Models Benefits Low Conservation Status Species.

    Directory of Open Access Journals (Sweden)

    Thibaud Rougier

    Full Text Available Species can respond to climate change by tracking appropriate environmental conditions in space, resulting in a range shift. Species Distribution Models (SDMs can help forecast such range shift responses. For few species, both correlative and mechanistic SDMs were built, but allis shad (Alosa alosa, an endangered anadromous fish species, is one of them. The main purpose of this study was to provide a framework for joint analyses of correlative and mechanistic SDMs projections in order to strengthen conservation measures for species of conservation concern. Guidelines for joint representation and subsequent interpretation of models outputs were defined and applied. The present joint analysis was based on the novel mechanistic model GR3D (Global Repositioning Dynamics of Diadromous fish Distribution which was parameterized on allis shad and then used to predict its future distribution along the European Atlantic coast under different climate change scenarios (RCP 4.5 and RCP 8.5. We then used a correlative SDM for this species to forecast its distribution across the same geographic area and under the same climate change scenarios. First, projections from correlative and mechanistic models provided congruent trends in probability of habitat suitability and population dynamics. This agreement was preferentially interpreted as referring to the species vulnerability to climate change. Climate change could not be accordingly listed as a major threat for allis shad. The congruence in predicted range limits between SDMs projections was the next point of interest. The difference, when noticed, required to deepen our understanding of the niche modelled by each approach. In this respect, the relative position of the northern range limit between the two methods strongly suggested here that a key biological process related to intraspecific variability was potentially lacking in the mechanistic SDM. Based on our knowledge, we hypothesized that local

  16. The Combined Use of Correlative and Mechanistic Species Distribution Models Benefits Low Conservation Status Species.

    Science.gov (United States)

    Rougier, Thibaud; Lassalle, Géraldine; Drouineau, Hilaire; Dumoulin, Nicolas; Faure, Thierry; Deffuant, Guillaume; Rochard, Eric; Lambert, Patrick

    2015-01-01

    Species can respond to climate change by tracking appropriate environmental conditions in space, resulting in a range shift. Species Distribution Models (SDMs) can help forecast such range shift responses. For few species, both correlative and mechanistic SDMs were built, but allis shad (Alosa alosa), an endangered anadromous fish species, is one of them. The main purpose of this study was to provide a framework for joint analyses of correlative and mechanistic SDMs projections in order to strengthen conservation measures for species of conservation concern. Guidelines for joint representation and subsequent interpretation of models outputs were defined and applied. The present joint analysis was based on the novel mechanistic model GR3D (Global Repositioning Dynamics of Diadromous fish Distribution) which was parameterized on allis shad and then used to predict its future distribution along the European Atlantic coast under different climate change scenarios (RCP 4.5 and RCP 8.5). We then used a correlative SDM for this species to forecast its distribution across the same geographic area and under the same climate change scenarios. First, projections from correlative and mechanistic models provided congruent trends in probability of habitat suitability and population dynamics. This agreement was preferentially interpreted as referring to the species vulnerability to climate change. Climate change could not be accordingly listed as a major threat for allis shad. The congruence in predicted range limits between SDMs projections was the next point of interest. The difference, when noticed, required to deepen our understanding of the niche modelled by each approach. In this respect, the relative position of the northern range limit between the two methods strongly suggested here that a key biological process related to intraspecific variability was potentially lacking in the mechanistic SDM. Based on our knowledge, we hypothesized that local adaptations to cold

  17. TRUNCATULIX--a data warehouse for the legume community.

    Science.gov (United States)

    Henckel, Kolja; Runte, Kai J; Bekel, Thomas; Dondrup, Michael; Jakobi, Tobias; Küster, Helge; Goesmann, Alexander

    2009-02-11

    Databases for either sequence, annotation, or microarray experiments data are extremely beneficial to the research community, as they centrally gather information from experiments performed by different scientists. However, data from different sources develop their full capacities only when combined. The idea of a data warehouse directly adresses this problem and solves it by integrating all required data into one single database - hence there are already many data warehouses available to genetics. For the model legume Medicago truncatula, there is currently no such single data warehouse that integrates all freely available gene sequences, the corresponding gene expression data, and annotation information. Thus, we created the data warehouse TRUNCATULIX, an integrative database of Medicago truncatula sequence and expression data. The TRUNCATULIX data warehouse integrates five public databases for gene sequences, and gene annotations, as well as a database for microarray expression data covering raw data, normalized datasets, and complete expression profiling experiments. It can be accessed via an AJAX-based web interface using a standard web browser. For the first time, users can now quickly search for specific genes and gene expression data in a huge database based on high-quality annotations. The results can be exported as Excel, HTML, or as csv files for further usage. The integration of sequence, annotation, and gene expression data from several Medicago truncatula databases in TRUNCATULIX provides the legume community with access to data and data mining capability not previously available. TRUNCATULIX is freely available at http://www.cebitec.uni-bielefeld.de/truncatulix/.

  18. Dynamic species distribution models from categorical survey data.

    Science.gov (United States)

    Mieszkowska, Nova; Milligan, Gregg; Burrows, Michael T; Freckleton, Rob; Spencer, Matthew

    2013-11-01

    1. Species distribution models are static models for the distribution of a species, based on Hutchinson's niche concept. They make probabilistic predictions about the distribution of a species, but do not have a temporal interpretation. In contrast, density-structured models based on categorical abundance data make it possible to incorporate population dynamics into species distribution modelling. 2. Using dynamic species distribution models, temporal aspects of a species' distribution can be investigated, including the predictability of future abundance categories and the expected persistence times of local populations, and how these may respond to environmental or anthropogenic drivers. 3. We built density-structured models for two intertidal marine invertebrates, the Lusitanian trochid gastropods Phorcus lineatus and Gibbula umbilicalis, based on 9 years of field data from around the United Kingdom. Abundances were recorded on a categorical scale, and stochastic models for year-to-year changes in abundance category were constructed with winter mean sea surface temperature (SST) and wave fetch (a measure of the exposure of a shore) as explanatory variables. 4. Both species were more likely to be present at sites with high SST, but differed in their responses to wave fetch. Phorcus lineatus had more predictable future abundance and longer expected persistence times than G. umbilicalis. This is consistent with the longer lifespan of P. lineatus. 5. Where data from multiple time points are available, dynamic species distribution models of the kind described here have many applications in population and conservation biology. These include allowing for changes over time when combining historical and contemporary data, and predicting how climate change might alter future abundance conditional on current distributions.

  19. Legume nodule senescence: roles for redox and hormone signalling in the orchestration of the natural aging process.

    Science.gov (United States)

    Puppo, Alain; Groten, Karin; Bastian, Fabiola; Carzaniga, Raffaella; Soussi, Mariam; Lucas, M Mercedes; de Felipe, Maria Rosario; Harrison, Judith; Vanacker, Hélène; Foyer, Christine H

    2005-03-01

    Research on legume nodule development has contributed greatly to our current understanding of plant-microbe interactions. However, the factors that orchestrate root nodule senescence have received relatively little attention. Accumulating evidence suggests that redox signals contribute to the establishment of symbiosis and senescence. Although degenerative in nature, nodule senescence is an active process programmed in development in which reactive oxygen species (ROS), antioxidants, hormones and proteinases have key roles. Nodules have high levels of the redox buffers, ascorbate and glutathione, which are important in the nodulation process and in senescence. These metabolites decline with N-fixation as the nodule ages but the resultant decrease in redox buffering capacity does not necessarily lead to enhanced ROS or oxidative stress. We propose models by which ROS and antioxidants interact with hormones such as abscisic acid in the orchestration of nodule senescence.

  20. In vitro ruminal fermentation characteristics and utilisable CP supply of sainfoin and birdsfoot trefoil silages and their mixtures with other legumes

    OpenAIRE

    Grosse Brinkhaus, A.; Wyss, U.; Arrigo, Y; Girard, M.; Bee, G.; Zeitz, J. O.; Kreuzer, M.; Dohme-Meier, F.

    2016-01-01

    The extensive protein degradation occurring during ensiling decreases the nutritive value of silages, but this might be counteracted by tannins. Therefore, silages from two legume species containing condensed tannins (CT) ? sainfoin (SF) and birdsfoot trefoil (two cultivars: birdsfoot trefoil, cv. Bull (BTB) and birdsfoot trefoil, cv. Polom) ? were compared for their in vitro ruminal fermentation characteristics. The effect of combining them with two CT-free legume silages (lucerne (LU) and r...

  1. PROSPECTS OF USING INVASIVE LEGUMES IN HERBAL MEDICINE

    Directory of Open Access Journals (Sweden)

    Shelepova O. V.

    2015-12-01

    Full Text Available The authors propose to consider alien invasive species as new bioresources. These plants form powerful (usually single-species thickets in the secondary range and their size are larger than at the native cenosis. The territory occupied by invasive species, especially in disturbed habitats, is quite high, so their possible yield is very high. The main problem of using alien species in the pharmacological purposes is the lack of information about the dynamics of the chemicals accumulation. Available data on the biochemistry in its natural habitat is inadaptable for the same taxon in the secondary range because of significant microevolutionary changes. In this work we present the results of phytochemical screening four legume species, formed invasive populations in the Middle Russia - Galega orientalis Lam., Lupinus polyphyllus Lindl., Robinia pseudoacacia L. & Caragana arborescens Lam. Information about these species as traditional medicine plants is given. Original data on the concentration phenolic compounds and biophile silicon in leaves and inflorescences are presented. Information on the fractional composition of the flavonoid complex is done. Taking into consideration the high adaptability of invasive species, the chemical analysis of the samples from different ecotypes was made. It is shown that accumulation of bioactive agents and biophile silicon isn’t depended on the environmental conditions. Concentrations of polyphenolic compounds were at the average level in comparison with medicinal plants. Thus, the combination of flavonoid complex with biophile silicon provides pharmacological significance of studied species, and justifies the needing the further study of invasive plant species in order to create new herbal medicines

  2. Species clustering in competitive Lotka-Volterra models.

    Science.gov (United States)

    Pigolotti, Simone; López, Cristóbal; Hernández-García, Emilio

    2007-06-22

    We study the properties of general Lotka-Volterra models with competitive interactions. The intensity of the competition depends on the position of species in an abstract niche space through an interaction kernel. We show analytically and numerically that the properties of these models change dramatically when the Fourier transform of this kernel is not positive definite, due to a pattern-forming instability. We estimate properties of the species distributions, such as the steady number of species and their spacings, for different types of interactions, including stretched exponential and constant kernels.

  3. Biomass models to estimate carbon stocks for hardwood tree species

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Peinado, R.; Montero, G.; Rio, M. del

    2012-11-01

    To estimate forest carbon pools from forest inventories it is necessary to have biomass models or biomass expansion factors. In this study, tree biomass models were developed for the main hardwood forest species in Spain: Alnus glutinosa, Castanea sativa, Ceratonia siliqua, Eucalyptus globulus, Fagus sylvatica, Fraxinus angustifolia, Olea europaea var. sylvestris, Populus x euramericana, Quercus canariensis, Quercus faginea, Quercus ilex, Quercus pyrenaica and Quercus suber. Different tree biomass components were considered: stem with bark, branches of different sizes, above and belowground biomass. For each species, a system of equations was fitted using seemingly unrelated regression, fulfilling the additivity property between biomass components. Diameter and total height were explored as independent variables. All models included tree diameter whereas for the majority of species, total height was only considered in the stem biomass models and in some of the branch models. The comparison of the new biomass models with previous models fitted separately for each tree component indicated an improvement in the accuracy of the models. A mean reduction of 20% in the root mean square error and a mean increase in the model efficiency of 7% in comparison with recently published models. So, the fitted models allow estimating more accurately the biomass stock in hardwood species from the Spanish National Forest Inventory data. (Author) 45 refs.

  4. Innovations in agronomy for food legumes. A review

    OpenAIRE

    Siddique, Kadambot H. M.; Johansen, Chris; Turner, Neil C.; Jeuffroy, Marie-Helene,; Hashem, Abul; Dogan SAKAR; Gan, Yantai; Alghamdi, Salem S.

    2012-01-01

    Although there is increasing awareness of the importance of food legumes in human, animal and soil health, adoption of improved production technologies for food legume crops is not proceeding at the same pace as for cereal crops. Over the previous decade, the only food legumes to have shown significant production increases have been chickpea, lentil and faba bean in North America, chickpea in Australia, and faba bean in Europe. In smallholder farming in developing countries, production trends...

  5. Antioxidant treatments counteract the non-culturability of bacterial endophytes isolated from legume nodules.

    Science.gov (United States)

    Muresu, Rosella; Tondello, Alessandra; Polone, Elisa; Sulas, Leonardo; Baldan, Barbara; Squartini, Andrea

    2013-06-01

    In many wild legumes, attempts to cultivate nodule bacteria fail. We hypothesized that the limited culturability could be related to injury from oxidative stress caused by disruption of plant tissues during isolation. To test that, we isolated bacteria from nodules of Hedysarum spinosissimum and Tetragonolobus purpureus using buffers supplemented with scavenging systems to prevent damage from reactive oxygen species (ROS). Treatments included the following: antioxidants (glutathione, ascorbate, EDTA) or enzymes (catalase, peroxidase, superoxide dismutase), tested either as modified squashing buffers or added in plates. Some combinations yielded dramatic increases of culturability. Different endophytes were found, including additional Rhizobiaceae that were not the primary symbiont and were unable to nodulate. Their H2O2 tolerance in broth culture showed differences consistent with the unequal culturability observed. In wild legumes species, ROS generation during extraction appears to be a major factor limiting microbiota isolation, and protocols presented here significantly improve the recovery of culturable bacterial endophytes from plants.

  6. Symbiotic ß-proteobacteria beyond legumes: Burkholderia in Rubiaceae.

    Directory of Open Access Journals (Sweden)

    Brecht Verstraete

    Full Text Available Symbiotic ß-proteobacteria not only occur in root nodules of legumes but are also found in leaves of certain Rubiaceae. The discovery of bacteria in plants formerly not implicated in endosymbiosis suggests a wider occurrence of plant-microbe interactions. Several ß-proteobacteria of the genus Burkholderia are detected in close association with tropical plants. This interaction has occurred three times independently, which suggest a recent and open plant-bacteria association. The presence or absence of Burkholderia endophytes is consistent on genus level and therefore implies a predictive value for the discovery of bacteria. Only a single Burkholderia species is found in association with a given plant species. However, the endophyte species are promiscuous and can be found in association with several plant species. Most of the endophytes are part of the plant-associated beneficial and environmental group, but others are closely related to B. glathei. This soil bacteria, together with related nodulating and non-nodulating endophytes, is therefore transferred to a newly defined and larger PBE group within the genus Burkholderia.

  7. An analytically tractable model for community ecology with many species

    Science.gov (United States)

    Dickens, Benjamin; Fisher, Charles; Mehta, Pankaj; Pankaj Mehta Biophysics Theory Group Team

    A fundamental problem in community ecology is to understand how ecological processes such as selection, drift, and immigration yield observed patterns in species composition and diversity. Here, we present an analytically tractable, presence-absence (PA) model for community assembly and use it to ask how ecological traits such as the strength of competition, diversity in competition, and stochasticity affect species composition in a community. In our PA model, we treat species as stochastic binary variables that can either be present or absent in a community: species can immigrate into the community from a regional species pool and can go extinct due to competition and stochasticity. Despite its simplicity, the PA model reproduces the qualitative features of more complicated models of community assembly. In agreement with recent work on large, competitive Lotka-Volterra systems, the PA model exhibits distinct ecological behaviors organized around a special (``critical'') point corresponding to Hubbell's neutral theory of biodiversity. Our results suggest that the concepts of ``phases'' and phase diagrams can provide a powerful framework for thinking about community ecology and that the PA model captures the essential ecological dynamics of community assembly. Pm was supported by a Simons Investigator in the Mathematical Modeling of Living Systems and a Sloan Research Fellowship.

  8. Yield and nutritive quality of forage legumes on reclaimed surface mined land

    Energy Technology Data Exchange (ETDEWEB)

    Ditsch, D.C.; Collins, M. [University of Kentucky, Quicksand, KY (United States). Robinson Experiment Station

    1998-07-01

    Legumes are important in the long-term nitrogen economy of surface mined lands and for establishing and maintaining quality livestock forage. Little information is available to reclamation specialists for use in selection of forage legume species based on productivity potential, persistence and nutritive quality for livestock. A study was initiated at two sites in the Appalachian coal fields of Kentucky to evaluate monocultures of alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.) and birdsfoot trefoil (Lotus corniculatus L.) under management regimes suitable for livestock production. Legumes were harvested at the early bloom stage throughout the growing season for dry matter (DM) yield determination. Forage quality was determined by measuring crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose (CEL) and acid detergent lignin (ADL). High DM yields were produced by all species during the first production season (range 6.2-9.2 Mg ha{sup -1}) but yields of all species declined rapidly by year three. Birdsfoot trefoil demonstrated slightly greater drought tolerance during mid-season (July/August) than alfalfa and red clover. With the exception of site {number_sign}1 in 1992 (4 harvests), no more than 3 harvests were made during a single growing season. Crude protein concentration of these forage legumes was found to be within the range commonly measured on undisturbed lands. However, high NDF and ADF values were observed above those reported by others for the same species. These results indicate that it may be difficult to maintain a high level of productivity throughout the five-year bonding period under hay management. Management practices such as summer stockpiling may be necessary to compensate for the rapid and wide fluctuations in DM yield and quality due to low water-holding capacity of mine spoils. 15 refs., 2 figs., 7 tabs.

  9. Population distribution models: species distributions are better modeled using biologically relevant data partitions.

    Science.gov (United States)

    Gonzalez, Sergio C; Soto-Centeno, J Angel; Reed, David L

    2011-09-19

    Predicting the geographic distribution of widespread species through modeling is problematic for several reasons including high rates of omission errors. One potential source of error for modeling widespread species is that subspecies and/or races of species are frequently pooled for analyses, which may mask biologically relevant spatial variation within the distribution of a single widespread species. We contrast a presence-only maximum entropy model for the widely distributed oldfield mouse (Peromyscus polionotus) that includes all available presence locations for this species, with two composite maximum entropy models. The composite models either subdivided the total species distribution into four geographic quadrants or by fifteen subspecies to capture spatially relevant variation in P. polionotus distributions. Despite high Area Under the ROC Curve (AUC) values for all models, the composite species distribution model of P. polionotus generated from individual subspecies models represented the known distribution of the species much better than did the models produced by partitioning data into geographic quadrants or modeling the whole species as a single unit. Because the AUC values failed to describe the differences in the predictability of the three modeling strategies, we suggest using omission curves in addition to AUC values to assess model performance. Dividing the data of a widespread species into biologically relevant partitions greatly increased the performance of our distribution model; therefore, this approach may prove to be quite practical and informative for a wide range of modeling applications.

  10. Multiple polyploidy events in the early radiation of nodulating and nonnodulating legumes.

    Science.gov (United States)

    Cannon, Steven B; McKain, Michael R; Harkess, Alex; Nelson, Matthew N; Dash, Sudhansu; Deyholos, Michael K; Peng, Yanhui; Joyce, Blake; Stewart, Charles N; Rolf, Megan; Kutchan, Toni; Tan, Xuemei; Chen, Cui; Zhang, Yong; Carpenter, Eric; Wong, Gane Ka-Shu; Doyle, Jeff J; Leebens-Mack, Jim

    2015-01-01

    Unresolved questions about evolution of the large and diverse legume family include the timing of polyploidy (whole-genome duplication; WGDs) relative to the origin of the major lineages within the Fabaceae and to the origin of symbiotic nitrogen fixation. Previous work has established that a WGD affects most lineages in the Papilionoideae and occurred sometime after the divergence of the papilionoid and mimosoid clades, but the exact timing has been unknown. The history of WGD has also not been established for legume lineages outside the Papilionoideae. We investigated the presence and timing of WGDs in the legumes by querying thousands of phylogenetic trees constructed from transcriptome and genome data from 20 diverse legumes and 17 outgroup species. The timing of duplications in the gene trees indicates that the papilionoid WGD occurred in the common ancestor of all papilionoids. The earliest diverging lineages of the Papilionoideae include both nodulating taxa, such as the genistoids (e.g., lupin), dalbergioids (e.g., peanut), phaseoloids (e.g., beans), and galegoids (=Hologalegina, e.g., clovers), and clades with nonnodulating taxa including Xanthocercis and Cladrastis (evaluated in this study). We also found evidence for several independent WGDs near the base of other major legume lineages, including the Mimosoideae-Cassiinae-Caesalpinieae (MCC), Detarieae, and Cercideae clades. Nodulation is found in the MCC and papilionoid clades, both of which experienced ancestral WGDs. However, there are numerous nonnodulating lineages in both clades, making it unclear whether the phylogenetic distribution of nodulation is due to independent gains or a single origin followed by multiple losses.

  11. Likelihood analysis of species occurrence probability from presence-only data for modelling species distributions

    Science.gov (United States)

    Royle, J. Andrew; Chandler, Richard B.; Yackulic, Charles; Nichols, James D.

    2012-01-01

    1. Understanding the factors affecting species occurrence is a pre-eminent focus of applied ecological research. However, direct information about species occurrence is lacking for many species. Instead, researchers sometimes have to rely on so-called presence-only data (i.e. when no direct information about absences is available), which often results from opportunistic, unstructured sampling. MAXENT is a widely used software program designed to model and map species distribution using presence-only data. 2. We provide a critical review of MAXENT as applied to species distribution modelling and discuss how it can lead to inferential errors. A chief concern is that MAXENT produces a number of poorly defined indices that are not directly related to the actual parameter of interest – the probability of occurrence (ψ). This focus on an index was motivated by the belief that it is not possible to estimate ψ from presence-only data; however, we demonstrate that ψ is identifiable using conventional likelihood methods under the assumptions of random sampling and constant probability of species detection. 3. The model is implemented in a convenient r package which we use to apply the model to simulated data and data from the North American Breeding Bird Survey. We demonstrate that MAXENT produces extreme under-predictions when compared to estimates produced by logistic regression which uses the full (presence/absence) data set. We note that MAXENT predictions are extremely sensitive to specification of the background prevalence, which is not objectively estimated using the MAXENT method. 4. As with MAXENT, formal model-based inference requires a random sample of presence locations. Many presence-only data sets, such as those based on museum records and herbarium collections, may not satisfy this assumption. However, when sampling is random, we believe that inference should be based on formal methods that facilitate inference about interpretable ecological quantities

  12. Socioeconomic Study of Grasses and Legumes in Baria and Godhra Forest Division, Gujarat

    Directory of Open Access Journals (Sweden)

    Dhara J. GANDHI

    2011-08-01

    Full Text Available Gujarat has rich traditional knowledge associated with biodiversity. The cultural diversity in the Indian society reflects close relationship between the existence of human life and nature including all other living creatures and non-living creatures. The present paper deals with the traditional knowledge of villagers in 10 villages nearby the grasslands in Panchmahal and Dahod districts of Gujarat, India, regarding the multipurpose use of grasses and associated legumes prevailing in these grasslands. A survey with the help of questionnaire was conducted to analyze the socioeconomic status. 69 grass species and 34 legumes could be identified growing in these grasslands of which 92 were used for livestocks. Among these grasses the most preferred grass species were Dichanthium annulatum and Sehima nervosum because of its high palatability. Three grasses and 8 legume species were used for food and medicine. The study emphasizes the use of plant wealth to human needs of the regions and assist in appraisal of various anthropogenic interventions accountable for loss of prevailing biodiversity of the region.

  13. Analytically tractable model for community ecology with many species

    Science.gov (United States)

    Dickens, Benjamin; Fisher, Charles K.; Mehta, Pankaj

    2016-08-01

    A fundamental problem in community ecology is understanding how ecological processes such as selection, drift, and immigration give rise to observed patterns in species composition and diversity. Here, we analyze a recently introduced, analytically tractable, presence-absence (PA) model for community assembly, and we use it to ask how ecological traits such as the strength of competition, the amount of diversity, and demographic and environmental stochasticity affect species composition in a community. In the PA model, species are treated as stochastic binary variables that can either be present or absent in a community: species can immigrate into the community from a regional species pool and can go extinct due to competition and stochasticity. Building upon previous work, we show that, despite its simplicity, the PA model reproduces the qualitative features of more complicated models of community assembly. In agreement with recent studies of large, competitive Lotka-Volterra systems, the PA model exhibits distinct ecological behaviors organized around a special ("critical") point corresponding to Hubbell's neutral theory of biodiversity. These results suggest that the concepts of ecological "phases" and phase diagrams can provide a powerful framework for thinking about community ecology, and that the PA model captures the essential ecological dynamics of community assembly.

  14. Contrasting effects of intraspecific trait variation on trait-based niches and performance of legumes in plant mixtures.

    Directory of Open Access Journals (Sweden)

    Christiane Roscher

    Full Text Available Niche differentiation, assumed to be a key mechanism of species coexistence, requires that species differ in their functional traits. So far it remains unclear to which extent trait plasticity leads to niche shifts of species at higher plant diversity, thereby increasing or decreasing niche overlap between species. To analyse this question it is convenient to measure niches indirectly via the variation in resource-uptake traits rather than directly via the resources used. We provisionally call these indirectly measured niches trait-based niches. We studied shoot- and leaf-morphological characteristics in seven legume species in monoculture and multi-species mixture in experimental grassland. Legume species varied in the extent of trait variation in response to plant diversity. Trait plasticity led to significant shifts in species niches in multiple dimensions. Single-species niches in several traits associated with height growth and filling of canopy space were expanded, while other niche dimensions were compressed or did not change with plant diversity. Niche separation among legumes decreased in dimensions related to height growth and space filling, but increased in dimensions related to leaf size and morphology. The total extent of occupied niche space was larger in mixture than in the combined monocultures for dimensions related to leaf morphology and smaller for dimensions related to whole-plant architecture. Taller growth, greater space filling and greater plasticity in shoot height were positively, while larger values and greater plasticity in specific leaf area were negatively related with increased performance of species in mixture. Our study shows that trait variation in response to plant diversity shifts species niches along trait axes. Plastically increased niche differentiation is restricted to niche dimensions that are apparently not related to size-dependent differences between species, but functional equivalence (convergence in

  15. Contrasting effects of intraspecific trait variation on trait-based niches and performance of legumes in plant mixtures.

    Science.gov (United States)

    Roscher, Christiane; Schumacher, Jens; Schmid, Bernhard; Schulze, Ernst-Detlef

    2015-01-01

    Niche differentiation, assumed to be a key mechanism of species coexistence, requires that species differ in their functional traits. So far it remains unclear to which extent trait plasticity leads to niche shifts of species at higher plant diversity, thereby increasing or decreasing niche overlap between species. To analyse this question it is convenient to measure niches indirectly via the variation in resource-uptake traits rather than directly via the resources used. We provisionally call these indirectly measured niches trait-based niches. We studied shoot- and leaf-morphological characteristics in seven legume species in monoculture and multi-species mixture in experimental grassland. Legume species varied in the extent of trait variation in response to plant diversity. Trait plasticity led to significant shifts in species niches in multiple dimensions. Single-species niches in several traits associated with height growth and filling of canopy space were expanded, while other niche dimensions were compressed or did not change with plant diversity. Niche separation among legumes decreased in dimensions related to height growth and space filling, but increased in dimensions related to leaf size and morphology. The total extent of occupied niche space was larger in mixture than in the combined monocultures for dimensions related to leaf morphology and smaller for dimensions related to whole-plant architecture. Taller growth, greater space filling and greater plasticity in shoot height were positively, while larger values and greater plasticity in specific leaf area were negatively related with increased performance of species in mixture. Our study shows that trait variation in response to plant diversity shifts species niches along trait axes. Plastically increased niche differentiation is restricted to niche dimensions that are apparently not related to size-dependent differences between species, but functional equivalence (convergence in height growth) rather

  16. Benchmarking novel approaches for modelling species range dynamics.

    Science.gov (United States)

    Zurell, Damaris; Thuiller, Wilfried; Pagel, Jörn; Cabral, Juliano S; Münkemüller, Tamara; Gravel, Dominique; Dullinger, Stefan; Normand, Signe; Schiffers, Katja H; Moore, Kara A; Zimmermann, Niklaus E

    2016-08-01

    Increasing biodiversity loss due to climate change is one of the most vital challenges of the 21st century. To anticipate and mitigate biodiversity loss, models are needed that reliably project species' range dynamics and extinction risks. Recently, several new approaches to model range dynamics have been developed to supplement correlative species distribution models (SDMs), but applications clearly lag behind model development. Indeed, no comparative analysis has been performed to evaluate their performance. Here, we build on process-based, simulated data for benchmarking five range (dynamic) models of varying complexity including classical SDMs, SDMs coupled with simple dispersal or more complex population dynamic models (SDM hybrids), and a hierarchical Bayesian process-based dynamic range model (DRM). We specifically test the effects of demographic and community processes on model predictive performance. Under current climate, DRMs performed best, although only marginally. Under climate change, predictive performance varied considerably, with no clear winners. Yet, all range dynamic models improved predictions under climate change substantially compared to purely correlative SDMs, and the population dynamic models also predicted reasonable extinction risks for most scenarios. When benchmarking data were simulated with more complex demographic and community processes, simple SDM hybrids including only dispersal often proved most reliable. Finally, we found that structural decisions during model building can have great impact on model accuracy, but prior system knowledge on important processes can reduce these uncertainties considerably. Our results reassure the clear merit in using dynamic approaches for modelling species' response to climate change but also emphasize several needs for further model and data improvement. We propose and discuss perspectives for improving range projections through combination of multiple models and for making these approaches

  17. A meta-analysis of relative crop yields in cereal/legume mixtures suggests options for management

    NARCIS (Netherlands)

    Yu, Yang; Stomph, Tjeerd-Jan; Makowski, David; Zhang, Lizhen; Werf, van der Wopke

    2016-01-01

    Intercrops of cereals and legumes are grown worldwide, both in smallholder agriculture in developing countries and in organic farming systems in developed countries. The competitive balance between species is a key factor determining productivity in mixtures. Management factors, e.g. sowing time,

  18. Transcriptome sequencing, and rapid development and application of SNP markers for the legume pod borer Maruca vitrata (Lepidoptera: Crambidae)

    Science.gov (United States)

    The legume pod borer, Maruca vitrata (Lepidoptera: Crambidae), is an insect pest species that is destructive to crops grown by subsistence farmers in tropical regions of West Africa. We present the de novo assembly of 3729 contigs from 454- and Sanger-derived sequencing reads for midgut, salivary, ...

  19. Modeling symbiosis by interactions through species carrying capacities

    Science.gov (United States)

    Yukalov, V. I.; Yukalova, E. P.; Sornette, D.

    2012-08-01

    We introduce a mathematical model of symbiosis between different species by taking into account the influence of each species on the carrying capacities of the others. The modeled entities can pertain to biological and ecological societies or to social, economic and financial societies. Our model includes three basic types: symbiosis with direct mutual interactions, symbiosis with asymmetric interactions, and symbiosis without direct interactions. In all cases, we provide a complete classification of all admissible dynamical regimes. The proposed model of symbiosis turned out to be very rich, as it exhibits four qualitatively different regimes: convergence to stationary states, unbounded exponential growth, finite-time singularity, and finite-time death or extinction of species.

  20. Modelling bioaccumulation of oil constituents in aquatic species

    NARCIS (Netherlands)

    Hoop, de L.; Huijbregts, M.A.J.; Schipper, A.M.; Veltman, K.; Laender, de F.; Viaene, K.P.J.; Klok, C.; Hendriks, A.J.

    2013-01-01

    Crude oil poses a risk to marine ecosystems due to its toxicity and tendency to accumulate in biota. The present study evaluated the applicability of the OMEGA model for estimating oil accumulation in aquatic species by comparing model predictions of kinetic rates (absorption and elimination) and bi

  1. Modelling the effect of climate change on species ranges

    NARCIS (Netherlands)

    Nagelkerke, C.J.; Alkemade, J.R.M.

    2003-01-01

    Three main types of models can be used to understand and predict climate-related range shifts. Equilibrium models predict potential future distributions from the current climate envelope of a species, but do not take migration constraints into account. They show that future range changes can be

  2. Species-free species distribution models describe macroecological properties of protected area networks

    Science.gov (United States)

    Fordyce, James A.

    2017-01-01

    Among the greatest challenges facing the conservation of plants and animal species in protected areas are threats from a rapidly changing climate. An altered climate creates both challenges and opportunities for improving the management of protected areas in networks. Increasingly, quantitative tools like species distribution modeling are used to assess the performance of protected areas and predict potential responses to changing climates for groups of species, within a predictive framework. At larger geographic domains and scales, protected area network units have spatial geoclimatic properties that can be described in the gap analysis typically used to measure or aggregate the geographic distributions of species (stacked species distribution models, or S-SDM). We extend the use of species distribution modeling techniques in order to model the climate envelope (or “footprint”) of individual protected areas within a network of protected areas distributed across the 48 conterminous United States and managed by the US National Park System. In our approach we treat each protected area as the geographic range of a hypothetical endemic species, then use MaxEnt and 5 uncorrelated BioClim variables to model the geographic distribution of the climatic envelope associated with each protected area unit (modeling the geographic area of park units as the range of a species). We describe the individual and aggregated climate envelopes predicted by a large network of 163 protected areas and briefly illustrate how macroecological measures of geodiversity can be derived from our analysis of the landscape ecological context of protected areas. To estimate trajectories of change in the temporal distribution of climatic features within a protected area network, we projected the climate envelopes of protected areas in current conditions onto a dataset of predicted future climatic conditions. Our results suggest that the climate envelopes of some parks may be locally unique or

  3. Species-free species distribution models describe macroecological properties of protected area networks.

    Science.gov (United States)

    Robinson, Jason L; Fordyce, James A

    2017-01-01

    Among the greatest challenges facing the conservation of plants and animal species in protected areas are threats from a rapidly changing climate. An altered climate creates both challenges and opportunities for improving the management of protected areas in networks. Increasingly, quantitative tools like species distribution modeling are used to assess the performance of protected areas and predict potential responses to changing climates for groups of species, within a predictive framework. At larger geographic domains and scales, protected area network units have spatial geoclimatic properties that can be described in the gap analysis typically used to measure or aggregate the geographic distributions of species (stacked species distribution models, or S-SDM). We extend the use of species distribution modeling techniques in order to model the climate envelope (or "footprint") of individual protected areas within a network of protected areas distributed across the 48 conterminous United States and managed by the US National Park System. In our approach we treat each protected area as the geographic range of a hypothetical endemic species, then use MaxEnt and 5 uncorrelated BioClim variables to model the geographic distribution of the climatic envelope associated with each protected area unit (modeling the geographic area of park units as the range of a species). We describe the individual and aggregated climate envelopes predicted by a large network of 163 protected areas and briefly illustrate how macroecological measures of geodiversity can be derived from our analysis of the landscape ecological context of protected areas. To estimate trajectories of change in the temporal distribution of climatic features within a protected area network, we projected the climate envelopes of protected areas in current conditions onto a dataset of predicted future climatic conditions. Our results suggest that the climate envelopes of some parks may be locally unique or have

  4. Towards a new classification system for legumes: Progress report from the 6th International Legume Conference

    NARCIS (Netherlands)

    Pontes Coelho Borges, L.M.; Bruneau, A.; Cardoso, D.; Crisp, M.; Delgado-Salinas, A.; Doyle, J.J.; Egan, A.; Herendeen, P.S.; Hughes, C.; Kenicer, G.; Klitgaard, B.; Koenen, E.; Lavin, M.; Lewis, G.; Luckow, M.; Mackinder, B.; Malecot, V.; Miller, J.T.; Pennington, R.T.; Queiroz, de L.P.; Schrire, B.; Simon, M.F.; Steele, K.; Torke, B.; Wieringa, J.J.; Wojciechowski, M.F.; Boatwright, S.; Estrella, de la M.; Mansano, V.D.; Prado, D.E.; Stirton, C.; Wink, M.

    2013-01-01

    Legume systematists have been making great progress in understanding evolutionary relationships within the Leguminosae (Fabaceae), the third largest family of flowering plants. As the phylogenetic picture has become clearer, so too has the need for a revised classification of the family. The

  5. Niche variability and its consequences for species distribution modeling.

    Directory of Open Access Journals (Sweden)

    Matt J Michel

    Full Text Available When species distribution models (SDMs are used to predict how a species will respond to environmental change, an important assumption is that the environmental niche of the species is conserved over evolutionary time-scales. Empirical studies conducted at ecological time-scales, however, demonstrate that the niche of some species can vary in response to environmental change. We use habitat and locality data of five species of stream fishes collected across seasons to examine the effects of niche variability on the accuracy of projections from Maxent, a popular SDM. We then compare these predictions to those from an alternate method of creating SDM projections in which a transformation of the environmental data to similar scales is applied. The niche of each species varied to some degree in response to seasonal variation in environmental variables, with most species shifting habitat use in response to changes in canopy cover or flow rate. SDMs constructed from the original environmental data accurately predicted the occurrences of one species across all seasons and a subset of seasons for two other species. A similar result was found for SDMs constructed from the transformed environmental data. However, the transformed SDMs produced better models in ten of the 14 total SDMs, as judged by ratios of mean probability values at known presences to mean probability values at all other locations. Niche variability should be an important consideration when using SDMs to predict future distributions of species because of its prevalence among natural populations. The framework we present here may potentially improve these predictions by accounting for such variability.

  6. Phytohormone regulation of legume-rhizobia interactions.

    Science.gov (United States)

    Ferguson, Brett J; Mathesius, Ulrike

    2014-07-01

    The symbiosis between legumes and nitrogen fixing bacteria called rhizobia leads to the formation of root nodules. Nodules are highly organized root organs that form in response to Nod factors produced by rhizobia, and they provide rhizobia with a specialized niche to optimize nutrient exchange and nitrogen fixation. Nodule development and invasion by rhizobia is locally controlled by feedback between rhizobia and the plant host. In addition, the total number of nodules on a root system is controlled by a systemic mechanism termed 'autoregulation of nodulation'. Both the local and the systemic control of nodulation are regulated by phytohormones. There are two mechanisms by which phytohormone signalling is altered during nodulation: through direct synthesis by rhizobia and through indirect manipulation of the phytohormone balance in the plant, triggered by bacterial Nod factors. Recent genetic and physiological evidence points to a crucial role of Nod factor-induced changes in the host phytohormone balance as a prerequisite for successful nodule formation. Phytohormones synthesized by rhizobia enhance symbiosis effectiveness but do not appear to be necessary for nodule formation. This review provides an overview of recent advances in our understanding of the roles and interactions of phytohormones and signalling peptides in the regulation of nodule infection, initiation, positioning, development, and autoregulation. Future challenges remain to unify hormone-related findings across different legumes and to test whether hormone perception, response, or transport differences among different legumes could explain the variety of nodules types and the predisposition for nodule formation in this plant family. In addition, the molecular studies carried out under controlled conditions will need to be extended into the field to test whether and how phytohormone contributions by host and rhizobial partners affect the long term fitness of the host and the survival and

  7. Diversity and symbiotic effectiveness of beta-rhizobia isolated from sub-tropical legumes of a Brazilian Araucaria Forest.

    Science.gov (United States)

    Lammel, Daniel R; Cruz, Leonardo M; Carrer, Helaine; Cardoso, Elke J B N

    2013-12-01

    While the occurrence of Betaproteobacteria occupying the nodules of tropical legumes has been shown, little is known about subtropical areas. Araucaria Forest is a subtropical endangered ecosystem, and a better understanding of the legume-rhizobial symbionts may allow their use in land reclamation. The 16S rRNA gene of bacteria isolated from nine leguminous species was sequenced and their nodulation tested in Mimosa scabrella and Phaseolus vulgaris. 196 isolates were identified as eight genotypes: Pantoea, Pseudomonas, Bradyrhizobium sp1-2, Rhizobium, and Burkholderia sp1-3. The majority of the isolates from native plants (87 %) were taxonomically related to β-rhizobia, namely Burkholderia, however the legumes Galactia crassifolia and Collea speciosa were nodulated by both α and β-rhizobia, and Acacia dealbata, an exotic plant, only by α-rhizobia. The nifH genes of some isolates were sequenced and N-fixing potential shown by the acetylene reduction test. Most of the isolates nodulated the test plants, some were effective in M. scabrella, but all presented low efficiency in the exotic promiscuous legume P. vulgaris. Pantoea and Pseudomonas did not nodulate and probably are endophytic bacteria. The presented data shows diversity of α, β and γ-Proteobacteria in nodules of subtropical legumes, and suggests host specificity with β-rhizobia. Potential isolates were found for M. scabrella, indicating that a high N-fixing strain may be further inoculated in plants for use in reforestation.

  8. GIS-based niche modeling for mapping species' habitat.

    Science.gov (United States)

    Rotenberry, John T; Preston, Kristine L; Knick, Steven T

    2006-06-01

    Ecological "niche modeling" using presence-only locality data and large-scale environmental variables provides a powerful tool for identifying and mapping suitable habitat for species over large spatial extents. We describe a niche modeling approach that identifies a minimum (rather than an optimum) set of basic habitat requirements for a species, based on the assumption that constant environmental relationships in a species' distribution (i.e., variables that maintain a consistent value where the species occurs) are most likely to be associated with limiting factors. Environmental variables that take on a wide range of values where a species occurs are less informative because they do not limit a species' distribution, at least over the range of variation sampled. This approach is operationalized by partitioning Mahalanobis D2 (standardized difference between values of a set of environmental variables for any point and mean values for those same variables calculated from all points at which a species was detected) into independent components. The smallest of these components represents the linear combination of variables with minimum variance; increasingly larger components represent larger variances and are increasingly less limiting. We illustrate this approach using the California Gnatcatcher (Polioptila californica Brewster) and provide SAS code to implement it.

  9. A Solvable Model of Species Body Mass Evolution

    CERN Document Server

    Clauset, Aaron

    2008-01-01

    We present a quantitative model for the biological evolution of species body masses within large groups of related species, e.g., terrestrial mammals, in which body mass M evolves according to branching (speciating) multiplicative diffusion and an extinction probability that increases logarithmically with mass. We describe this evolution in terms of a convection-diffusion-reaction equation for ln M. The steady-state behavior is in good agreement with empirical data on recent terrestrial mammals, and the time-dependent behavior also agrees with data on extinct mammal species between 95 - 50 million years ago.

  10. Can fire atlas data improve species distribution model projections?

    Science.gov (United States)

    Crimmins, Shawn M; Dobrowski, Solomon Z; Mynsberge, Alison R; Safford, Hugh D

    2014-07-01

    Correlative species distribution models (SDMs) are widely used in studies of climate change impacts, yet are often criticized for failing to incorporate disturbance processes that can influence species distributions. Here we use two temporally independent data sets of vascular plant distributions, climate data, and fire atlas data to examine the influence of disturbance history on SDM projection accuracy through time in the mountain ranges of California, USA. We used hierarchical partitioning to examine the influence of fire occurrence on the distribution of 144 vascular plant species and built a suite of SDMs to examine how the inclusion of fire-related predictors (fire occurrence and departure from historical fire return intervals) affects SDM projection accuracy. Fire occurrence provided the least explanatory power among predictor variables for predicting species' distributions, but provided improved explanatory power for species whose regeneration is tied closely to fire. A measure of the departure from historic fire return interval had greater explanatory power for calibrating modern SDMs than fire occurrence. This variable did not improve internal model accuracy for most species, although it did provide marginal improvement to models for species adapted to high-frequency fire regimes. Fire occurrence and fire return interval departure were strongly related to the climatic covariates used in SDM development, suggesting that improvements in model accuracy may not be expected due to limited additional explanatory power. Our results suggest that the inclusion of coarse-scale measures of disturbance in SDMs may not be necessary to predict species distributions under climate change, particularly for disturbance processes that are largely mediated by climate.

  11. The position of prenylation of isoflavonoids and stilbenoids from legumes (Fabaceae) modulates the antimicrobial activity against Gram positive pathogens.

    Science.gov (United States)

    Araya-Cloutier, Carla; den Besten, Heidy M W; Aisyah, Siti; Gruppen, Harry; Vincken, Jean-Paul

    2017-07-01

    The legume plant family (Fabaceae) is a potential source of antimicrobial phytochemicals. Molecular diversity in phytochemicals of legume extracts was enhanced by germination and fungal elicitation of seven legume species, as established by RP-UHPLC-UV-MS. The relationship between phytochemical composition, including different types of skeletons and substitutions, and antibacterial properties of extracts was investigated. Extracts rich in prenylated isoflavonoids and stilbenoids showed potent antibacterial activity against Listeria monocytogenes and methicillin-resistant Staphylococcus aureus at concentrations between 0.05 and 0.1% (w/v). Prenylated phenolic compounds were significantly (plegume seedlings can serve multiple purposes, e.g. as phytoestrogens they can provide health benefits and as natural antimicrobials they offer preservation of foods.

  12. Modelling survival: exposure pattern, species sensitivity and uncertainty.

    Science.gov (United States)

    Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B; Van den Brink, Paul J; Veltman, Karin; Vogel, Sören; Zimmer, Elke I; Preuss, Thomas G

    2016-07-06

    The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans.

  13. Modelling survival: exposure pattern, species sensitivity and uncertainty

    Science.gov (United States)

    Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I.; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B.; van den Brink, Paul J.; Veltman, Karin; Vogel, Sören; Zimmer, Elke I.; Preuss, Thomas G.

    2016-07-01

    The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans.

  14. Considerations for building climate-based species distribution models

    Science.gov (United States)

    Bucklin, David N.; Basille, Mathieu; Romanach, Stephanie; Brandt, Laura A.; Mazzotti, Frank J.; Watling, James I.

    2016-01-01

    Climate plays an important role in the distribution of species. A given species may adjust to new conditions in-place, move to new areas with suitable climates, or go extinct. Scientists and conservation practitioners use mathematical models to predict the effects of future climate change on wildlife and plan for a biodiverse future. This 8-page fact sheet written by David N. Bucklin, Mathieu Basille, Stephanie S. Romañach, Laura A. Brandt, Frank J. Mazzotti, and James I. Watling and published by the Department of Wildlife Ecology and Conservation explains how, with a better understanding of species distribution models, we can predict how species may respond to climate change. The models alone cannot tell us how a certain species will actually respond to changes in climate, but they can inform conservation planning that aims to allow species to both adapt in place and (for those that are able to) move to newly suitable areas. Such planning will likely minimize loss of biodiversity due to climate change.

  15. Seed softening patterns of forage legumes in a temperate/subtropical environment in Uruguay

    Directory of Open Access Journals (Sweden)

    Javier Do Canto

    2013-03-01

    Full Text Available Few studies have been conducted in annual and perennial forage legumes to investigate the development of hardseededness and the subsequent pattern of seed softening in temperate and subtropical regions of South America. Experiments were conducted during 2007 and 2008 in central Uruguay to follow the pattern of seed softening in 35 annual and perennial forage legumes, including three native species of Uruguay and five commercial cultivars. Newly ripened seeds of each plant material were placed in mesh packets on the soil surface in mid-summer. Samples were recovered monthly for germination tests and the proportion of residual hard seeds determined. The native species Adesmia bicolor (Poir. DC., Adesmia securigerifolia Herter, and Ornithopus micranthus (Benth. Arechav., together with Ornithopus pinnatus (Mill. Druce cv. INIA Molles behaved similarly. They showed high levels of initial hard seed from 78% in A. bicolor to 99% in A. securigerifolia and O. pinnatus cv. INIA Molles in 2007; displayed pulses of seed softening, particularly in autumn, and retained moderate levels of residual hard seed for the development of a soil seed bank ranging from 15% in A. bicolor to 49% in O. micranthus. These appear to be desirable characteristics for persistence of forage legumes in subtropical grasslands, both for annual and perennial species. Trifolium repens L. and Lotus corniculatus L. produced few hard seeds, only 2% and 13% respectively were hard after 1-mo in the field and were completely soft by July placing extra reliance on their vegetative propagation for persistence. Materials of L. arenarius Brot. showed pronounced late autumn softening, while materials of L. ornithopodioides L. showed extremely high levels of hardseededness (between 96% and 100% and no softening during the evaluation period, apart from two materials that were completely soft seeded. Mediterranean forage legumes should be properly evaluated in temperate and subtropical regions as

  16. Induction of prenylated isoflavonoids and stilbenoids in legumes

    NARCIS (Netherlands)

    Aisyah, S.

    2015-01-01

    The germination of legume seeds in the presence or absence of stress factors was studied with respect to compositional changes in prenylated isoflavonoids and stilbenoids. Different strategies were applied using (i) different types of legume seed, (ii) different stress factors i.e. biotic, abiotic

  17. Nitrogen fertilizer response of cotton in rotation with summer legumes

    Science.gov (United States)

    The potential of using summer legumes as N sources in corn and vegetable rotations has recently been documented. The objective of this study was to evaluate the potential of using summer legumes [Crotolaria juncea and cowpeas (Vigna unguiculata)] as an N source for cotton (Gossypium hirsutum L.) pro...

  18. Improving germination and establishment of Great Basin legumes

    Science.gov (United States)

    As part of the Great Basin Native Plant Selection and Increase Project, we have collected and evaluated several native western legumes. Germplasm releases were made, but much work remains to be done concerning how to establish these legumes for seed production and on rangelands. We report herein h...

  19. Legumes affect alpine tundra community composition via multiple biotic interactions

    NARCIS (Netherlands)

    Soudzilovskaia, N.A.; Aksenova, A.A.; Makarov, M.I.; Onipchenko, V.G.; Logvinenko, O.A.; Braak, ter C.J.F.; Cornelissen, J.H.C.

    2012-01-01

    The soil engineering function of legumes in natural ecosystems is paramount but associated solely with soil nitrogen (N) subsidies, ignoring concomitant biotic interactions such as competitive or inhibitory effects and exchange between mycorrhizas and rhizobia. We aim to (1) disentangle legume effec

  20. Induction of prenylated isoflavonoids and stilbenoids in legumes

    NARCIS (Netherlands)

    Aisyah, S.

    2015-01-01

    The germination of legume seeds in the presence or absence of stress factors was studied with respect to compositional changes in prenylated isoflavonoids and stilbenoids. Different strategies were applied using (i) different types of legume seed, (ii) different stress factors i.e. biotic, abiotic a

  1. Probing nod factor perception in legumes by fluorescence microspectroscopy

    NARCIS (Netherlands)

    Goedhart, J.

    2001-01-01

    Plants of the family of legumes are capable of forming a symbiosis with Rhizobium bacteria. These Gram-negative bacteria invade the root system of a host legume and fix nitrogen in a specialized organ, the so-called root nodule. In exchange for sugars, the bacteria convert atmospheric

  2. [Examination and composition of some legume seeds (author's transl)].

    Science.gov (United States)

    Nierle, W; el Wahab el Bayâ, A

    1977-05-26

    The chemical composition of some legume seeds is reviewed. It was found that soy (Glycine soja), field beans (Vicia faba), Vicia sativa and Lens culingris (red seeds) have the highest protein content. There were only minor differences in amino acid composition except for glutamic acid. The lysine content of legume seeds was high. Lysine is the most limiting essential amino acid in cereal proteins, therefore cereal products can be improved nutritionally by addition of legume seed flour. Examination of polar lipids by thin layer chromatography revealed that lecithin, phosphatidyl ethanolamine and phosphatidyl inositol were the major components. However, Lupinus angustifolius contained two unknown polar lipid classes.--In contrary to previous literature the ripe legume seeds contained only a very small amount of galactosyl diglycerides; however legume seeds contain higher amounts of the compounds. The conection between biosynthesis of linolenic acid and the presence of galactosyl diglycerides in higher plants is discussed.

  3. Legumes steam allergy in childhood: Update of the reported cases.

    Science.gov (United States)

    Vitaliti, G; Pavone, P; Spataro, G; Giunta, L; Guglielmo, F; Falsaperla, R

    2015-01-01

    In the past few decades, the prevalence of allergic diseases has deeply increased, with a key role played by food allergies. Legumes seem to play a major role towards the overall increase in the scenario of food allergy, since they are an appreciated source, consumed worldwide, due to their high protein content, variable amounts of lipids and for the presence of vitamins. In literature there are numerous descriptions of adverse reactions after ingestion of uncooked and cooked legumes. Nevertheless, cases of allergic reactions induced by inhaling vapours from cooking legumes have rarely been described. Herein the authors report an update of the literature data on allergic reactions caused by legume steam inhalation, underlying the possible pathogenic mechanism of these atopic events and the knowledge of literature data in paediatric age. The importance of this review is the focus on the clinical aspects concerning legume vapour allergy, referring to literature data in childhood.

  4. GIS-based niche modeling for mapping species' habitats

    Science.gov (United States)

    Rotenberry, J.T.; Preston, K.L.; Knick, S.

    2006-01-01

    Ecological a??niche modelinga?? using presence-only locality data and large-scale environmental variables provides a powerful tool for identifying and mapping suitable habitat for species over large spatial extents. We describe a niche modeling approach that identifies a minimum (rather than an optimum) set of basic habitat requirements for a species, based on the assumption that constant environmental relationships in a species' distribution (i.e., variables that maintain a consistent value where the species occurs) are most likely to be associated with limiting factors. Environmental variables that take on a wide range of values where a species occurs are less informative because they do not limit a species' distribution, at least over the range of variation sampled. This approach is operationalized by partitioning Mahalanobis D2 (standardized difference between values of a set of environmental variables for any point and mean values for those same variables calculated from all points at which a species was detected) into independent components. The smallest of these components represents the linear combination of variables with minimum variance; increasingly larger components represent larger variances and are increasingly less limiting. We illustrate this approach using the California Gnatcatcher (Polioptila californica Brewster) and provide SAS code to implement it.

  5. Modeling of Alkane Oxidation Using Constituents and Species

    Science.gov (United States)

    Bellan, Jasette; Harstad, Kenneth G.

    2010-01-01

    It is currently not possible to perform simulations of turbulent reactive flows due in particular to complex chemistry, which may contain thousands of reactions and hundreds of species. This complex chemistry results in additional differential equations, making the numerical solution of the equation set computationally prohibitive. Reducing the chemical kinetics mathematical description is one of several important goals in turbulent reactive flow modeling. A chemical kinetics reduction model is proposed for alkane oxidation in air that is based on a parallel methodology to that used in turbulence modeling in the context of the Large Eddy Simulation. The objective of kinetic modeling is to predict the heat release and temperature evolution. This kinetic mechanism is valid over a pressure range from atmospheric to 60 bar, temperatures from 600 K to 2,500 K, and equivalence ratios from 0.125 to 8. This range encompasses diesel, HCCI, and gas-turbine engines, including cold ignition. A computationally efficient kinetic reduction has been proposed for alkanes that has been illustrated for n-heptane using the LLNL heptane mechanism. This model is consistent with turbulence modeling in that scales were first categorized into either those modeled or those computed as progress variables. Species were identified as being either light or heavy. The heavy species were decomposed into defined 13 constituents, and their total molar density was shown to evolve in a quasi-steady manner. The light species behave either in a quasi-steady or unsteady manner. The modeled scales are the total constituent molar density, Nc, and the molar density of the quasi-steady light species. The progress variables are the total constituent molar density rate evolution and the molar densities of the unsteady light species. The unsteady equations for the light species contain contributions of the type gain/loss rates from the heavy species that are modeled consistent with the developed mathematical

  6. Nitrogen fixation (acetylene reduction) by annual winter legumes on a coal surface mine

    Energy Technology Data Exchange (ETDEWEB)

    Gabrielson, F.C.

    1982-01-01

    The winter annuals, crimson clover, rose clover, subterranean clover and hairy vetch, were evaluated for their ability to fix nitrogen on coal surface mine substrates by measuring their ability to reduce acetylene to ethylene. The effects of fertilizer, Abruzzi ryegrass, Kentucky 31 fescue grass and a phytotoxic plant Chenopodium album on nitrogen fixation was also assessed. Crimson clover was recommended as the best legume to use on topsoil and shale in the South. Hairy vetch gave good results on shale and subterranean clover did well on topsoil. The use of these species for revegetation is discussed. Overall, no correlation between substrate pH and ethylene levels was found and effects of substrate depended upon the legume species. Super phosphate fertilizer supported less nitrogen fixation than 13-13-13. Abruzzi ryegrass in some unknown way inhibited plant density and nitrogen fixation by legumes but not by free living substrate micro-organisms. Shale from under dead Chenopodium plants in both field and greenhouse experiments did not inhibit nitrogen fixation. 11 references, 7 tables.

  7. Nitrogen fixation (Acetylene Reduction) by annual winter legumes on a coal surface mine

    Energy Technology Data Exchange (ETDEWEB)

    Gabrielson, F.C.

    1982-01-01

    The winter annuals, crimson clover, rose clover, subterranean clover and hairy vetch, were evaluated for nitrogen fixing capacity on coal surface mine substrates by measuring their ability to reduce acetylene to ethylene. The effects of fertilizer, Abruzzi rye, Kentucky 31 fescue grass and a phytotoxic plant Chenopodium album on nitrogen fixation were also assessed. Crimson clover was recommended as the best legume to use on topsoil and shale in the south. Hairy vetch gave good results on shale and subterranean clover did well on topsoil. The use of these species for revegetation is discussed. Overall, no correlation between substrate pH and ethylene levels was found and effects of substrate depended upon the legume species. Super phosphate fertilizer supported less nitrogen fixation than 13-13-13. Abruzzi rye in some unknown way inhibited plant density and nitrogen fixation by legumes but not by free living substrate micro-organisms. Shale from under dead Chenopodium plants in both field and greehouse experiments did not inhibit nitrogen fixation. 7 tables.

  8. Effects of feeding dairy cows different legume-grass silages on milk phytoestrogen concentration

    DEFF Research Database (Denmark)

    Höjer, A; Adler, S; Purup, Stig

    2012-01-01

    interval of legume-grass silage on phytoestrogen intake and milk phytoestrogen concentrations. In one experiment, 15 Swedish Red dairy cows were fed 2- or 3-cut red clover-grass silage, or 2-cut birdsfoot trefoil-grass silage. In a second experiment, 16 Norwegian Red dairy cows were fed short-term ley....... Concentrations of secoisolariciresinol and matairesinol were higher in 2-cut birdsfoot trefoil-grass and long-term ley silage mixtures, those with legume species other than red clover, and the highest grass proportions. The 2-cut birdsfoot trefoil-grass silage diet also resulted in higher enterolactone...... silage with red clover or long-term ley silage with white clover, and the effects of supplementation with α-tocopherol were also tested. High concentrations of formononetin and biochanin A were found in all silage mixtures with red clover. The milk concentration of equol was highest for cows on the 2-cut...

  9. Beyond the zebrafish: diverse fish species for modeling human disease

    Directory of Open Access Journals (Sweden)

    Manfred Schartl

    2014-02-01

    Full Text Available In recent years, zebrafish, and to a lesser extent medaka, have become widely used small animal models for human diseases. These organisms have convincingly demonstrated the usefulness of fish for improving our understanding of the molecular and cellular mechanisms leading to pathological conditions, and for the development of new diagnostic and therapeutic tools. Despite the usefulness of zebrafish and medaka in the investigation of a wide spectrum of traits, there is evidence to suggest that other fish species could be better suited for more targeted questions. With the emergence of new, improved sequencing technologies that enable genomic resources to be generated with increasing efficiency and speed, the potential of non-mainstream fish species as disease models can now be explored. A key feature of these fish species is that the pathological condition that they model is often related to specific evolutionary adaptations. By exploring these adaptations, new disease-causing and disease-modifier genes might be identified; thus, diverse fish species could be exploited to better understand the complexity of disease processes. In addition, non-mainstream fish models could allow us to study the impact of environmental factors, as well as genetic variation, on complex disease phenotypes. This Review will discuss the opportunities that such fish models offer for current and future biomedical research.

  10. LEA polypeptide profiling of recalcitrant and orthodox legume seeds reveals ABI3-regulated LEA protein abundance linked to desiccation tolerance.

    Science.gov (United States)

    Delahaie, Julien; Hundertmark, Michaela; Bove, Jérôme; Leprince, Olivier; Rogniaux, Hélène; Buitink, Julia

    2013-11-01

    In contrast to orthodox seeds that acquire desiccation tolerance during maturation, recalcitrant seeds are unable to survive drying. These desiccation-sensitive seeds constitute an interesting model for comparative analysis with phylogenetically close species that are desiccation tolerant. Considering the importance of LEA (late embryogenesis abundant) proteins as protective molecules both in drought and in desiccation tolerance, the heat-stable proteome was characterized in cotyledons of the legume Castanospermum australe and it was compared with that of the orthodox model legume Medicago truncatula. RNA sequencing identified transcripts of 16 homologues out of 17 LEA genes for which polypeptides are detected in M. truncatula seeds. It is shown that for 12 LEA genes, polypeptides were either absent or strongly reduced in C. australe cotyledons compared with M. truncatula seeds. Instead, osmotically responsive, non-seed-specific dehydrins accumulated to high levels in the recalcitrant cotyledons compared with orthodox seeds. Next, M. truncatula mutants of the abscisic acid insensitive3 (ABI3) gene were characterized. Mature Mtabi3 seeds were found to be desiccation sensitive when dried below a critical water content of 0.4 g H2O g DW(-1). Characterization of the LEA proteome of the Mtabi3 seeds revealed a subset of LEA proteins with severely reduced abundance that were also found to be reduced or absent in C. australe cotyledons. Transcripts of these genes were indeed shown to be ABI3 responsive. The results highlight those LEA proteins that are critical to desiccation tolerance and suggest that comparable regulatory pathways responsible for their accumulation are missing in both desiccation-sensitive genotypes, revealing new insights into the mechanistic basis of the recalcitrant trait in seeds.

  11. Model for Predicting Passage of Invasive Fish Species Through Culverts

    Science.gov (United States)

    Neary, V.

    2010-12-01

    Conservation efforts to promote or inhibit fish passage include the application of simple fish passage models to determine whether an open channel flow allows passage of a given fish species. Derivations of simple fish passage models for uniform and nonuniform flow conditions are presented. For uniform flow conditions, a model equation is developed that predicts the mean-current velocity threshold in a fishway, or velocity barrier, which causes exhaustion at a given maximum distance of ascent. The derivation of a simple expression for this exhaustion-threshold (ET) passage model is presented using kinematic principles coupled with fatigue curves for threatened and endangered fish species. Mean current velocities at or above the threshold predict failure to pass. Mean current velocities below the threshold predict successful passage. The model is therefore intuitive and easily applied to predict passage or exclusion. The ET model’s simplicity comes with limitations, however, including its application only to uniform flow, which is rarely found in the field. This limitation is addressed by deriving a model that accounts for nonuniform conditions, including backwater profiles and drawdown curves. Comparison of these models with experimental data from volitional swimming studies of fish indicates reasonable performance, but limitations are still present due to the difficulty in predicting fish behavior and passage strategies that can vary among individuals and different fish species.

  12. Effects of Shade on Nitrogen and Phosphorus Acquisition in Cereal-Legume Intercropping Systems

    Directory of Open Access Journals (Sweden)

    Marney E. Isaac

    2012-01-01

    Full Text Available With increasing economic and environmental costs associated with fertilizer use, the need for low-input agroecological systems is on the rise. It is well documented that intercropping legumes can increase the supply of nutrients, through N2-fixation and P mobilization. Concurrently, the integration of trees in the agricultural landscape shows increasing evidence of nutrient inputs through efficient biogeochemical cycles. However, little is known about the effects shade has on legume-crop performance. This research aims to determine whether intercropping of the legumes soybean (Glycine max L. Merr. and alfalfa (Medicago sativa with wheat (Triticum turgidum durum is beneficial for performance, particularly under shady conditions associated with tree-based intercropping. Test species were cultivated in hydroponics with a broad nutrient solution and steady state addition of N for 3 weeks. Individual plants were transferred to rhizoboxes with a 2 mm zone of soil for 16 days under (i full sun or (ii shade to mimic light levels at the tree-crop interface. Under monocropping, shading was found to significantly decrease wheat biomass. Intercropping wheat with alfalfa under full sun had no negative effect on growth but did increase wheat P uptake as compared to monocropped wheat. In contrast, intercropping wheat with soybean under full sun decreased wheat biomass, suggesting competition. However, under shade, this competitive effect was mitigated, as wheat exhibited similar biomass and higher N and P shoot concentration when associated with soybean as compared to monocropped wheat under lower light levels. This effect may be attributed to reduced biomass of soybean combined with higher soybean N2-fixation under shade. Legume-based intercrops may increase nutrient supply and growth but these beneficial effects will be dependent on matching species selection to light levels under tree-based intercropping.

  13. The Sinorhizobium meliloti MsbA2 protein is essential for the legume symbiosis.

    Science.gov (United States)

    Beck, Sebastian; Marlow, Victoria L; Woodall, Katy; Doerrler, William T; James, Euan K; Ferguson, Gail P

    2008-04-01

    Sinorhizobium meliloti is a beneficial legume symbiont, closely related to Brucella species, which are chronic mammalian pathogens. We discovered that the S. meliloti MsbA2 protein is essential to ensure the symbiotic interaction with the host plant, alfalfa. S. meliloti invades plant cells via plant-derived structures known as infection threads. However, in the absence of MsbA2, S. meliloti remains trapped within abnormally thickened infection threads and induces a heightened plant defence response, characterized by a substantial thickening of the nodule endodermis layer and the accumulation of polyphenolic compounds. The S. meliloti MsbA2 protein is homologous to the Escherichia coli lipopolysaccharide/phospholipid trafficking protein MsbA. However, MsbA2 was not essential for the membrane transport of either lipopolysaccharide or phospholipids in S. meliloti. We determined that the msbA2 gene is transcribed in free-living S. meliloti and that in the absence of MsbA2 the polysaccharide content of S. meliloti is altered. Consequently, we propose a model whereby the altered polysaccharide content of the S. meliloti msbA2 mutant could be responsible for its symbiotic defect by inducing an inappropriate host response.

  14. Models to relate species to environment: a hierarchical statistical approac

    NARCIS (Netherlands)

    Jamil, T.

    2012-01-01

    In the last two decades, the interest of community ecologists in trait-based approaches has grown dramatically and these approaches have been increasingly applied to explain and predict response of species to environmental conditions. A variety of modelling techniques are available. The dominant

  15. Models to relate species to environment: a hierarchical statistical approac

    NARCIS (Netherlands)

    Jamil, T.

    2012-01-01

    In the last two decades, the interest of community ecologists in trait-based approaches has grown dramatically and these approaches have been increasingly applied to explain and predict response of species to environmental conditions. A variety of modelling techniques are available. The dominant tec

  16. Coexistence of two species in a strongly coupled cooperating model

    DEFF Research Database (Denmark)

    Pedersen, Michael

    In this paper, the cooperating two-species Lotka-Volterra model is discussed. We study the existence of solutions to a elliptic system with homogeneous Dirichlet boundary conditions. Our results show that this problem possesses at least one coexistence state if the birth rates are big and self...

  17. Coexistence of two species in a strongly coupled cooperating model

    DEFF Research Database (Denmark)

    Pedersen, Michael

    In this paper, the cooperating two-species Lotka-Volterra model is discussed. We study the existence of solutions to a elliptic system with homogeneous Dirichlet boundary conditions. Our results show that this problem possesses at least one coexistence state if the birth rates are big and self...

  18. Analysis of interspecies physicochemical variation of grain legume seeds

    Science.gov (United States)

    Rybiński, Wojciech; Rusinek, Robert; Szot, Bogusław; Bocianowski, Jan; Starzycki, Michał

    2014-10-01

    The paper presents an attempt to assess the reaction of seeds to mechanical loads taking into account their geometry expressed as seed thickness and 1000 seed weight. The initial material comprised 33 genotypes of grain legume plants and included cultivars registered in the country and breeding lines that are subject to pre-registration trials. The analysis of variance revealed significant diversity of the cultivars and lines of the species studied in terms of each of the analysed trait. The highest weight of 1000 seeds were obtained for white lupine seeds and peas, the lowest for andean lupine seeds. The maximum deformation and energy were obtained for white lupine seeds, the lowest for pea seeds, the maximum force and module the lowest values were determined for narrow-leafed lupine and pea. The highest values of protein were obtained for andean and yellow lupine, a fat content for andean and white lupine. The fatty acid profile as much as 70% or more were linoleic and oleic acids. Against the background of all the species are distinguished by white lupine seeds with a high content of oleic acid and the lowest of linoleic acid, for yellow lupine were obtained the inverse ratio of the two acids.

  19. Development of Solar Drying Model for Selected Cambodian Fish Species

    Directory of Open Access Journals (Sweden)

    Anna Hubackova

    2014-01-01

    Full Text Available A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h−1. Based on coefficient of determination (R2, chi-square (χ2 test, and root-mean-square error (RMSE, the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing.

  20. Development of solar drying model for selected Cambodian fish species.

    Science.gov (United States)

    Hubackova, Anna; Kucerova, Iva; Chrun, Rithy; Chaloupkova, Petra; Banout, Jan

    2014-01-01

    A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6 °C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg · h(-1). Based on coefficient of determination (R(2)), chi-square (χ(2)) test, and root-mean-square error (RMSE), the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing.

  1. TRUNCATULIX – a data warehouse for the legume community

    Directory of Open Access Journals (Sweden)

    Runte Kai J

    2009-02-01

    Full Text Available Abstract Background Databases for either sequence, annotation, or microarray experiments data are extremely beneficial to the research community, as they centrally gather information from experiments performed by different scientists. However, data from different sources develop their full capacities only when combined. The idea of a data warehouse directly adresses this problem and solves it by integrating all required data into one single database – hence there are already many data warehouses available to genetics. For the model legume Medicago truncatula, there is currently no such single data warehouse that integrates all freely available gene sequences, the corresponding gene expression data, and annotation information. Thus, we created the data warehouse TRUNCATULIX, an integrative database of Medicago truncatula sequence and expression data. Results The TRUNCATULIX data warehouse integrates five public databases for gene sequences, and gene annotations, as well as a database for microarray expression data covering raw data, normalized datasets, and complete expression profiling experiments. It can be accessed via an AJAX-based web interface using a standard web browser. For the first time, users can now quickly search for specific genes and gene expression data in a huge database based on high-quality annotations. The results can be exported as Excel, HTML, or as csv files for further usage. Conclusion The integration of sequence, annotation, and gene expression data from several Medicago truncatula databases in TRUNCATULIX provides the legume community with access to data and data mining capability not previously available. TRUNCATULIX is freely available at http://www.cebitec.uni-bielefeld.de/truncatulix/.

  2. Mechanistic species distribution modeling reveals a niche shift during invasion.

    Science.gov (United States)

    Chapman, Daniel S; Scalone, Romain; Štefanić, Edita; Bullock, James M

    2017-06-01

    Niche shifts of nonnative plants can occur when they colonize novel climatic conditions. However, the mechanistic basis for niche shifts during invasion is poorly understood and has rarely been captured within species distribution models. We quantified the consequence of between-population variation in phenology for invasion of common ragweed (Ambrosia artemisiifolia L.) across Europe. Ragweed is of serious concern because of its harmful effects as a crop weed and because of its impact on public health as a major aeroallergen. We developed a forward mechanistic species distribution model based on responses of ragweed development rates to temperature and photoperiod. The model was parameterized and validated from the literature and by reanalyzing data from a reciprocal common garden experiment in which native and invasive populations were grown within and beyond the current invaded range. It could therefore accommodate between-population variation in the physiological requirements for flowering, and predict the potentially invaded ranges of individual populations. Northern-origin populations that were established outside the generally accepted climate envelope of the species had lower thermal requirements for bud development, suggesting local adaptation of phenology had occurred during the invasion. The model predicts that this will extend the potentially invaded range northward and increase the average suitability across Europe by 90% in the current climate and 20% in the future climate. Therefore, trait variation observed at the population scale can trigger a climatic niche shift at the biogeographic scale. For ragweed, earlier flowering phenology in established northern populations could allow the species to spread beyond its current invasive range, substantially increasing its risk to agriculture and public health. Mechanistic species distribution models offer the possibility to represent niche shifts by varying the traits and niche responses of individual

  3. Modelling bioaccumulation of oil constituents in aquatic species.

    Science.gov (United States)

    De Hoop, Lisette; Huijbregts, Mark A J; Schipper, Aafke M; Veltman, Karin; De Laender, Frederik; Viaene, Karel P J; Klok, Chris; Hendriks, A Jan

    2013-11-15

    Crude oil poses a risk to marine ecosystems due to its toxicity and tendency to accumulate in biota. The present study evaluated the applicability of the OMEGA model for estimating oil accumulation in aquatic species by comparing model predictions of kinetic rates (absorption and elimination) and bioconcentration factors (BCF) with measured values. The model was a better predictor than the means of the measurements for absorption and elimination rate constants, but did not outperform the mean measured BCF. Model estimates and measurements differed less than one order of magnitude for 91%, 80% and 61% of the absorption and elimination rates and BCFs of all oil constituents, respectively. Of the "potentially modifying" factors: exposure duration, biotransformation, molecular mass, and water temperature, the last two tended to influence the performance of the model. Inclusion of more explanatory variables in the bioaccumulation model, like the molecular mass, is expected to improve model performance.

  4. SESAM – a new framework integrating macroecological and species distribution models for predicting spatio-temporal patterns of species assemblages

    DEFF Research Database (Denmark)

    Guisan, Antoine; Rahbek, Carsten

    2011-01-01

    , and ecological assembly rules to constrain predictions of the richness and composition of species assemblages obtained by stacking predictions of individual species distributions. We believe that such a framework could prove useful in many theoretical and applied disciplines of ecology and evolution, both......Two different approaches currently prevail for predicting spatial patterns of species assemblages. The first approach (macroecological modelling, MEM) focuses directly on realized properties of species assemblages, whereas the second approach (stacked species distribution modelling, S-SDM) starts...... with constituent species to approximate the properties of assemblages. Here, we propose to unify the two approaches in a single ‘spatially explicit species assemblage modelling’ (SESAM) framework. This framework uses relevant designations of initial species source pools for modelling, macroecological variables...

  5. Mimosoid legume plastome evolution: IR expansion, tandem repeat expansions, and accelerated rate of evolution in clpP

    Science.gov (United States)

    Dugas, Diana V.; Hernandez, David; Koenen, Erik J.M.; Schwarz, Erika; Straub, Shannon; Hughes, Colin E.; Jansen, Robert K.; Nageswara-Rao, Madhugiri; Staats, Martijn; Trujillo, Joshua T.; Hajrah, Nahid H.; Alharbi, Njud S.; Al-Malki, Abdulrahman L.; Sabir, Jamal S. M.; Bailey, C. Donovan

    2015-01-01

    The Leguminosae has emerged as a model for studying angiosperm plastome evolution because of its striking diversity of structural rearrangements and sequence variation. However, most of what is known about legume plastomes comes from few genera representing a subset of lineages in subfamily Papilionoideae. We investigate plastome evolution in subfamily Mimosoideae based on two newly sequenced plastomes (Inga and Leucaena) and two recently published plastomes (Acacia and Prosopis), and discuss the results in the context of other legume and rosid plastid genomes. Mimosoid plastomes have a typical angiosperm gene content and general organization as well as a generally slow rate of protein coding gene evolution, but they are the largest known among legumes. The increased length results from tandem repeat expansions and an unusual 13 kb IR-SSC boundary shift in Acacia and Inga. Mimosoid plastomes harbor additional interesting features, including loss of clpP intron1 in Inga, accelerated rates of evolution in clpP for Acacia and Inga, and dN/dS ratios consistent with neutral and positive selection for several genes. These new plastomes and results provide important resources for legume comparative genomics, plant breeding, and plastid genetic engineering, while shedding further light on the complexity of plastome evolution in legumes and angiosperms. PMID:26592928

  6. Energy use in legume cultivation in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Ertekin, C.; Canakci, M.; Yaldiz, O. [Akdeniz Univ., Antalya (Turkey). Faculty of Agriculture, Dept. of Farm Machinery; Kulcu, R. [Suleyman Demirel Univ., Isparta (Turkey). Faculty of Agriculture, Dept. of Farm Machinery

    2010-07-01

    A study was conducted to analyze the energy required to produce different legumes in 11 different regions of Turkey. The objective was to improve energy efficiency. Data was collected for the production of dry bean, chickpea and soybean under rainfed and irrigated conditions, as well as for the production of lentil under rainfed conditions. The data was evaluated in terms of energy use efficiency, energy productivity and specific energy for different regions of Turkey. The main energy sources are human, diesel, fertilizer, seed, machine, chemicals and water. The main agricultural operations are seedbed preparation, seeding, fertilization, hoeing, irrigation, spraying, harvesting, threshing and transporting. The total energy input ranged between 3361.5 and 25229.7 MJ/ha. Based on product yields, the energy use efficiency varied between 0.96 and 4.32.

  7. Genome-Wide Identification, Characterization, and Expression Analysis of Small RNA Biogenesis Purveyors Reveal Their Role in Regulation of Biotic Stress Responses in Three Legume Crops

    Directory of Open Access Journals (Sweden)

    Rajeev K. Varshney

    2017-04-01

    Full Text Available Biotic stress in legume crops is one of the major threats to crop yield and productivity. Being sessile organisms, plants have evolved a myriad of mechanisms to combat different stresses imposed on them. One such mechanism, deciphered in the last decade, is small RNA (sRNA mediated defense in plants. Small RNAs (sRNAs have emerged as one of the major players in gene expression regulation in plants during developmental stages and under stress conditions. They are known to act both at transcriptional and post-transcriptional levels. Dicer-like (DCL, Argonaute (AGO, and RNA dependent RNA polymerase (RDR constitute the major components of sRNA biogenesis machinery and are known to play a significant role in combating biotic and abiotic stresses. This study is, therefore, focused on identification and characterization of sRNA biogenesis proteins in three important legume crops, namely chickpea, pigeonpea, and groundnut. Phylogenetic analysis of these proteins between legume species classified them into distinct clades and suggests the evolutionary conservation of these genes across the members of Papillionidoids subfamily. Variable expression of sRNA biogenesis genes in response to the biotic stresses among the three legumes indicate the possible existence of specialized regulatory mechanisms in different legumes. This is the first ever study to understand the role of sRNA biogenesis genes in response to pathogen attacks in the studied legumes.

  8. Establishing endangered species recovery criteria using predictive simulation modeling

    Science.gov (United States)

    McGowan, Conor P.; Catlin, Daniel H.; Shaffer, Terry L.; Gratto-Trevor, Cheri L.; Aron, Carol

    2014-01-01

    Listing a species under the Endangered Species Act (ESA) and developing a recovery plan requires U.S. Fish and Wildlife Service to establish specific and measurable criteria for delisting. Generally, species are listed because they face (or are perceived to face) elevated risk of extinction due to issues such as habitat loss, invasive species, or other factors. Recovery plans identify recovery criteria that reduce extinction risk to an acceptable level. It logically follows that the recovery criteria, the defined conditions for removing a species from ESA protections, need to be closely related to extinction risk. Extinction probability is a population parameter estimated with a model that uses current demographic information to project the population into the future over a number of replicates, calculating the proportion of replicated populations that go extinct. We simulated extinction probabilities of piping plovers in the Great Plains and estimated the relationship between extinction probability and various demographic parameters. We tested the fit of regression models linking initial abundance, productivity, or population growth rate to extinction risk, and then, using the regression parameter estimates, determined the conditions required to reduce extinction probability to some pre-defined acceptable threshold. Binomial regression models with mean population growth rate and the natural log of initial abundance were the best predictors of extinction probability 50 years into the future. For example, based on our regression models, an initial abundance of approximately 2400 females with an expected mean population growth rate of 1.0 will limit extinction risk for piping plovers in the Great Plains to less than 0.048. Our method provides a straightforward way of developing specific and measurable recovery criteria linked directly to the core issue of extinction risk. Published by Elsevier Ltd.

  9. Species distribution models of tropical deep-sea snappers.

    Directory of Open Access Journals (Sweden)

    Céline Gomez

    Full Text Available Deep-sea fisheries provide an important source of protein to Pacific Island countries and territories that are highly dependent on fish for food security. However, spatial management of these deep-sea habitats is hindered by insufficient data. We developed species distribution models using spatially limited presence data for the main harvested species in the Western Central Pacific Ocean. We used bathymetric and water temperature data to develop presence-only species distribution models for the commercially exploited deep-sea snappers Etelis Cuvier 1828, Pristipomoides Valenciennes 1830, and Aphareus Cuvier 1830. We evaluated the performance of four different algorithms (CTA, GLM, MARS, and MAXENT within the BIOMOD framework to obtain an ensemble of predicted distributions. We projected these predictions across the Western Central Pacific Ocean to produce maps of potential deep-sea snapper distributions in 32 countries and territories. Depth was consistently the best predictor of presence for all species groups across all models. Bathymetric slope was consistently the poorest predictor. Temperature at depth was a good predictor of presence for GLM only. Model precision was highest for MAXENT and CTA. There were strong regional patterns in predicted distribution of suitable habitat, with the largest areas of suitable habitat (> 35% of the Exclusive Economic Zone predicted in seven South Pacific countries and territories (Fiji, Matthew & Hunter, Nauru, New Caledonia, Tonga, Vanuatu and Wallis & Futuna. Predicted habitat also varied among species, with the proportion of predicted habitat highest for Aphareus and lowest for Etelis. Despite data paucity, the relationship between deep-sea snapper presence and their environments was sufficiently strong to predict their distribution across a large area of the Pacific Ocean. Our results therefore provide a strong baseline for designing monitoring programs that balance resource exploitation and

  10. Predicting the fate of biodiversity using species' distribution models: enhancing model comparability and repeatability.

    Directory of Open Access Journals (Sweden)

    Genoveva Rodríguez-Castañeda

    Full Text Available Species distribution modeling (SDM is an increasingly important tool to predict the geographic distribution of species. Even though many problems associated with this method have been highlighted and solutions have been proposed, little has been done to increase comparability among studies. We reviewed recent publications applying SDMs and found that seventy nine percent failed to report methods that ensure comparability among studies, such as disclosing the maximum probability range produced by the models and reporting on the number of species occurrences used. We modeled six species of Falco from northern Europe and demonstrate that model results are altered by (1 spatial bias in species' occurrence data, (2 differences in the geographic extent of the environmental data, and (3 the effects of transformation of model output to presence/absence data when applying thresholds. Depending on the modeling decisions, forecasts of the future geographic distribution of Falco ranged from range contraction in 80% of the species to no net loss in any species, with the best model predicting no net loss of habitat in Northern Europe. The fact that predictions of range changes in response to climate change in published studies may be influenced by decisions in the modeling process seriously hampers the possibility of making sound management recommendations. Thus, each of the decisions made in generating SDMs should be reported and evaluated to ensure conclusions and policies are based on the biology and ecology of the species being modeled.

  11. Predicting the fate of biodiversity using species' distribution models: enhancing model comparability and repeatability.

    Science.gov (United States)

    Rodríguez-Castañeda, Genoveva; Hof, Anouschka R; Jansson, Roland; Harding, Larisa E

    2012-01-01

    Species distribution modeling (SDM) is an increasingly important tool to predict the geographic distribution of species. Even though many problems associated with this method have been highlighted and solutions have been proposed, little has been done to increase comparability among studies. We reviewed recent publications applying SDMs and found that seventy nine percent failed to report methods that ensure comparability among studies, such as disclosing the maximum probability range produced by the models and reporting on the number of species occurrences used. We modeled six species of Falco from northern Europe and demonstrate that model results are altered by (1) spatial bias in species' occurrence data, (2) differences in the geographic extent of the environmental data, and (3) the effects of transformation of model output to presence/absence data when applying thresholds. Depending on the modeling decisions, forecasts of the future geographic distribution of Falco ranged from range contraction in 80% of the species to no net loss in any species, with the best model predicting no net loss of habitat in Northern Europe. The fact that predictions of range changes in response to climate change in published studies may be influenced by decisions in the modeling process seriously hampers the possibility of making sound management recommendations. Thus, each of the decisions made in generating SDMs should be reported and evaluated to ensure conclusions and policies are based on the biology and ecology of the species being modeled.

  12. Legumes or nitrification inhibitors to reduce N2O emissions in subtropical cereal cropping systems? A simulation study

    Science.gov (United States)

    The DAYCENT biogeochemical model was used to investigate how the use of fertilisers coated with nitrification inhibitors and the introduction of legumes in the crop rotation can affect subtropical cereal production and N2O emissions. The model was validated using comprehensive multi-seasonal, high-f...

  13. On the dynamical behavior of three species food web model

    Energy Technology Data Exchange (ETDEWEB)

    Naji, R.K. [Department of Mathematics, College of Science, University of Baghdad (Iraq)]. E-mail: rknaji@yahoo.com; Balasim, A.T. [Department of Mathematics, College of Science, University of Baghdad (Iraq)]. E-mail: alkhazrejy@yahoo.com

    2007-12-15

    In this paper, a mathematical model consisting of two preys one predator with Beddington-DeAngelis functional response is proposed and analyzed. The local stability analysis of the system is carried out. The necessary and sufficient conditions for the persistence of three species food web model are obtained. For the biologically reasonable range of parameter values, the global dynamics of the system has been investigated numerically. Number of bifurcation diagrams has been obtained; Lyapunov exponents have been computed for different attractor sets. It is observed that the model has different types of attractors including chaos.

  14. Effect of species rarity on the accuracy of species distribution models for reptiles and amphibians in southern California

    Science.gov (United States)

    Franklin, J.; Wejnert, K.E.; Hathaway, S.A.; Rochester, C.J.; Fisher, R.N.

    2009-01-01

    Aim: Several studies have found that more accurate predictive models of species' occurrences can be developed for rarer species; however, one recent study found the relationship between range size and model performance to be an artefact of sample prevalence, that is, the proportion of presence versus absence observations in the data used to train the model. We examined the effect of model type, species rarity class, species' survey frequency, detectability and manipulated sample prevalence on the accuracy of distribution models developed for 30 reptile and amphibian species. Location: Coastal southern California, USA. Methods: Classification trees, generalized additive models and generalized linear models were developed using species presence and absence data from 420 locations. Model performance was measured using sensitivity, specificity and the area under the curve (AUC) of the receiver-operating characteristic (ROC) plot based on twofold cross-validation, or on bootstrapping. Predictors included climate, terrain, soil and vegetation variables. Species were assigned to rarity classes by experts. The data were sampled to generate subsets with varying ratios of presences and absences to test for the effect of sample prevalence. Join count statistics were used to characterize spatial dependence in the prediction errors. Results: Species in classes with higher rarity were more accurately predicted than common species, and this effect was independent of sample prevalence. Although positive spatial autocorrelation remained in the prediction errors, it was weaker than was observed in the species occurrence data. The differences in accuracy among model types were slight. Main conclusions: Using a variety of modelling methods, more accurate species distribution models were developed for rarer than for more common species. This was presumably because it is difficult to discriminate suitable from unsuitable habitat for habitat generalists, and not as an artefact of the

  15. Bacterial-induced calcium oscillations are common to nitrogen-fixing associations of nodulating legumes and nonlegumes.

    Science.gov (United States)

    Granqvist, Emma; Sun, Jongho; Op den Camp, Rik; Pujic, Petar; Hill, Lionel; Normand, Philippe; Morris, Richard J; Downie, J Allan; Geurts, Rene; Oldroyd, Giles E D

    2015-08-01

    Plants that form root-nodule symbioses are within a monophyletic 'nitrogen-fixing' clade and associated signalling processes are shared with the arbuscular mycorrhizal symbiosis. Central to symbiotic signalling are nuclear-associated oscillations in calcium ions (Ca(2+) ), occurring in the root hairs of several legume species in response to the rhizobial Nod factor signal. In this study we expanded the species analysed for activation of Ca(2+) oscillations, including nonleguminous species within the nitrogen-fixing clade. We showed that Ca(2+) oscillations are a common feature of legumes in their association with rhizobia, while Cercis, a non-nodulating legume, does not show Ca(2+) oscillations in response to Nod factors from Sinorhizobium fredii NGR234. Parasponia andersonii, a nonlegume that can associate with rhizobia, showed Nod factor-induced calcium oscillations to S. fredii NGR234 Nod factors, but its non-nodulating sister species, Trema tomentosa, did not. Also within the nitrogen-fixing clade are actinorhizal species that associate with Frankia bacteria and we showed that Alnus glutinosa induces Ca(2+) oscillations in root hairs in response to exudates from Frankia alni, but not to S. fredii NGR234 Nod factors. We conclude that the ability to mount Ca(2+) oscillations in response to symbiotic bacteria is a common feature of nodulating species within the nitrogen-fixing clade.

  16. Confronting different models of community structure to species-abundance data: a Bayesian model comparison

    NARCIS (Netherlands)

    Etienne, R.S.; Olff, H.

    2005-01-01

    Species abundances are undoubtedly the most widely available macroecological data, but can we use them to distinguish among several models of community structure? Here we present a Bayesian analysis of species-abundance data that yields a full joint probability distribution of each model's

  17. Confronting different models of community structure to species-abundance data : a Bayesian model comparison

    NARCIS (Netherlands)

    Etienne, RS; Olff, H

    Species abundances are undoubtedly the most widely available macroecological data, but can we use them to distinguish among several models of community structure? Here we present a Bayesian analysis of species-abundance data that yields a full joint probability distribution of each model's

  18. Using genetic data to improve species distribution models.

    Science.gov (United States)

    Bouyer, Jérémy; Lancelot, Renaud

    2017-03-23

    Tsetse flies (Diptera, Glossinidae) transmit human and animal trypanosomoses in Africa, respectively a neglected human disease (sleeping sickness) and the most important constraint to cattle production in infested countries (nagana). We recently developed a methodology to map landscape friction (i.e. resistance to movement) for tsetse in West Africa. The goal was to identify natural barriers to tsetse dispersal, and potentially isolated tsetse populations for targeting elimination programmes. Most species distribution models neglect landscape functional connectivity whereas environmental factors affecting suitability or abundance are not necessarily the same as those influencing gene flows. Geographic distributions of a given species can be seen as the intersection between biotic (B), abiotic (A) and movement (M) factors (BAM diagram). Here we show that the suitable habitat for Glossina palpalis gambiensis as modelled by Maxent can be corrected by landscape functional connectivity (M) extracted from our friction analysis. This procedure did not degrade the specificity of the distribution model (P=0.751) whereas the predicted distribution area was reduced. The added value of this approach is that it reveals unconnected habitat patches. The approach we developed on tsetse to inform landscape connectivity (M) is reproducible and does not rely on expert knowledge. It can be applied to any species: we call for a generalization of the use of M to improve distribution models. Copyright © 2017. Published by Elsevier B.V.

  19. Forage potential of winter cereal/legume intercrops in organic farming

    Directory of Open Access Journals (Sweden)

    Marco Mariotti

    2006-09-01

    Full Text Available This research was performed to assess the potential of cereal/legume intercropping to enhance forage yield and quality when compared with cereal sole crops under the constrains imposed by UE organic farming regulations. Sole crops (SC and intercrops (IC of two winter cereals, barley (Hordeum vulgare L. and durum wheat (Triticum durum Desf., and two legumes, white lupin (Lupinus albus L. and common vetch (Vicia sativa L., were evaluated at two harvest times for dry matter yield (DMY, crude protein concentration (CPC, and nitrogen yield (NY. Yield values and dry matter concentration (DMC were generally higher when cereals were at the hard dough compared to the late milk stage. On average, intercropping increased forage yield by 72%, NY by 190%, and CPC by 40 g kg-1, compared to cereal sole crops, but the choice of legume species affected the yield advantage and the composition of forage. Land equivalent ratio (LER of intercrops was always higher than 1, ranging from 1.39 to 1.61. Intercropping also enhanced weed suppression, compared to sole crop.

  20. Plant growth and soil microbial community structure of legumes and grasses grown in monoculture or mixture

    Institute of Scientific and Technical Information of China (English)

    CHEN Meimei; CHEN Baodong; MARSCHNER Petra

    2008-01-01

    A greenhouse pot experiment was conducted to investigate the influence of soil moisture eontent on plant growth and the rhizospheremicrobial community structure of four plant species (white clover, alfalfa, sudan grass, tall fescue), grown individually or in a mixture.The soil moisture content was adjusted to 55% or 80% water holding capacity (WHC). The results indicated that the total plant biomassof one pot was lower at 55% WHC. At a given soil moisture, the total plant biomass of white clover and tall fescue in the mixture waslower than that in a monoculture, indicating their poor competitiveness. For leguminous plants, the decrease in soil moisture reducedthe total microbial biomass, bacterial biomass, fungal biomass, and fungal/baeterial ratio in soil as assessed by the phospholipid fattyacid analysis, whereas, lower soil moisture increased those parameters in the tall fescue. The microbial biomass in the soil with legumeswas higher than that in the soil with grasses and the two plant groups differed in soil microbial community composition. At high soilmoisture content, microbial communities of the plant mixture were similar to those of the legume monoculture, and the existenceof legumes in the mixture enhanced the bacterial and fungal biomass in the soil compared to the grasses grown in the monoculture,indicating that legumes played a dominant role in the soil microbial community changes in the plant mixture.

  1. Production and chemical composition of grasses and legumes cultivated in pure form, mixed or in consortium

    Directory of Open Access Journals (Sweden)

    Antonio Augusto Cortiana Tambara

    2017-07-01

    Full Text Available The objective of this study was to assess the edible biomass and chemical composition of forages grown on pure form, as a grass mix, and in grass-legume consortia. The following species were tested: white oats (Avena sativa, black oats (Avena strigosa, ryegrass (Lolium multiflorum, forage peanut (Arachis pintoi, white clover (Trifolium repens, and red clover (Trifolium pratense. The experiment consisted of sixteen treatments arranged in a completely randomized design. The parameters measured were total dry matter (PMST, neutral detergent fiber (NDF, acid detergent fiber (ADF, and crude protein (CP. No significant differences in PMST were found among the consortia (p > 0.05. Only the pure cultivated white clover (p > 0.05 was comparable to the consortia in terms of biomass production. The three legumes had the lowest average NDF values (p > 0.05, based on their contributions to the total NDF content of the consortia along the cuts. The ADF content increased for all treatments during the cuts. The results indicate that in pasture, legumes increase protein content, and forage consortia increase both the pasture production and the grazing period. Their chemical composition is adequate for boosting livestock production in pastures.

  2. Genome-wide analysis of homeobox gene family in legumes: identification, gene duplication and expression profiling.

    Science.gov (United States)

    Bhattacharjee, Annapurna; Ghangal, Rajesh; Garg, Rohini; Jain, Mukesh

    2015-01-01

    Homeobox genes encode transcription factors that are known to play a major role in different aspects of plant growth and development. In the present study, we identified homeobox genes belonging to 14 different classes in five legume species, including chickpea, soybean, Medicago, Lotus and pigeonpea. The characteristic differences within homeodomain sequences among various classes of homeobox gene family were quite evident. Genome-wide expression analysis using publicly available datasets (RNA-seq and microarray) indicated that homeobox genes are differentially expressed in various tissues/developmental stages and under stress conditions in different legumes. We validated the differential expression of selected chickpea homeobox genes via quantitative reverse transcription polymerase chain reaction. Genome duplication analysis in soybean indicated that segmental duplication has significantly contributed in the expansion of homeobox gene family. The Ka/Ks ratio of duplicated homeobox genes in soybean showed that several members of this family have undergone purifying selection. Moreover, expression profiling indicated that duplicated genes might have been retained due to sub-functionalization. The genome-wide identification and comprehensive gene expression profiling of homeobox gene family members in legumes will provide opportunities for functional analysis to unravel their exact role in plant growth and development.

  3. ALUMINUM TOXICITY IN ROOTS OF LEGUME SEEDLINGS ASSESSED BY TOPOLOGICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Simone Meredith Scheffer-Basso

    2014-11-01

    Full Text Available abstract: The effect of the aluminum in root has been evaluated by linear and weight measurements, but remains to be understood about the influence of this element on branching configuration of the root system. This study had the objective to assess the aluminum toxicity in roots of 21-day-old seedlings of three forage legumes, Adesmia latifolia, Trifolium repens and T. pratense (Fabaceae, by topological analysis. The legumes were grown in Oxisol treated or not with dolomite lime, which resulted in two Al saturation and pH: (a Al= 0 %, pH= 6.2; (b Al= 16 %, pH= 4.8. Number of first-order roots, external links (magnitude, total links in the longest unique path (altitude, total links in the primary root (altitude of primary root, total exterior path length, total links, internal links, branching points, and proportion of branching in primary root were determined. The topological variables were significantly reduced by Al, regardless to the legumes. The altitude-slope on magnitude showed that there was a more randomized branching configuration in seedlings grown in acid soil. A. latifolia was the most plastic species, with reducing of the slopes from 0.9758 (Al-absence to 0.6858 (Al-presence, showing herringbone and randomized branching, respectively.

  4. ESTABLISHMENT TECHNIQUES FOR TROPICAL LEGUMES IN THE UNDERSTORY OF A EUCALYPTUS PLANTATION

    Directory of Open Access Journals (Sweden)

    Maria Luiza Franceschi Nicodemo

    2015-04-01

    Full Text Available This study evaluated establishment methods for a mixture of herbaceous forage legumes [Centrosema acutifolium, Clitoria ternatea, Pueraria phaseoloides, Stylosanthes Campo Grande (Stylosanthes capitata + S. macrocephala, Calopogonium mucunoides, Lablab purpureus, Arachis pintoi, and Aeschynomene villosa] under the shade of an Eucalyptus grandis plantation submitted to thinning (40% 8 years after planting in Anhembi, São Paulo (22°40'S, 48°10'W, altitude of 455 m. The experiment started in December 2008 and consisted of the comparison of the following four types of seed incorporation by light disc harrowing: (1 broadcast sowing without seed incorporation; disc harrowing before (2 or after (3 planting, and (4 disc harrowing before and after planting. Ninety days after planting, the number of legume plants/m2 and the percentage of ground cover by the plants varied between the treatments tested; however, the treatments had no effect on the dry matter accumulation of forage legumes. Disc harrowing before planting yielded superior results compared to the treatments without disc harrowing and disc harrowing after planting. At the end of the experimental period, the plots contained Arachis, Centrosema, Stylosanthes, and Pueraria. The dry matter accumulated by Centrosema corresponded to 73% of total dry matter yield of the plots. The participation of Arachis, Centrosema and Stylosanthes in final dry matter composition of the plots varied according to establishment method. The advantages of the use of species mixtures rather than monocultures in the understory of forest plantations were discussed.

  5. Carbon-Chain Species in Warm-up Models

    CERN Document Server

    Hassel, George E; Herbst, Eric

    2011-01-01

    In previous warm-up chemical models of the low-mass star-forming region L1527, we investigated the evolution of carbon-chain unsaturated hydrocarbon species when the envelope temperature is slightly elevated to $T\\approx 30$ K. These models demonstrated that enhanced abundances of such species can be explained by gas-phase ion-molecule chemistry following the partial sublimation of methane from grain surfaces. We also concluded that the abundances of hydrocarbon radicals such as the C$_{\\rm n}$H family should be further enhanced as the temperatures increase to higher values, but this conclusion stood in contrast with the lack of unambiguous detection of these species toward hot core and corino sources. Meanwhile, observational surveys have identified C$_2$H, C$_4$H, CH$_3$CCH, and CH$_3$OH toward hot corinos (especially IRAS 16293-2422) as well as towards L1527, with lower abundances for the carbon chain radicals and higher abundances for the other two species toward the hot corinos. In addition, the {\\it Her...

  6. Competing species system as a qualitative model of radiation therapy

    Science.gov (United States)

    Wendykier, Jacek; Bieniasiewicz, Marcin; Lipowski, Adam; Pawlak, Andrzej

    2016-07-01

    To examine complex features of tumor dynamics we analyze a competing-species lattice model that takes into account the competition for nutrients or space as well as interaction with therapeutic factors such as drugs or radiation. Our model might be interpreted as a certain prey-predator system having three trophic layers: (i) the basal species that might be interpreted as nutrients; (ii) normal and tumor cells that consume nutrients, and (iii) therapeutic factors that might kill either nutrient, normal or tumor cells. Using a wide spectrum of parameters we examined survival of our species and tried to identify the corresponding dynamical regimes. It was found that the radiotherapy influences mainly the limit of starvation i.e. the value of an update probability where the tumor cells go extinct as a result of insufficient nutrient supply and competition with normal cells. The other limiting value of this probability, corresponding to the coexistence of the normal and tumor cells in abundance of nutrients, is almost not affected by radiotherapy. We have also found the coexistence of all species on the phase diagrams.

  7. Did greater burial depth increase the seed size of domesticated legumes?

    Science.gov (United States)

    Kluyver, Thomas A; Charles, Michael; Jones, Glynis; Rees, Mark; Osborne, Colin P

    2013-10-01

    The independent domestication of crop plants in several regions of the world formed the basis of human civilizations, and attracts considerable interest from archaeologists and biologists. Selection under cultivation led to a suite of domestication traits which distinguish crops from their wild progenitors, including larger seeds in most seed crops. This selection may be classified as 'conscious' or 'unconscious' selection according to whether humans were aware of the changes that they were driving. The hypothesis that human cultivation buried seeds deeper than natural dispersal, exerting unconscious selection favouring larger seeds with greater reserves, was tested. Using a comparative approach, accessions of eight grain legumes, originating from independent domestication centres across several continents, were sampled. Seeds were planted at different depths in a controlled environment, and seedling emergence scored for 5 weeks after sowing. Domestication in all species was associated with increased seed mass. In three species, greater mass was not correlated with increased ability to emerge from depth. In five species, emergence depth did correlate with mass, suggesting that selection during domestication may have acted on emergence depth. However, domestication only had a significant effect in two of these species (lentil and mung bean), and the increase in depth was no more than predicted by a cube-root allometric relationship with seed mass. The results do not support the hypothesis that burial under cultivation was a general selection mechanism for increased seed mass during the domestication of grain legumes, but it may have acted in particular species or regions.

  8. The role of the testa during development and in establishment of dormancy of the legume seed

    Science.gov (United States)

    Smýkal, Petr; Vernoud, Vanessa; Blair, Matthew W.; Soukup, Aleš; Thompson, Richard D.

    2014-01-01

    Timing of seed germination is one of the key steps in plant life cycles. It determines the beginning of plant growth in natural or agricultural ecosystems. In the wild, many seeds exhibit dormancy and will only germinate after exposure to certain environmental conditions. In contrast, crop seeds germinate as soon as they are imbibed usually at planting time. These domestication-triggered changes represent adaptations to cultivation and human harvesting. Germination is one of the common sets of traits recorded in different crops and termed the “domestication syndrome.” Moreover, legume seed imbibition has a crucial role in cooking properties. Different seed dormancy classes exist among plant species. Physical dormancy (often called hardseededness), as found in legumes, involves the development of a water-impermeable seed coat, caused by the presence of phenolics- and suberin-impregnated layers of palisade cells. The dormancy release mechanism primarily involves seed responses to temperature changes in the habitat, resulting in testa permeability to water. The underlying genetic controls in legumes have not been identified yet. However, positive correlation was shown between phenolics content (e.g., pigmentation), the requirement for oxidation and the activity of catechol oxidase in relation to pea seed dormancy, while epicatechin levels showed a significant positive correlation with soybean hardseededness. myeloblastosis family of transcription factors, WD40 proteins and enzymes of the anthocyanin biosynthesis pathway were involved in seed testa color in soybean, pea and Medicago, but were not tested directly in relation to seed dormancy. These phenolic compounds play important roles in defense against pathogens, as well as affecting the nutritional quality of products, and because of their health benefits, they are of industrial and medicinal interest. In this review, we discuss the role of the testa in mediating legume seed germination, with a focus on

  9. The role of the testa during development and in establishment of dormancy of the legume seed

    Directory of Open Access Journals (Sweden)

    Petr eSmýkal

    2014-07-01

    Full Text Available Timing of seed germination is one of the key steps in plant life cycles. It determines the beginning of plant growth in natural or agricultural ecosystems. In the wild, many seeds exhibit dormancy and will only germinate after exposure to certain environmental conditions. In contrast, crop seeds germinate as soon as they are imbibed usually at planting time. These domestication-triggered changes represent adaptations to cultivation and human harvesting. Germination is one of the common sets of traits recorded in different crops and termed the domestication syndrome. Moreover, legume seed imbibition has a crucial role in cooking properties. Different seed dormancy classes exist among plant species. Physical dormancy (often called hardseededness, as found in legumes, involves the development of a water-impermeable seed coat, caused by the presence of phenolics- and suberin-impregnated layers of palisade cells. The dormancy release mechanism primarily involves seed responses to temperature changes in the habitat, resulting in testa permeability to water. The underlying genetic controls in legumes have not been identified yet. However, positive correlation was shown between phenolics content (e.g., pigmentation, the requirement for oxidation and the activity of catechol oxidase in relation to pea seed dormancy, while epicatechin levels showed a significant positive correlation with soybean hardseededness. MYB transcription factors, WD40 proteins and enzymes of the anthocyanin biosynthesis pathway were involved in seed testa colour in soybean, pea and Medicago, but were not tested directly in relation to seed dormancy. These phenolic compounds play important roles in defence against pathogens, as well as affecting the nutritional quality of products, and because of their health benefits, they are of industrial and medicinal interest. In this review, we discuss the role of the testa in mediating legume seed germination, with a focus on structural and

  10. Bifurcation analysis in single-species population model with delay

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A single-species population model is investigated in this paper.Firstly,we study the existence of Hopf bifurcation at the positive equilibrium.Furthermore,an explicit algorithm for determining the direction of the Hopf bifurcation and stability of the bifurcation periodic solutions are derived by using the normal form and the center manifold theory.At last,numerical simulations to support the analytical conclusions are carried out.

  11. Population dynamics of species-rich ecosystems: the mixture of matrix population models approach

    DEFF Research Database (Denmark)

    Mortier, Frédéric; Rossi, Vivien; Guillot, Gilles;

    2013-01-01

    Matrix population models are widely used to predict population dynamics, but when applied to species-rich ecosystems with many rare species, the small population sample sizes hinder a good fit of species-specific models. This issue can be overcome by assigning species to groups to increase the size...... species with similar population dynamics....

  12. Ensuring sustainable grain legume-cereal cropping systems

    DEFF Research Database (Denmark)

    Bedoussac, Laurent; Journet, E-P; Hauggaard-Nielsen, Henrik

    2017-01-01

    health makes them a key rotation crop in the sustainable intensification and diversification of smallholder farming. This makes grain legumes a key food security crop. However, yields in developing countries are low as a result of such factors as the need for improved varieties of seed, poor seed......Grain legumes are widely cultivated, particularly for their dry seeds (known as pulses). Grain legumes are an important crop for a number of reasons. They are a rich source of protein and fibre, minerals and vitamins. In addition, their rapid growth and ability to fix nitrogen and improve soil...... as in Denmark using spring and winter cereal-grain legume intercrops. Intercropping involves simultaneously growing two or more crops in the same field for a significant period of time. The practice is ancient as early records from many human societies all over the world have shown. Intercropping systems...

  13. mechanisms of drought resistance in grain legumes i: osmotic ...

    African Journals Online (AJOL)

    Preferred Customer

    in grain legumes, namely Common bean (Phaseolus vulgaris) faba bean (Vicia faba), pea (Pisum sativum), and chickpea (Cicer ... accumulated as a response to water loss and ... At harvesting, fresh weight was determined and ... The whole.

  14. A Comparative Nitrogen Balance and Productivity Analysis of Legume and Non-legume Supported Cropping Systems: The Potential Role of Biological Nitrogen Fixation

    DEFF Research Database (Denmark)

    Iannetta, Pietro P M; Young, Mark; Bachinger, Johann

    2016-01-01

    studies have systematically evaluated the effect of optimizing the balance between legumes and non N-fixing crops to optimize production. In addition, the shortage, or even absence in some regions, of measurements of BNF in crops and forages severely limits the ability to design and evaluate new legume......–based agroecosystems. To provide an indication of the magnitude of BNF in European agriculture, a soil-surface N-balance approach was applied to historical data from 8 experimental cropping systems that compared legume and non-legume crop types (e.g., grains, forages and intercrops) across pedoclimatic regions...... of Europe. Mean BNF for different legume types ranged from 32 to 115 kg ha−1 annually. Output in terms of total biomass (grain, forage, etc.) was 30% greater in non-legumes, which used N to produce dry matter more efficiently than legumes, whereas output of N was greater from legumes. When examined over...

  15. Conditions Affecting Shelf-Life of Inoculated Legume Seed

    OpenAIRE

    Greg Gemell; Elizabeth Hartley; Rosalind Deaker

    2012-01-01

    Microbial inoculants are becoming more available as sustainable alternatives to fertilizers and other agrichemicals in broad-acre cropping. However, with the exception of legume inoculants little is understood about effective delivery and survival of the inoculum. Legume inoculants are applied to both seed and soil but seed inoculation is the most economical technique. Large quantities of pasture seed in Australia are inoculated by commercial seed coating companies, but the long-term survival...

  16. Species distribution modelling for conservation of an endangered endemic orchid.

    Science.gov (United States)

    Wang, Hsiao-Hsuan; Wonkka, Carissa L; Treglia, Michael L; Grant, William E; Smeins, Fred E; Rogers, William E

    2015-04-21

    Concerns regarding the long-term viability of threatened and endangered plant species are increasingly warranted given the potential impacts of climate change and habitat fragmentation on unstable and isolated populations. Orchidaceae is the largest and most diverse family of flowering plants, but it is currently facing unprecedented risks of extinction. Despite substantial conservation emphasis on rare orchids, populations continue to decline. Spiranthes parksii (Navasota ladies' tresses) is a federally and state-listed endangered terrestrial orchid endemic to central Texas. Hence, we aimed to identify potential factors influencing the distribution of the species, quantify the relative importance of each factor and determine suitable habitat for future surveys and targeted conservation efforts. We analysed several geo-referenced variables describing climatic conditions and landscape features to identify potential factors influencing the likelihood of occurrence of S. parksii using boosted regression trees. Our model classified 97 % of the cells correctly with regard to species presence and absence, and indicated that probability of existence was correlated with climatic conditions and landscape features. The most influential variables were mean annual precipitation, mean elevation, mean annual minimum temperature and mean annual maximum temperature. The most likely suitable range for S. parksii was the eastern portions of Leon and Madison Counties, the southern portion of Brazos County, a portion of northern Grimes County and along the borders between Burleson and Washington Counties. Our model can assist in the development of an integrated conservation strategy through: (i) focussing future survey and research efforts on areas with a high likelihood of occurrence, (ii) aiding in selection of areas for conservation and restoration and (iii) framing future research questions including those necessary for predicting responses to climate change. Our model could also

  17. Model-based uncertainty in species range prediction

    DEFF Research Database (Denmark)

    Pearson, R. G.; Thuiller, Wilfried; Bastos Araujo, Miguel;

    2006-01-01

    Aim Many attempts to predict the potential range of species rely on environmental niche (or 'bioclimate envelope') modelling, yet the effects of using different niche-based methodologies require further investigation. Here we investigate the impact that the choice of model can have on predictions...... day (using the area under the receiver operating characteristic curve (AUC) and kappa statistics) and by assessing consistency in predictions of range size changes under future climate (using cluster analysis). Results Our analyses show significant differences between predictions from different models......, with predicted changes in range size by 2030 differing in both magnitude and direction (e.g. from 92% loss to 322% gain). We explain differences with reference to two characteristics of the modelling techniques: data input requirements (presence/absence vs. presence-only approaches) and assumptions made by each...

  18. Legume root symbioses: Natural history and prospects for improvement

    Directory of Open Access Journals (Sweden)

    Shtark Oksana

    2011-01-01

    Full Text Available Legumes develop different mutually beneficial microbial-root symbioses such as arbuscular mysorrhiza (AM, rhizobium-legume symbiosis (RLS and epiphytic or endophytic associations with plant growth-promoting bacteria (PGPB which are distinguished in level of integration of the partners. Evidences of the role of AM as ancestral form of symbiosis which might be a source of the legume pre-adaptation to form some RLS are demonstrated. The RLS is supposed to evolve for a few times in ancient legumes in parallel ways based on the universal organization and regulatory mechanisms of the plant genetic material. Associations of plant roots with PGPB probably are the vestige of the early stages of evolution in morphologically differentiated RLS. Also, it is quite possible that 'first' rhizobia have originated from bacterial endosymbionts of AM fungi; then AM fungi might operate as effective vectors for introducing bacteria into the plants. Thus, the legume root symbioses may be considered as a single 'evolutionary plant-microbial continuum'. The acquired knowledge about evolution of plantmicrobe symbioses would contribute to the creation of new commercial varieties of plants with the use of both bio-engineered methods and traditional plant breeding. An original conception of legume breeding to improve their symbiotic effectiveness is proposed.

  19. Legumes can increase cadmium contamination in neighboring crops.

    Science.gov (United States)

    Liu, Ling; Zhang, Qian; Hu, Liangliang; Tang, Jianjun; Xu, Ligen; Yang, Xiantian; Yong, Jean W H; Chen, Xin

    2012-01-01

    Legumes are widely used in many cropping systems because they share their nitrogen fixation products and phosphorus mobilization activities with their neighbors. In the current study, however, we showed that co-cultivation with legumes increased cadmium (Cd) contamination in the adjacent crops. Both field and mesocosm experiments indicated that legumes increased Cd levels in edible parts and shoots of four neighboring crops and five maize varieties tested, regardless of the Cd levels in the soil. This enhanced Cd accumulation in crops was attributed to root interactions that alter the rhizosphere environment. Co-cultivation with legumes reduced soil pH, which somewhat increased the exchangeable forms of Cd. Our results have demonstrated the inevitable increases in Cd levels of crops as a direct result of co-cultivation with legumes even under situations when these levels are below the permissible threshold. With this new revelation, we need to consider carefully the current cropping systems involving legumes and perhaps to re-design the current and future cropping systems in view of avoiding food contamination by Cd.

  20. Growing tropical forage legumes in full sun and silvopastoral systems

    Directory of Open Access Journals (Sweden)

    Saulo Alberto do Carmo Araújo

    2017-02-01

    Full Text Available Growth was evaluated three tropical forage legumes in two cropping systems: silvopastoral system (SSP and full sun. A completely randomized design was adopted in factorial three legumes (estilosanthes cv. Campo Grande (Stylozanthes macrocephala x Stylozanthes capitata, tropical kudzu (Pueraria phaseoloides (Roxb. Benth and macrotiloma (Macrotyloma axillare cv. Java x two farming systems, with 4 repetitions. A eucalyptus SSP already deployed, with spatial arrangement of 12 x 2 m between trees was used. Legumes were planted in January 2014 a uniform cut being made in May 2014. The court assessment was carried out 125 days after the uniformity cut. There was difference for mass production of dry legumes (PMMSL between cultivation systems, evidencing increased productivity in the farming full sun. The macrotiloma showed higher PMSL (5.29 kg DM ha-1 cut-1, while the kudzu obtained the lowest yield (3.42 kg DM ha-1 cut-1 in the sun growing full. The cultivation of legumes in SSP increased the levels of mineral matter, crude protein and neutral detergent fiber. The shade provided by the SSP caused a reduction in the mass of dry matter production, but also altered the chemical composition of the studied legumes.

  1. Bradyrhizobium BclA Is a Peptide Transporter Required for Bacterial Differentiation in Symbiosis with Aeschynomene Legumes.

    Science.gov (United States)

    Guefrachi, Ibtissem; Pierre, Olivier; Timchenko, Tatiana; Alunni, Benoît; Barrière, Quentin; Czernic, Pierre; Villaécija-Aguilar, José-Antonio; Verly, Camille; Bourge, Mickaël; Fardoux, Joël; Mars, Mohamed; Kondorosi, Eva; Giraud, Eric; Mergaert, Peter

    2015-11-01

    Nodules of legume plants are highly integrated symbiotic systems shaped by millions of years of evolution. They harbor nitrogen-fixing rhizobium bacteria called bacteroids. Several legume species produce peptides called nodule-specific cysteine-rich (NCR) peptides in the symbiotic nodule cells which house the bacteroids. NCR peptides are related to antimicrobial peptides of innate immunity. They induce the endosymbionts into a differentiated, enlarged, and polyploid state. The bacterial symbionts, on their side, evolved functions for the response to the NCR peptides. Here, we identified the bclA gene of Bradyrhizobium sp. strains ORS278 and ORS285, which is required for the formation of differentiated and functional bacteroids in the nodules of the NCR peptide-producing Aeschynomene legumes. The BclA ABC transporter promotes the import of NCR peptides and provides protection against the antimicrobial activity of these peptides. Moreover, BclA can complement the role of the related BacA transporter of Sinorhizobium meliloti, which has a similar symbiotic function in the interaction with Medicago legumes.

  2. Ecological risk assessment conceptual model formulation for nonindigenous species.

    Science.gov (United States)

    Landis, Wayne G

    2004-08-01

    This article addresses the application of ecological risk assessment at the regional scale to the prediction of impacts due to invasive or nonindigenous species (NIS). The first section describes risk assessment, the decision-making process, and introduces regional risk assessment. A general conceptual model for the risk assessment of NIS is then presented based upon the regional risk assessment approach. Two diverse examples of the application of this approach are presented. The first example is based upon the dynamics of introduced plasmids into bacteria populations. The second example is the application risk assessment approach to the invasion of a coastal marine site of Cherry Point, Washington, USA by the European green crab. The lessons learned from the two examples demonstrate that assessment of the risks of invasion of NIS will have to incorporate not only the characteristics of the invasive species, but also the other stresses and impacts affecting the region of interest.

  3. The predictive performance and stability of six species distribution models.

    Science.gov (United States)

    Duan, Ren-Yan; Kong, Xiao-Quan; Huang, Min-Yi; Fan, Wei-Yi; Wang, Zhi-Gao

    2014-01-01

    Predicting species' potential geographical range by species distribution models (SDMs) is central to understand their ecological requirements. However, the effects of using different modeling techniques need further investigation. In order to improve the prediction effect, we need to assess the predictive performance and stability of different SDMs. We collected the distribution data of five common tree species (Pinus massoniana, Betula platyphylla, Quercus wutaishanica, Quercus mongolica and Quercus variabilis) and simulated their potential distribution area using 13 environmental variables and six widely used SDMs: BIOCLIM, DOMAIN, MAHAL, RF, MAXENT, and SVM. Each model run was repeated 100 times (trials). We compared the predictive performance by testing the consistency between observations and simulated distributions and assessed the stability by the standard deviation, coefficient of variation, and the 99% confidence interval of Kappa and AUC values. The mean values of AUC and Kappa from MAHAL, RF, MAXENT, and SVM trials were similar and significantly higher than those from BIOCLIM and DOMAIN trials (pMAXENT, and SVM. Compared to BIOCLIM and DOMAIN, other SDMs (MAHAL, RF, MAXENT, and SVM) had higher prediction accuracy, smaller confidence intervals, and were more stable and less affected by the random variable (randomly selected pseudo-absence points). According to the prediction performance and stability of SDMs, we can divide these six SDMs into two categories: a high performance and stability group including MAHAL, RF, MAXENT, and SVM, and a low performance and stability group consisting of BIOCLIM, and DOMAIN. We highlight that choosing appropriate SDMs to address a specific problem is an important part of the modeling process.

  4. The predictive performance and stability of six species distribution models.

    Directory of Open Access Journals (Sweden)

    Ren-Yan Duan

    Full Text Available Predicting species' potential geographical range by species distribution models (SDMs is central to understand their ecological requirements. However, the effects of using different modeling techniques need further investigation. In order to improve the prediction effect, we need to assess the predictive performance and stability of different SDMs.We collected the distribution data of five common tree species (Pinus massoniana, Betula platyphylla, Quercus wutaishanica, Quercus mongolica and Quercus variabilis and simulated their potential distribution area using 13 environmental variables and six widely used SDMs: BIOCLIM, DOMAIN, MAHAL, RF, MAXENT, and SVM. Each model run was repeated 100 times (trials. We compared the predictive performance by testing the consistency between observations and simulated distributions and assessed the stability by the standard deviation, coefficient of variation, and the 99% confidence interval of Kappa and AUC values.The mean values of AUC and Kappa from MAHAL, RF, MAXENT, and SVM trials were similar and significantly higher than those from BIOCLIM and DOMAIN trials (p<0.05, while the associated standard deviations and coefficients of variation were larger for BIOCLIM and DOMAIN trials (p<0.05, and the 99% confidence intervals for AUC and Kappa values were narrower for MAHAL, RF, MAXENT, and SVM. Compared to BIOCLIM and DOMAIN, other SDMs (MAHAL, RF, MAXENT, and SVM had higher prediction accuracy, smaller confidence intervals, and were more stable and less affected by the random variable (randomly selected pseudo-absence points.According to the prediction performance and stability of SDMs, we can divide these six SDMs into two categories: a high performance and stability group including MAHAL, RF, MAXENT, and SVM, and a low performance and stability group consisting of BIOCLIM, and DOMAIN. We highlight that choosing appropriate SDMs to address a specific problem is an important part of the modeling process.

  5. Abundance modelling of invasive and indigenous Culicoides species in Spain

    Directory of Open Access Journals (Sweden)

    Els Ducheyne

    2013-11-01

    Full Text Available In this paper we present a novel methodology applied in Spain to model spatial abundance patterns of potential vectors of disease at a medium spatial resolution of 5 x 5 km using a countrywide database with abundance data for five Culicoides species, random regression Forest modelling and a spatial dataset of ground measured and remotely sensed eco-climatic and environmental predictor variables. First the probability of occurrence was computed. In a second step a direct regression between the probability of occurrence and trap abundance was established to verify the linearity of the relationship. Finally the probability of occurrence was used in combination with the set of predictor variables to model abundance. In each case the variable importance of the predictors was used to biologically interpret results and to compare both model outputs, and model performance was assessed using four different accuracy measures. Results are shown for C. imicola, C. newsteadii, C. pulicaris group, C. punctatus and C. obsoletus group. In each case the probability of occurrence is a good predictor of abundance at the used spatial resolution of 5 x 5 km. In addition, the C. imicola and C. obsoletus group are highly driven by summer rainfall. The spatial pattern is inverse between the two species, indicating that the lower and upper thresholds are different. C. pulicaris group is mainly driven by temperature. The patterns for C. newsteadii and C. punctatus are less clear. It is concluded that the proposed methodology can be used as an input to transmission-infection-recovery (TIR models and R0 models. The methodology will become available to the general public as part of the VECMAPTM software.

  6. Burkholderia kirstenboschensis sp. nov. nodulates papilionoid legumes indigenous to South Africa.

    Science.gov (United States)

    Steenkamp, Emma T; van Zyl, Elritha; Beukes, Chrizelle W; Avontuur, Juanita R; Chan, Wai Yin; Palmer, Marike; Mthombeni, Lunghile S; Phalane, Francina L; Sereme, T Karabo; Venter, Stephanus N

    2015-12-01

    Despite the diversity of Burkholderia species known to nodulate legumes in introduced and native regions, relatively few taxa have been formally described. For example, the Cape Floristic Region of South Africa is thought to represent one of the major centres of diversity for the rhizobial members of Burkholderia, yet only five species have been described from legumes occurring in this region and numerous are still awaiting taxonomic treatment. Here, we investigated the taxonomic status of 12 South African root-nodulating Burkholderia isolates from native papilionoid legumes (Hypocalyptus coluteoides, H. oxalidifolius, H. sophoroides and Virgilia oroboides). Analysis of four gene regions (16S rRNA, recA, atpD and rpoB) revealed that the isolates represent a genealogically unique and exclusive assemblage within the genus. Its distinctness was supported by all other aspects of the polyphasic approach utilized, including the genome-based criteria DNA-DNA hybridization (≥70.9%) and average nucleotide identities (≥96%). We accordingly propose the name B. kirstenboschensis sp. nov. for this taxon with isolate Kb15(T) (=LMG 28727(T); =SARC 695(T)) as its type strain. Our data showed that intraspecific genome size differences (≥0.81 Mb) and the occurrence of large DNA regions that are apparently unique to single individuals (16-23% of an isolate's genome) can significantly limit the value of data obtained from DNA-DNA hybridization experiments. Substitution of DNA-DNA hybridization with whole genome sequencing as a prerequisite for the description of Burkholderia species will undoubtedly speed up the pace at which their diversity are documented, especially in hyperdiverse regions such as the Cape Floristic Region.

  7. The effects of model and data complexity on predictions from species distributions models

    DEFF Research Database (Denmark)

    García-Callejas, David; Bastos, Miguel

    2016-01-01

    study contradicts the widely held view that the complexity of species distributions models has significant effects in their predictive ability while findings support for previous observations that the properties of species distributions data and their relationship with the environment are strong...

  8. Proteolytic modification of selected legume flours

    Directory of Open Access Journals (Sweden)

    Barbara Baraniak

    2008-03-01

    Full Text Available The influence of pepsin (EC 3.4.1.1 and trypsin (EC 3.4.4.4 action on the chemical composition of legume flours was the aim of this study. The level of proteins and lipids in hydrolysed flours was changed significantly. In comparison to the raw flours also fatty acid composition in treated flours was altered. In the lentil flours both trypsin and pepsin digestion conditions have decreased the level of unsaturated fatty acid. It is noteworthy that in all investigated, hydrolysed flours ratio linoleic: oleic fatty acid was significantly decreased in comparison to unhydrolysed flours (about 40%-pea; 60%- -lentil. Our investigations were also focused on the potential implementations of IMAC method in the separation and purification of peptides. Generally, peptides separation profiles, performed on immobilized Zn (II, were dependent on the kind of flour and enzyme used in the hydrolysis process. In the lights of our results is clearly visible that investigated peptides had a weak affinity to the chelated metal ions. It is noteworthy, that in some cases the influences of chelating factor on separation profiles were noticeable.

  9. Immunosuppression during Rhizobium-legume symbiosis.

    Science.gov (United States)

    Luo, Li; Lu, Dawei

    2014-01-01

    Rhizobium infects host legumes to elicit new plant organs, nodules where dinitrogen is fixed as ammonia that can be directly utilized by plants. The nodulation factor (NF) produced by Rhizobium is one of the determinant signals for rhizobial infection and nodule development. Recently, it was found to suppress the innate immunity on host and nonhost plants as well as its analogs, chitins. Therefore, NF can be recognized as a microbe/pathogen-associated molecular pattern (M/PAMP) like chitin to induce the M/PAMP triggered susceptibility (M/PTS) of host plants to rhizobia. Whether the NF signaling pathway is directly associated with the innate immunity is not clear till now. In fact, other MAMPs such as lipopolysaccharide (LPS), exopolysaccharide (EPS) and cyclic-β-glucan, together with type III secretion system (T3SS) effectors are also required for rhizobial infection or survival in leguminous nodule cells. Interestingly, most of them play similarly negative roles in the innate immunity of host plants, though their signaling is not completely elucidated. Taken together, we believe that the local immunosuppression on host plants induced by Rhizobium is essential for the establishment of their symbiosis.

  10. Species Coexistence in Nitrifying Chemostats: A Model of Microbial Interactions

    Directory of Open Access Journals (Sweden)

    Maxime Dumont

    2016-12-01

    Full Text Available In a previous study, the two nitrifying functions (ammonia oxidizing bacteria (AOB or nitrite-oxidizing bacteria (NOB of a nitrification reactor—operated continuously over 525 days with varying inputs—were assigned using a mathematical modeling approach together with the monitoring of bacterial phylotypes. Based on these theoretical identifications, we develop here a chemostat model that does not explicitly include only the resources’ dynamics (different forms of soluble nitrogen but also explicitly takes into account microbial inter- and intra-species interactions for the four dominant phylotypes detected in the chemostat. A comparison of the models obtained with and without interactions has shown that such interactions permit the coexistence of two competing ammonium-oxidizing bacteria and two competing nitrite-oxidizing bacteria in competition for ammonium and nitrite, respectively. These interactions are analyzed and discussed.

  11. Tackling Biocomplexity with Meta-models for Species Risk Assessment

    Directory of Open Access Journals (Sweden)

    Philip J. Nyhus

    2007-06-01

    Full Text Available We describe results of a multi-year effort to strengthen consideration of the human dimension into endangered species risk assessments and to strengthen research capacity to understand biodiversity risk assessment in the context of coupled human-natural systems. A core group of social and biological scientists have worked with a network of more than 50 individuals from four countries to develop a conceptual framework illustrating how human-mediated processes influence biological systems and to develop tools to gather, translate, and incorporate these data into existing simulation models. A central theme of our research focused on (1 the difficulties often encountered in identifying and securing diverse bodies of expertise and information that is necessary to adequately address complex species conservation issues; and (2 the development of quantitative simulation modeling tools that could explicitly link these datasets as a way to gain deeper insight into these issues. To address these important challenges, we promote a "meta-modeling" approach where computational links are constructed between discipline-specific models already in existence. In this approach, each model can function as a powerful stand-alone program, but interaction between applications is achieved by passing data structures describing the state of the system between programs. As one example of this concept, an integrated meta-model of wildlife disease and population biology is described. A goal of this effort is to improve science-based capabilities for decision making by scientists, natural resource managers, and policy makers addressing environmental problems in general, and focusing on biodiversity risk assessment in particular.

  12. Arrowleaf Clover (Trifolium vesiculosum Savi: A New Species of Annual Legumes for High Rainfall Areas of the Mediterranean Climate Zone of Chile Trébol Vesiculoso (Trifolium vesiculosum Savi: Una Nueva Especie de Leguminosa Anual para Áreas de Alta Precipitación en la Zona Mediterránea de Chile

    Directory of Open Access Journals (Sweden)

    Carlos Ovalle M

    2010-03-01

    Full Text Available The present review examines the main attributes and agronomic characteristics of arrowleaf clover (Trifolium vesiculosum Savi and its incorporation into production systems in dryland areas of the Andean foothills of the humid Mediterranean climate zone of Chile. It is a new species of annual legume in Chile for light and medium textured soils. The root system can reach a depth of 1.5 m and its seeds have a high percentage of hardseedness (99.8%. It is an upright plant, with purplish-white flowers. The mature plant has large arrow-shaped leaves up to 50 mm long, often marked with a large white “V”. Dry matter and seed production in the Andean foothills is high (3.9-8.8 t DM ha-1 and 700-900 kg ha-1, respectively, surpassing the productivity of sub clover (Trifolium subterraneum L. cv. Mount Barker and crimson clover (Trifolium incarnatum L.. However, DM production in the second year was lower, possibly because the high percentage of hardseedness inhibited plant emergence. The phenological records and productive performance suggest that arrowleaf clover could contribute to improving pastoral production in dryland areas with annual rainfall levels of more than 800 mm, such as the Andean foothills in the central-southern region of Chile.En la presente revisión se examinan los principales atributos y características agronómicas del trébol vesiculoso (Trifolium vesiculosum Savi y su eventual incorporación a sistemas de producción en la precordillera andina de la zona de clima mediterráneo húmedo de Chile. Se trata de una nueva especie de leguminosa forrajera anual para suelos de textura liviana y media. El sistema radical puede alcanzar 1,5 m de profundidad y las semillas tienen un alto porcentaje de dureza seminal (99,8%. Es una planta de crecimiento erecto, flores de color blanco con una leve coloración púrpura. Las plantas adultas tienen grandes hojas con forma de flecha de más de 50 mm de largo, a menudo muestran una marca blanca en

  13. Periodicity and blowup in a two-species cooperating model

    DEFF Research Database (Denmark)

    Lin, Zhigui; Liu, Jiahong; Pedersen, Michael

    2011-01-01

    In this paper, the cooperating two-species Lotka–Volterra model is discussed. The existence and asymptotic behavior of T -periodic solutions for the periodic reaction diffusion system under homogeneous Dirichlet boundary conditions are first investigated. The blowup properties of solutions...... for the same system are then given. It is shown that periodic solutions exist if the intra-specific competitions are strong whereas blowup solutions exist under certain conditions if the intra-specific competitions are weak. Numerical simulations and a brief discussion are also presented in the last section....

  14. Biodiversity of Rhizospheric Soil Bacteria and Arbuscular Mycorrhizal (AM Fungi in Some of The Wild Medicinal Legumes of Barak Valley

    Directory of Open Access Journals (Sweden)

    F. Malina Singha

    2013-04-01

    Full Text Available Present investigation was aimed to isolate and study the rhizobacteria and AM fungi from rhizosphere of wild legumes: Mimosa pudica (sensitive plant, Crotolaria pallida (Sunhemp, Cassia tora (Sickle pod and Desmodium . The molecular characterization of four bacterial isolates were done. Four bacterial species - Bacillus megaterium, Bacillus aerophilus, Microbacterium laevaniformans and - Staphylococcus xylosus were isolated from strains M1, RT, D5 and D7 respectively. Also, the distribution of AM fungi population was studied from rhizosphere soils of these legumes. Among the AM fungi, Glomus species was dominant and bacterial genus - Bacillus was found to be dominant. Maximum number of VAM infection was found in the rhizosphere soil of Mimosa pudica of Srikona.

  15. Bradyrhizobia from wild Phaseolus, Desmodium, and Macroptilium species in northern Mexico.

    Science.gov (United States)

    Parker, Matthew A

    2002-04-01

    rRNA genetic markers were analyzed in 97 isolates of nodule bacteria from six legume species in Chihuahua, Mexico. The most common genotypes were widely shared across host species and had 16S rRNA sequences identical to those of strains from an eastern North American legume (Amphicarpaea) that are closely related to Bradyrhizobium elkanii.

  16. Policing the legume-Rhizobium symbiosis: a critical test of partner choice.

    Science.gov (United States)

    Westhoek, Annet; Field, Elsa; Rehling, Finn; Mulley, Geraldine; Webb, Isabel; Poole, Philip S; Turnbull, Lindsay A

    2017-05-03

    In legume-Rhizobium symbioses, specialised soil bacteria fix atmospheric nitrogen in return for carbon. However, ineffective strains can arise, making discrimination essential. Discrimination can occur via partner choice, where legumes prevent ineffective strains from entering, or via sanctioning, where plants provide fewer resources. Several studies have inferred that legumes exercise partner choice, but the rhizobia compared were not otherwise isogenic. To test when and how plants discriminate ineffective strains we developed sets of fixing and non-fixing strains that differed only in the expression of nifH - essential for nitrogen fixation - and could be visualised using marker genes. We show that the plant is unable to select against the non-fixing strain at the point of entry, but that non-fixing nodules are sanctioned. We also used the technique to characterise mixed nodules (containing both a fixing and a non-fixing strain), whose frequency could be predicted using a simple diffusion model. We discuss that sanctioning is likely to evolve in preference to partner choice in any symbiosis where partner quality cannot be adequately assessed until goods or services are actively exchanged.

  17. Flavonoid glycosides isolated from unique legume plant extracts as novel inhibitors of xanthine oxidase.

    Directory of Open Access Journals (Sweden)

    Chrysoula Spanou

    Full Text Available Legumes and the polyphenolic compounds present in them have gained a lot of interest due to their beneficial health implications. Dietary polyphenolic compounds, especially flavonoids, exert antioxidant properties and are potent inhibitors of xanthine oxidase (XO activity. XO is the main contributor of free radicals during exercise but it is also involved in pathogenesis of several diseases such as vascular disorders, cancer and gout. In order to discover new natural, dietary XO inhibitors, some polyphenolic fractions and pure compounds isolated from two legume plant extracts were tested for their effects on XO activity. The fractions isolated from both Vicia faba and Lotus edulis plant extracts were potent inhibitors of XO with IC(50 values range from 40-135 µg/mL and 55-260 µg/mL, respectively. All the pure polyphenolic compounds inhibited XO and their K(i values ranged from 13-767 µM. Ten of the compounds followed the non competitive inhibitory model whereas one of them was a competitive inhibitor. These findings indicate that flavonoid isolates from legume plant extracts are novel, natural XO inhibitors. Their mode of action is under investigation in order to examine their potential in drug design for diseases related to overwhelming XO action.

  18. Phylogenetic relationship of Lotus uliginosus symbionts with bradyrhizobia nodulating genistoid legumes.

    Science.gov (United States)

    Lorite, María J; Videira e Castro, Isabel; Muñoz, Socorro; Sanjuán, Juan

    2012-02-01

    Lotus species are legumes with potential for pastures in soils with low-fertility and environmental constraints. The aim of this work was to characterize bacteria that establish efficient nitrogen-fixing symbiosis with the forage species Lotus uliginosus. A total of 39 isolates were obtained from nodules of L. uliginosus naturally growing in two different locations of Portugal. Molecular identification of the isolates plus the commercial inoculant strain NZP2039 was performed by REP-PCR, 16S rRNA RFLP, and 16S rRNA, glnII and recA sequence analyses. Limited genetic diversity was found among the L. uliginosus symbionts, which showed a close phylogenetic relationship with the species Bradyrhizobium japonicum. The symbiotic nifH, nodA and nodC gene sequences were closely related with the corresponding genes of various Bradyrhizobium strains isolated from Lupinus and other genistoid legumes and therefore were phylogenetically separated from other Lotus spp. rhizobia. The L. uliginosus bradyrhizobia were able to nodulate and fix nitrogen in association with L. uliginosus, could nodulate Lotus corniculatus with generally poor nitrogen-fixing efficiency, formed nonfixing nodules in Lotus tenuis and Lupinus luteus roots and were unable to nodulate Glycine soja or Glycine max. Thus, L. uliginosus rhizobia seem closely related to B. japonicum biovar genistearum strains.

  19. Floral evolution and phylogeny of the Dialioideae, a diverse subfamily of tropical legumes.

    Science.gov (United States)

    Zimmerman, Erin; Herendeen, Patrick S; Lewis, Gwilym P; Bruneau, Anne

    2017-07-01

    The Dialioideae is an early diverging clade of caesalpinioid legumes containing approximately 85 species in 17 genera. Dialioideae floral morphology is highly variable and may provide clues to caesalpinioid evolution, but a well-resolved phylogeny is needed. Here, we have carried out a comprehensive morphological study of 78 Dialioideae and four outgroup species. For all available Dialioideae DNA samples, the plastid rpS16 and trnL introns were sequenced. A combined phylogenetic analysis using the parsimony criterion was completed on a reduced taxon set for which both molecular and morphological data were available. Highly supported clades from the strict consensus tree of this analysis were then used to constrain the nodes of a second analysis on an expanded taxon set with missing molecular data for some taxa. Several new, highly supported relationships have been discovered at the species and genus levels. The loss of the antepetalous stamen whorl was found to be a synapomorphy for most of the clade. A high degree of organ loss is common in the Dialioideae and often results in a bilaterally symmetrical flower. The absence of consistent morphological features in the Dialioideae, coupled with the small size of each florally diagnosed genus, suggests a lack of canalization in the floral evolution in early diverging legume lineages. © 2017 Botanical Society of America.

  20. Call for papers--Legume Genomics and Genetics (ISSN 1925-1580)

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Legume Genomics and Genetics (LGG) (IS SN 1925-1580 online, http://lgg, sophiapublisher.com) propscd by legume geneticist Dr. Da Luo from Sun Yat-Sen University in China, is an open access and peer-reviewed journal publishing original research papers relevant to genomics and genetics in legume plants. It is committed to serving for legume genomics and genetics, especially featuring innovative research findings in the basic and applied fields of structural genomics, functional genomics, proteomics, epigenomics within the field of Legume sciences, as well as legume genetics from the molecular level to whole plant level.

  1. The tropical African legume Scorodophloeus clade includes two undescribed Hymenostegia segregate genera and Micklethwaitia, a rare, monospecific genus from Mozambique

    DEFF Research Database (Denmark)

    Mackinder, B. A.; Saslis-Lagoudakis, H.; Wieringa, J. J.

    2013-01-01

    Legume subfamily Caesalpinioideae accommodates approximately 2250 species in 171 genera which traditionally are placed in four tribes: Caesalpinieae, Cassieae, Cercideae and Detarieae. The monophyletic tribe Detarieae includes the Amherstieae subclade which contains about 55 genera. Our knowledge......, and the previously unsampled rare monospecific genus Micklethwaitia from Mozambique. Zenkerella is suggested as a possible sister genus to the Scorodophloeus clade. © 2013 South African Association of Botanists....

  2. Adaptive invasive species distribution models: A framework for modeling incipient invasions

    Science.gov (United States)

    Uden, Daniel R.; Allen, Craig R.; Angeler, David G.; Corral, Lucia; Fricke, Kent A.

    2015-01-01

    The utilization of species distribution model(s) (SDM) for approximating, explaining, and predicting changes in species’ geographic locations is increasingly promoted for proactive ecological management. Although frameworks for modeling non-invasive species distributions are relatively well developed, their counterparts for invasive species—which may not be at equilibrium within recipient environments and often exhibit rapid transformations—are lacking. Additionally, adaptive ecological management strategies address the causes and effects of biological invasions and other complex issues in social-ecological systems. We conducted a review of biological invasions, species distribution models, and adaptive practices in ecological management, and developed a framework for adaptive, niche-based, invasive species distribution model (iSDM) development and utilization. This iterative, 10-step framework promotes consistency and transparency in iSDM development, allows for changes in invasive drivers and filters, integrates mechanistic and correlative modeling techniques, balances the avoidance of type 1 and type 2 errors in predictions, encourages the linking of monitoring and management actions, and facilitates incremental improvements in models and management across space, time, and institutional boundaries. These improvements are useful for advancing coordinated invasive species modeling, management and monitoring from local scales to the regional, continental and global scales at which biological invasions occur and harm native ecosystems and economies, as well as for anticipating and responding to biological invasions under continuing global change.

  3. Marmosets as model species in neuroscience and evolutionary anthropology.

    Science.gov (United States)

    Burkart, Judith M; Finkenwirth, Christa

    2015-04-01

    Marmosets are increasingly used as model species by both neuroscientists and evolutionary anthropologists, but with a different rationale for doing so. Whereas neuroscientists stress that marmosets share many cognitive traits with humans due to common descent, anthropologists stress those traits shared with marmosets - and callitrichid monkeys in general - due to convergent evolution, as a consequence of the cooperative breeding system that characterizes both humans and callitrichids. Similarities in socio-cognitive abilities due to convergence, rather than homology, raise the question whether these similarities also extend to the proximate regulatory mechanisms, which is particularly relevant for neuroscientific investigations. In this review, we first provide an overview of the convergent adaptations to cooperative breeding at the psychological and cognitive level in primates, which bear important implications for our understanding of human cognitive evolution. In the second part, we zoom in on two of these convergent adaptations, proactive prosociality and social learning, and compare their proximate regulation in marmosets and humans with regard to oxytocin and cognitive top down regulation. Our analysis suggests considerable similarity in these regulatory mechanisms presumably because the convergent traits emerged due to small motivational changes that define how pre-existing cognitive mechanisms are quantitatively combined. This finding reconciles the prima facie contradictory rationale for using marmosets as high priority model species in neuroscience and anthropology. Copyright © 2014 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  4. Delay driven spatiotemporal chaos in single species population dynamics models.

    Science.gov (United States)

    Jankovic, Masha; Petrovskii, Sergei; Banerjee, Malay

    2016-08-01

    Questions surrounding the prevalence of complex population dynamics form one of the central themes in ecology. Limit cycles and spatiotemporal chaos are examples that have been widely recognised theoretically, although their importance and applicability to natural populations remains debatable. The ecological processes underlying such dynamics are thought to be numerous, though there seems to be consent as to delayed density dependence being one of the main driving forces. Indeed, time delay is a common feature of many ecological systems and can significantly influence population dynamics. In general, time delays may arise from inter- and intra-specific trophic interactions or population structure, however in the context of single species populations they are linked to more intrinsic biological phenomena such as gestation or resource regeneration. In this paper, we consider theoretically the spatiotemporal dynamics of a single species population using two different mathematical formulations. Firstly, we revisit the diffusive logistic equation in which the per capita growth is a function of some specified delayed argument. We then modify the model by incorporating a spatial convolution which results in a biologically more viable integro-differential model. Using the combination of analytical and numerical techniques, we investigate the effect of time delay on pattern formation. In particular, we show that for sufficiently large values of time delay the system's dynamics are indicative to spatiotemporal chaos. The chaotic dynamics arising in the wake of a travelling population front can be preceded by either a plateau corresponding to dynamical stabilisation of the unstable equilibrium or by periodic oscillations.

  5. Predicting environmental suitability for a rare and threatened species (Lao newt, Laotriton laoensis using validated species distribution models.

    Directory of Open Access Journals (Sweden)

    Amanda J Chunco

    Full Text Available The Lao newt (Laotriton laoensis is a recently described species currently known only from northern Laos. Little is known about the species, but it is threatened as a result of overharvesting. We integrated field survey results with climate and altitude data to predict the geographic distribution of this species using the niche modeling program Maxent, and we validated these predictions by using interviews with local residents to confirm model predictions of presence and absence. The results of the validated Maxent models were then used to characterize the environmental conditions of areas predicted suitable for L. laoensis. Finally, we overlaid the resulting model with a map of current national protected areas in Laos to determine whether or not any land predicted to be suitable for this species is coincident with a national protected area. We found that both area under the curve (AUC values and interview data provided strong support for the predictive power of these models, and we suggest that interview data could be used more widely in species distribution niche modeling. Our results further indicated that this species is mostly likely geographically restricted to high altitude regions (i.e., over 1,000 m elevation in northern Laos and that only a minute fraction of suitable habitat is currently protected. This work thus emphasizes that increased protection efforts, including listing this species as endangered and the establishment of protected areas in the region predicted to be suitable for L. laoensis, are urgently needed.

  6. Integrative modelling reveals mechanisms linking productivity and plant species richness.

    Science.gov (United States)

    Grace, James B; Anderson, T Michael; Seabloom, Eric W; Borer, Elizabeth T; Adler, Peter B; Harpole, W Stanley; Hautier, Yann; Hillebrand, Helmut; Lind, Eric M; Pärtel, Meelis; Bakker, Jonathan D; Buckley, Yvonne M; Crawley, Michael J; Damschen, Ellen I; Davies, Kendi F; Fay, Philip A; Firn, Jennifer; Gruner, Daniel S; Hector, Andy; Knops, Johannes M H; MacDougall, Andrew S; Melbourne, Brett A; Morgan, John W; Orrock, John L; Prober, Suzanne M; Smith, Melinda D

    2016-01-21

    How ecosystem productivity and species richness are interrelated is one of the most debated subjects in the history of ecology. Decades of intensive study have yet to discern the actual mechanisms behind observed global patterns. Here, by integrating the predictions from multiple theories into a single model and using data from 1,126 grassland plots spanning five continents, we detect the clear signals of numerous underlying mechanisms linking productivity and richness. We find that an integrative model has substantially higher explanatory power than traditional bivariate analyses. In addition, the specific results unveil several surprising findings that conflict with classical models. These include the isolation of a strong and consistent enhancement of productivity by richness, an effect in striking contrast with superficial data patterns. Also revealed is a consistent importance of competition across the full range of productivity values, in direct conflict with some (but not all) proposed models. The promotion of local richness by macroecological gradients in climatic favourability, generally seen as a competing hypothesis, is also found to be important in our analysis. The results demonstrate that an integrative modelling approach leads to a major advance in our ability to discern the underlying processes operating in ecological systems.

  7. A comparison of different legume seeds as protein supplement to optimise the use of low quality forages by ruminants.

    Science.gov (United States)

    Yáñez-Ruiz, David R; Martín-García, Antonio I; Weisbjerg, Martin R; Hvelplund, Torben; Molina-Alcaide, Eduarda

    2009-02-01

    The potential of different legume seeds species, including recently new developed varieties (Vicia faba: a commercial variety and varieties Alameda, Palacio and Baraka; Lupinus angustifolius; Pisum sativum and Cicer arietinum: varieties Fardon and Zegri) as protein supplements to low quality forages was evaluated. First, the chemical composition, in vitro digestibility, in situ degradability and in vitro/in situ intestinal digestibility of legume seeds were determined. The chemical composition was rather similar within genus. Vicia faba beans contained more condensed tannins (35.8-56.4 g/kg DM) and less ether extract (12.8-9.5 g/kg DM) than the other legumes. The rumen degradability and intestinal digestibility of the undegraded protein in the rumen was very similar among the seeds, with exception of lupins, having a much higher degradation rate than the rest. Second, the fermentation characteristics of diets, which were based on two low quality forages (olive leaves and barley straw) and feed blocks without or with supplementation of legume seeds or soybean meal, were investigated by using single-flow continuous culture fermenters. In this trial, the fermentation parameters (ammonia, pH and volatile fatty acids), the microbial protein synthesis and the degradation of olive leaves and barley straw promoted by the different diets were studied. Compared to soybean meal, beans and peas showed similar suitability as protein supplements for sustaining in vitro fermentation of low-quality forages. However, our results suggest a significant interaction between the type of legume used as supplement and the type of forage used, which need to be further studied in vivo.

  8. Transport processes of the legume symbiosome membrane

    Directory of Open Access Journals (Sweden)

    Victoria C Clarke

    2014-12-01

    Full Text Available The symbiosome membrane (SM is a physical barrier between the host plant and nitrogen-fixing bacteria in the legume-rhizobium symbiosis, and represents a regulated interface for the movement of solutes between the symbionts that is under plant control. The primary nutrient exchange across the SM is the transport of a carbon energy source from plant to bacteroid in exchange for fixed nitrogen. At a biochemical level two channels have been implicated in movement of fixed nitrogen across the SM and a uniporter that transports monovalent dicarboxylate ions has been characterized that would transport fixed carbon. The aquaporin NOD26 may provide a channel for ammonia, but the genes encoding the other transporters have not been identified. Transport of several other solutes, including calcium and potassium, have been demonstrated in isolated symbiosomes, and genes encoding transport systems for the movement of iron, nitrate, sulfate and zinc in nodules have been identified. However, definitively matching transport activities with these genes has proved difficult and many further transport processes are expected on the SM to facilitate the movement of nutrients between the symbionts. Recently, work detailing the SM proteome in soybean has been completed, contributing significantly to the database of known SM proteins. This represents a valuable resource for the identification of transporter protein candidates, some of which may correspond to transport processes previously described, or to novel transport systems in the symbiosis. Putative transporters identified from the proteome include homologues of transporters of sulfate, calcium, peptides and various metal ions. Here we review current knowledge of transport processes of the SM and discuss the requirements for additional transport routes of other nutrients exchanged in the symbiosis, with a focus on transport systems identified through the soybean SM proteome.

  9. Evaluation of discrepancy between measured and modelled oxidized mercury species

    Directory of Open Access Journals (Sweden)

    G. Kos

    2013-05-01

    Full Text Available L. Zhang et al. (2012, in a recent report, compared model estimates with new observations of oxidized and particulate mercury species (Hg2+ and Hgp in the Great Lakes region and found that the sum of Hg2+ and Hgp varied between a factor of 2 to 10 between measurements and model. They suggested too high emission inputs as Hg2+ and too fast oxidative conversion of Hg0 to Hg2+ and Hgp as possible causes. This study quantitatively explores measurement uncertainties in detail. These include sampling efficiency, composition of sample, interfering species and calibration errors. Model (Global/Regional Atmospheric Heavy Metals Model – GRAHM sensitivity experiments are used to examine the consistency between various Hg measurements and speciation of Hg near emission sources to better understand the discrepancies between modelled and measured concentrations of Hg2+ and Hgp. We find that the ratio of Hg0, Hg2+ and Hgp in the emission inventories, measurements of surface air concentrations of oxidized Hg and measurements of wet deposition are currently inconsistent with each other in the vicinity of emission sources. Current speciation of Hg emissions suggests higher concentrations of Hg2+ in air and in precipitation near emission sources; however, measured air concentrations of Hg2+ and measured concentrations of Hg in precipitation are not found to be significantly elevated near emission sources compared to the remote regions. The averaged unbiased root mean square error (RMSE between simulated and observed concentrations of Hg2+ is found to be reduced by 42% and for Hgp reduced by 40% for 21 North American sites investigated, when a ratio for Hg0 : Hg2+ : Hgp in the emissions is changed from 50 : 40 : 10 (as specified in the original inventories to 90 : 8 : 2. Unbiased RMSE reductions near emissions sources in the eastern United States and Canada are found to be reduced by up to 58% for Hg2+. Significant improvement in the model simulated spatial

  10. South african papilionoid legumes are nodulated by diverse burkholderia with unique nodulation and nitrogen-fixation Loci.

    Science.gov (United States)

    Beukes, Chrizelle W; Venter, Stephanus N; Law, Ian J; Phalane, Francina L; Steenkamp, Emma T

    2013-01-01

    The root-nodule bacteria of legumes endemic to the Cape Floristic Region are largely understudied, even though recent reports suggest the occurrence of nodulating Burkholderia species unique to the region. In this study, we considered the diversity and evolution of nodulating Burkholderia associated with the endemic papilionoid tribes Hypocalypteae and Podalyrieae. We identified distinct groups from verified rhizobial isolates by phylogenetic analyses of the 16S rRNA and recA housekeeping gene regions. In order to gain insight into the evolution of the nodulation and diazotrophy of these rhizobia we analysed the genes encoding NifH and NodA. The majority of these 69 isolates appeared to be unique, potentially representing novel species. Evidence of horizontal gene transfer determining the symbiotic ability of these Cape Floristic Region isolates indicate evolutionary origins distinct from those of nodulating Burkholderia from elsewhere in the world. Overall, our findings suggest that Burkholderia species associated with fynbos legumes are highly diverse and their symbiotic abilities have unique ancestries. It is therefore possible that the evolution of these bacteria is closely linked to the diversification and establishment of legumes characteristic of the Cape Floristic Region.

  11. Production and transcriptional regulation of proanthocyanidin biosynthesis in forage legumes.

    Science.gov (United States)

    Zhou, Meiliang; Wei, Li; Sun, Zhanmin; Gao, Lihua; Meng, Yu; Tang, Yixiong; Wu, Yanmin

    2015-05-01

    Proanthocyanidins (PA), also known as condensed tannins, contribute to important forage legumes traits including disease resistance and forage quality. PA in forage plants has both positive and negative effects on feed digestibility and animal performance. The analytical methods and their applicability in measuring the contents of PA in forage plants are essential to studies on their nutritional effects. In spite of important breakthroughs in our understanding of the PA biosynthesis, important questions still remain to be answered such as the PA polymerization and transport. Recent advances in the understanding of transcription factor-mediated gene regulation mechanisms in anthocyanin and PA biosynthetic pathway in model plants suggest new approaches for the metabolic engineering of PA in forage plants. The present review will attempt to present the state-of-the-art of research in these areas and provide an update on the production and metabolic engineering of PA in forage plants. We hope that this will contribute to a better understanding of the ways in which PA production to manipulate the content of PA for beneficial effects in forage plants.

  12. Are Vicilins Another Major Class of Legume Lectins?

    Directory of Open Access Journals (Sweden)

    Ana C. Ribeiro

    2014-12-01

    Full Text Available Legume lectins comprise a structurally related, Ca/Mn-dependent, widespread, abundant and well characterized lectin family when compared to the large number of lectins from other sources described in the literature. Strangely enough, no specific function has been assigned to them aside from a possible role in storage and/or defense. Using a recent and fine-tuned methodology capable of specific lectin identification, β-conglutin, Vicia faba vicilin and β-lathyrin, the vicilin storage globulins from Lupinus albus, V. faba and Lathyrus sativus, respectively, were shown to be capable of affinity binding to thoroughly washed erythrocyte membranes and of specific elution with appropriate sugars. Based on this evidence and on sparse data published in the literature, a second family of legume lectins is proposed: the 7S family of storage proteins from leguminous seeds, or family II of legume lectins. These lectins are also structurally related, widespread and well characterized. In addition, they self-aggregate in a Ca/Mg, electrostatic dependent manner and are even more abundant than the family I of legume lectins. Using the same evidence, reserve and defense roles may be attributed to family II of legume lectins.

  13. Enzymatic hydrolysis: a method in alleviating legume allergenicity.

    Science.gov (United States)

    Kasera, Ramkrashan; Singh, A B; Lavasa, S; Prasad, Komarla Nagendra; Arora, Naveen

    2015-02-01

    Legumes are involved in IgE mediated food allergy in many countries. Avoidance of allergenic food is the only way to avoid symptomatic reaction. The present study investigated the effect of enzymatic hydrolysis on the allergenicity of three legumes - kidney bean (Phaseolus vulgaris), black gram (Vigna mungo) and peanut (Arachis hypogaea). Soluble protein extracts of the study legumes were sequentially treated by Alcalase(®) and Flavourzyme(®). Allergenicity of hydrolysates was then determined by ELISA, immunoblot, stripped basophil histamine release and skin prick test (SPT). Hydrolysis resulted in the loss of all IgE binding fractions determined by immunoblot in the three legumes. Specific IgE binding in ELISA was reduced by 62.2 ± 7.7%, 87.1 ± 9.6% and 91.8 ± 7.2% in the hydrolysates of kidney bean, black gram and peanut, respectively (p release of histamine was decreased significantly when sensitized basophils were challenged with hydrolysates as compared to raw extracts. Significant reduction in the biopotency of hydrolysates was also observed in SPT where only 1/10 kidney bean-sensitive individuals, 2/6 black gram-sensitive individuals and 1/7 peanut-sensitive individuals were found positive to their respective hydrolysates. In conclusion, enzymatic hydrolysis is effective in attenuating allergenicity of legume proteins and may be employed for preparing hypoallergenic food extracts.

  14. Biogenic amines in rhizobia and legume root nodules.

    Science.gov (United States)

    Fujihara, Shinsuke

    2009-01-01

    Root-nodule bacteria (rhizobia) are of great importance for nitrogen acquisition through symbiotic nitrogen fixation in a wide variety of leguminous plants. These bacteria differ from most other soil microorganisms by taking dual forms, i.e. a free-living form in soils and a symbiotic form inside of host legumes. Therefore, they should have a versatile strategy for survival, whether inhabiting soils or root nodules formed through rhizobia-legume interactions. Rhizobia generally contain large amounts of the biogenic amine homospermidine, an analog of spermidine which is an essential cellular component in most living systems. The external pH, salinity and a rapid change in osmolarity are thought to be significant environmental factors affecting the persistence of rhizobia. The present review describes the regulation of homospermidine biosynthesis in response to environmental stress and its possible functional role in rhizobia. Legume root nodules, an alternative habitat of rhizobia, usually contain a variety of biogenic amines besides homospermidine and the occurrence of some of these amines is closely associated with rhizobial infections. In the second half of this review, novel biogenic amines found in certain legume root nodules and the mechanism of their synthesis involving cooperation between the rhizobia and host legume cells are also described.

  15. Diurnal Leaf Starch Content: An Orphan Trait in Forage Legumes

    Directory of Open Access Journals (Sweden)

    Michael E. Ruckle

    2017-02-01

    Full Text Available Forage legumes have a relatively high biomass yield and crude protein content, but their grazed and harvested biomass lacks the high-energy carbohydrates required to meet the productivity potential of modern livestock breeds. Because of their low carbohydrate content, forage legume diets are typically supplemented with starch rich cereal grains or maize (Zea mays, leading to the disruption of local nutrient cycles. Although plant leaves were first reported to accumulate starch in a diurnal pattern over a century ago, leaf starch content has yet to be exploited as an agronomic trait in forage crops. Forage legumes such as red clover (Trifolium pratense have the genetic potential to accumulate up to one third of their leaf dry mass as starch, but this starch is typically degraded at night to support nighttime growth and respiration. Even when diurnal accumulation is considered with regard to the time the crop is harvested, only limited gains are realized due to environmental effects and post-harvest losses from respiration. Here we present original data for starch metabolism in red clover and place it in the broader context of other forage legumes such as, white clover (T. repens, and alfalfa (Medicago sativa. We review the application of recent advances in molecular breeding, plant biology, and crop phenotyping, to forage legumes to improve and exploit a potentially valuable trait for sustainable ruminant livestock production.

  16. Priority regions for research on dryland cereals and legumes

    Science.gov (United States)

    Hyman, Glenn; Barona, Elizabeth; Biradar, Chandrashekhar; Guevara, Edward; Dixon, John; Beebe, Steve; Castano, Silvia Elena; Alabi, Tunrayo; Gumma, Murali Krishna; Sivasankar, Shoba; Rivera, Ovidio; Espinosa, Herlin; Cardona, Jorge

    2016-01-01

    Dryland cereals and legumes  are important crops in farming systems across the world.  Yet they are frequently neglected among the priorities for international agricultural research and development, often due to lack of information on their magnitude and extent. Given what we know about the global distribution of dryland cereals and legumes, what regions should be high priority for research and development to improve livelihoods and food security? This research evaluated the geographic dimensions of these crops and the farming systems where they are found worldwide. The study employed geographic information science and data to assess the key farming systems and regions for these crops. Dryland cereal and legume crops should be given high priority in 18 farming systems worldwide, where their cultivated area comprises more than 160 million ha. These regions include the dryer areas of South Asia, West and East Africa, the Middle East and North Africa, Central America and other parts of Asia. These regions are prone to drought and heat stress, have limiting soil constraints, make up half of the global population and account for 60 percent of the global poor and malnourished. The dryland cereal and legume crops and farming systems merit more research and development attention to improve productivity and address development problems. This project developed an open access dataset and information resource that provides the basis for future analysis of the geographic dimensions of dryland cereals and legumes. PMID:27303632

  17. Equivalence of MAXENT and Poisson point process models for species distribution modeling in ecology.

    Science.gov (United States)

    Renner, Ian W; Warton, David I

    2013-03-01

    Modeling the spatial distribution of a species is a fundamental problem in ecology. A number of modeling methods have been developed, an extremely popular one being MAXENT, a maximum entropy modeling approach. In this article, we show that MAXENT is equivalent to a Poisson regression model and hence is related to a Poisson point process model, differing only in the intercept term, which is scale-dependent in MAXENT. We illustrate a number of improvements to MAXENT that follow from these relations. In particular, a point process model approach facilitates methods for choosing the appropriate spatial resolution, assessing model adequacy, and choosing the LASSO penalty parameter, all currently unavailable to MAXENT. The equivalence result represents a significant step in the unification of the species distribution modeling literature. Copyright © 2013, The International Biometric Society.

  18. Rumen-degradable protein in roll conditioned or macerated legume hays and silages estimated by in situ kinetics vs. alternative methods

    Science.gov (United States)

    Alternatives to the in situ method for estimating rumen-degradable protein (RDP) in diverse forage legumes should be validated. In this study, RDP in roll conditioned or macerated silages and hays of Medicago, Lotus, and Trifolium species with differing polyphenol compositions were estimated from in...

  19. Do species distribution models predict species richness in urban and natural green spaces? A case study using amphibians

    Science.gov (United States)

    Urban green spaces are potentially important to biodiversity conservation because they represent habitat islands in a mosaic of development, and could harbor high biodiversity or provide connectivity to nearby habitat. Presence only species distribution models (SDMs) represent a ...

  20. Do species distribution models predict species richness in urban and natural green spaces? A case study using amphibians

    Science.gov (United States)

    Urban green spaces are potentially important to biodiversity conservation because they represent habitat islands in a mosaic of development, and could harbor high biodiversity or provide connectivity to nearby habitat. Presence only species distribution models (SDMs) represent a ...

  1. Advances in Forage Legume Technology%豆科牧草研究进展

    Institute of Scientific and Technical Information of China (English)

    John Frame

    2001-01-01

    Breeding and selection within the vast pool of genetic variability that exists among and within the species of different genera of forage legumes have led to cultivars that are well adapted to a wide range of environmental and management conditions; genetic manipulation techniques offer further scope. There is increased understanding of the N2-fixation process, the routes of N transfer to associated grasses and the residual N value to subsequent arable crops. The interacting factors that include fertiliser N, de foliation strategies and stresses for example, and which govern the grass-legume balance in mixed associa tions, have been elucidated. Nitrogen losses with their adverse effects on the environment are lower in animal production systems based on grass/white clover than on highly N-fertilised grass swards. The physical, chemical and anatomical features of forage legumes, whether utilised as grazing, silage or hay, .all contribute to enhanced acceptability and voluntary food intake compared with grasses. The net result of the legume nutritive value, nutrient availability and intake characteristics is superior individual animal performance from different types and classes of livestock fed on legume monocultures or legume-rich grass -legume mixtures relative to being fed on grass. A notable finding is the beneficial role in animal nutrition of condensed tannins, present in Lotus corniculatus, Onobrychis viciifolia and Hedysarum coronarium for instance; these tannirs prevent bloat in livestock, improve N utilisation through more non-ammonia N reaching the small intestine, and alleviate the effects of intestinal nematodes in sheep. The develop ment of transgenic legumes containing conde nsed tannins is clearly a major objective for plant breeders. A number of alternative uses for forage legumes has been identified that include protective vegetation in vineyards, a living understorey for cereals, and provision of secondary compounds for the pharmaceutical industry

  2. Enchytraeus crypticus as model species in soil ecotoxicology.

    Science.gov (United States)

    Castro-Ferreira, Marta P; Roelofs, Dick; van Gestel, Cornelis A M; Verweij, Rudo A; Soares, Amadeu M V M; Amorim, Mónica J B

    2012-06-01

    Enchytraeids are ecologically relevant soil organisms, due to their activity in decomposition and bioturbation in many soil types worldwide. The enchytraeid reproduction test (ERT) guidelines ISO 16387 and OECD 220 are exclusive to the genus Enchytraeus and recommend using the species E. albidus with a 6-week test period. The suggested alternative, E. crypticus has a shorter generation time which may enable the ERT to be twice as fast. To confirm the suitability of a 3-week test period for E. crypticus, the toxicity of five chemicals, with distinct properties and modes of action, was assessed in LUFA 2.2 soil. In all controls the validity criteria were met, as survival of E. crypticus was above 92% and more than 772 juveniles were produced. The good performance supports its appropriateness as model species. Reproduction was more sensitive than survival, with only cadmium and 3,5-dichloroaniline causing significant lethal effects in the tested concentration ranges. The effect concentration causing 50% reduction in the number of juveniles (EC50) was 35 mg kg(-1) for cadmium, ecotoxicology, with advantages such as good control performance and speed, leading to a reliable and faster ERT.

  3. Concentrations of lead, cadmium, mercury and other elements in seeds of Lupinus mutabilis and of other legumes.

    Science.gov (United States)

    Gross, R; Auslitz, J; Schramel, P; Payer, H D

    1987-01-01

    Several species of legumes and varieties of lupins were examined for their heavy metal content in the seeds. Atomic absorption spectrometry was the main analytical tool. Validity and reproducibility of the results was checked by analyzing the same materials at two different laboratories performing the same technique. Additionally, inductively coupled plasma emission spectroscopy was applied. In grains of Lupinus mutabilis which constitute a traditional food in Andean populations, the following contents of heavy metals were determined: 0.10-0.25 microgram/g Cd; 0.5-1.6 microgram/g Pb; 0.10-0.15 microgram/g Hg. Seeds of other legumes contained 0.05-0.35 microgram/g Cd; 0.1-0.2 microgram/g Pb; 0.01-0.04 microgram/g Hg. The high lead content of lupins is easily reduced to one tenth by traditional extraction with boiling water. The mercury content, too, is decreased by this technique. The high manganese content of 1 300-1,400 micrograms/g of Lupinus albus compared to other legumes (25-37 micrograms/g) seems to be characteristic for this species and may be of nutritional significance. The comparison of the heavy metal contents of legume seeds of different origin and variety indicates a complex pattern of environmental and genetic factors that contribute to the specific metal contents of individual harvests. On the level of varieties the environmental factors (climate, soil, geology, agricultural techniques) seem to exhibit more important influences on the specific accumulation of heavy metals than genetic factors. In contrast, on the level of species or genera, the accumulation of heavy metals seems to be dominated by genetic factors rather than by environmental influences.

  4. Effects of sample survey design on the accuracy of classification tree models in species distribution models

    Science.gov (United States)

    Thomas C. Edwards; D. Richard Cutler; Niklaus E. Zimmermann; Linda Geiser; Gretchen G. Moisen

    2006-01-01

    We evaluated the effects of probabilistic (hereafter DESIGN) and non-probabilistic (PURPOSIVE) sample surveys on resultant classification tree models for predicting the presence of four lichen species in the Pacific Northwest, USA. Models derived from both survey forms were assessed using an independent data set (EVALUATION). Measures of accuracy as gauged by...

  5. The Distribution and Abundance of Bird Species: Towards a Satellite, Data Driven Avian Energetics and Species Richness Model

    Science.gov (United States)

    Smith, James A.

    2003-01-01

    This paper addresses the fundamental question of why birds occur where and when they do, i.e., what are the causative factors that determine the spatio-temporal distributions, abundance, or richness of bird species? In this paper we outline the first steps toward building a satellite, data-driven model of avian energetics and species richness based on individual bird physiology, morphology, and interaction with the spatio-temporal habitat. To evaluate our model, we will use the North American Breeding Bird Survey and Christmas Bird Count data for species richness, wintering and breeding range. Long term and current satellite data series include AVHRR, Landsat, and MODIS.

  6. Squares of different sizes: effect of geographical projection on model parameter estimates in species distribution modeling.

    Science.gov (United States)

    Budic, Lara; Didenko, Gregor; Dormann, Carsten F

    2016-01-01

    In species distribution analyses, environmental predictors and distribution data for large spatial extents are often available in long-lat format, such as degree raster grids. Long-lat projections suffer from unequal cell sizes, as a degree of longitude decreases in length from approximately 110 km at the equator to 0 km at the poles. Here we investigate whether long-lat and equal-area projections yield similar model parameter estimates, or result in a consistent bias. We analyzed the environmental effects on the distribution of 12 ungulate species with a northern distribution, as models for these species should display the strongest effect of projectional distortion. Additionally we choose four species with entirely continental distributions to investigate the effect of incomplete cell coverage at the coast. We expected that including model weights proportional to the actual cell area should compensate for the observed bias in model coefficients, and similarly that using land coverage of a cell should decrease bias in species with coastal distribution. As anticipated, model coefficients were different between long-lat and equal-area projections. Having progressively smaller and a higher number of cells with increasing latitude influenced the importance of parameters in models, increased the sample size for the northernmost parts of species ranges, and reduced the subcell variability of those areas. However, this bias could be largely removed by weighting long-lat cells by the area they cover, and marginally by correcting for land coverage. Overall we found little effect of using long-lat rather than equal-area projections in our analysis. The fitted relationship between environmental parameters and occurrence probability differed only very little between the two projection types. We still recommend using equal-area projections to avoid possible bias. More importantly, our results suggest that the cell area and the proportion of a cell covered by land should be

  7. Physiological role of calcium in legume-rhizobium symbiosis

    Directory of Open Access Journals (Sweden)

    Vasil’eva G.G.

    2011-12-01

    Full Text Available Literature data on the physiological role of calcium (Ca2+ in legume-rhizobium symbiosis development on initial stages - the infection and symbiotic structures formation, are generalized. The questions about the Ca2+ function in plants, special feature the formation of legume-rhizobium symbiosis and role of calcium in the interaction of two organisms are considered. Data on the interaction of ROS and Ca2+ in the development of the legume-rhizobium symbiosis and the relationship of NADPH-oxidase activity with the calcium signaling system are analyzed. The special attention is given to the role of Ca22+-spiking and calcium and calmodulin-like kinase in the initiation of plant symbiotic ways operation leads to infection and the formation of symbiotic structures.

  8. Transport and metabolism in legume-rhizobia symbioses.

    Science.gov (United States)

    Udvardi, Michael; Poole, Philip S

    2013-01-01

    Symbiotic nitrogen fixation by rhizobia in legume root nodules injects approximately 40 million tonnes of nitrogen into agricultural systems each year. In exchange for reduced nitrogen from the bacteria, the plant provides rhizobia with reduced carbon and all the essential nutrients required for bacterial metabolism. Symbiotic nitrogen fixation requires exquisite integration of plant and bacterial metabolism. Central to this integration are transporters of both the plant and the rhizobia, which transfer elements and compounds across various plant membranes and the two bacterial membranes. Here we review current knowledge of legume and rhizobial transport and metabolism as they relate to symbiotic nitrogen fixation. Although all legume-rhizobia symbioses have many metabolic features in common, there are also interesting differences between them, which show that evolution has solved metabolic problems in different ways to achieve effective symbiosis in different systems.

  9. Linking Biomarker and Comparative Omics to Pathogens in Legumes.

    Science.gov (United States)

    Diapari, Marwan

    2016-01-01

    It is envisioned that a more precise study of the association between the traits and biomarkers will dramatically decrease the time and costs required to bring new improved disease resistance lines to market. The field of omics has an enormous potential to assess diseases more precise, including the identification and understanding of pathogenic mechanisms in legume crops, and have been exemplified by a relatively large number of studies. Recently, molecular genetic studies have accumulated a huge amount of genotypic data, through a more affordable next generation sequencing (NGS) technology, causing the omics approaches to fall behind. In this paper I provide an overview of genomics and proteomics and their use in legume crops, including the use of comparative genomics to identify homologous markers within legume crops.

  10. Populus euphratica, a Tolerant Model but Endangered Arborescent Species

    Institute of Scientific and Technical Information of China (English)

    Gu Ruisheng; Pei Dong

    2005-01-01

    @@ Populus euphratica is a most tolerant arborescent species to abiotic stress. It can adapt to extreme conditions, ranging from flood to atmosphere extremely dry, hot from + 54 ℃ to - 45 ℃, and from normal soil to the soil with very high salt concentration ( to 2 ~5%) although being a non-halophyte. However, the natural stands of P. euphratica have been shrinking tremendously for the past decades and some populations are facing the fate of extinction. The preservation of existing resources should be carried out as a burning issue. In parallel, P. euphratica could be taken as a model plant to explore the molecular mechanism of abiotic-stress tolerance and to exploit its tolerant genes due to its smaller genome and easy molecular manipulation. The measures for preservation, germ-plasma exploitation, tolerance mechanism exploration and resource utilization were also discussed in this paper.

  11. Peanut cross-reacting allergens in seeds and sprouts of a range of legumes

    DEFF Research Database (Denmark)

    Jensen, L.B.; Pedersen, M.H.; Skov, P.S.

    2008-01-01

    Recently, peanut-allergic patients have reported symptoms upon ingestion of bean sprouts produced from various legumes.......Recently, peanut-allergic patients have reported symptoms upon ingestion of bean sprouts produced from various legumes....

  12. Mapping National Plant Biodiversity Patterns in South Korea with the MARS Species Distribution Model.

    Directory of Open Access Journals (Sweden)

    Hyeyeong Choe

    Full Text Available Accurate information on the distribution of existing species is crucial to assess regional biodiversity. However, data inventories are insufficient in many areas. We examine the ability of Multivariate Adaptive Regression Splines (MARS multi-response species distribution model to overcome species' data limitations and portray plant species distribution patterns for 199 South Korean plant species. The study models species with two or more observations, examines their contribution to national patterns of species richness, provides a sensitivity analysis of different range threshold cutoff approaches for modeling species' ranges, and presents considerations for species modeling at fine spatial resolution. We ran MARS models for each species and tested four threshold methods to transform occurrence probabilities into presence or absence range maps. Modeled occurrence probabilities were extracted at each species' presence points, and the mean, median, and one standard deviation (SD calculated to define data-driven thresholds. A maximum sum of sensitivity and specificity threshold was also calculated, and the range maps from the four cutoffs were tested using independent plant survey data. The single SD values were the best threshold tested for minimizing omission errors and limiting species ranges to areas where the associated occurrence data were correctly classed. Eight individual species range maps for rare plant species were identified that are potentially affected by resampling predictor variables to fine spatial scales. We portray spatial patterns of high species richness by assessing the combined range maps from three classes of species: all species, endangered and endemic species, and range-size rarity of all species, which could be used in conservation planning for South Korea. The MARS model is promising for addressing the common problem of few species occurrence records. However, projected species ranges are highly dependent on the

  13. Mapping National Plant Biodiversity Patterns in South Korea with the MARS Species Distribution Model.

    Science.gov (United States)

    Choe, Hyeyeong; Thorne, James H; Seo, Changwan

    2016-01-01

    Accurate information on the distribution of existing species is crucial to assess regional biodiversity. However, data inventories are insufficient in many areas. We examine the ability of Multivariate Adaptive Regression Splines (MARS) multi-response species distribution model to overcome species' data limitations and portray plant species distribution patterns for 199 South Korean plant species. The study models species with two or more observations, examines their contribution to national patterns of species richness, provides a sensitivity analysis of different range threshold cutoff approaches for modeling species' ranges, and presents considerations for species modeling at fine spatial resolution. We ran MARS models for each species and tested four threshold methods to transform occurrence probabilities into presence or absence range maps. Modeled occurrence probabilities were extracted at each species' presence points, and the mean, median, and one standard deviation (SD) calculated to define data-driven thresholds. A maximum sum of sensitivity and specificity threshold was also calculated, and the range maps from the four cutoffs were tested using independent plant survey data. The single SD values were the best threshold tested for minimizing omission errors and limiting species ranges to areas where the associated occurrence data were correctly classed. Eight individual species range maps for rare plant species were identified that are potentially affected by resampling predictor variables to fine spatial scales. We portray spatial patterns of high species richness by assessing the combined range maps from three classes of species: all species, endangered and endemic species, and range-size rarity of all species, which could be used in conservation planning for South Korea. The MARS model is promising for addressing the common problem of few species occurrence records. However, projected species ranges are highly dependent on the threshold and scale

  14. The effect of fire on the dormancy break of three annual legume seeds

    Directory of Open Access Journals (Sweden)

    Fabio Gresta

    2011-07-01

    Full Text Available Fire is a common phenomenon in the Mediterranean environment and strongly influences vegetal population dynamics through its impact on vegetation and the soil seed bank. Fire is able to break down the seed coat of hard-seeded legumes within the soil and trigger germination. To evaluate the effect of fire on the dormancy break in Medicago ciliaris, Medicago rugosa and Scorpiurus muricatus subsp. subvillosus, the seeds were placed at three different depths (surface, 25 mm and 50 mm and subjected to fires at two different intensities (high and low. As a control sample, a batch of seeds was buried at 25 mm for the duration of the trial and not subjected to fire. Soil temperatures during the fire were compared directly to stubble quantity and indirectly related to soil depth. The two Medicago species survived exposure to 90°C for a few minutes and displayed a significant increase in germination with exposure to high temperatures (over 70°C for several minutes. On the other hand, no germination occurred in Scorpiurus, irrespective of treatment. In conclusion, fire had a significant and positive effect in triggering germination of the Medicago species, but the dispersal strategies of these hard-seeded legumes are only partially interrupted by fire as a large number of seeds (>50% remained non-germinated in the soil.

  15. Use of EST database markers from M. truncatula in the transferability to other forage legumes.

    Science.gov (United States)

    Chandra, Amaresh

    2011-05-01

    In general tropical forage legumes lack microsatellites or simple sequence repeat (SSR) markers. Development of genic SSR markers from expressed sequence tagged (EST) database is an alternate and efficient approach to generate the standard DNA markers for genome analysis of such crop species. In the present paper a total of 816 EST-SSRs containing perfect repeats of mono (33.5%), di (14.7%), tri (39.3%), tetra (2.7%), penta (0.7%) and hexa (0.4%) nucleotides were identified from 1,87,763 ESTs of Medicago truncatula. Along with, 70 (8.5%) SSRs of a compound type were also observed. Seven primer pairs of tri repeats were tested for cross transferability in 19 accessions of forage legumes comprising 11 genera. At two different annealing temperatures (55 and 60 degreesC) all primer pairs except AJ410087 reacted with many accessions of forage legumes. Atotal of 51 alleles were detected with six M. truncatula EST-SSRs primer-pairs against DNAfrom 19 accessions representing 11 genera where number of alleles ranged from 2 to 13. The cross-transferability of these EST-SSRs was 40.6% at 55 degreesC and 32.3% at 60 degreesC annealing temperature. 24 alleles of the total 50 (48%) at 55 degreesC and 27 of 51 (53%) at 60 degreesC were polymorphic among the accessions. These 27 polymorphic amplicons identified could be used as DNA markers. This study demonstrates the developed SSR markers from M. truncatula ESTs as a valuable genetic markers and also proposes the possibility of transferring these markers between species of different genera of the legumes of forage importance. It was evident from the results obtained with a set of Desmanthus virgatus accessions where SequentialAgglomerative Hierarchical and Nested (SAHN) cluster analysis based on Dice similarity and Unweighted Pair Group Method with Arithmetic mean Algorithm (UPGMA) revealed significant variability (24 to 74%) among the accessions. High bootstrap values (>30) supported the nodes generated by dendrogram analysis of

  16. Selection bias in species distribution models: An econometric approach on forest trees based on structural modeling

    Science.gov (United States)

    Martin-StPaul, N. K.; Ay, J. S.; Guillemot, J.; Doyen, L.; Leadley, P.

    2014-12-01

    Species distribution models (SDMs) are widely used to study and predict the outcome of global changes on species. In human dominated ecosystems the presence of a given species is the result of both its ecological suitability and human footprint on nature such as land use choices. Land use choices may thus be responsible for a selection bias in the presence/absence data used in SDM calibration. We present a structural modelling approach (i.e. based on structural equation modelling) that accounts for this selection bias. The new structural species distribution model (SSDM) estimates simultaneously land use choices and species responses to bioclimatic variables. A land use equation based on an econometric model of landowner choices was joined to an equation of species response to bioclimatic variables. SSDM allows the residuals of both equations to be dependent, taking into account the possibility of shared omitted variables and measurement errors. We provide a general description of the statistical theory and a set of applications on forest trees over France using databases of climate and forest inventory at different spatial resolution (from 2km to 8km). We also compared the outputs of the SSDM with outputs of a classical SDM (i.e. Biomod ensemble modelling) in terms of bioclimatic response curves and potential distributions under current climate and climate change scenarios. The shapes of the bioclimatic response curves and the modelled species distribution maps differed markedly between SSDM and classical SDMs, with contrasted patterns according to species and spatial resolutions. The magnitude and directions of these differences were dependent on the correlations between the errors from both equations and were highest for higher spatial resolutions. A first conclusion is that the use of classical SDMs can potentially lead to strong miss-estimation of the actual and future probability of presence modelled. Beyond this selection bias, the SSDM we propose represents

  17. [LEGUME-RHIZOBIUM SYMBIOSIS PROTEOMICS: ACHIEVEMENTS AND PERSPECTIVES].

    Science.gov (United States)

    Kondratiuk, Iu Iu; Mamenko, P M; Kots, S Ya

    2015-01-01

    The present review contains results of proteomic researches of legume-rhizobium symbiosis. The technical difficulties associated with the methods of obtaining protein extracts from symbiotic structures and ways of overcoming them were discussed. The changes of protein synthesis under formation and functioning of symbiotic structures were shown. Special attention has been given to the importance of proteomic studies of plant-microbe structures in the formation of adaptation strategies under adverse environmental conditions. The technical and conceptual perspectives of legume-rhizobium symbiosis proteomics were shown.

  18. Rhizobium-legume symbioses: the crucial role of plant immunity.

    Science.gov (United States)

    Gourion, Benjamin; Berrabah, Fathi; Ratet, Pascal; Stacey, Gary

    2015-03-01

    New research results have significantly revised our understanding of the rhizobium-legume infection process. For example, Nod factors (NFs), previously thought to be absolutely essential for this symbiosis, were shown to be dispensable under particular conditions. Similarly, an NF receptor, previously considered to be solely involved in symbiosis, was shown to function during plant pathogen infections. Indeed, there is a growing realization that plant innate immunity is a crucial component in the establishment and maintenance of symbiosis. We review here the factors involved in the suppression of plant immunity during rhizobium-legume symbiosis, and we attempt to place this information into context with the most recent and sometimes surprising research results.

  19. Legume Seed Production Meeting Market Requirements and Economic Impacts

    DEFF Research Database (Denmark)

    Boelt, Birte; Julier, Bernadette; Karagić, Đura

    2015-01-01

    L.), crop management techniques are applied to stimulate reproductive development in order to obtain high seed yields. These include a low plant density, manipulation of canopy size to avoid lodging and shading of fruiting organs, synchronization of flowering with pollinating insects as well...... to be an increasing emphasis on the role of forage legumes in producing high-quality meat and milk, combined with the requirement to reduce the environmental footprint of grassland agriculture. A high forage legume seed yield is a prerequisite to meet market requirements for new, improved cultivars and hence achieve...

  20. Effects of alternative legume seeds on Barbaresca lamb meat quality

    Directory of Open Access Journals (Sweden)

    P. Pennisi

    2011-03-01

    Full Text Available In recent years a renewed interest towards the use of local legume seeds in animal nutrition was raising in Mediterranean areas. Conventional feedstuffs such as maize and soybean and animal by-products, the former widely diffused as genetically modified organisms (GMO and the latter related to “mad cow disease” produced significative changes in public perceptions, justifying a dramatic increase of the use of alternative protein and energy sources such as legume seeds (peas, faba beans, chickpeas (Hanbury et al., 2000...

  1. Performance of tropical legumes grown as understory of a eucalypt plantation in a seasonally dry area of the Brazilian Cerrado

    Directory of Open Access Journals (Sweden)

    Maria Luiza F. Nicodemo

    2015-09-01

    Full Text Available Nine tropical legumes were grown outside the canopy and in the understory of an 8-year-old Eucalyptus grandis stand in order to assess their seasonal production and forage quality for 4 evaluation periods. Incident photosynthetically active radiation in the understory was 18% of that outside the canopy. In the understory, production of Lablab purpureus, Centrosema schiedeanum, Clitoria ternatea, Pueraria phaseoloides, Alysicarpus vaginalis, Aeschynomene villosa, Estilosantes Campo Grande (Stylosanthes capitata + S. macrocephala, Calopogonium mucunoides and Arachis pintoi was <1 kg/ha/d for most samples. Even considering this low production, the large area available for animal production in forest plantations might justify the interest in legumes because of their high nutritive value. Lablab purpureus produced the greatest amount of dry matter in the understory in the establishment phase (12.1 kg/ha/d, but did not persist. It could be a suitable candidate for a cover legume species mixture to provide early growth. Centrosema schiedeanum developed rapidly and showed a high capacity for ground cover (>70% and persistence, and had high nitrogen concentration, thus demonstrating good potential for protecting soils and promoting nutrient cycling in forest plantations. Another species with potential is A. pintoi, which established slowly but towards the end of the experiment showed moderate to high understory ground cover.Keywords: Dry matter production, forage quality, shade, silvopastoral system.DOI: 10.17138/TGFT(3151-160

  2. Deciphering composition and function of the root microbiome of a legume plant.

    Science.gov (United States)

    Hartman, Kyle; van der Heijden, Marcel Ga; Roussely-Provent, Valexia; Walser, Jean-Claude; Schlaeppi, Klaus

    2017-01-17

    Diverse assemblages of microbes colonize plant roots and collectively function as a microbiome. Earlier work has characterized the root microbiomes of numerous plant species, but little information is available for legumes despite their key role in numerous ecosystems including agricultural systems. Legumes form a root nodule symbiosis with nitrogen-fixing Rhizobia bacteria and thereby account for large, natural nitrogen inputs into soils. Here, we describe the root bacteria microbiome of the legume Trifolium pratense combining culture-dependent and independent methods. For a functional understanding of individual microbiome members and their impact on plant growth, we began to inoculate root microbiome members alone or in combination to Trifolium roots. At a whole-root scale, Rhizobia bacteria accounted for ~70% of the root microbiome. Other enriched members included bacteria from the genera Pantoea, Sphingomonas, Novosphingobium, and Pelomonas. We built a reference stock of 200 bacteria isolates, and we found that they corresponded to ~20% of the abundant root microbiome members. We developed a microcosm system to conduct simplified microbiota inoculation experiments with plants. We observed that while an abundant root microbiome member reduced plant growth when inoculated alone, this negative effect was alleviated if this Flavobacterium was co-inoculated with other root microbiome members. The Trifolium root microbiome was dominated by nutrient-providing Rhizobia bacteria and enriched for bacteria from genera that may provide disease protection. First microbiota inoculation experiments indicated that individual community members can have plant growth compromising activities without being apparently pathogenic, and a more diverse root community can alleviate plant growth compromising activities of its individual members. A trait-based characterization of the reference stock bacteria will permit future microbiota manipulation experiments to decipher overall

  3. Rhizobial Diversity and Nodulation Characteristics of the Extremely Promiscuous Legume Sophora flavescens.

    Science.gov (United States)

    Jiao, Yin Shan; Liu, Yuan Hui; Yan, Hui; Wang, En Tao; Tian, Chang Fu; Chen, Wen Xin; Guo, Bao Lin; Chen, Wen Feng

    2015-12-01

    In present study, we report our extensive survey on the diversity and biogeography of rhizobia associated with Sophora flavescens, a sophocarpidine (matrine)-containing medicinal legume. We additionally investigated the cross nodulation, infection pattern, light and electron microscopies of root nodule sections of S. flavescens infected by various rhizobia. Seventeen genospecies of rhizobia belonging to five genera with seven types of symbiotic nodC genes were found to nodulate S. flavescens in natural soils. In the cross-nodulation tests, most representative rhizobia in class α-Proteobacteria, whose host plants belong to different cross-nodulation groups, form effective indeterminate nodules, while representative rhizobia in class β-Proteobacteria form ineffective nodules on S. flavescens. Highly host-specific biovars of Rhizobium leguminosarum (bv. trifolii and bv. viciae) and Rhizobium etli bv. phaseoli could establish symbioses with S. flavescens, providing further evidence that S. flavescens is an extremely promiscuous legume and it does not have strict selectivity on either the symbiotic genes or the species-determining housekeeping genes of rhizobia. Root-hair infection is found as the pattern that rhizobia have gained entry into the curled root hairs. Electron microscopies of ultra-thin sections of S. flavescens root nodules formed by different rhizobia show that the bacteroids are regular or irregular rod shape and nonswollen types. Some bacteroids contain poly-β-hydroxybutyrate (PHB), while others do not, indicating the synthesis of PHB in bacteroids is rhizobia-dependent. The extremely promiscuous symbiosis between S. flavescens and different rhizobia provide us a basis for future studies aimed at understanding the molecular interactions of rhizobia and legumes.

  4. 会泽铅锌尾矿区自然生长的3种豆科植物铅锌耐性的研究%Tolerance to Pb2+ and Zn2+ of three local legumes species growing in lead-zinc mining tailing of Huize

    Institute of Scientific and Technical Information of China (English)

    李彪; 熊智; 王金华; 汪姝; 孙浩; 缪福俊

    2011-01-01

    为了解会泽铅锌尾矿区自然发生的豆科植物对重金属的耐性,研究了该地区自然发生的3种豆科植物在Pb2+/Zn2+单盐和双盐胁迫下种子萌发及其幼苗生长的情况.研究表明:在本实验所设的浓度范围内,Pb2+/Zn2+单独胁迫时,对供试植物种子及幼苗的生长主要表现为抑制作用,除苕子(ViciaCraccaL.)外,金属离子的质量浓度越大抑制作用越强;Pb2+/Zn2+共同胁迫时出现复杂的交互作用.对于苕子的种子及幼苗的生长,Pb2+/Zn2+呈现明显的相互加强抑制作用;对于其它2种植物,当Zn2+浓度在低质量浓度时,Pb2+似乎对Zn2+抑制有缓解作用,同样当Pb2+浓度在低质量浓度时,Zn2+似乎对Pb2+抑制有缓解作用,但是当Pb2+/Zn2+高浓度时,Pb2+/Zn2+呈现明显的相互加强抑制作用.不论是单盐还是双盐,苕子对的耐性最强,其次为白三叶(Trifolium repens L.),紫花苜蓿(Medicago sativa L.)最弱.会泽铅锌尾矿区重金属含量高是该区植被恢复的最大障碍,进一步研究植物对Pb2+及Zn2+的耐受性对于铅锌尾矿区的植被恢复有极其重要的意义.%In this paper, the effects of Pb2+/Zn2+ on seed germination and seedling growth of three legumes species which occurred naturally in lead-zinc mining tailings in Huize were studied. The result showed that, under Pb2+ or Zn2+ stress, the seed germination and seedling growth of three plants were inhibited under concentration of Pb2+-Zn2+ on this paper, and except Vicia Cracca, the higher concentration of heavy metal ion was, the stronger inhibition was exerted on two others. Under double Pb2+-Zn2+salts, the complicated interaction existed commonly among the experiment plants. For Vicia Cracca, the interaction on the seed germination and seedling growth was increased strongly under interaction of Pb2+ and Zn2+. When the concentration of Zn2+ was low, the inhibition of Pb2+ was alleviated by Zn2+ in two others. Similarly, when the concentration

  5. Intraguild interactions implicating invasive species: Harmonia axyridis as a model species

    Directory of Open Access Journals (Sweden)

    Francis, F.

    2010-01-01

    Full Text Available Understanding the mechanisms that result in the success of exotic species will contribute to predicting future invasions and managing invaded systems. Exotic animal species, whether introduced accidentally or deliberately, may impact communities of native species through different intraguild interactions. As an effective generalist predator of aphids and other soft-body pests the harlequin ladybird Harmonia axyridis Pallas has been a successful biological control agent. This species was deliberately introduced into several countries for biological control of different arthropods pests, but it was also introduced accidentally into several other countries. It became an invasive species, affecting the dynamic and composition of several guilds through direct or indirect interactions. In this paper we will specifically review the existing data on mechanisms of intraguild interactions, within exotic guilds, that result in the success of H. axyridis as an invasive alien. We will use these studies to interpret the observed population declines in predator diversity in the field, and predict species at risk in regions not yet invaded. Finally, we will review the available data on the impact of intraguild interactions implicating H. axyridis on pest biocontrol.

  6. Evolutionary dynamics of nitrogen fixation in the legume-rhizobia symbiosis.

    Science.gov (United States)

    Fujita, Hironori; Aoki, Seishiro; Kawaguchi, Masayoshi

    2014-01-01

    The stabilization of host-symbiont mutualism against the emergence of parasitic individuals is pivotal to the evolution of cooperation. One of the most famous symbioses occurs between legumes and their colonizing rhizobia, in which rhizobia extract nutrients (or benefits) from legume plants while supplying them with nitrogen resources produced by nitrogen fixation (or costs). Natural environments, however, are widely populated by ineffective rhizobia that extract benefits without paying costs and thus proliferate more efficiently than nitrogen-fixing cooperators. How and why this mutualism becomes stabilized and evolutionarily persists has been extensively discussed. To better understand the evolutionary dynamics of this symbiosis system, we construct a simple model based on the continuous snowdrift game with multiple interacting players. We investigate the model using adaptive dynamics and numerical simulations. We find that symbiotic evolution depends on the cost-benefit balance, and that cheaters widely emerge when the cost and benefit are similar in strength. In this scenario, the persistence of the symbiotic system is compatible with the presence of cheaters. This result suggests that the symbiotic relationship is robust to the emergence of cheaters, and may explain the prevalence of cheating rhizobia in nature. In addition, various stabilizing mechanisms, such as partner fidelity feedback, partner choice, and host sanction, can reinforce the symbiotic relationship by affecting the fitness of symbionts in various ways. This result suggests that the symbiotic relationship is cooperatively stabilized by various mechanisms. In addition, mixed nodule populations are thought to encourage cheater emergence, but our model predicts that, in certain situations, cheaters can disappear from such populations. These findings provide a theoretical basis of the evolutionary dynamics of legume-rhizobia symbioses, which is extendable to other single-host, multiple

  7. Seeing the forest and the trees: multilevel models reveal both species and community patterns

    Science.gov (United States)

    Michelle M. Jackson; Monica G. Turner; Scott M. Pearson; Anthony R. Ives

    2012-01-01

    Studies designed to understand species distributions and community assemblages typically use separate analytical approaches (e.g., logistic regression and ordination) to model the distribution of individual species and to relate community composition to environmental variation. Multilevel models (MLMs) offer a promising strategy for integrating species and community-...

  8. Uses of tree legumes in semi-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    Felker, P.

    1980-01-01

    Uses of tree legumes in semi-arid and arid regions are reviewed. This review is divided into sections according to the following general use categories: fuels; human food; livestock food; to increase yields of crops grown beneath their canopies;and control of desertification. (MHR)

  9. Nutritive evaluation of legume seeds for ruminant feeding.

    Science.gov (United States)

    Ramos-Morales, E; Sanz-Sampelayo, M R; Molina-Alcaide, E

    2010-02-01

    Chemical composition, rumen degradability and the effect of particle losses, and intestinal digestibility of protein by using in situ-in vitro and in vitro techniques were stated for beans (Vicia faba), lupin (Lupinus albus), vetch (Vicia sativa) and bitter vetch (Vicia ervilia) and four diets including those legume seeds. In addition, the apparent digestibility of experimental diets was determined in goats. The legume seeds showed high protein content (206-319 g/kg dry matter). Effective degradability of protein for legumes and diets varied from 0.80 to 0.87 and 0.76 to 0.82, respectively, decreasing to 0.53-0.76 and 0.61-0.67, respectively, when particle loss was taken into account. Different intestinal digestibility values were obtained with both methodologies without significant relationship between them (y = 1.058-0.463x; R(2)=0.068; RSD = 0.140; p = 0.53). There were no differences in the apparent nutrients and energy digestibility among diets (p > 0.05). These legumes can supply rapidly degradable protein for microbial protein synthesis and contribute to the pool of amino acids available for the synthesis of milk protein and for retention in the body.

  10. Antinutritional effects of legume seeds in piglets, rats and chickens.

    NARCIS (Netherlands)

    Huisman, J.

    1990-01-01

    There is a growing interest in Europe to be self-supporting with regard to the protein supply for animal diets. Peas and beans growing well under European climatic conditions could provide alternatives to soya. However, these legume seeds contain the same classes of antinutritional factors (ANFs) as

  11. Biological nitrogen fixation in non-legume plants.

    Science.gov (United States)

    Santi, Carole; Bogusz, Didier; Franche, Claudine

    2013-05-01

    Nitrogen is an essential nutrient in plant growth. The ability of a plant to supply all or part of its requirements from biological nitrogen fixation (BNF) thanks to interactions with endosymbiotic, associative and endophytic symbionts, confers a great competitive advantage over non-nitrogen-fixing plants. Because BNF in legumes is well documented, this review focuses on BNF in non-legume plants. Despite the phylogenic and ecological diversity among diazotrophic bacteria and their hosts, tightly regulated communication is always necessary between the microorganisms and the host plant to achieve a successful interaction. Ongoing research efforts to improve knowledge of the molecular mechanisms underlying these original relationships and some common strategies leading to a successful relationship between the nitrogen-fixing microorganisms and their hosts are presented. Understanding the molecular mechanism of BNF outside the legume-rhizobium symbiosis could have important agronomic implications and enable the use of N-fertilizers to be reduced or even avoided. Indeed, in the short term, improved understanding could lead to more sustainable exploitation of the biodiversity of nitrogen-fixing organisms and, in the longer term, to the transfer of endosymbiotic nitrogen-fixation capacities to major non-legume crops.

  12. Quality of buffalo meat burger containing legume flours as binders.

    Science.gov (United States)

    Modi, V K; Mahendrakar, N S; Narasimha Rao, D; Sachindra, N M

    2004-01-01

    The effect of addition of different decorticated legume flours, viz., soya bean, bengal gram, green gram and black gram, on the quality of buffalo meat burger was studied. The burgers consisted of optimized quantities of roasted or unroasted legume flour, spices and common salt. Inclusion of roasted black gram flour registered the highest yield of 95.7%, lowest shrinkage of 5% and lowest fat absorption of 26.6% on frying. Protein content of 18-20% was highest in the soya flour formulation. Free fatty acid (FFA) values (as% oleic) increased from 14.3 to 17.3 in freshly prepared samples (before frying) to 16.0-19.4 in 4 m frozen (-16±2 °C) stored samples and fried samples had about 25% lower FFA values. Formulations with roasted flours registered lower thiobarbituric acid (TBA) values (mg malonaldehyde/kg sample) of 0.6-1.5 as against 0.6-2.1 for unroasted flours before frying. The burgers prepared with any of these binders were organoleptically acceptable even after storage at -16±2 °C for 4 months., However, the burger with black gram dhal (dehulled split legume) flour had better sensory quality attributes compared to other legumes.

  13. Contribution of Legume Rotations to the Nitrogen Requirements of a ...

    African Journals Online (AJOL)

    of legumes rotation in meeting the N fertilizer requirements of maize. The experimental site ... This study was carried out on a Rhodic Ferralsol at. Mlingano Agricultural .... different according to Duncan's New Multiple Range Test. *, ** and *** indicate .... and 16 kg N ha-1 in the case of the cowpea, pigeonpea and greengram ...

  14. Nod factor signal transduction in the Rhizobium-legume symbiosis

    NARCIS (Netherlands)

    Limpens, E.H.M.; Bisseling, T.

    2008-01-01

    The symbiotic interaction between Rhizobium bacteria and most legume plants is initiated by the perception of bacterial signal molecules, the nodulation (Nod) factors, at the root hairs of the plant. This induces responses both in the root hairs, leading to infection by the bacteria, as well as at a

  15. Genetic considerations in developing germplasm sources of native legumes

    Science.gov (United States)

    There is a great need for biological diversity in reseeding efforts on western rangelands. Legumes provide a crucial component of reseedings, by allowing for higher forage quality, soil nitrogen fixation, pollinator sustenance, and wildlife and wild-fowl feed. In efforts to collect and produce see...

  16. Converting perennial legumes to organic cropland without tillage

    Science.gov (United States)

    Organic producers are interested in developing a no-till system for crop production. In this study, we examined management tactics to convert perennial legumes to annual crops without tillage. Our hypothesis was that reducing carbohydrate production in the fall by mowing would favor winterkill. M...

  17. Nitrogen and phosphorus economy of a legume tree-cereal intercropping system under controlled conditions

    Energy Technology Data Exchange (ETDEWEB)

    Isaac, M.E., E-mail: marney.isaac@utoronto.ca [CIRAD, UMR Eco and Sols, 34060 Montpellier (France); University of Toronto, Department of Physical and Environmental Sciences, 1265 Military Trail, Toronto, Canada M1C 1A4 (Canada); Hinsinger, P. [INRA, UMR Eco and Sols, 34060 Montpellier (France); Harmand, J.M. [CIRAD, UMR Eco and Sols, 34060 Montpellier (France)

    2012-09-15

    Considerable amounts of nitrogen (N) and phosphorus (P) fertilizers have been mis-used in agroecosystems, with profound alteration to the biogeochemical cycles of these two major nutrients. To reduce excess fertilizer use, plant-mediated nutrient supply through N{sub 2}-fixation, transfer of fixed N and mobilization of soil P may be important processes for the nutrient economy of low-input tree-based intercropping systems. In this study, we quantified plant performance, P acquisition and belowground N transfer from the N{sub 2}-fixing tree to the cereal crop under varying root contact intensity and P supplies. We cultivated Acacia senegal var senegal in pot-culture containing 90% sand and 10% vermiculite under 3 levels of exponentially supplied P. Acacia plants were then intercropped with durum wheat (Triticum turgidum durum) in the same pots with variable levels of adsorbed P or transplanted and intercropped with durum wheat in rhizoboxes excluding direct root contact on P-poor red Mediterranean soils. In pot-culture, wheat biomass and P content increased in relation to the P gradient. Strong isotopic evidence of belowground N transfer, based on the isotopic signature ({delta}{sup 15}N) of tree foliage and wheat shoots, was systematically found under high P in pot-culture, with an average N transfer value of 14.0% of wheat total N after 21 days of contact between the two species. In the rhizoboxes, we observed limitations on growth and P uptake of intercropped wheat due to competitive effects on soil resources and minimal evidence of belowground N transfer of N from acacia to wheat. In this intercrop, specifically in pot-culture, facilitation for N transfer from the legume tree to the crop showed to be effective especially when crop N uptake was increased (or stimulated) as occurred under high P conditions and when competition was low. Understanding these processes is important to the nutrient economy and appropriate management of legume-based agroforestry systems

  18. Model reduction for stochastic chemical systems with abundant species

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Stephen; Cianci, Claudia; Grima, Ramon [School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH93JR, Scotland (United Kingdom)

    2015-12-07

    Biochemical processes typically involve many chemical species, some in abundance and some in low molecule numbers. We first identify the rate constant limits under which the concentrations of a given set of species will tend to infinity (the abundant species) while the concentrations of all other species remains constant (the non-abundant species). Subsequently, we prove that, in this limit, the fluctuations in the molecule numbers of non-abundant species are accurately described by a hybrid stochastic description consisting of a chemical master equation coupled to deterministic rate equations. This is a reduced description when compared to the conventional chemical master equation which describes the fluctuations in both abundant and non-abundant species. We show that the reduced master equation can be solved exactly for a number of biochemical networks involving gene expression and enzyme catalysis, whose conventional chemical master equation description is analytically impenetrable. We use the linear noise approximation to obtain approximate expressions for the difference between the variance of fluctuations in the non-abundant species as predicted by the hybrid approach and by the conventional chemical master equation. Furthermore, we show that surprisingly, irrespective of any separation in the mean molecule numbers of various species, the conventional and hybrid master equations exactly agree for a class of chemical systems.

  19. Multiple-purpose trees for pastoral farming in New Zealand: with emphasis on tree legumes. [Lucerne Tree: Medick Tree

    Energy Technology Data Exchange (ETDEWEB)

    Davies, D.J.G.; Macfarlane, R.P.

    1979-01-01

    The potential for soil conservation and agroforestry of several native and exotic legumes is discussed. Flowering period, chemical composition of leaves/pods, hardiness to frost and drought, timber value, forage potential for livestock and bees, ornamental value and other products are tabulated with information on up to 38 species. Two low-growing species that have proved useful for slope stabilization as well as forage are tree lucerne (Cytisus palmensis) and tree medick (Medicago arborea), the latter being shrubby and more suitable for cold districts. Gleditsia triacanthos is recommended as a shade and fodder tree for farm pasture.

  20. Modeling Stratospheric Constituents: Reactive Species That Regulate Ozone

    Science.gov (United States)

    Salawitch, Ross J.

    2000-01-01

    Photochemical loss of stratospheric ozone occurs primarily by catalytic cycles whose rates are limited by the concentration of OH, HO2, NO2, ClO, and/or BrO as well as the concentration of either atomic oxygen or of ozone itself. Once the concentrations of these gases are established, the photochemical loss rate of O3 depends on the rate coefficient of only a handful of key reactions. We have developed a method for testing our understanding of stratospheric ozone photochemistry by comparing measured and modeled concentrations of reactive hydrogen, nitrogen, chlorine and bromine radicals using a photochemical steady state model constrained by observed concentrations of long-lived precursors (e.g., NO(y), Cl(y), Br(y), O3, H2O, CH4) and environmental parameters such as ozone column, reflectivity, and aerosol surface area. We will show based on analyses of observations obtained by aircraft, balloon, and satellite platforms during the POLARIS campaign that our overall understanding of the processes that regulate these radical species is very good. The most notable current discrepancies are the tendency to underestimate observed NO2 by 15 to 30% for air masses that experience near continuous solar illumination over a 24 hour period and the tendency to underestimate observed OH and H02 by about 10 to 20% during midday and by much larger amounts at high solar zenith angle (SZA > 85). Possible resolutions to these discrepancies will be discussed. This study was carried out in close collaboration with many members of the POLARIS science team.

  1. [The Littorina species of the European coasts: No model for the evolution of terrestrial gastropods].

    Science.gov (United States)

    Remmert, Hermann

    1968-12-01

    The Littorina-species of the European coasts are completely isoosmotic with their environment.Small specimens (species) have very small gills; with increasing size the gills grow rapidly. The gills of different species of identical size show no difference. The reproduction does not trend towards direct development parallel to the habitat of the species.Therefore the Littorina species are no model for the evolution of terrestrial gastropods, their characteristics are merely those of intertidal animals.

  2. Legumes in Finnish agriculture: history, present status and future prospects

    Directory of Open Access Journals (Sweden)

    F. L. STODDARD

    2008-12-01

    Full Text Available Legumes are important in world agriculture, providing biologically fixed nitrogen, breaking cereal disease cycles and contributing locally grown food and feed, including forage. Pea and faba bean were grown by early farmers in Finland, with remains dated to 500 BC. Landraces of pea and faba bean were gradually replaced by better adapted, higher quality materials for food use. While grain legumes have been restricted by their long growing seasons to the south of the country, red, white and alsike clovers are native throughout and have long been used in leys for grazing, hay and silage. Breeding programmes released many cultivars of these crops during the 1900s, particularly pea and red clover. A.I. Virtanen earned the 1945 Nobel Prize in Chemistry for his work on both nitrogen fixation and silage preservation. Use of crop mixtures may appear modern, but farmers used them already in the early 1800s, when oat was used to support pea, and much effort has been devoted to improving the system and establishing its other benefits. Although international cultivars have been easily accessible since Finland’s 1995 entry into the European Union, the combination of feed quality and appropriate earliness is still needed, as < 1% of arable land is sown to grain legumes and an increase to 9–10% would allow replacement of imported protein feeds. Climate change will alter the stresses on legume crops, and investment in agronomy, physiology and breeding is needed so that farmers can gain from the many advantages of a legume-supported rotation.;

  3. Contribution of legumes to the soil N pool.

    Science.gov (United States)

    Fustec, Joëlle; Malagoli, Philippe; Mahieu, Stéphanie

    2010-05-01

    Grain legumes can be used for nitrogen acquisition in different ways in sustainable agriculture (Fustec et al., 2009). They are seen as a tool to reduce mineral N fertilizers in cropping systems. However, estimates of biological N fixation, N balance and N benefit either for the following crop or in mixed crops, remain unclear. The contribution of legumes to the soil N pool is difficult to measure, especially N rhizodeposition, since it is a critical point for assessing N benefits for other crops and for soil biological activity, and for reducing water pollution (Mayer et al., 2003). We adapted and refined the cotton-wick 15N stem labeling method for measuring the amount of soil N derived from rhizodeposition by field peas (Mahieu et al., 2007, 2009). The method was tested in different conditions in the field and in the greenhouse with various pea varieties and isolines. In addition, we used the cotton-wick method for assessing N transfers from pea to neighbouring durum wheat. In the greenhouse, a positive relationship was found between the amount of N rhizodeposits and the legume N content. N rhizodeposition was about 15% of the plant N and 30% in the field. In field pea / durum wheat intercrops, plant-plant N transfers were quantified and found to be bidirectional. Such results should be taken into account when estimating N benefits from biological N fixation by a grain legume crop and for the prediction of N economies in legume-based cropping systems. More studies dealing with rhizodeposit compounds and soil biological activity would now be necessary. Fustec et al. 2009. Agron. Sustain. Dev., DOI 10.1051/agro/2009003, in press. Mahieu et al. 2007. Plant Soil 295, 193-205. Mahieu et al. 2009. Soil Biol. Biochem. 41, 2236-2243. Mayer et al. 2003. Soil Biol. Biochem. 35, 21-28.

  4. A comparative nitrogen balance and productivity analysis of legume and non-legume supported cropping systems: the potential role of biological nitrogen fixation

    Directory of Open Access Journals (Sweden)

    Pietro P M Iannetta

    2016-11-01

    Full Text Available The potential of biological nitrogen fixation (BNF to provide sufficient N for production have encouraged re-appraisal of cropping systems that deploy legumes. It has been argued that legume-derived N can maintain productivity as an alternative to the application of mineral fertiliser, although few studies have systematically evaluated the effect of optimising the balance between legumes and non N-fixing crops to optimise production. In addition, the shortage, or even absence in some regions, of measurements of BNF in crops and forages severely limits the ability to design and evaluate new, legume–based agroecosystems. To provide an indication of the magnitude of BNF in European agriculture, a soil-surface N-balance approach was applied to historical data from 8 experimental cropping systems that compared legume and non-legume crop types (e.g. grains, forages and intercrops across pedoclimatic regions of Europe. Mean BNF for different legume types ranged from 32-115 kg ha-1 annually. Output in terms of total biomass (grain, forage, etc. was 30% greater in non-legumes, which used N to produce dry matter more efficiently than legumes, whereas output of N was greater from legumes. When examined over the crop sequence, the contribution of BNF to the N-balance increased to reach a maximum when the legume fraction was around 0.5 (legume crops were present in half the years. BNF was lower when the legume fraction increased to 0.6-0.8, not because of any feature of the legume, but because the cropping systems in this range were dominated by mixtures of legume and non-legume forages to which inorganic N as fertiliser was normally applied. Forage (e.g. grass and clover, as opposed to grain crops in this range maintained high outputs of biomass and N. In conclusion, BNF through grain and forage legumes have the potential to generate major benefit in terms of reducing or dispensing with the need for mineral N without loss of total output.

  5. A Comparative Nitrogen Balance and Productivity Analysis of Legume and Non-legume Supported Cropping Systems: The Potential Role of Biological Nitrogen Fixation

    Science.gov (United States)

    Iannetta, Pietro P. M.; Young, Mark; Bachinger, Johann; Bergkvist, Göran; Doltra, Jordi; Lopez-Bellido, Rafael J.; Monti, Michele; Pappa, Valentini A.; Reckling, Moritz; Topp, Cairistiona F. E.; Walker, Robin L.; Rees, Robert M.; Watson, Christine A.; James, Euan K.; Squire, Geoffrey R.; Begg, Graham S.

    2016-01-01

    The potential of biological nitrogen fixation (BNF) to provide sufficient N for production has encouraged re-appraisal of cropping systems that deploy legumes. It has been argued that legume-derived N can maintain productivity as an alternative to the application of mineral fertilizer, although few studies have systematically evaluated the effect of optimizing the balance between legumes and non N-fixing crops to optimize production. In addition, the shortage, or even absence in some regions, of measurements of BNF in crops and forages severely limits the ability to design and evaluate new legume–based agroecosystems. To provide an indication of the magnitude of BNF in European agriculture, a soil-surface N-balance approach was applied to historical data from 8 experimental cropping systems that compared legume and non-legume crop types (e.g., grains, forages and intercrops) across pedoclimatic regions of Europe. Mean BNF for different legume types ranged from 32 to 115 kg ha−1 annually. Output in terms of total biomass (grain, forage, etc.) was 30% greater in non-legumes, which used N to produce dry matter more efficiently than legumes, whereas output of N was greater from legumes. When examined over the crop sequence, the contribution of BNF to the N-balance increased to reach a maximum when the legume fraction was around 0.5 (legume crops were present in half the years). BNF was lower when the legume fraction increased to 0.6–0.8, not because of any feature of the legume, but because the cropping systems in this range were dominated by mixtures of legume and non-legume forages to which inorganic N as fertilizer was normally applied. Forage (e.g., grass and clover), as opposed to grain crops in this range maintained high outputs of biomass and N. In conclusion, BNF through grain and forage legumes has the potential to generate major benefit in terms of reducing or dispensing with the need for mineral N without loss of total output. PMID:27917178

  6. Application of perennial legume green manures to improve growth and yield of organic lowland rice

    Directory of Open Access Journals (Sweden)

    M Winarni

    2016-10-01

    Full Text Available A pot experiment in green house was done to study the effect of the dosage and speciesof perennial legume green manures to the physiological traits, growth and yield of organic lowland rice (Oryza sativaL., and to obtain the optimal dosage as well.  The research was arranged in a factorial randomized block design consistedof two factors with three replications.The first factor was the species of perennial legume thatconsisted of threespecies: Turi (Sesbaniagrandiflora, Glirisidia (Gliricidiasepium, and Lamtoro (Leucaenaleucocephala and cow manure as control treatment. The second factor was the dosage of green manure thatconsisted of four levels: 5, 10, 20 and 40 t/ha.  The results showed that application ofperennial legumesinto the soil significantly improved the growth and yield of rice.  The application of  20 t Glirisidia leaves/haproduced the highest grain yield, followed by 20 t Lamtoro leaves/ha and 20 t Turi leaves/ha.  The optimal dosages of S. grandiflora, G. sepium and L. leucochepala leaves that could yield 58.03 g/hill (equivalent to14.51 t/ha, 53.67 g/hill (equivalent to 13.42 t/ha, and 49.67 g/hill (equivalent to 12.42 t/ha were 28.05, 25.46 and 26.41 t/ha, respectively.

  7. Legume Nodulating Bacterium, Achromobacter xylosoxidans Found in Tropical Shrub Agroecosystem, Sumatera, Indonesia

    Directory of Open Access Journals (Sweden)

    Sri Wedhastri

    2015-11-01

    Full Text Available Legume nodulating bacteria (LNB, known also as rhizobia, are soil bacteria, which are able to form rootnodules and fi x nitrogen in the leguminous plants. The LNB availability in the soil depends on the type ofagroecosystem, where plant grows. In this study, we isolated LNB from the shrub agroecosystem in Sumatera,Indonesia, and obtained four selected bacterial strains. Among them, the isolate UGM48a formed root nodulein Macroptilium atropurpureum and showed highest number of nitrogenase activity. UGM48a also contains nifHand nodA genes. An analysis of the PCR-amplifi ed 16S rDNA and BLASTn analysis showed that UGM48adisplayed 96% similarity with Achromobacter xylosoxidans. In addition, UGM48a were successfully nodulatedGlycine max (L. merr var. wilis. This is the fi rst report detecting A. xylosoxidans as nodule-forming species forGlycine max possesing the positive copy of nodA gene.Keywords : Legume Nodulating Bacteria, shrub agroecosystem, Achromobacter xylosoxidans, nodA, Glycine max

  8. Accumulation of some metals by legumes and their extractability from acid mine spoils. [USA - Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, R.W.; Ibeabuchi, I.O.; Sistani, K.R.; Shuford, J.W. (Alabama A M University, Normal, AL (USA). Dept. of Plant and Soil Science)

    A greenhouse study was conducted to investigate the growth (dry matter yield) of selected legume cover crops; phytoaccumulation of metals such as Zn, Mn, Pb, Cu, Ni, and Al; the extractability of heavy metals from three different Alabama acid mine spoils. The spoils were amended based on soil test recommended levels of N, P, K, Ca and Mg prior to plant growth. Metals were extracted by three extractants (Mehlich 1, DTPA, and 0.1 M HCl) and values correlated with their accumulation by the selected legumes. Among the cover crops, kobe lespedeza {ital Lespedeza striata} (Thung.) Hook and Arn, sericea lespedeza {ital Lespedeza cuneata} (Dum.) G. Don, and red clover (Trifolium pratense L.) did not survive the stressful conditions of the spoils. However, cowpea (Vigna unguiculata L.) followed by Bragg' soybean {ital Glycine max} (L.) Merr. generally produced the highest dry matter yield while accumulating the largest quantity of metals, except Al, from spoils. The extractability of most metals from the spoils was generally in the order of: 0.1 MHCl {gt} DTPA. Mehlich 1 did not extract Pb and 0.1 M HCl did not extract Ni, whereas DTPA extracted all the metals in a small amount relative to HCl and Mehlich 1. All the extractants were quite effective in removing plant-available Zn from the spoils. In general, the extractants' ability to predict plant-available metals depended on the crop species, spoil type, and extractant used. 28 refs., 4 tabs.

  9. The genetic and biochemical basis for nodulation of legumes by rhizobia

    Energy Technology Data Exchange (ETDEWEB)

    Pueppke, S.G. [Univ. of Missouri, Columbia, MO (United States). Dept. of Plant Pathology

    1996-05-01

    Soil bacteria of the genera Azorhizobium, Bradyrhizobium, and Rhizobium are collectively termed rhizobia. They share the ability to penetrate legume roots and elicit morphological responses that lead to the appearance of nodules. Bacteria within these symbiotic structures fix atmosphere nitrogen and thus are of immense ecological and agricultural significance. Although modern genetic analysis of rhizobia began less than 20 years ago, dozens of nodulation genes have now been identified, some in multiple species of rhizobia. These genetic advances have led to the discovery of a host surveillance system encoded by nodD and to the identification of Nod factor signals. These derivatives of oligochitin are synthesized by the protein products of nodABC, nodFE, NodPQ, and other nodulation genes: they provoke symbiotic responses on the part of the host and have generated immense interest in recent years. The symbiotic functions of other nodulation genes are nonetheless uncertain, and there remain significant gaps in the knowledge of several large groups of rhizobia with interesting biological properties. This review focuses on the nodulation genes of rhizobia, with particular emphasis on the concept of biological specificity of symbiosis with legume host plants. 419 refs.

  10. Response of Short Duration Tropical Legumes and Maize to Water Stress: A Glasshouse Study

    Directory of Open Access Journals (Sweden)

    Hossain Sohrawardy

    2014-01-01

    Full Text Available The study was conducted as a pot experiment in the tropical glasshouse to evaluate the response of grain legumes (Phaseolus vulgaris, Vigna unguiculata, and Lablab purpureus in comparison to maize (Zea mays and estimate their potential and performance. Two experiments were established using completely randomized design. Physiological measurements (stomatal conductance, photosynthetic activities, and transpiration rates were measured using LCpro instrument. Scholander bomb was used for the measurement of plant cell water potential. Significant difference was observed in different plant species with increase of different water regimes. Among the legumes, L. purpureus showed better response in water stressed conditions. At the beginning, in dry watered treatment the photosynthetic rate was below 0 µmol m−2 s−1 and in fully watered condition it was 48 µmol m−2 s−1. In dry treatment, total dry weight was 10 g/pot and in fully watered condition it was near to 20 g/pot in P. vulgaris. The study concludes that water stress condition should be taken into consideration for such type of crop cultivation in arid and semiarid regions.

  11. Characterisation of the legume SERK-NIK gene superfamily including splice variants: Implications for development and defence

    Directory of Open Access Journals (Sweden)

    Rose Ray J

    2011-03-01

    Full Text Available Abstract Background SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK genes are part of the regulation of diverse signalling events in plants. Current evidence shows SERK proteins function both in developmental and defence signalling pathways, which occur in response to both peptide and steroid ligands. SERKs are generally present as small gene families in plants, with five SERK genes in Arabidopsis. Knowledge gained primarily through work on Arabidopsis SERKs indicates that these proteins probably interact with a wide range of other receptor kinases and form a fundamental part of many essential signalling pathways. The SERK1 gene of the model legume, Medicago truncatula functions in somatic and zygotic embryogenesis, and during many phases of plant development, including nodule and lateral root formation. However, other SERK genes in M. truncatula and other legumes are largely unidentified and their functions unknown. Results To aid the understanding of signalling pathways in M. truncatula, we have identified and annotated the SERK genes in this species. Using degenerate PCR and database mining, eight more SERK-like genes have been identified and these have been shown to be expressed. The amplification and sequencing of several different PCR products from one of these genes is consistent with the presence of splice variants. Four of the eight additional genes identified are upregulated in cultured leaf tissue grown on embryogenic medium. The sequence information obtained from M. truncatula was used to identify SERK family genes in the recently sequenced soybean (Glycine max genome. Conclusions A total of nine SERK or SERK-like genes have been identified in M. truncatula and potentially 17 in soybean. Five M. truncatula SERK genes arose from duplication events not evident in soybean and Lotus. The presence of splice variants has not been previously reported in a SERK gene. Upregulation of four newly identified SERK genes (in addition to the

  12. Place prioritization for biodiversity content using species ecological niche modeling

    Directory of Open Access Journals (Sweden)

    Víctor Sánchez-Cordero

    2005-01-01

    Full Text Available Place prioritization for biodiversity representation is essential for conservation planning, particularly in megadiverse countries where high deforestation threatens biodiversity. Given the collecting biases and uneven sampling of biological inventories, there is a need to develop robust models of species’ distributions. By modeling species’ ecological niches using point occurrence data and digitized environmental feature maps, we can predict potential and extant distributions of species in untransformed landscapes, as well as in those transformed by vegetation change (including deforestation. Such distributional predictions provide a framework for use of species as biodiversity surrogates in place prioritization procedures such as those based on rarity and complementarity. Beyond biodiversity conservation, these predictions can also be used for place prioritization for ecological restoration under current conditions and under future scenarios of habitat change (e.g., deforestation scenarios. To illustrate these points, we (1 predict distributions under current and future deforestation scenarios for the Mexican endemic mammal Dipodomys phillipsii, and show how areas for restoration may be selected; and (2 propose conservation areas by combining nonvolant mammal distributional predictions as biodiversity surrogates with place prioritization procedures, to connect decreed natural protected areas in a region holding exceptional biodiversity: the Transvolcanic Belt in central Mexico. La selección de áreas prioritarias de conservación es fundamental en la planeación sistemática de la conservación, particularmente en países de mega-diversidad, en donde la alta deforestación es una de las amenazas a la biodiversidad. Debido a los sesgos taxonómicos y geográficos de colecta de los inventarios biológicos, es indispensable generar modelos robustos de distribución de especies. Al modelar el nicho ecológico de especies usando localidades de

  13. Biotic modifiers, environmental modulation and species distribution models

    NARCIS (Netherlands)

    Linder, H. Peter; Bykova, Olga; Dyke, James; Etienne, Rampal S.; Hickler, Thomas; Kuehn, Ingolf; Marion, Glenn; Ohlemueller, Ralf; Schymanski, Stanislaus J.; Singer, Alexander

    2012-01-01

    The ability of species to modulate environmental conditions and resources has long been of interest. In the past three decades the impacts of these biotic modifiers have been investigated as ecosystem engineers, niche constructors, facilitators and keystone species. This environmental modulation can

  14. Biotic modifiers, environmental modulation and species distribution models

    NARCIS (Netherlands)

    Linder, H. Peter; Bykova, Olga; Dyke, James; Etienne, Rampal S.; Hickler, Thomas; Kuehn, Ingolf; Marion, Glenn; Ohlemueller, Ralf; Schymanski, Stanislaus J.; Singer, Alexander

    2012-01-01

    The ability of species to modulate environmental conditions and resources has long been of interest. In the past three decades the impacts of these biotic modifiers have been investigated as ecosystem engineers, niche constructors, facilitators and keystone species. This environmental modulation can

  15. Thematic and spatial resolutions affect model-based predictions of tree species distribution.

    Directory of Open Access Journals (Sweden)

    Yu Liang

    Full Text Available Subjective decisions of thematic and spatial resolutions in characterizing environmental heterogeneity may affect the characterizations of spatial pattern and the simulation of occurrence and rate of ecological processes, and in turn, model-based tree species distribution. Thus, this study quantified the importance of thematic and spatial resolutions, and their interaction in predictions of tree species distribution (quantified by species abundance. We investigated how model-predicted species abundances changed and whether tree species with different ecological traits (e.g., seed dispersal distance, competitive capacity had different responses to varying thematic and spatial resolutions. We used the LANDIS forest landscape model to predict tree species distribution at the landscape scale and designed a series of scenarios with different thematic (different numbers of land types and spatial resolutions combinations, and then statistically examined the differences of species abundance among these scenarios. Results showed that both thematic and spatial resolutions affected model-based predictions of species distribution, but thematic resolution had a greater effect. Species ecological traits affected the predictions. For species with moderate dispersal distance and relatively abundant seed sources, predicted abundance increased as thematic resolution increased. However, for species with long seeding distance or high shade tolerance, thematic resolution had an inverse effect on predicted abundance. When seed sources and dispersal distance were not limiting, the predicted species abundance increased with spatial resolution and vice versa. Results from this study may provide insights into the choice of thematic and spatial resolutions for model-based predictions of tree species distribution.

  16. Thematic and spatial resolutions affect model-based predictions of tree species distribution.

    Science.gov (United States)

    Liang, Yu; He, Hong S; Fraser, Jacob S; Wu, ZhiWei

    2013-01-01

    Subjective decisions of thematic and spatial resolutions in characterizing environmental heterogeneity may affect the characterizations of spatial pattern and the simulation of occurrence and rate of ecological processes, and in turn, model-based tree species distribution. Thus, this study quantified the importance of thematic and spatial resolutions, and their interaction in predictions of tree species distribution (quantified by species abundance). We investigated how model-predicted species abundances changed and whether tree species with different ecological traits (e.g., seed dispersal distance, competitive capacity) had different responses to varying thematic and spatial resolutions. We used the LANDIS forest landscape model to predict tree species distribution at the landscape scale and designed a series of scenarios with different thematic (different numbers of land types) and spatial resolutions combinations, and then statistically examined the differences of species abundance among these scenarios. Results showed that both thematic and spatial resolutions affected model-based predictions of species distribution, but thematic resolution had a greater effect. Species ecological traits affected the predictions. For species with moderate dispersal distance and relatively abundant seed sources, predicted abundance increased as thematic resolution increased. However, for species with long seeding distance or high shade tolerance, thematic resolution had an inverse effect on predicted abundance. When seed sources and dispersal distance were not limiting, the predicted species abundance increased with spatial resolution and vice versa. Results from this study may provide insights into the choice of thematic and spatial resolutions for model-based predictions of tree species distribution.

  17. Estimating species - area relationships by modeling abundance and frequency subject to incomplete sampling.

    Science.gov (United States)

    Yamaura, Yuichi; Connor, Edward F; Royle, J Andrew; Itoh, Katsuo; Sato, Kiyoshi; Taki, Hisatomo; Mishima, Yoshio

    2016-07-01

    Models and data used to describe species-area relationships confound sampling with ecological process as they fail to acknowledge that estimates of species richness arise due to sampling. This compromises our ability to make ecological inferences from and about species-area relationships. We develop and illustrate hierarchical community models of abundance and frequency to estimate species richness. The models we propose separate sampling from ecological processes by explicitly accounting for the fact that sampled patches are seldom completely covered by sampling plots and that individuals present in the sampling plots are imperfectly detected. We propose a multispecies abundance model in which community assembly is treated as the summation of an ensemble of species-level Poisson processes and estimate patch-level species richness as a derived parameter. We use sampling process models appropriate for specific survey methods. We propose a multispecies frequency model that treats the number of plots in which a species occurs as a binomial process. We illustrate these models using data collected in surveys of early-successional bird species and plants in young forest plantation patches. Results indicate that only mature forest plant species deviated from the constant density hypothesis, but the null model suggested that the deviations were too small to alter the form of species-area relationships. Nevertheless, results from simulations clearly show that the aggregate pattern of individual species density-area relationships and occurrence probability-area relationships can alter the form of species-area relationships. The plant community model estimated that only half of the species present in the regional species pool were encountered during the survey. The modeling framework we propose explicitly accounts for sampling processes so that ecological processes can be examined free of sampling artefacts. Our modeling approach is extensible and could be applied to a

  18. A solvable two-species catalysis-driven aggregation model

    CERN Document Server

    Ke Jian Hong

    2003-01-01

    We study the kinetics of a two-species catalysis-driven aggregation system, in which an irreversible aggregation between any two clusters of one species occurs only with the catalytic action of another species. By means of a generalized mean-field rate equation, we obtain the asymptotic solutions of the cluster mass distributions in a simple process with a constant rate kernel. For the case without any consumption of the catalyst, the cluster mass distribution of either species always approaches a conventional scaling law. However, the evolution behaviour of the system in the case with catalyst consumption is complicated and depends crucially on the relative data of the initial concentrations of the two species.

  19. Phytoremediation of heavy and transition metals aided by legume-rhizobia symbiosis

    DEFF Research Database (Denmark)

    Hao, X.; Taghavi, S.; Xie, P.

    2014-01-01

    nitrogen fixation, phosphorus solubilization, phytohormone synthesis, siderophore release, and production of ACC deaminase and the volatile compounds of acetoin and 2, 3-butanediol may facilitate legume growth while lessening metal toxicity. The benefits of using legumes inoculated with naturally resistant...... rhizobia or recombinant rhizobia with enhanced resistance, as well as co-inoculation with other plant growth promoting bacteria (PGPB) are discussed. However, the legume-rhizobia symbiosis appears to be sensitive to metals, and the effect of metal toxicity on the interaction between legumes and rhizobia......Legumes are important for nitrogen cycling in the environment and agriculture due to the ability of nitrogen fixation by rhizobia. In this review, we introduce an important and potential role of legume-rhizobia symbiosis in aiding phytoremediation of some metal contaminated soils as various legumes...

  20. Sward characteristics and performance of dairy cows in organic grass-legume pastures shaded by tropical trees.

    Science.gov (United States)

    Paciullo, D S C; Pires, M F A; Aroeira, L J M; Morenz, M J F; Maurício, R M; Gomide, C A M; Silveira, S R

    2014-08-01

    The silvopastoral system (SPS) has been suggested to ensure sustainability in animal production systems in tropical ecosystems. The objective of this study was to evaluate pasture characteristics, herbage intake, grazing activity and milk yield of Holstein×Zebu cows managed in two grazing systems (treatments): SPS dominated by a graminaceous forage (Brachiaria decumbens) intercropped with different leguminous herbaceous forages (Stylosanthes spp., Pueraria phaseoloides and Calopogonium mucunoides) and legume trees (Acacia mangium, Gliricidia sepium and Leucaena leucocephala), and open pasture (OP) of B. decumbens intercropped only with Stylosanthes spp. Pastures were managed according to the rules for organic cattle production. The study was carried out by following a switch back format with 12 cows, 6 for each treatment, over 3 experimental years. Herbage mass was similar (P>0.05) for both treatments, supporting an average stocking rate of 1.23 AU/ha. Daily dry matter intake did not vary (P>0.05) between treatments (average of 11.3±1.02 kg/cow per day, corresponding to 2.23±0.2% BW). Milk yield was higher (P0.05) in subsequent years. The highest (P0.05) milk yields. Low persistence of Stylosanthes guianensis was observed over the experimental period, indicating that the persistence of forage legumes under grazing could be improved using adapted cultivars that have higher annual seed production. The SPS and a diversified botanical composition of the pasture using