Allelopathic effects of aqueous extracts of the legumes crotalaria [Crotalaria juncea (L.) 'Tropic Sun'], jack bean [Canavalia ensiformis (L.)] and pigeon pea [Cajanus cajan (L.) 'Lazaro'] on crop development

En el laboratorio se evaluaron los efectos alelopáticos de extractos acuosos 3.3% m/v de crotalaria [Crotalaria júncea(L.) 'Tropic Sun'], canavalia [Canavalia ensiformis (L.)] y gandul [Cajanus cajan (L.) 'Lázaro'] en siete cultivos agronómicos: maíz (Zea mays 'Mayorbela 2011'), sorgo (Sorghum bicolor), habichuela (Phaseolus vulgaris 'Verano'), soya [Glycine max (L.)], caupí [Vigna unguiculata (L.)], lechuga [Lactuca sativa (L.) 'Nevada'] y gandul. Se encontró una Interacción entre cultivos x extracto acuoso en el séptimo día de germinación. Se determinó el efecto alelopátlco contrastando con el tratamiento control el largo del coleóptllo y la radícula en maíz y sorgo y el largo hlpocótllo y radícula en habichuela, soya, caupí, lechuga y gandul. El sorgo y la lechuga presentaron Inhibición de crecimiento del coleóptllo e hlpocótllo (respectlvamete) y radícula al tratarse con los tres extractos acuosos, donde el extracto acuoso de canavalia mostró mayores porcentajes de Inhibición (66% en lechuga y 49% en sorgo). Por el contrario, en los cultivos de maíz, habichuela y caupí, el extracto acuoso de crotalaria estimuló el crecimiento. De acuerdo a estos resultados se debe experimentar en el campo las asociaciones de leguminosas con cultivos agronómicos para determinar si las Interacciones estimulan o Inhiben el desarrollo de los cultivos ya que la Influencia de los factores ambientales son determinantes en el efecto alelopátlco.Allelopathic effects of aqueous extracts 3.3% w/v of crotalaria [Crotalaria júncea (L.)' Tropic Sun'], jack bean [Canavalia ensiformis(L.)] and pigeon pea [Cajanus cajan (L.) 'Lázaro'] were determined on seven agronomic crops: corn (Zea mays 'Mayorbela 2011'), sorghum (Sorghum bicolor), bean (Phaseolus vulgaris 'Verano'), soybean (Glycine max), cowpea [Vigna unguiculata (L.)], lettuce [Lactuca sativa (L.) 'Nevada'] and pigeon pea in the laboratory. There was interaction between aqueous extracts x agronomic crops on the seventh day of germination. Allelopathic effect was determined by contrasting with the control coleoptile and radicle length in corn and sorghum, and the hypocotyl and radicle length in bean, soybean, cowpea, lettuce and pigeon pea. Sorghum and lettuce showed growth inhibition of the coleoptile and hypocotyl (respectively) and radicle when treated with the three aqueous extracts, where jack bean aqueous extracts showed higher inhibitions percentages (66% in lettuce and 49% in sorghum). By contrast, corn, bean and cowpea treated with crotalaria aqueous extracts exhibited growth stimulation. According to these results, field experiments must be conducted using legume associations with agronomic crops to confirm if the interactions stimulate or inhibit crop development because environmental factors are a major determinant of allelopathic effects

Yield evaluation of sweet corn (Zea mays L. 'Suresweet') with cover crops dwarf velvet bean (Mucuna pruriens) and crotalaria (Crotalaría júncea 'Tropic Sun') on an Oxisol of Puerto Rico

Sustainable agriculture requires crop rotation and legume cover crop associations to increase organic matter and reduce inorganic fertilizer use. In this study, three experiments were conducted to evaluate the effects of crimped legumes (CL) using dwarf velvet bean (Mucuna pruriens) and sun hemp (Crotalaria júncea 'Tropic Sun') versus conventional planting (CP; plowing and disking) on ear yield and size, insect damage and seed yield of sweet corn [Zea mays(L.)' Suresweet 2011']. Experiments were conducted in April and July 2013, and February 2014 at the Isabela Agricultural Experiment Station (Puerto Rico) on an Oxisol. Greater biomass (DM) and nitrogen (N) contribution were found in the July (summer) planting, where dwarf velvet bean produced 1.66 Mg/ha DM and 45.5 kg/ha of N compared to 'Tropic Sun' with 0.96 Mg/ha DM and 26.33 kg/ha of N. This difference was possibly related to the photosensitive responses of CL. Contrast analysis between CL vs. CP and dwarf velvet bean vs. Tropic Sun showed no significant differences on ear yield and marketable yield seed in the April planting. However, for the July planting, dwarf velvet bean surpassed (P<0.05) 'Tropic Sun' by 4.09 Mg/ ha on ear yield and 2.57 Mg/ha on marketable seed yield. In the February planting, ear yield was better (P3.63 Mg/ha) than in CL. Ear corn damage caused by Helicoverpa zea averaged 1 to 2 cm and was not significantly different among the three planting dates in the three systems. Despite the differences in yields with seeding systems, dwarf velvet bean yields were uniform across planting datesLa agricultura sostenible requiere la rotación de cultivos y asociación con leguminosas para aumentar la materia orgánica y reducir el uso de fertilizantes inorgánicos. En este estudio se llevaron a cabo tres experimentos (diferentes fechas de siembra) para evaluar el efecto de dos leguminosas apisonadas (LA), mucuna enana (Mucuna pruriens) y crotalaria {Crotalaria júncea 'Tropic Sun'), versus siembra convencional (SC; arado y pases de disco) sobre el rendimiento y tamaño de mazorca verde, daño por insectos y rendimiento de semilla del maíz [Zea mays (L.) 'Suresweet 2011']. Los experimentos se llevaron a cabo en abril y julio 2013, y febrero 2014 en la Estación Experimental Agrícola de Isabela (Puerto Rico) en un suelo Oxisol. Se encontró mayor aporte de biomasa (MS) y nitrógeno (N) en julio (verano), cuando la mucuna enana produjo 1.66 Mg/ha MS y 45.54 kg/ha de N comparado con crotalaria 'Tropic Sun' con 0.96 Mg/ha MS y 26.33 kg/ha de N. Esta diferencia posiblemente está relacionada con las respuestas fotosensitivas de las LA. Análisis de contrastes entre LA vs. SC y comparaciones entre mucuna enana vs. 'Tropic Sun', no mostraron diferencias significativas para el rendimiento de mazorca fresca y semilla comerciable en la siembra de abril. Sin embargo, en la siembra de julio, la mucuna enana sobrepasó (P3.63 Mg/ha) que con LA. El daño promedio de la mazorca ocasionado por Helicoverpa zea fue de 1 a 2 cm y no presentó diferencias significativas entre las tres fechas de siembra en los tres sistemas. A pesar de las diferencias en los rendimientos con sistemas de siembra, la mucuna enana proporcionó rendimientos más uniformes en las tres siembras

A consensus linkage map for molecular markers and Quantitative Trait Loci associated with economically important traits in melon (Cucumis melo L.)

Background A number of molecular marker linkage maps have been developed for melon (Cucumis melo L.) over the last two decades. However, these maps were constructed using different marker sets, thus, making comparative analysis among maps difficult. In order to solve this problem, a consensus genetic map in melon was constructed using primarily highly transferable anchor markers that have broad potential use for mapping, synteny, and comparative quantitative trait loci (QTL) analysis, increasing breeding effectiveness and efficiency via marker-assisted selection (MAS). Results Under the framework of the International Cucurbit Genomics Initiative (ICuGI, http://www.icugi.org webcite), an integrated genetic map has been constructed by merging data from eight independent mapping experiments using a genetically diverse array of parental lines. The consensus map spans 1150 cM across the 12 melon linkage groups and is composed of 1592 markers (640 SSRs, 330 SNPs, 252 AFLPs, 239 RFLPs, 89 RAPDs, 15 IMAs, 16 indels and 11 morphological traits) with a mean marker density of 0.72 cM/marker. One hundred and ninety-six of these markers (157 SSRs, 32 SNPs, 6 indels and 1 RAPD) were newly developed, mapped or provided by industry representatives as released markers, including 27 SNPs and 5 indels from genes involved in the organic acid metabolism and transport, and 58 EST-SSRs. Additionally, 85 of 822 SSR markers contributed by Syngenta Seeds were included in the integrated map. In addition, 370 QTL controlling 62 traits from 18 previously reported mapping experiments using genetically diverse parental genotypes were also integrated into the consensus map. Some QTL associated with economically important traits detected in separate studies mapped to similar genomic positions. For example, independently identified QTL controlling fruit shape were mapped on similar genomic positions, suggesting that such QTL are possibly responsible for the phenotypic variability observed for this trait in a broad array of melon germplasm. Conclusions Even though relatively unsaturated genetic maps in a diverse set of melon market types have been published, the integrated saturated map presented herein should be considered the initial reference map for melon. Most of the mapped markers contained in the reference map are polymorphic in diverse collection of germplasm, and thus are potentially transferrable to a broad array of genetic experimentation (e.g., integration of physical and genetic maps, colinearity analysis, map-based gene cloning, epistasis dissection, and marker-assisted selection).This work was supported in part by SNC Laboratoire ASL, Ruiter Seeds B.V., Enza Zaden B.V., Gautier Semences S.A., Nunhems B.V., Rijk Zwaan B.V., Sakata Seed Inc, Semillas Fito S. A., Seminis Vegetable Seeds Inc, Syngenta Seeds B. V., Takii and Company Ltd, Vilmorin & Cie S. A., and Zeraim Gedera Ltd (all of them as part of the support to the ICuGI); the grants AGL2009-12698-C02-02 from the Spanish "Ministerio de Ciencia e Innovacion" to AJM. NK lab was supported in part by Research Grant Award No. IS-4223-09C from BARD, the United States - Israel Binational Agricultural Research and Development Fund, and in part by Israel Science Foundation Grant No. 38606, De Ruiter Seeds, Enza Zaden, Keygene, Rijk Zwaan, Sakata Seed Corporation, Semillas Fito, Syngenta Seeds and Vilmorin Clause & Cie. AD was supported by a JAE-Doc contract from "Consejo Superior de Investigaciones Cientificas" (CSIC-Spain). MF was supported by a postdoctoral contract from CRAG. The research carried out at YX's laboratory was supported by Chinese funds (Grant No. 2008-Z42(3), 5100001, 2010AA101907).Díaz Bermúdez, A.; Fergany, M.; Formisano, G.; Ziarsolo, P.; Blanca Postigo, JM.; Fei, Z.; Staub, JE.... (2011). A consensus linkage map for molecular markers and Quantitative Trait Loci associated with economically important traits in melon. BMC Plant Biology. 11. https://doi.org/10.1186/1471-2229-11-111S1

Association analysis of photoperiodic flowering time genes in west and central African sorghum [Sorghum bicolor (L.) Moench]

Abstract Background: Photoperiod-sensitive flowering is a key adaptive trait for sorghum (Sorghum bicolor) in West and Central Africa. In this study we performed an association analysis to investigate the effect of polymorphisms within the genes putatively related to variation in flowering time on photoperiod-sensitive flowering in sorghum. For this purpose a genetically characterized panel of 219 sorghum accessions from West and Central Africa was evaluated for their photoperiod response index (PRI) based on two sowing dates under field conditions. Results: Sorghum accessions used in our study were genotyped for single nucleotide polymorphisms (SNPs) in six genes putatively involved in the photoperiodic control of flowering time. Applying a mixed model approach and previously-determined population structure parameters to these candidate genes, we found significant associations between several SNPs with PRI for the genes CRYPTOCHROME 1 (CRY1-b1) and GIGANTEA (GI)

Syntenic relationships between cucumber (Cucumis sativus L.) and melon (C. melo L.) chromosomes as revealed by comparative genetic mapping

<p>Abstract</p> <p>Background</p> <p>Cucumber, <it>Cucumis sativus </it>L. (2n = 2 × = 14) and melon, <it>C. melo </it>L. (2n = 2 × = 24) are two important vegetable species in the genus <it>Cucumis </it>(family Cucurbitaceae). Both species have an Asian origin that diverged approximately nine million years ago. Cucumber is believed to have evolved from melon through chromosome fusion, but the details of this process are largely unknown. In this study, comparative genetic mapping between cucumber and melon was conducted to examine syntenic relationships of their chromosomes.</p> <p>Results</p> <p>Using two melon mapping populations, 154 and 127 cucumber SSR markers were added onto previously reported F₂- and RIL-based genetic maps, respectively. A consensus melon linkage map was developed through map integration, which contained 401 co-dominant markers in 12 linkage groups including 199 markers derived from the cucumber genome. Syntenic relationships between melon and cucumber chromosomes were inferred based on associations between markers on the consensus melon map and cucumber draft genome scaffolds. It was determined that cucumber Chromosome 7 was syntenic to melon Chromosome I. Cucumber Chromosomes 2 and 6 each contained genomic regions that were syntenic with melon chromosomes III+V+XI and III+VIII+XI, respectively. Likewise, cucumber Chromosomes 1, 3, 4, and 5 each was syntenic with genomic regions of two melon chromosomes previously designated as II+XII, IV+VI, VII+VIII, and IX+X, respectively. However, the marker orders in several syntenic blocks on these consensus linkage maps were not co-linear suggesting that more complicated structural changes beyond simple chromosome fusion events have occurred during the evolution of cucumber.</p> <p>Conclusions</p> <p>Comparative mapping conducted herein supported the hypothesis that cucumber chromosomes may be the result of chromosome fusion from a 24-chromosome progenitor species. Except for a possible inversion, cucumber Chromosome 7 has largely remained intact in the past nine million years since its divergence from melon. Meanwhile, many structural changes may have occurred during the evolution of the remaining six cucumber chromosomes. Further characterization of the genomic nature of <it>Cucumis </it>species closely related to cucumber and melon might provide a better understanding of the evolutionary history leading to modern cucumber.</p

Structural Basis for Broad Neutralization of Hepatitis C Virus Quasispecies

Monoclonal antibodies directed against hepatitis C virus (HCV) E2 protein can neutralize cell-cultured HCV and pseudoparticles expressing envelopes derived from multiple HCV subtypes. For example, based on antibody blocking experiments and alanine scanning mutagenesis, it was proposed that the AR3B monoclonal antibody recognized a discontinuous conformational epitope comprised of amino acid residues 396–424, 436–447, and 523–540 of HCV E2 envelope protein. Intriguingly, one of these segments (436–447) overlapped with hypervariable region 3 (HVR3), a domain that exhibited significant intrahost and interhost genetic diversity. To reconcile these observations, amino-acid sequence variability was examined and homology-based structural modelling of E2 based on tick-borne encephalitis virus (TBEV) E protein was performed based on 413 HCV sequences derived from 18 subjects with chronic hepatitis C. Here we report that despite a high degree of amino-acid sequence variability, the three-dimensional structure of E2 is remarkably conserved, suggesting broad recognition of structural determinants rather than specific residues. Regions 396–424 and 523–540 were largely exposed and in close spatial proximity at the surface of E2. In contrast, region 436–447, which overlaps with HVR3, was >35 Å away, and estimates of buried surface were inconsistent with HVR3 being part of the AR3B binding interface. High-throughput structural analysis of HCV quasispecies could facilitate the development of novel vaccines that target conserved structural features of HCV envelope and elicit neutralizing antibody responses that are less vulnerable to viral escape

Do smallholder farmer-led seed systems have the capacity to supply good-quality, fungal-free sorghum seed?

Local seed systems that are developed, managed and maintained by farmers are a fundamental practice in smallholder crop production, supporting more than 80% of farmers in sub-Saharan Africa and feeding more than 70% of its population. The resilience of such systems is under threat from poverty, climate change, drought, increased pests and diseases, over-promotion of modern crop varieties, change of lifestyles and restrictive seed policies. The system continues to be maligned as having inferior quality, yet few studies support this assertion. This study aims to fll this research gap by evaluating 60 sorghum seed samples collected from smallholder farmers in Uzumba-MarambaPfungwe and Chimanimani districts of Zimbabwe. We investigated the efect of farmer-led seed management practices (e.g. seed acquisition and seed storage practices) on farm-derived sorghum seed quality (moisture, germination and fungal incidences). We found farmers using diverse seed sources and seed storage practices. Seeds were typically of good quality in that their storage moisture content was low, their germination was high, and fungal incidences were low. Seed sourced from local markets, non-governmental organizations and other farmers had germination and moisture standards that met the sorghum certifcation standards in Zimbabwe. However, few samples obtained from the relatives and government failed to meet the germination and/or moisture certifcation standards. We detected low incidences of fungi (Aspergillus favus, Aspergillus niger, Curvularia lunata, Fusarium sp. and Penicillium sp.) in sorghum seed samples tested and in particular Fusarium sp., which is the most economic important fungus in sorghum production. We conclude that farmer-led seed systems have the capacity to supply seeds of good quality and recommend that such systems should be recognized and promoted to meet the ever-evolving needs of smallholder farmers in sub-Saharan Africa

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements