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1.
Nat Commun ; 12(1): 829, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33547303

RESUMO

Among legumes (Fabaceae) capable of nitrogen-fixing nodulation, several Aeschynomene spp. use a unique symbiotic process that is independent of Nod factors and infection threads. They are also distinctive in developing root and stem nodules with photosynthetic bradyrhizobia. Despite the significance of these symbiotic features, their understanding remains limited. To overcome such limitations, we conduct genetic studies of nodulation in Aeschynomene evenia, supported by the development of a genome sequence for A. evenia and transcriptomic resources for 10 additional Aeschynomene spp. Comparative analysis of symbiotic genes substantiates singular mechanisms in the early and late nodulation steps. A forward genetic screen also shows that AeCRK, coding a receptor-like kinase, and the symbiotic signaling genes AePOLLUX, AeCCamK, AeCYCLOPS, AeNSP2, and AeNIN are required to trigger both root and stem nodulation. This work demonstrates the utility of the A. evenia model and provides a cornerstone to unravel mechanisms underlying the rhizobium-legume symbiosis.


Assuntos
Bradyrhizobium/crescimento & desenvolvimento , Fabaceae/genética , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Proteínas de Plantas/genética , Nodulação/genética , Simbiose/genética , Sequência de Aminoácidos , Evolução Biológica , Fabaceae/classificação , Fabaceae/crescimento & desenvolvimento , Fabaceae/microbiologia , Ontologia Genética , Sequenciamento de Nucleotídeos em Larga Escala , Anotação de Sequência Molecular , Fotossíntese/genética , Filogenia , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Caules de Planta/genética , Caules de Planta/crescimento & desenvolvimento , Caules de Planta/microbiologia , Transdução de Sinais , Transcriptoma
2.
PLoS One ; 15(10): e0239673, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33027289

RESUMO

This study used high throughput, image-based phenotyping (HTP) to distinguish growth patterns, detect facilitation and interpret variations to nutrient uptake in a model mixed-pasture system in response to factorial low and high nitrogen (N) and phosphorus (P) application. HTP has not previously been used to examine pasture species in mixture. We used red-green-blue (RGB) imaging to obtain smoothed projected shoot area (sPSA) to predict absolute growth (AG) up to 70 days after planting (sPSA, DAP 70), to identify variation in relative growth rates (RGR, DAP 35-70) and detect overyielding (an increase in yield in mixture compared with monoculture, indicating facilitation) in a grass-legume model pasture. Finally, using principal components analysis we interpreted between species changes to HTP-derived temporal growth dynamics and nutrient uptake in mixtures and monocultures. Overyielding was detected in all treatments and was driven by both grass and legume. Our data supported expectations of more rapid grass growth and augmented nutrient uptake in the presence of a legume. Legumes grew more slowly in mixture and where growth became more reliant on soil P. Relative growth rate in grass was strongly associated with shoot N concentration, whereas legume RGR was not strongly associated with shoot nutrients. High throughput, image-based phenotyping was a useful tool to quantify growth trait variation between contrasting species and to this end is highly useful in understanding nutrient-yield relationships in mixed pasture cultivations.


Assuntos
Fabaceae/crescimento & desenvolvimento , Nutrientes/metabolismo , Poaceae/crescimento & desenvolvimento , Agricultura/métodos , Variação Biológica da População/genética , Variação Biológica da População/fisiologia , Biomassa , Fabaceae/genética , Pradaria , Ensaios de Triagem em Larga Escala/métodos , Nitrogênio/metabolismo , Fósforo/metabolismo , Poaceae/genética , Solo
3.
J Appl Microbiol ; 129(5): 1133-1156, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32592603

RESUMO

Nitrogen fixation is an important biological process in terrestrial ecosystems and for global crop production. Legume nodulation and N2 fixation have been improved using nodule-enhancing rhizobacteria (NER) under both regular and stressed conditions. The positive effect of NER on legume-rhizobia symbiosis can be facilitated by plant growth-promoting (PGP) mechanisms, some of which remain to be identified. NER that produce aminocyclopropane-1-carboxylic acid deaminase and indole acetic acid enhance the legume-rhizobia symbiosis through (i) enhancing the nodule induction, (ii) improving the competitiveness of rhizobia for nodulation, (iii) prolonging functional nodules by suppressing nodule senescence and (iv) upregulating genes associated with legume-rhizobia symbiosis. The means by which these processes enhance the legume-rhizobia symbiosis is the focus of this review. A better understanding of the mechanisms by which PGP rhizobacteria operate, and how they can be altered, will provide opportunities to enhance legume-rhizobial interactions, to provide new advances in plant growth promotion and N2 fixation.


Assuntos
Bactérias/metabolismo , Fabaceae/crescimento & desenvolvimento , Fabaceae/microbiologia , Simbiose/fisiologia , Carbono-Carbono Liases/metabolismo , Ácidos Indolacéticos/metabolismo , Fixação de Nitrogênio , Nodulação , Nódulos Radiculares de Plantas/microbiologia , Nódulos Radiculares de Plantas/fisiologia
4.
Artigo em Inglês | MEDLINE | ID: mdl-32516924

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are health-concerning organic compounds that accumulate in the environment. Bioremediation and phytoremediation are studied to develop eco-friendly remediation techniques. In this study, the effects of two plants (Medicago sativa L. and Trifolium pratense L.) on the PAHs' bioaccessibility in an aged-contaminated soil throughout a long-term rhizoremediation trial was investigated. A bioaccessibility measurement protocol, using Tenax® beads, was adapted to the studied soil. The aged-contaminated soil was cultured with each plant type and compared to unplanted soil. The bioaccessible and residual PAH contents were quantified after 3, 6 and 12 months. The PAHs' desorption kinetics were established for 15 PAHs and described by a site distribution model. A common Tenax® extraction time (24 h) was established as a comparison basis for PAHs bioaccessibility. The rhizoremediation results show that M. sativa developed better than T. pratense on the contaminated soil. When plants were absent (control) or small (T. pratense), the global PAHs' residual contents dissipated from the rhizosphere to 8% and 10% of the total initial content, respectively. However, in the presence of M. sativa, dissipation after 12 months was only 50% of the total initial content. Finally, the PAHs' bioaccessible content increased more significantly in the absence of plants. This one-year trial brought no evidence that the presence of M. sativa or T. pratense on this tested aged-contaminated soil was beneficial in the PAH remediation process, compared to unplanted soil.


Assuntos
Fabaceae/crescimento & desenvolvimento , Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Biodegradação Ambiental , Medicago sativa , Solo
5.
PLoS One ; 15(5): e0232453, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32369501

RESUMO

Soil-based microorganisms assume a direct and crucial role in the promotion of soil health, quality and fertility, all factors known to contribute heavily to the quality and yield of agricultural products. Cover cropping, used in both traditional and organic farming, is a particularly efficient and environmentally favorable tool for manipulating microbiome composition in agricultural soils and has had clear benefits for soil quality and crop output. Several long-term investigations have evaluated the influence of multi-mix (multiple species) cover crop treatments on soil health and microbial diversity. The present study investigated the short-term effects of a seven species multi-mix cover crop treatment on soil nutrient content and microbial diversity, compared to a single-mix cover crop treatment and control. Analysis of 16S sequencing data of isolated soil DNA revealed that the single-mix cover crop treatment decreased overall microbial abundance and diversity, whereas the control and multi-mix treatments altered the overall microbial composition in similar fluctuating trends. Furthermore, we observed significant changes in specific bacteria belonging to the phyla Acidobacteria, Actinobacteria, Planctomycetes, Proteobacteria and Verrucombicrobia for all treatments, but only the single-mix significantly decreased in abundance of the selected bacteria over time. Our findings indicate that the control and multi-mix treatments are better at maintaining overall microbial composition and diversity compared to the single-mix. Further study is required to elucidate the specific difference between the treatment effect of the multi-mix treatment and the control, given that their microbial composition changes over time were similar but they diverge into two populations of unique bacterial types by the end of this short-term study.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Microbiota , Microbiologia do Solo , Agricultura/métodos , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , DNA Bacteriano/genética , Fabaceae/crescimento & desenvolvimento , Fagopyrum/crescimento & desenvolvimento , Microbiota/genética , Nitrogênio/análise , Filogenia , Poaceae/crescimento & desenvolvimento , RNA Ribossômico 16S/genética , Solo/química
6.
PLoS One ; 15(2): e0229443, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32109939

RESUMO

The relationship between plant traits and species relative abundance along environmental gradients can provide important insights on the determinants of community structure. Here we bring extensive data on six key traits (specific leaf area (SLA), seed mass, seed germination rate, height, leaf proline content and photosynthesis rate) to test trait-abundance relationships in a successional chronosequence of subalpine meadow plant communities. Our results show that in late-successional meadows, abundant species had higher values for seed mass, seed germination rate, and SLA, but had lower values for height, photosynthesis rate, and leaf proline content than rarer species. The opposite patterns of trait-abundance relationships were observed for early-successional meadows. Observations of strong trait convergence and divergence in these successional communities lend greater support for niche processes compared to neutral community assembly. We conclude that species' niches that determine plant growth (plant height and photosynthesis rate), carbon balance (SLA, photosynthesis rate), regeneration (seed mass and seed germination rate), and abiotic stress resistance (leaf proline content) under different environmental conditions have strong influence on species relative abundance in these sub-alpine meadow communities during succession.


Assuntos
Carbono/metabolismo , Cyperaceae/crescimento & desenvolvimento , Fabaceae/crescimento & desenvolvimento , Desenvolvimento Vegetal , Dinâmica Populacional , Regeneração , Estresse Fisiológico , Ecossistema , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento
7.
Arch Microbiol ; 202(2): 399-409, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31686120

RESUMO

In addition to rhizobia, other non-symbiotic endophytic bacteria also have been simultaneously isolated from the same root nodules. The existence of non-symbiotic endophytic bacteria in leguminous root nodules is a universal phenomenon. The vast majority of studies have detected endophytic bacteria in other plant tissues. In contrast, little systemic observation has been made on the non-symbiotic endophytic bacteria within leguminous root nodules. The present investigation was carried out to isolate plant growth-promoting endophytic non-symbiotic bacteria from indigenous leguminous Sphaerophysa salsula and their influence on plant growth. A total of 65 endophytic root nodule-associated bacteria were isolated from indigenous legume S. salsula growing in the northwestern arid regions of China. When combining our previous work with the current study, sequence analysis of the nifH gene revealed that the strain belonging to non-nodulating Bacillus pumilus Qtx-10 had genes similar to those of Rhizobium leguminosarum Qtx-10-1. The results indicated that horizontal gene transfer could have occurred between rhizobia and non-symbiotic endophyties. Under pot culture conditions, out of the 20 representative endophytic isolates, 15 with plant growth-promoting traits, such as IAA production, ACC deaminase, phosphate solubilization, chitinase, siderophore, and fungal inhibition activity showed plant growth-promoting activity with respect to various plant parameters such as chlorophyll content, fresh weight of plant, shoot length, nodule number per plant and average nodule weight per plant when co-inoculated with rhizobial bioinoculant Mesorhizobium sp. Zw-19 under N-free culture conditions. Among them, Bacillus pumilus Qtx-10 and Streptomyces bottropensis Gt-10 were excellent plant growth-promoting bacteria, which enhanced the seeding fresh weight by 87.5% and the shoot length by 89.4%, respectively. The number of nodules grew more than 31.89% under field conditions. Our findings indicate the frequent presence of these non-symbiotic endophytic bacteria within root nodules, and that they help to improve nodulation and nitrogen fixation in legume plants through synergistic interactions with rhizobia.


Assuntos
Bacillus pumilus/metabolismo , Fabaceae/crescimento & desenvolvimento , Fabaceae/microbiologia , Mesorhizobium/metabolismo , Nódulos Radiculares de Plantas/microbiologia , Streptomyces/metabolismo , Carbono-Carbono Liases , China , Endófitos/isolamento & purificação , Transferência Genética Horizontal , Mesorhizobium/genética , Fixação de Nitrogênio , Filogenia , Desenvolvimento Vegetal/fisiologia , Sideróforos
8.
Sci Rep ; 9(1): 18536, 2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31811223

RESUMO

Anthropogenic disturbance, such as agricultural and architectural activities, can greatly influence belowground soil microbes, and thus soil formation and nutrient cycling. The objective of this study was to investigate microbial community variation in deep soils affected by strong disturbances. In present study, twelve soil samples were collected from different depths (0-300 cm) and placed onto the surface. We investigated the structure variation of the microbial community down through the soil profiles in response to disturbance originated by legume plants (robinia and clover) cultivation vs. plant-free controls. The high-throughput sequencing of 16S rRNA genes showed that microbial α-diversity decreased with depth, and that growing both plants significantly impacted the diversity in the topsoil. The soil profile was clustered into three layers: I (0-40 cm), II (40-120 cm), and III (120-300 cm); with significantly different taxa found among them. Soil properties explained a large amount of the variation (23.5%) in the microbial community, and distinct factors affected microbial assembly in the different layers, e.g., available potassium in layer I, pH and total nitrogen in layer II, pH and organic matter in layer III. The prediction of metabolic functions and oxygen requirements indicated that the number of aerobic bacteria increased with more air exposure, which may further accelerate the transformation of nitrogen, sulfur, carbon, and pesticides in the soil. The diversity of soil microorganisms followed a depth-decay pattern, but became higher following legume growth and air exposure, with notable abundance variation of several important bacterial species, mainly belonging to Nitrospira, Verrucomicrobia, and Planctomycetes, and soil properties occurring across the soil profiles.


Assuntos
Fabaceae/crescimento & desenvolvimento , Microbiota/genética , Microbiologia do Solo , Solo/química , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Concentração de Íons de Hidrogênio , Nitrogênio/análise , Praguicidas/análise , Potássio/análise , RNA Ribossômico 16S/genética
9.
PLoS One ; 14(12): e0227074, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31869394

RESUMO

Smallholders throughout sub-Saharan Africa produce legume crops as sources of food, fodder, and cash income, as well as to improve soil fertility. Ethiopian farmers have developed diverse legume varieties that enable adaptation to changing agroecological and sociocultural conditions. However, over the past several decades, as farm sizes declined and extension services promoted new varieties developed by plant breeders, changes in legume diversity have not been monitored. Based on interviews with smallholder farmers (n = 1296), we investigated the status of inter- and intraspecific legume diversity in major production areas of Ethiopia for five food legumes: common bean (Phaseolus vulgaris L.), field pea (Pisum sativum L.), faba bean (Vicia faba L.), groundnut (Arachis hypogaea L.) and fenugreek (Trigonella foenum-graecum L.). Legume species richness increased with altitude, relative household wealth, and land area planted to legumes. The highest numbers of varieties were found for common bean, followed by field pea, faba bean, groundnut and fenugreek. The average number of varieties planted per household was low (ranging from 1 to 2) and often much lower than the number reported in the same community or zone, which ranged from 2 to 18. For three out of the five species, the number of varieties significantly increased with total land area planted to legumes. Most varieties were rare, planted by less than 1/3 of farmers; however, informants accurately named varieties planted by others in the same community, demonstrating awareness of legume diversity at the community level. Given that the ability to plant multiple legume varieties is limited by land size, policies need to strengthen community-level conservation based on the diverse interests and needs of individual households.


Assuntos
Produção Agrícola , Produtos Agrícolas/crescimento & desenvolvimento , Fabaceae/crescimento & desenvolvimento , Biodiversidade , Produção Agrícola/métodos , Etiópia , Características da Família , Fazendeiros , Abastecimento de Alimentos , Humanos
10.
Microbes Environ ; 34(4): 393-401, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31597890

RESUMO

The nifV gene encodes homocitrate synthase, the enzyme that catalyzes the formation of homocitrate, which is essential for arranging the FeMo-cofactor in the catalytic center of nitrogenase. Some host plants, such as Lotus japonicus, supply homocitrate to their symbionts, in this case, Mesorhizobium loti, which lacks nifV. In contrast, Bradyrhizobium ORS285, a symbiont of Aeschynomene cross-inoculation (CI) groups 2 and 3, requires nifV for symbiosis with Aeschynomene species that belong to CI group 3, and some species belonging to CI group 2. However, it currently remains unclear whether rhizobial nifV is required for symbiosis with Aeschynomene species belonging to CI group 1 or with other legumes. We generated nifV-disruption (ΔnifV) mutants of two wide-host-range rhizobia, Bradyrhizobium SUTN9-2 and DOA9, to investigate whether they require nifV for symbiosis. Both ΔnifV mutant strains showed significantly less nitrogenase activity in a free-living state than the respective wild-type strains. The symbiotic phenotypes of SUTN9-2, DOA9, and their ΔnifV mutants were examined with four legumes, Aeschynomene americana, Stylosanthes hamata, Indigofera tinctoria, and Desmodium tortuosum. nifV was required for the efficient symbiosis of SUTN9-2 with A. americana (CI group 1), but not for that of DOA9. SUTN9-2 established symbiosis with all three other legumes; nifV was required for symbiosis with I. tinctoria and D. tortuosum. These results suggest that, in addition to Aeschynomene CI groups 2 and 3, CI group 1 and several other legumes require the rhizobial nifV for symbiosis.


Assuntos
Proteínas de Bactérias/metabolismo , Bradyrhizobium/fisiologia , Fabaceae/microbiologia , Oxo-Ácido-Liases/metabolismo , Simbiose , Proteínas de Bactérias/genética , Bradyrhizobium/classificação , Bradyrhizobium/enzimologia , Bradyrhizobium/genética , Fabaceae/classificação , Fabaceae/crescimento & desenvolvimento , Especificidade de Hospedeiro , Mutação , Fixação de Nitrogênio , Nitrogenase/metabolismo , Oxo-Ácido-Liases/genética , Filogenia , Nódulos Radiculares de Plantas/classificação , Nódulos Radiculares de Plantas/crescimento & desenvolvimento , Nódulos Radiculares de Plantas/microbiologia
11.
PLoS One ; 14(10): e0223149, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31600251

RESUMO

Mutualistic plant-microbe associations are widespread in natural ecosystems and have made major contributions throughout the evolutionary history of terrestrial plants. Amongst the most remarkable of these are the so-called root endosymbioses, resulting from the intracellular colonization of host tissues by either arbuscular mycorrhizal (AM) fungi or nitrogen-fixing bacteria that both provide key nutrients to the host in exchange for energy-rich photosynthates. Actinorhizal host plants, members of the Eurosid 1 clade, are able to associate with both AM fungi and nitrogen-fixing actinomycetes known as Frankia. Currently, little is known about the molecular signaling that allows these plants to recognize their fungal and bacterial partners. In this article, we describe the use of an in vivo Ca2+ reporter to identify symbiotic signaling responses to AM fungi in roots of both Casuarina glauca and Discaria trinervis, actinorhizal species with contrasting modes of Frankia colonization. This approach has revealed that, for both actinorhizal hosts, the short-chain chitin oligomer chitotetraose is able to mimic AM fungal exudates in activating the conserved symbiosis signaling pathway (CSSP) in epidermal root cells targeted by AM fungi. These results mirror findings in other AM host plants including legumes and the monocot rice. In addition, we show that chitotetraose is a more efficient elicitor of CSSP activation compared to AM fungal lipo-chitooligosaccharides. These findings reinforce the likely role of short-chain chitin oligomers during the initial stages of the AM association, and are discussed in relation to both our current knowledge about molecular signaling during Frankia recognition as well as the different microsymbiont root colonization mechanisms employed by actinorhizal hosts.


Assuntos
Fagales/genética , Frankia/genética , Oligossacarídeos/genética , Simbiose/genética , Fabaceae/genética , Fabaceae/crescimento & desenvolvimento , Fabaceae/microbiologia , Fagales/crescimento & desenvolvimento , Fagales/microbiologia , Frankia/crescimento & desenvolvimento , Frankia/metabolismo , Micorrizas/crescimento & desenvolvimento , Micorrizas/metabolismo , Fixação de Nitrogênio/genética , Nodulação/genética , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Transdução de Sinais/genética
12.
Braz. j. biol ; 79(3): 369-376, July-Sept. 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1001452

RESUMO

Abstract This study aimed to inventory the herbivore insects associated with Enterolobium contortisiliquum (Vell.) Morong (Fabaceae) fruits and seeds and their primary and secondary parasitoids. Six samples collected between May and October 2013 yielded 210 fruits, from which 326 insects of six orders emerged: Coleoptera, Hymenoptera, Lepidoptera, Diptera, Thysanoptera and Psocoptera. Coleoptera (five families) was represented by the seed consumers Merobruchus bicoloripes Pic, Stator sp. Bridwell (Chrysomelidae, Bruchinae), two species of Silvanidae, one species of Scolytinae (Curculionidae), one species of Nitidulidae and one species of Cerambycidae. The cerambycid was also observed forming galleries on fruit mesocarp. Immature individuals of Lepidoptera were observed consuming the fruits and seeds. From the seven Hymenoptera families, only two species were associated with Coleoptera, being Horismenus Walker sp. (Eulophidae) as parasitoid of M. bicoloripes, and Neoheterospilus falcatus (Marsh) (Braconidae) as parasitoid of Scolytinae. The Lepidoptera parasitoids represented four genera: Pseudophanerotoma Zetel, Chelonus Panzer (Braconidae), Orgilus Nees (Braconidae) and Goniozus Forster (Bethylidae). The host associations for the reared parasitoids Bracon Fabricius (Braconidae), Pimplinae sp. (Ichneumonidae) and Perilampus Forster (Perilampidae) were not confirmed. We obtained a single representative of Diptera (Tachinidae) associated with Lepidoptera hosts in this food web.


Resumo Este estudo teve como objetivo inventariar os insetos herbívoros associados a frutos e sementes de Enterolobium contortisiliquum (Vell.) Morong (Fabaceae) e seus parasitoides primários e secundários. De seis amostras coletadas entre maio e outubro de 2013, obteve-se 210 frutos, dos quais emergiram 326 insetos pertencentes a seis ordens: Coleoptera, Hymenoptera, Lepidoptera, Diptera, Thysanoptera e Psocoptera. Coleoptera (cinco famílias) foi representada pelos consumidores de sementes: Merobruchus bicoloripes Pic, Stator sp. Bridwell (Chrysomelidae, Bruchinae), Silvanidae sp. 1 e sp. 2, Scolytinae sp. (Curculionidae), Nitidulidae sp. e Cerambycidae sp. A última espécie também foi observada formando galerias no mesocarpo do fruto. Indivíduos imaturos de Lepidoptera também foram observados consumindo os frutos e sementes. Dos Hymenoptera (sete famílias), duas espécies foram associadas a Coleoptera, sendo Horismenus Walker sp. (Eulophidae) parasitoide de M. bicoloripes e Neoheterospilus falcatus (Marsh) (Braconidae) parasitoide de Scolytinae. Os parasitoides de Lepidoptera foram totalizados em quatro gêneros: Pseudophanerotoma Zetel e Chelonus Panzer (Braconidae), Orgilus Nees (Braconidae) e Goniozus Forster (Bethylidae). As interações para os parasitoides Bracon Fabricius (Braconidae), Pimplinae sp. (Ichneumonidae) e Perilampus Forster (Perilampidae) não foram confirmadas. Nós encontramos apenas um único representante de Diptera (Tachinidae) como parasitoide de Lepidoptera nesta rede trófica.


Assuntos
Animais , Cadeia Alimentar , Herbivoria , Interações Hospedeiro-Parasita , Insetos/fisiologia , Insetos/parasitologia , Fabaceae/crescimento & desenvolvimento , Besouros/crescimento & desenvolvimento , Besouros/fisiologia , Besouros/parasitologia , Brasil , Dípteros/fisiologia , Frutas/fisiologia , Insetos/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento
13.
Braz J Microbiol ; 50(4): 1011-1020, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31396863

RESUMO

Positive feedback between arbuscular mycorrhizal fungal (AMF) and vascular plants can contribute to plant species establishment, but how this feedback affects plant invasion by Prosopis juliflora SW. (DC.), or resistance to invasion by Mimosa tenuiflora (Willd.) Poir in Brazilian semi-arid region is not well known. In this work, we tested how modified and native AMF communities affect the establishment of P. juliflora and M. tenuiflora plants. We examined the effects of inoculation with modified and native AMF communities on number of AMF spores, root colonization, number of N-fixing nodules, plant dry biomass, plant phosphorous concentration, and plant responsiveness to mycorrhizas of P. juliflora and M. tenuiflora. We found that the modified AMF community enhanced the root colonization, plant dry biomass, and plant phosphorous concentration of invasive P. juliflora, whereas native AMF enhanced M. tenuiflora. Our results demonstrate that the invasive P. juliflora alters soil AMF community composition, and this change generates positive feedback to the invasive P. juliflora itself and decreases AMF associations with native M. tenuiflora.


Assuntos
Fabaceae/microbiologia , Fungos/isolamento & purificação , Mimosa/microbiologia , Micorrizas/isolamento & purificação , Biodiversidade , Brasil , Fabaceae/crescimento & desenvolvimento , Fungos/classificação , Fungos/genética , Fungos/metabolismo , Espécies Introduzidas , Mimosa/crescimento & desenvolvimento , Micorrizas/classificação , Micorrizas/genética , Micorrizas/metabolismo , Fósforo/metabolismo , Raízes de Plantas/microbiologia , Solo/química , Microbiologia do Solo , Esporos Fúngicos/classificação , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Esporos Fúngicos/metabolismo
14.
PLoS One ; 14(8): e0220151, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31412055

RESUMO

The Gran Chaco is a wide ecologic-geographic region comprising northern Argentina, western Paraguay, southern Bolivia and the southwestern extreme of Brazil. This region exhibits extreme temperatures, annually regular frosts, and sedimentary soils; it has been dramatically threatened by agriculture expansion in recent decades. Therefore, increasing knowledge of plant diversity is critical for conservation purposes. We present a Legume checklist of the Gran Chaco ecoregion including conservation status of its endemic species. Leguminosae is the third most diverse plant family in the Neotropics. Assuming a rigorous spatial definition of the Gran Chaco, we recorded 98 genera, 362 species, and 404 specific and infraspecific taxa. Endemic/typical taxa were 17%, comparable to adjacent tropical plant formations, and they were found in higher percentages in Caesalpinioideae (24%) and Cercidoideae (33%) than Papilionoideae (11%) subfamily. We also analyzed the plant diversity comparing lineages and subregions. The Gran Chaco Legumes are predominantly widespread generalists, or they belong to either Chaco sensu stricto or Neotropical Seasonally Dry Tropical Forest (SDTF) lineages. Though the Humid Chaco registered the highest species richness, Dry Chaco and Sierra Chaco, the most threatrened subregions, exhibited the highest percentages of exclusive and proper Chaco-lineage species. These results suggest that diversification of Legumes has been most relevant in Dry Chaco and Sierra Chaco, probably by their more demanding and harsh environmental conditions limiting the dispersion of generalists or intrusive-invading species. This study is paramount to reach an improved delimitation of the Gran Chaco ecoregion in transitional areas with the SDTF and Cerrado formations. Conservation status is critical in genera of high economic interest, such as Arachis, Mimosa and Prosopis. At least one third of endemic taxa exhibit a critical status of conservation or are endangered, many of them being relevant to inbreeding program or exhibiting multiple economic uses.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Fabaceae/classificação , Argentina , Fabaceae/crescimento & desenvolvimento , Florestas , Geografia
15.
Sci Rep ; 9(1): 10356, 2019 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-31346187

RESUMO

Increasingly large proportions of tropical forests are anthropogenically disturbed. Where natural regeneration is possible at all, it requires the input of plant seeds through seed dispersal from the forest matrix. Zoochorous seed dispersal - the major seed dispersal mode for woody plants in tropical forests - is particularly important for natural regeneration. In this study, covering a period of more than 20 years, we show that small New World primates, the tamarins Saguinus mystax and Leontocebus nigrifrons, increase their use of an anthropogenically disturbed area over time and disperse seeds from primary forest tree species into this area. Through monitoring the fate of seeds and through parentage analyses of seedlings of the legume Parkia panurensis from the disturbed area and candidate parents from the primary forest matrix, we show that tamarin seed dispersal is effective and contributes to the natural regeneration of the disturbed area.


Assuntos
Callitrichinae , Florestas , Dispersão de Sementes , Animais , Biodiversidade , Conservação dos Recursos Naturais , Fabaceae/genética , Fabaceae/crescimento & desenvolvimento , Comportamento Alimentar , Humanos , Periodicidade , Estações do Ano , Plântula/genética , Plântula/crescimento & desenvolvimento , Clima Tropical
16.
Sci Rep ; 9(1): 8539, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31189881

RESUMO

Inclusion of legumes in cropping systems is essential for sustainable management of farming systems and reducing the nitrogen (N) fertilizer requirement for maize production. The study evaluated the effect of growing legumes (soybean, cowpea and velvet bean) and maize the same year in rotation, on maize yield and soil fertility indices. The agronomic practices implemented were residue management (residue added and residue removed) and fertilizer N application (0 kg N ha-1 and 60 kg N ha-1) under four rotation systems. The result showed that growing velvet bean the same year in rotation with maize was effective in increasing maize yield and improving some soil fertility indices over growing maize after maize the same year in the same location. Compared to maize monocropping, over 100% increase in maize yield was obtained with velvet bean-maize rotation even in absence of residue incorporation. In addition, velvet bean-maize rotation increased maize yield over cowpea- and soybean- maize rotations. The rotation effect occurred as a result of improvement in soil nitrogen, avail phosphorus (P), exchangeable magnesium (exch Mg) and effective cation exchange capacity (ECEC). Grain legumes-maize rotations equally increased maize yield over sole maize. Generally legume-maize rotations increased total N, avail P, exch K, Mg and effective cation exchange capacity over sole maize. Crop residue incorporation and N fertilizer application significantly improved soil N and maize grain yield (0.18%, 2.74 tha-1 in 2008; 0.22%, 1.16 tha-1 in 2009 and 0.19%, 2.72 tha-1 in 2008; 1.35 tha-1 in 2009 respectively) over non-residue incorporation (0.16% and 1.84 tha-1 in 2008, 0.66 tha-1 in 2009) and zero N application (0.16% and 1.83 tha-1 in 2008 and 0.17% and 0.85 tha-1 in 2009). Therefore, velvet bean could be planted the same season with subsequent maize in rotation cropping for intensive sustainable maize production in sandy-loam soils without fertilizer N. For grain legumes such as soybean and cowpea to be effective in rotation cropping with maize, the grain legumes have to be planted early before the full set of rain because excess rain would affect their growth and development.


Assuntos
Produção Agrícola , Fabaceae/crescimento & desenvolvimento , Solo , Zea mays/crescimento & desenvolvimento
17.
Genes (Basel) ; 10(6)2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31234426

RESUMO

Chitinase is a kind of hydrolase with chitin as a substrate and is proposed to play an essential role in plant defense system by functioning against fungal pathogens through degrading chitin. Recent studies indicated chitinase is also involved in abiotic stress response in plants, helping plants to survive in stressful environments. A. nanus, a rare evergreen broad-leaved shrub distrusted in deserts in Central Asia, exhibits a high level of tolerance to drought and low temperature stresses. To identify the chitinase gene involved in drought and low temperature responses in A. nanus, we performed genome-wide identification, classification, sequence alignment, and spatio-temporal gene expression analysis of the chitinases in A. nanus under osmotic and low temperature stress. A total of 32 chitinase genes belonging to glycosyl hydrolase 18 (GH18) and GH19 families were identified from A. nanus. Class III chitinases appear to be amplified quantitatively in A. nanus, and their genes carry less introns, indicating their involvement in stress response in A. nanus. The expression level of the majority of chitinases varied in leaves, stems, and roots, and regulated under environmental stress. Some chitinases, such as EVM0022783, EVM0020238, and EVM0003645, are strongly induced by low temperature and osmotic stress, and the MYC/ICE1 (inducer of CBF expression 1) binding sites in promoter regions may mediate the induction of these chitinases under stress. These chitinases might play key roles in the tolerance to these abiotic stress in A. nanus and have potential for biotechnological applications. This study provided important data for understanding the biological functions of chitinases in A. nanus.


Assuntos
Quitinases/genética , Resposta ao Choque Frio/genética , Fabaceae/genética , Filogenia , Quitinases/classificação , Secas , Fabaceae/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/genética , Genoma de Planta/genética , Pressão Osmótica/fisiologia , Folhas de Planta/genética , Alinhamento de Sequência , Estresse Fisiológico/genética
18.
Proc Natl Acad Sci U S A ; 116(28): 14339-14348, 2019 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-31239345

RESUMO

The establishment of nitrogen-fixing root nodules in legume-rhizobia symbiosis requires an intricate communication between the host plant and its symbiont. We are, however, limited in our understanding of the symbiosis signaling process. In particular, how membrane-localized receptors of legumes activate signal transduction following perception of rhizobial signaling molecules has mostly remained elusive. To address this, we performed a coimmunoprecipitation-based proteomics screen to identify proteins associated with Nod factor receptor 5 (NFR5) in Lotus japonicus. Out of 51 NFR5-associated proteins, we focused on a receptor-like cytoplasmic kinase (RLCK), which we named NFR5-interacting cytoplasmic kinase 4 (NiCK4). NiCK4 associates with heterologously expressed NFR5 in Nicotiana benthamiana, and directly binds and phosphorylates the cytoplasmic domains of NFR5 and NFR1 in vitro. At the cellular level, Nick4 is coexpressed with Nfr5 in root hairs and nodule cells, and the NiCK4 protein relocates to the nucleus in an NFR5/NFR1-dependent manner upon Nod factor treatment. Phenotyping of retrotransposon insertion mutants revealed that NiCK4 promotes nodule organogenesis. Together, these results suggest that the identified RLCK, NiCK4, acts as a component of the Nod factor signaling pathway downstream of NFR5.


Assuntos
Lipopolissacarídeos/genética , Lotus/genética , Nodulação/genética , Simbiose/genética , Citoplasma/enzimologia , Fabaceae/genética , Fabaceae/crescimento & desenvolvimento , Fabaceae/microbiologia , Regulação da Expressão Gênica de Plantas/genética , Lotus/crescimento & desenvolvimento , Lotus/microbiologia , Fosfotransferases/genética , Raízes de Plantas/genética , Raízes de Plantas/microbiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Rhizobium/genética , Rhizobium/crescimento & desenvolvimento , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/crescimento & desenvolvimento , Nódulos Radiculares de Plantas/microbiologia , Tabaco/genética , Tabaco/crescimento & desenvolvimento , Tabaco/microbiologia
19.
PLoS One ; 14(6): e0219100, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31242263

RESUMO

Dugout canoes are boats made from a single tree trunk. Even with the modernization of fishing, they are still made and used for artisanal fishing on the coast of southern and southeastern Brazil and in other regions of the world. Various tree species are used to construct these canoes and choosing a species is related to characteristics of the location, available raw materials and purpose of the boat. Our objective was to better understand the variation in dugout canoes in relation to tree species, tree size and fishing use, over time, along a coastal strip of southern and southeastern Brazil within the Atlantic Forest domain. We interviewed 53 artisans and analyzed 358 canoes that ranged from 1 to around 200 years old. Schizolobium parahyba is currently used the most. In the past, species of the family Lauraceae (Nectandra sp. / Ocotea sp.) were frequently used, as well as Cedrela fissilis and Ficus sp. The size of the canoes varied based on time, coastal region, environment where the boat is used (exposed or sheltered) and type of fishing. The average size of recent canoes was smaller than older canoes for more common species (S. parahyba and C. fissilis), reflecting changes in the vegetation of the biome over time, both in the species and size of individuals available. Latitudinal variation can also influence the availability of tree species along the studied regions. An increase in environmental monitoring has contributed to a decline in constructing dugout canoes, resulting in the use of fiberglass canoes and other motorized boats. Although canoe size varied based on region, location and use, today some of the older canoes represent large trees of the past and pieces of Atlantic Forest history.


Assuntos
Navios/métodos , Árvores/crescimento & desenvolvimento , Brasil , Cedrela/crescimento & desenvolvimento , Ecossistema , Fabaceae/crescimento & desenvolvimento , Florestas , Humanos , Lauraceae/crescimento & desenvolvimento , Clima Tropical
20.
Antonie Van Leeuwenhoek ; 112(9): 1369-1385, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31053961

RESUMO

Twelve nodulating Paraburkholderia strains isolated from indigenous South African fynbos legume Hypocalyptus sophoroides were investigated to determine their taxonomic status. Genealogical concordance analysis, based on six loci (16S rRNA, atpD, recA, rpoB, lepA and gltB), revealed that they separate into two consistent and exclusive groups. Average nucleotide identity and DNA-DNA hybridisation comparisons indicated that they were sufficiently divergent from their closest known phylogenetic relatives (Paraburkholderia caledonica and Paraburkholderia terrae, respectively) to be regarded as novel species. This was also supported by the results of fatty acid analysis and metabolic characterisation. For these two isolate groups, we accordingly propose the new species Paraburkholderia strydomiana sp. nov. with WK1.1fT (= LMG 28731T = SARCC1213T) as its type strain and Paraburkholderia steynii sp. nov. with HC1.1baT (= LMG 28730T = SARCC696T) as its type strain. Our data thus showed that H. sophoroides may be considered a promiscuous symbiotic partner due to its ability to associate with multiple species of Paraburkholderia.


Assuntos
Burkholderiaceae/classificação , Burkholderiaceae/isolamento & purificação , Fabaceae/microbiologia , Raízes de Plantas/microbiologia , Microbiologia do Solo , Proteínas de Bactérias/genética , Técnicas de Tipagem Bacteriana , Burkholderiaceae/genética , Burkholderiaceae/fisiologia , Análise por Conglomerados , Citosol/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Fabaceae/crescimento & desenvolvimento , Ácidos Graxos/análise , Hibridização de Ácido Nucleico , Filogenia , Nodulação , RNA Ribossômico 16S/genética , Rizosfera , Análise de Sequência de DNA
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