Genetic diversity and population structure in Vicia faba L. landraces and wild related species assessed by nuclear SSRs

Research Article

Differential allocation and deployment of direct and indirect defences by Vicia sepium along elevation gradients

Dissecting drivers of plant defence investment remains central for understanding the assemblage of communities across different habitats. There is increasing evidence that direct defence strategies against herbivores, including secondary metabolites production, differ along ecological gradients in response to variation in biotic and abiotic conditions. In contrast, intraspecific variation in indirect defences remains unexplored. Here, we investigated variation in herbivory rate, resistance to herbivores, and indirect defences in ant-attracting Vicia species along the elevation gradient of the Alps. Specifically, we compared volatile organic compounds (VOCs) and ant attraction in high and low elevation ecotypes. Consistent with adaptation to the lower herbivory conditions that we detected at higher elevations in the field, high elevation plants were visited by fewer ants and were more susceptible to herbivore attack. In parallel, constitutive volatile organic compound production and subsequent ant attraction were lower in the high elevation ecotypes. We observed an elevation-driven trade-off between constitutive and inducible production of VOCs and ant attraction along the environmental cline. At higher elevations, inducible defences increased, while constitutive defence decreased, suggesting that the high elevation ecotypes compensate for lower indirect constitutive defences only after herbivore attack. Synthesis. Overall, direct and indirect defences of plants vary along elevation gradients. Our findings show that plant allocation to defences are subject to trade-offs depending on local conditions, and point to a feedback mechanism linking local herbivore pressure, predator abundance and the defence investment of plants.

Flow cytofluorometric analysis of the binding of Vicia villosa lectin to T lymphoblasts: lack of correlation with cytolytic function.

The relationship between the binding of Vicia villosa (VV) lectin and the expression of cytolytic function in T lymphoblasts has been investigated using flow cytofluorometric techniques. Spleen cells activated in vitro in 5-day mixed leukocyte cultures (MLC) were incubated sequentially with VV, rabbit anti-V antiserum, and fluoresceinated sheep anti-rabbit IgG. When these stained MLC cells were passed on a flow cytometer gated to exclude nonviable cells and small lymphocytes, a single heterogeneous peak of fluorescence was seen, as compared to control MLC cells that had not been incubated with VV. Fluorescence of lymphoblasts was dependent upon lectin dose and was eliminated when staining was performed in the presence of N-acetyl-D-galactosamine, the appropriate competitive sugar for VV. T cell blast populations activated against H-2, Mls, or parasite antigens all had comparable levels of fluorescence after staining with VV, although the cytolytic activity of these cells varied widely. Furthermore, when MLC lymphoblasts binding large or small amounts of VV were sorted on the basis of their relative fluorescence intensity and tested for cytolytic function, no appreciable difference in activity between the 2 populations was observed. These results are inconsistent with the hypothesis that VV binds selectively to cytolytic T lymphocytes.

Doença granulomatosa sistêmica em bovinos no Rio Grande do Sul associada ao pastoreio de ervilhaca (Vicia spp)

Dois surtos de uma doença associada ao pastoreio de duas espécies de ervilhaca (predominantemente Vicia villosa e, em menor grau, V. sativa) foram observados em agosto-setembro de 2001, em vacas Holandesas adultas de duas propriedades rurais do Rio Grande do Sul. Foram afetadas, em uma das propriedades, quatro de 42 vacas (9,5%) e, na outra, uma de oito vacas (12,5%). Os sinais clínicos incluíam, embora não em todos os casos, febre, prurido, espessamento e enrugamento da pele com placas multifocais de alopecia, conjuntivite, corrimento nasal seroso, perda de peso, acentuada queda na produção de leite e diarréia. O curso clínico foi de aproximadamente duas semanas. Todas as vacas afetadas clinicamente morreram, uma foi sacrificada; três foram necropsiadas. Em cada um desses animais havia um padrão de lesões sistêmicas que consistiam de nódulos multifocais ou coalescentes, macios ou moderadamente firmes e branco-acinzentados, que infiltravam vários órgãos, mas eram particularmente proeminentes no miocárdio, nos linfonodos, no baço, na glândula adrenal e no córtex renal. Essas lesões resultavam em aumento de volume e alteração na arquitetura do órgão invadido. Microscopicamente, as lesões consis-tiam de extensa infiltração celular composta de proporções variáveis de macrófagos epitelióides, linfócitos, plasmócitos, células gigantes multinucleadas e eosinófilos. Os números de eosinófilos eram geralmente altos. Essa infiltração granulomatosa causava degeneração e perda de células parenquimatosas no órgão afetado. A intensidade das lesões variou entre as três vacas e entre os vários órgãos de cada animal. Essa é a primeira documentação no Brasil de doença granulomatosa sistêmica em bovinos associada ao pastoreio de ervilhaca.

Meningoencefalite granulomatosa em bovinos em pastoreio de ervilhaca (Vicia spp)

Meningoencefalite granulomatosa foi observada em 7 de 8 vacas leiteiras adultas afetadas por doença granulomatosa sistêmica associada ao consumo de ervilhaca, embora nenhum dos bovinos afetados apresentasse sinais de distúrbios nervosos. Os infiltrados inflamatórios localizavam-se nas leptomeninges e como manguitos perivasculares no interior do encéfalo; consistiam de macrófagos epitelióides, linfócitos, plasmócitos e eosinófilos. Essas alterações inflamatórias variavam de leves a acentuadas de animal para animal e entre diferentes regiões do encéfalo de um mesmo animal. Geralmente, os manguitos perivasculares eram mais acentuados que os infiltrados nas leptomeninges. As regiões do encéfalo afetadas, em ordem decrescente de intensidade, diencéfalo através da massa intermedia; mesencéfalo na altura dos colículos rostrais; ponte e pedúnculos cerebelares, bulbo na altura do óbex, lobo frontal na altura do joelho do corpo caloso e cerebelo. O tipo e a distribuição das alterações inflamatórias são enfatizados em relação ao diagnóstico diferencial de outras doenças e lesões do sistema nervoso central de bovinos no contexto do programa brasileiro de vigilância para a encefalopatia espongiforme bovina.

Achados patológicos e imuno-histoquímicos em bovinos com doença granulomatosa sistêmica pelo consumo de Vicia villosa (Leg. Papilionoideae) no Rio Grande do Sul

A doença granulomatosa sistêmica associada ao consumo de Vicia villosa (Leg. Papilionoideae) foi diagnosticada em 5 bovinos no período de 2005 a 2008. Os bovinos apresentavam alopecia, lesões crostosas na pele, prurido, febre, queda da produção leiteira, anorexia e emagrecimento. O curso clínico médio da doença foi de 2 semanas. Dos bovinos analisados três morreram e dois foram eutanasiados. As lesões macroscópicas de alopecia e crostas na pele eram localizadas principalmente na face e pescoço. Observava-se nódulos multifocais a coalescentes branco-acinzentados que infiltravam vários órgãos especialmente em linfonodos, rins e coração. As lesões microscópicas consistiam na infiltração de linfócitos, macrófagos, células epitelioides, células gigantes multinucleadas, eosinófilos e plasmócitos. Linfonodos, rins, adrenal, baço e fígado de todos os bovinos apresentaram infiltrado granulomatoso, porém de intensidade variável. Nos testes imuno-histoquímicos dos órgãos com infiltrado inflamatório, as principais células visualizadas foram os linfócitos T, seguidos de macrófagos/células epitelioides/células gigantes multi-nucleadas e os linfócitos B foram raramente detectados nos locais de inflamação granulomatosa. O número reduzido de células marcadas por Ki-67 nas lesões granulomatosas, tende a indicar que a proliferação celular não foi responsável pela hipercelularidade das lesões e que o recrutamento de macrófagos e linfócitos para o local da inflamação provavelmente tenha sido o responsável pelo acúmulo de células no infiltrado inflamatório.

Weed control under integrated nutrient management systems in faba bean (Vicia faba) production in Egypt

Two field experiments were conducted in two successive seasons, 2005/2006 and 2006/2007, to determine whether management can improve faba bean competitiveness with weeds, thus helping to achieve its yield potential. The experiment included five treatments, composed of organic and mineral fertilizers, alone and mixed at different rates, along with a control and six weed control treatments, including oxadiargyl, prometryn, hand hoeing treatments alone or mixed with the herbicides, and a nonweeded treatment (control).The herbicide treatments were not superior to the two hand-hoeing treatments. Using compost favored growth and yield of faba bean more than of weeds. Adding fertilizer also improved most yield parameters. Application of compost alone or combined with 50 or 100% of the recommended NPK rate improved faba bean growth in terms of net assimilation rate, specific leaf area, and leaf weight ratio as components of relative growth rate. This improvement in growth resulted in increase of seed yield, yield components and protein of faba bean. Faba bean yield performance improved under interactive fertilizer effects and weed control treatments as growth improved, as a result of nutrient release from fertilizers and weed control.

Physiological response of vicia faba to prohexadione-calcium under saline conditions

Changes in the activities of oxidative enzymes (indole acetic acid oxidase, peroxidase and catalase), endogenous hormones (gibberellic acid (GA3), indole acetic acid (IAA), abscisic acid (ABA) and cytokinins (AsZeatin), photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), total carbohydrates, total soluble sugars, amino acid proline and vegetative growth parameters were used as indicators to explain the physiological role of the growth retardant prohexadione-calcium on Vicia faba seedlings 40 days after sowing under salinity stress for 30 days. The obtained results show that soaking faba bean seeds prior to sowing at different concentrations of prohexadione-calcium (0, 10, 20 and 30 ppm) significantly increased the activities of indole acetic acid oxidase (IAA-oxidase) and peroxidase enzymes, but decreased the catalase enzyme activity as compared with their respective control. Application of prohexadione-Ca caused markedly decreases in the endogenous contents of gibberellins and indole acetic acid (IAA) but increased the levels of natural growth inhibitor abscisic acid (ABA) and cytokinins in the shoots of faba bean seedlings. All the prohexadione-Ca concentrations increased the contents of amino acid proline, photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), total carbohydrates and total soluble sugars in faba bean seedlings grown under salt stress. Application of prohexadione-Ca decreased significantly seedling height and shoot fresh weight but significantly increased shoot dry weight.

Integration of sunflower (Helianthus annuus) residues with a pre-plant herbicide enhances weed suppression in broad bean (Vicia faba)

Field trial was conducted with the aim of utilizing allelopathic crop residues to reduce the use of synthetic herbicides in broad bean (Vicia faba) fields. Sunflower residue at 600 and 1,400 g m-2 and Treflan (trifluralin) at 50, 75 and 100% of recommended dose were incorporated into the soil alone or in combination with each other. Untreated plots were maintained as a control. Herbicide application in plots amended with sunflower residue had the least total weed count and biomass, which was even better than herbicide used alone. Integration of recommended dose of Treflan with sunflower residue at 1,400 g m-² produced maximum (987.5 g m-2) aboveground biomass of broad bean, which was 74 and 36% higher than control and recommended herbicide dose applied alone, respectively. Combination of herbicide and sunflower residue appeared to better enhance pod number and yield per unit area than herbicide alone. Application of 50% dose of Treflan in plots amended with sunflower residue resulted in similar yield advantage as was noticed with 100% herbicide dose. Chromatographic analysis of residue-infested field soil indicated the presence of several phytotoxic compounds of phenolic nature. Periodic data revealed that maximum suppression in weed density and dry weight synchronized with peak values of phytotoxins observed 4 weeks after incorporation of sunflower residues. Integration of sunflower residues with lower herbicide rates can produce effective weed suppression without compromising yield as a feasible and environmentally sound approach in broad bean fields.

Inoculación de Vicia villosa R (Veza) y Melilotus alba M (Trébol dulce) con cepas de Rhizobium y su efecto como abonos verdes en la fertilización del suelo

Tesis (Maestría en Ciencias con Especialidad en Microbiología) UANL

Induction of mitotic aberrations by Argon ion lasers in Vicia faba L. and Allium cepa L.

A comparat ive study of the effect oflaser in inducing chro mosomal aberrat ions at 4gg nm was done in View j aba L. (faba bean) and Allium ccpa L. (onion) with Argon ion laser (Spectra Physics Model 171). Seeds and bulbs of V.jaba and A. eepa were subjected to laser irra diation by 4gg nm excitations from Argon ion laser source at power levels 200 and 400 mW with power densities 2.25 mW em" and 4.49 mW em" and ditTerent exposure times (10, 20, 30 & 40 minutes). Similar to the effect of oth er physical and chemical mutagens, laser caused a dose dependent decrease in mitotic index and a rise in mitotic aberrations when compared to the control. In both plant species, mutations were observed in all stages of mitotic cell cycle. The total percentage of aberrations was two fold higher at 400 mW than at 200 mW exposure.

Transcriptomic analysis of rhizobium leguminosarum biovar viciae in symbiosis with host plants pisum sativum and Vicia cracca

Rhizobium leguminosarum bv. viciae forms nitrogen-fixing nodules on several legumes, including pea (Pisum sativum) and vetch (Vicia cracca), and has been widely used as a model to study nodule biochemistry. To understand the complex biochemical and developmental changes undergone by R. leguminosarum bv. viciae during bacteroid development, microarray experiments were first performed with cultured bacteria grown on a variety of carbon substrates (glucose, pyruvate, succinate, inositol, acetate, and acetoacetate) and then compared to bacteroids. Bacteroid metabolism is essentially that of dicarboxylate-grown cells (i.e., induction of dicarboxylate transport, gluconeogenesis and alanine synthesis, and repression of sugar utilization). The decarboxylating arm of the tricarboxylic acid cycle is highly induced, as is gamma-aminobutyrate metabolism, particularly in bacteroids from early (7-day) nodules. To investigate bacteroid development, gene expression in bacteroids was analyzed at 7, 15, and 21 days postinoculation of peas. This revealed that bacterial rRNA isolated from pea, but not vetch, is extensively processed in mature bacteroids. In early development (7 days), there were large changes in the expression of regulators, exported and cell surface molecules, multidrug exporters, and heat and cold shock proteins. fix genes were induced early but continued to increase in mature bacteroids, while nif genes were induced strongly in older bacteroids. Mutation of 37 genes that were strongly upregulated in mature bacteroids revealed that none were essential for nitrogen fixation. However, screening of 3,072 mini-Tn5 mutants on peas revealed previously uncharacterized genes essential for nitrogen fixation. These encoded a potential magnesium transporter, an AAA domain protein, and proteins involved in cytochrome synthesis.

When are ant-attractant devices a worthwhile investment? Vicia faba extrafloral nectaries and Lasius niger ants

Most studies aiming to determine the beneficial effect of ants on plants simply consider the effects of the presence or exclusion of ants on plant yield. This approach is often inadequate, however, as ants interact with both non-tended herbivores and tended Homoptera. Moreover, the interaction with these groups of organisms is dependent on ant density, and these functional relationships are likely to be non-linear. A model is presented here that segregates plant herbivores into two categories depending on the sign of their numerical response to ants (myrmecophiles increase with ants, non-tended herbivores decline). The changes in these two components of herbivores with increasing ant density and the resulting implications for ant-plant mutualisms are considered. It emerges that a wide range of ant densities needs to be considered as the interaction sign (mutualism or parasitism) and strength is likely to change with ant density. The model is used to interpret the results of an experimental study that varied levels of Aphis fabae infestation and Lasius niger ant attendance on Vicia faba bean plants. Increasing ant density consistently reduced plant fitness and thus, in this location, the interaction between the ants and the plant can be considered parasitic. In the Vicia faba system, these costs of ants are unlikely to be offset by other beneficial agents (e.g., parasitoids), which also visit extrafloral nectaries.

A baseline study of vicine–convicine levels in faba bean (Vicia faba L.) germplasm

Vicine and convicine are anti-nutritional compounds that accumulate in the cotyledons of faba beans. When humans consume beans with high levels of these compounds, it can cause a condition called favism in individuals harbouring a deficiency in the activity of their glucose-6-phosphate dehydrogenase. When faba beans are used in animal feeds, there can be effects on performance. These concerns have resulted in increasing interest within plant breeding in developing low vicine and convicine faba bean germplasm. In order to facilitate this objective, we developed a rapid and robust screening method for vicine and convicine, capable of distinguishing between faba beans that are either high (wild type) or low in vicine and convicine. In the absence of reliable commercial reference materials, we report an adaptation of a previously published method where a biochemical assay and spectral data were used to confirm the identity of our analytes, vicine and convicine. This method could be readily adopted in other facilities and open the way to the efficient exploitation of diverse germplasm in regions where faba beans play a significant role in human nutrition. We screened a collection of germplasm of interest to a collaborative plant breeding programme developing between the National Institute for Agricultural Botany in the UK and L'Institut Nationale d'Agronomie de Tunisie in Tunisia. We report the results obtained and discuss the prospects for developing molecular markers for the low vicine and convicine trait.

Genetic analysis reveals a novel locus in Vicia faba decoupling pigmentation in the flower from that in the extra-floral nectaries

The genetics of the stipule spot pigmentation (SSP) in faba bean (Vicia faba L.) was studied using four inbred lines, of which Disco/2 was zero-tannin (zt2) with colourless stipule spots, ILB938/2 was normal-tannin (ZT2) with colourless stipule spots, and both Aurora/2 and Mélodie/2 were ZT2 with coloured stipule spots. Crosses Mélodie/2 × ILB 938/2, Mélodie/2 × Disco/2, ILB 938/2 × Aurora/2 and ILB 938/2 × Disco/2 (A, B, C and D, respectively) were prepared, along with reciprocals and backcrosses, and advanced through single-seed descent. All F1 hybrid plants had pigmented stipule spots, and in the F2 generation, the segregation ratio fit 3 coloured:1 colourless in crosses A, B and C and 9:7 in cross D. In the F3 generation, the ratio fit 5:3 in crosses A and C and 25:39 in cross D, and in the F4 generation, 9:7 in cross A. SSP was linked to the zero-tannin characteristics (white flower) only in cross B. The results show that coloured stipule spot is dominant to colourless and that colouration is determined by two unlinked complementary recessive genes. We propose the symbols ssp2 for the gene associated with zt2 in Disco/2 and ssp1 for the gene not associated with tannin content in ILB938/2. The novel ssp1 locus was mapped at F5 in cross ‘A’ using Medicago truncatula-derived single-nucleotide polymorphism and was on chromosome 1 of faba bean, in a well-conserved region of M. truncatula chromosome 5 containing some candidate Myb and basic helix–loop–helix transcription factor genes.