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1.
Arch Virol ; 165(7): 1659-1665, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32405827

RESUMO

In this work, a begomovirus isolated from a bean plant coinfected with the potyviruses bean common mosaic virus and bean common mosaic necrosis virus was characterized. The three viruses were detected by high-throughput sequencing and assembly of total small RNAs, but the begomovirus-related contigs did not allow precise identification. Molecular analysis based on standard DNA amplification techniques revealed the presence of a single bipartite virus, which is a novel begomovirus according to the current taxonomic criteria. Infectious clones were generated and agroinoculated into Phaseolus vulgaris and Nicotiana benthamiana plants. In all cases, viral DNA-A and DNA-B were detected in new growths, but no symptoms were observed, thus indicating that this virus produces asymptomatic infections in both host species.


Assuntos
Begomovirus/isolamento & purificação , Phaseolus/virologia , Doenças das Plantas/virologia , Potyvirus/fisiologia , Tabaco/virologia , Begomovirus/classificação , Begomovirus/genética , Begomovirus/fisiologia , Coinfecção/virologia
2.
Food Chem ; 321: 126680, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247181

RESUMO

Seed phytic acid reduces mineral bioavailability by chelating minerals. Consumption of common bean seeds with the low phytic acid 1 (lpa1) mutation improved iron status in human trials but caused adverse gastrointestinal effects, presumably due to increased stability of lectin phytohemagglutinin L (PHA-L) compared to the wild type (wt). A hard-to-cook (HTC) defect observed in lpa1 seeds intensified this problem. We quantified the HTC phenotype of lpa1 common beans with three genetic backgrounds. The HTC phenotype in the lpa1 black bean line correlated with the redistribution of calcium particularly in the cell walls, providing support for the "phytase-phytate-pectin" theory of the HTC mechanism. Furthermore, the excess of free cations in the lpa1 mutation in combination with different PHA alleles affected the stability of PHA-L lectin.


Assuntos
Cálcio/química , Lectinas/química , Phaseolus/química , Ácido Fítico/química , Fito-Hemaglutininas/química , Culinária , Dureza , Temperatura Alta , Mutação , Phaseolus/genética , Sementes/química , Sementes/genética
3.
Arch Virol ; 165(6): 1505-1509, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32277282

RESUMO

The complete genome sequence of a novel comovirus identified in Guanajuato, Mexico, in a common bean plant (Phaseolus vulgaris L.) coinfected with Phaseolus vulgaris alphaendornavirus 1 (PvEV-1) and Phaseolus vulgaris alphaendornavirus 2 (PvEV-2) is presented. According to the current ICTV taxonomic criteria, this comovirus corresponds to a new species, and the name "Phaseolus vulgaris severe mosaic virus" (PvSMV) is proposed for this virus based on the observed symptoms of "severe mosaic" syndrome caused by comoviruses in common bean. PvSMV is closely related to bean pod mosaic virus (BPMV), and its genome consists of two polyadenylated RNAs. RNA-1 (GenBank accession number MN837498) is 5969 nucleotides (nt) long and encodes a single polyprotein of 1856 amino acids (aa), with an estimated molecular weight (MW) of 210 kDa, that contains putative proteins responsible for viral replication and proteolytic processing. RNA-2 (GenBank accession number MN837499) is 3762 nt long and encodes a single polyprotein of 1024 aa, with an estimated MW of 114 kDa, that contains putative movement and coat proteins. Cleavage sites were predicted based on similarities in size and homology to aa sequences of other comoviruses available in the GenBank database. Symptoms associated with PvSMV include mosaic, local necrotic lesions, and apical necrosis. This is the first report of a comovirus infecting common bean in Mexico.


Assuntos
Comovirus/genética , Genoma Viral , Phaseolus/virologia , Doenças das Plantas/virologia , Sequência de Aminoácidos , Comovirus/classificação , Comovirus/isolamento & purificação , México , Filogenia , RNA Viral/genética , Proteínas Virais/genética , Sequenciamento Completo do Genoma
4.
PLoS One ; 15(3): e0229909, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32134988

RESUMO

Stable transformation of common bean (Phaseolus vulgaris L.) has been successful, to date, only using biolistic-mediated transformation and shoot regeneration from meristem-containing embryo axes. In this study, using precultured embryo axes, and optimal co-cultivation conditions resulted in a successful transformation of the common bean cultivar Olathe using Agrobacterium tumefaciens strain EHA105. Plant regeneration through somatic embryogenesis was attained through the preculture of embryo axes for 12 weeks using induced competent cells for A. tumefaciens-mediated gene delivery. Using A. tumefaciens at a low optical density (OD) of 0.1 at a wavelength of 600 nm for infection and 4-day co-cultivation, compared to OD600 of 0.5, increased the survival rate of the inoculated explants from 23% to 45%. Selection using 0.5 mg L-1 glufosinate (GS) was effective to identify transformed cells when the bialaphos resistance (bar) gene under the constitutive 35S promoter was used as a selectable marker. After an 18-week selection period, 1.5% -2.5% inoculated explants, in three experiments with a total of 600 explants, produced GS-resistant plants through somatic embryogenesis. The expression of bar was confirmed in first- and second-generation seedlings of the two lines through reverse polymerase chain reaction. Presence of the bar gene was verified through genome sequencing of two selected transgenic lines. The induction of regenerable, competent cells is key for the successful transformation, and the protocols described may be useful for future transformation of additional Phaseolus germplasm.


Assuntos
Agrobacterium tumefaciens/genética , Phaseolus/genética , Melhoramento Vegetal/métodos , Plantas Geneticamente Modificadas/genética , Transformação Genética , Agrobacterium tumefaciens/efeitos dos fármacos , Aminobutiratos/farmacologia , DNA de Plantas/genética , Farmacorresistência Bacteriana/genética , Vetores Genéticos , Herbicidas/farmacologia , Compostos Organofosforados/farmacologia , Fenótipo , RNA de Plantas/genética
5.
PLoS One ; 15(2): e0228680, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32017794

RESUMO

Common bean (Phaseolus vulgaris L.) is a major source of proteins and one of the most important edible foods for more than three hundred million people in the world. The common bean plants are frequently attacked by spider mite (Tetranychus urticae Koch), leading to a significant decrease in plant growth and economic performance. The use of resistant cultivars and the identification of the genes involved in plant-mite resistance are practical solutions to this problem. Hence, a comprehensive study of the molecular interactions between resistant and susceptible common bean cultivars and spider mite can shed light into the understanding of mechanisms and biological pathways of resistance. In this study, one resistant (Naz) and one susceptible (Akhtar) cultivars were selected for a transcriptome comparison at different time points (0, 1 and 5 days) after spider mite feeding. The comparison of cultivars in different time points revealed several key genes, which showed a change increase in transcript abundance via spider mite infestation. These included genes involved in flavonoid biosynthesis process; a conserved MYB-bHLH-WD40 (MBW) regulatory complex; transcription factors (TFs) TT2, TT8, TCP, Cys2/His2-type and C2H2-type zinc finger proteins; the ethylene response factors (ERFs) ERF1 and ERF9; genes related to metabolism of auxin and jasmonic acid (JA); pathogenesis-related (PR) proteins and heat shock proteins.


Assuntos
Ácaros/patogenicidade , Phaseolus/imunologia , Transcriptoma , Animais , Perfilação da Expressão Gênica , Genes de Plantas , Interações Hospedeiro-Patógeno , Infestações por Ácaros , Phaseolus/genética , Phaseolus/parasitologia , Fatores de Tempo
6.
Environ Pollut ; 260: 114048, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32014748

RESUMO

Selenium (Se) is an essential micronutrient for animals with a narrow margin between essentiality and toxicity. Se toxicity is largely related to inorganic forms of Se in soil, i.e., selenite and selenate that enter food chains through plant uptake, threatening higher trophic level organisms. This experiment investigated effects of earthworm activity on Se bioavailability in soil and the subsequent plant uptake, using earthworm Eisenia fetida and bean plant Phaseolus vulgaris L, both exposed to either selenite or selenate at 1 or 4 mg Se kg-1 for 16 weeks. Plants took up selenate (up to 221-fold) faster than selenite, with up to 84% of the Se rapidly transported to shoots. In the presence of earthworms, Se accumulation obviously increased for selenate-supplied plants, leading to an up to 4% increase in Se translocation factor for all treatments except for 1 mg kg-1 selenite treatment. Earthworms also concentrated Se faster in tissues (up to 274 mg kg-1 DW) at exposure to selenate. For Se toxicity, Se speciation analysis was conducted on the plants and earthworms using XAS. Compared to worm-free treatments, the percentage of organo-Se, i.e., SeMet and CysSeSeCys, increased in beans (up to 34%) in the presence of earthworms for selenate, while the elemental Se portion was significantly reduced or absent, opposite to the results for selenite. Surprisingly, elemental Se (up to 65%) dominated earthworms, regardless of the form of Se supplied. In conclusion, earthworms clearly enhanced Se uptake and translocation in plants, leading to elevated Se levels in shoots. To prevent resulting hazards to humans and other animals, caution should be taken while consuming the shoots, particularly beans, harvested from the Se contaminated soil where earthworm activity is high. Finally, the significant reduction in soil Se suggests phytoextraction of Se from the soil could be improved using earthworms as an aid to plants.


Assuntos
Oligoquetos , Phaseolus , Selênio , Animais , Ácido Selênico , Solo
7.
Ecotoxicology ; 29(2): 203-216, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32006192

RESUMO

Common bean (Phaseolus vulgaris) cultivation occurs mainly in regions with acidic soils, where high aluminum (Al) concentration is a major constraint to crop production. In this study, we evaluated tolerance and sensitivity traits to Al exposure and calcium (Ca) deficiency in bean plants, and determined the efficiency of Ca to mitigate the toxic Al effects. Two bean cultivars (BRS Estilo and Campos Gerais) were grown in three soil conditions: (I) soil liming with calcium hydroxide Ca(OH)2 and Al unavailable (-Al+Ca); (II) fertilized soil with calcium nitrate [Ca(NO3)2·4H2O] and Al available (+Al+Ca); and (III) soil without Ca addition and Al available (+Al-Ca). At the beginning of the reproductive stage, we evaluated the photosynthetic processes, mineral nutrition, and leaf anatomy and morphological traits of plants. The photosynthetic parameters were good tools for monitor Al sensitivity in bean. +Al+Ca soil treatment mitigated the deleterious effects of Al on growth and mineral nutrition of both bean cultivars. However, Ca did not prevent the toxic effects of Al on leaf anatomy. Al stress and Ca deficiency caused negative effects on nutrient content, photosynthetic activity and leaf anatomy of bean plants. Calcium mitigated Al toxicity, primarily in the Campos Gerais cultivar, showing the potential to improve bean crop productivity in acid soils.


Assuntos
Alumínio/toxicidade , Compostos de Cálcio , Nitratos , Phaseolus/fisiologia , Poluentes do Solo/toxicidade , Fotossíntese/efeitos dos fármacos
8.
Food Chem ; 315: 126268, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32018083

RESUMO

Starch digestion in pulse cellular matrices is primarily determined by the hindrance of cell walls limiting enzyme diffusion as well as the retention of starch granular structure. However, the effect of hydrothermal treatment on structure and digestion properties of entrapped pulse starches is not fully elucidated. In present study, we reported the variations in structure and enzyme susceptibility of pulse cells isolated at 60 °C followed by heated at 70, 80, 90, 100 °C, which were higher than the starch gelatinization temperature. Based on the thermal and crystalline properties, entrapped starches in pulse cells were not fully gelatinized even treated at 100 °C. Whilst, the digestion of entrapped pulse starches increased with higher temperature, but still much lower than the isolated starch treated at the same temperature. In addition to physical barriers (intact cell wall) and starch structural features (partial ordered crystalline structure), the soluble/insoluble proteinaceous materials in cells also synergistically reduced the starch digestibility.


Assuntos
Cicer/química , Cotilédone/química , Phaseolus/química , Amido/química , Parede Celular/química , Cotilédone/citologia , Digestão , Enzimas/química , Enzimas/metabolismo , Gelatina/química , Temperatura Alta , Células Vegetais , Temperatura , Difração de Raios X
9.
Chem Commun (Camb) ; 56(18): 2799-2802, 2020 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-32030396

RESUMO

Both the activity and regioselectivity of Phaseolus vulgaris epoxide hydrolase were remarkably improved via reshaping two substrate tunnels based on rational design. The elegant one-step enantioconvergent hydrolysis of seven rac-epoxides was achieved by single mutants, allowing green and efficient access to valuable (R)-1,2 diols with high eep (90.1-98.3%) and yields.


Assuntos
Álcoois/metabolismo , Epóxido Hidrolases/metabolismo , Compostos de Epóxi/metabolismo , Phaseolus/enzimologia , Álcoois/química , Epóxido Hidrolases/química , Compostos de Epóxi/química , Modelos Moleculares , Conformação Molecular , Estereoisomerismo
10.
J Agric Food Chem ; 68(4): 1091-1100, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31896257

RESUMO

The physical structure of type 1 resistant starch (RS 1) could influence the metabolite production and stimulate the growth of specific bacteria in the human colon. In the present study, we isolated intact cotyledon cells from pinto bean seeds as whole pulse food and RS 1 model and obtained a series of cell wall integrities through controlled enzymolysis. In vitro human fecal fermentation performance and microbiota responses were tested, and we reported that the cell wall integrity controls the in vitro fecal fermentation rate of heat-treated pinto bean cells. The concentration of butyrate produced by pinto bean cell fermentation enhanced with weakened cell wall integrity, and certain beneficial bacterial groups such as Blautia and Roseburia genera were remarkably promoted by pinto bean cells with damaged cell wall integrity. However, the intact cell sample had a shape more similar to microbiota composition with the purified cell wall polysaccharides, rather than the damaged cells.


Assuntos
Bactérias/metabolismo , Parede Celular/metabolismo , Fezes/microbiologia , Microbioma Gastrointestinal , Phaseolus/metabolismo , Bactérias/química , Bactérias/classificação , Bactérias/isolamento & purificação , Parede Celular/química , Fermentação , Humanos , Phaseolus/química , Polissacarídeos/metabolismo , Sementes/química , Sementes/metabolismo
11.
Anal Bioanal Chem ; 412(7): 1701-1707, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31965247

RESUMO

Two "mass ratio-DNA copy concentration ratio" formulas were established respectively on droplet digital PCR (ddPCR) and chip-based digital PCR (cdPCR) to determine the mass ratio of kidney bean, a common alternative plant-derived ingredient in lotus seed paste. The limit of detection for DNA copy concentration of kidney bean and lotus seed was 6 copies/µL. Quantitative detection range was set from 5 to 80%, and the limit of quantification for mass ratio of kidney bean in lotus seed paste was defined as 5%. Results of 6 simulated samples and 16 prepackaged pastes in this work offer compelling evidence that an innovative scheme for quantitative detection of kidney bean in lotus seed paste was available, and provide technical support for the identification of suspicious ingredients from fraudulent substitution or adventitious contamination. Graphical abstract Two "mass ratio-DNA copy concentration ratio" formulas were established respectively on droplet digital PCR (ddPCR) and chip digital PCR (cdPCR) to determine the mass ratio of kidney bean in adulterated lotus seed paste. It was the first time to quantify adulterate food by directly converting DNA copy concentration ratio obtained from digital PCR to mass ratio, which could provide strong technical support for quantitative detection of adulterated food.


Assuntos
Contaminação de Alimentos/análise , Lotus/embriologia , Phaseolus , Reação em Cadeia da Polimerase/métodos , Sementes , Variações do Número de Cópias de DNA , DNA de Plantas/análise , Genes de Plantas , Limite de Detecção , Lotus/genética , Phaseolus/genética , Reprodutibilidade dos Testes
12.
Ecotoxicol Environ Saf ; 190: 110178, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31927193

RESUMO

Given the limitation of crop production in Cd-polluted areas, the identification and selection of plant genotypes tolerant to Cd stress are of great significance. In the present work, we show the existence of genotypic variation for Cd tolerance in common bean. The laboratory screening of 25 bean genotypes indicated a significant positive correlation of the mean productivity (MP) and the geometric mean productivity (GMP) with plant fresh weight both in control and Cd-treated plants. A principal component analysis further confirmed this variation and, together with other analyses, led to the selection of genotypes G-11867, Taylor, Emerson, and D-81083 as tolerant genotypes. A total of six bean genotypes with different degrees of Cd tolerance were selected, and their long-term physiological responses to Cd (0, 45, and 90 mg/kg soil) were evaluated. Increasing Cd concentrations led to higher Cd accumulation both in roots and shoots, and to significant rises in the levels of the oxidative stress biomarkers malondialdehyde (MDA), dityrosine (D-T), and 8-hydroxy-2'-deoxyguanosine (8-OH-2'-dG). Remarkable reductions in plant hormone levels and chlorophyll contents, as well as in dry and fresh weight, were observed in Cd-treated plants. Among the examined genotypes, Emerson, Taylor, and G-11867 were found to be more tolerant to Cd owing to lower Cd accumulation and lower oxidative stress levels, as well as higher chlorophyll and hormone contents. Our results contribute to the understanding of the physiological and biochemical basis of Cd tolerance in bean plants and may therefore, be useful for breeding programs directed towards obtaining bean varieties showing low Cd accumulation.


Assuntos
Aclimatação/genética , Cádmio/toxicidade , Phaseolus/efeitos dos fármacos , Poluentes do Solo/toxicidade , 8-Hidroxi-2'-Desoxiguanosina/metabolismo , Clorofila/metabolismo , Genótipo , Malondialdeído/metabolismo , Phaseolus/genética , Phaseolus/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/genética , Brotos de Planta/metabolismo , Estresse Fisiológico/genética , Tirosina/análogos & derivados , Tirosina/metabolismo
13.
Plant Mol Biol ; 102(4-5): 431-445, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31907707

RESUMO

KEY MESSAGE: Iron deficiency conditions as well as iron supplied as a Fe(III)-mimosine complex induced a number of strategy I and strategy II genes for iron uptake in leucaena. Leucaena leucocephala (leucaena) is a tree-legume that can grow in alkaline soils, where metal-cofactors like Fe(III) are sparingly available. Mimosine, a known chelator of Fe(III), may facilitate Fe(III) uptake in leucaena by serving as a phytosiderophore. To test if mimosine can serve as a phytosiderophore, three sets of experiments were carried out. First, the binding properties and solubility of metal-mimosine complexes were assessed through spectrophotometry. Second, to study mimosine uptake in plants, pole bean, common bean, and tomato plants were supplied with mimosine alone and metal-mimosine complexes. Third, the expression of strategy I (S1) and strategy II (S2) genes for iron uptake from the soil was studied in leucaena plants exposed to different Fe(III) complexes. The results of this study show that (i) mimosine has high binding affinity for metallic cations at alkaline pH, Fe(III)-mimosine complexes are water soluble at alkaline pH, and that mimosine can bind soil iron under alkaline pH; (ii) pole bean, common bean, and tomato plants can uptake mimosine and transport it throughout the plant; and (iii) a number of S1 and S2 genes were upregulated in leucaena under iron-deficiency condition or when Fe(III) was supplied as a Fe(III)-mimosine complex. These findings suggest that leucaena may utilize both S1 and S2 strategies for iron uptake; and mimosine may play an important role in both strategies.


Assuntos
Fabaceae/efeitos dos fármacos , Fabaceae/metabolismo , Mimosina/farmacocinética , Transporte Biológico , Tampões (Química) , Cátions , Compostos Férricos/metabolismo , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Ferro/metabolismo , Metais/metabolismo , Nitrogênio , Phaseolus/efeitos dos fármacos , Phaseolus/metabolismo , Folhas de Planta/metabolismo , Caules de Planta/metabolismo , Ligação Proteica , Sideróforos/metabolismo , Solo , Solanum/efeitos dos fármacos , Solanum/metabolismo , Solubilidade
14.
Food Chem ; 310: 125699, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31810727

RESUMO

The capacity of high-fiber foods to sequester BS during digestion is considered a mechanism to lower serum-cholesterol. We investigated the effect of hydrothermal (HT) and high-hydrostatic-pressure (HHP) on the bile salt (BS)-binding ability of dry beans, and how this relates to changes in bean microstructure, fiber content (insoluble-IDF/soluble-SDF), and viscosity. HT and HHP-600 MPa led to significant IDF reduction, including resistant starch (RS), whereas 150-450 MPa significantly increased RS, without modifying IDF/SDF content. Microscopy analysis showed that heating disrupted the bean cell wall integrity, protein matrix and starch granules more severely than 600 MPa; however, tightly-packed complexes of globular starch granules-protein-cell wall fiber formed at HHP ≤ 450 MPa. While HT significantly reduced BS-binding efficiency despite no viscosity change, HHP-treatments maintained or enhanced BS-retention. 600 MPa-treatment induced the maximum BS-binding ability and viscosity. These results demonstrate that BS-binding by beans is not solely based on their fiber content or viscosity, but is influenced by additional microstructural factors.


Assuntos
Ácidos e Sais Biliares/metabolismo , Fibras na Dieta , Manipulação de Alimentos/métodos , Phaseolus/química , Phaseolus/ultraestrutura , Parede Celular/química , Parede Celular/ultraestrutura , Fibras na Dieta/análise , Pressão Hidrostática , Phaseolus/metabolismo , Proteínas de Vegetais Comestíveis/química , Solubilidade , Amido/química , Viscosidade
15.
Biosci Biotechnol Biochem ; 84(3): 598-605, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31724491

RESUMO

Red kidney beans (Phaseolus vulgaris L.) contain bioactive compounds that are known to exhibit antidiabetic effects via inhibition of α-glucosidase. However, information on the nonpolar components that exhibit antidiabetic activity is limited. Here, we report the isolation and structure determination of components with α-glucosidase inhibitory activity, which were obtained from the hexane extract of red kidney beans. Triacylglycerols (TAGs) were identified as the major components exhibiting inhibitory activity against α-glucosidase. The chemical structure of TAGs was determined by a combination of GC-MS and UPLC-MS/MS. The primary TAGs identified were LnLnLn (trilinolenin) and LnLLn (1,3-dilinolenoyl-2-linoleoyl glycerol). The major fatty acids present in these TAGs were α-linolenic acid (ω-3) and linoleic acid (ω-6). These TAGs were also found to inhibit the α-glucosidase activity in a similar fashion as acarbose. These results suggest that TAGs have potency as antidiabetics and support the potential suitability of red kidney beans for diabetes treatment.


Assuntos
Inibidores de Glicosídeo Hidrolases/isolamento & purificação , Hexanos/química , Phaseolus/química , Triglicerídeos/isolamento & purificação , Cromatografia Líquida/métodos , Diabetes Mellitus/tratamento farmacológico , Ácidos Graxos/análise , Cromatografia Gasosa-Espectrometria de Massas , Inibidores de Glicosídeo Hidrolases/química , Inibidores de Glicosídeo Hidrolases/farmacologia , Inibidores de Glicosídeo Hidrolases/uso terapêutico , Estrutura Molecular , Espectrometria de Massas em Tandem , Triglicerídeos/química
16.
Lett Appl Microbiol ; 70(3): 181-188, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31784998

RESUMO

(R)-m-Nitrophenyl-1,2-ethanediol (m-NPED) is a versatile and highly value-added chiral building block for the synthesis of some bioactive compounds, such as (R)-Nifenalol. To efficiently produce (R)-m-NPED through the enantioconvergent hydrolysis of racemic (rac-) m-nitrostyrene oxide (m-NSO) using the whole resting cells of Escherichia coli/pCold-pveh2 intracellularly expressing PvEH2, an epoxide hydrolase from Phaseolus vulgaris, two reaction systems were investigated. In the Na2 HPO4 -NaH2 PO4 buffer (50 mmol l-1 , pH 7·0) system, merely 15 mmol l-1 rac-m-NSO was successfully subjected to enantioconvergent hydrolysis, producing (R)-m-NPED with 86·0% enantiomeric excess (eep ) and 177·6 mg l-1  h-1 space-time yield (STY). The experimental result indicated that there is inhibitory effect of rac-m-NSO at high concentration on PvEH2. To efficiently increase the concentration of rac-m-NSO and the STY of (R)-m-NPED, petroleum ether was first selected to construct an organic/aqueous two-phase system. Then, both the volume ratio (vo /vb ) of petroleum ether to phosphate buffer and the weight ratio (wc /ws ) of E. coli/pCold-pveh2 dry cells to rac-m-NSO were optimized as 2 : 8 and 5 : 1, respectively. In the optimized petroleum ether/phosphate buffer two-phase system, the enantioconvergent hydrolysis of rac-m-NSO at 40 mmol l-1 (6·6 mg ml-1 ) was carried out at 25°C for 12 h using 33·0 mg ml-1 vacuum freeze-dried cells of E. coli/pCold-pveh2, producing (R)-m-NPED with 87·4% eep , 82·3% yield and 502·4 mg l-1  h-1 STY. SIGNIFICANCE AND IMPACT OF THE STUDY: Epoxide hydrolases play a crucial role in producing enantiopure epoxides and/or vicinal diols. However, numerous biocatalytic reactions of organic compounds, such as epoxides, in aqueous phase suffered various restrictions. Herein, the enantioconvergent hydrolysis of rac-m-NSO in two reaction systems was investigated using the whole cells of Escherichia coli/pCold-pveh2. As a result, the concentration of rac-m-NSO and the space-time yield of (R)-m-NPED in organic/aqueous two-phase system were significantly increased, when compared with those in aqueous phase. To our knowledge, this is the first report about the production of (R)-m-NPED from rac-m-NSO at an elevated concentration by PvEH2 in the two-phase system.


Assuntos
Alcanos/química , Epóxido Hidrolases/metabolismo , Escherichia coli/metabolismo , Nitrocompostos/síntese química , Phaseolus/metabolismo , Biocatálise , Compostos de Epóxi , Hidrólise/efeitos dos fármacos , Phaseolus/enzimologia , Estereoisomerismo
17.
Arch Virol ; 165(1): 257-260, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31773325

RESUMO

A new geminivirus was identified in common bean (Phaseolus vulgaris) showing severe stunt and leaf curling symptoms in Heilongjiang province of China, via sequencing and assembly of small RNAs. The genome of this geminivirus comprises 2,959 nucleotides (nt) and shares 21.77-54.97% nt sequence identity with other geminiviruses. The coat protein (CP) shares the highest amino acid (aa) sequence identity (23.5%) with that of sesame curly top virus (SeYMV; genus Turncurtovirus), whereas the C1 (Rep) shares the highest aa sequence identity (66.5%) with that of beet severe curly top virus (BSCTV; genus Curtovirus). This geminivirus neighbors the turncurtoviruses in phylogenetic trees based on the full genome sequence or the amino acid sequence of the Rep protein, but it forms a distinct clade in the phylogenetic tree based on the coat protein. Recombination analysis showed that parts of the C1 coding region of this geminivirus were recombined from a curtovirus or turncurtovirus. Based on these results, the name "common bean curly stunt virus" (CBCSV) is proposed for this virus.


Assuntos
Geminiviridae/genética , Phaseolus/virologia , Vírus Reordenados/genética , Sequência de Aminoácidos , Proteínas do Capsídeo/genética , China , Evolução Molecular , Geminiviridae/classificação , Tamanho do Genoma , Filogenia , Folhas de Planta/virologia , Vírus Reordenados/classificação , Sequenciamento Completo do Genoma
18.
Plant Dis ; 104(1): 198-203, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31738688

RESUMO

A single loop-mediated isothermal amplification (LAMP) assay was developed for specific detection of both pathogens that cause bacterial blight in common bean, Xanthomonas phaseoli pv. phaseoli (Xpp) and Xanthomonas citri pv. fuscans (Xcf). The objective was to provide a simple, easy-to-use, specific, and sensitive method to investigate the presence of one or both pathogens in plant material and seeds for routine diagnosis. The detection limits for both pathogens were 10 CFU/ml for cell suspensions and 1 fg of DNA, whereas in conventional PCR, the primers detected up to 105 CFU/ml and 1 ng of DNA. Specificity was confirmed by testing DNA from bean leaves, other Xanthomonas species, common fungal and bacterial bean pathogens, and bacteria from the leaf microbiota. The method was tested with bean leaves inoculated with Xpp, and the pathogen could be detected from 4 h up to 15 days postinoculation, even before disease symptoms were visible. When the method was applied to bacterium detection (Xpp or Xcf) in seed lots from infected plants, the bacterium detection rate was 100% (24 of 24). The pathogens were detected in seeds incubated for just 1 h in saline solution (0.85%), reducing the time needed for bacterium detection. The LAMP assay could be useful as a tool in bean bacterial blight management. Rapid and sensitive detection of bacteria in bean seed lots would reduce the risks of planting highly contaminated seeds in environments favorable to blight multiplication.


Assuntos
Agricultura , Técnicas de Amplificação de Ácido Nucleico , Phaseolus , Xanthomonas , Agricultura/métodos , Limite de Detecção , Phaseolus/microbiologia , Doenças das Plantas/microbiologia , Sementes/microbiologia , Xanthomonas/fisiologia
19.
Can J Microbiol ; 66(3): 186-193, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31751146

RESUMO

Lipopolysaccharide (LPS) is essential for successful nodulation during the symbiosis of rhizobia and legumes. However, the detailed mechanism of the LPS in this process has not yet been clearly elucidated. In this study, the effects of common bean seed exudates on the growth, lipopolysaccharide production, and lipopolysaccharide transport genes expression (lpt) of Rhizobium anhuiense were investigated. Rhizobium anhuiense exposed to exudates showed changes in LPS electrophoretic profiles and content, whereby the LPS band was wider and the LPS content was higher in R. anhuiense treated with seed exudates. Exudates enhanced cell growth of R. anhuiense in a concentration-dependent manner; R. anhuiense exposed to higher doses of the exudate showed faster growth. Seven lpt genes of R. anhuiense were amplified and sequenced. Sequences of six lpt genes, except for lptE, were the same as those found in previously analyzed R. anhuiense strains, while lptE shared low sequence similarity with other strains. Exposure to the exudates strongly stimulated the expression of all lpt genes. Approximately 6.7- (lptG) to 301-fold (lptE) increases in the transcriptional levels were observed after only 15 min of exposure to exudates. These results indicate that seed exudates affect the LPS by making the cell wall structure more conducive to symbiotic nodulation.


Assuntos
Proteínas de Bactérias/genética , Lipopolissacarídeos/metabolismo , Phaseolus/química , Exsudatos de Plantas/farmacologia , Rhizobium/efeitos dos fármacos , Rhizobium/metabolismo , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Phaseolus/metabolismo , Phaseolus/microbiologia , Exsudatos de Plantas/metabolismo , Rhizobium/genética , Rhizobium/crescimento & desenvolvimento , Sementes/química , Sementes/metabolismo , Sementes/microbiologia , Simbiose
20.
J Agric Food Chem ; 68(1): 67-76, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31710472

RESUMO

Nanoparticles (NPs) are known to significantly alter plant metabolism in a dose-dependent manner, with effects ranging from stimulation to toxicity. The metabolic adjustment and ionomic balance of bean (Phaseolus vulgaris L.) roots and leaves gained from plants grown in a solid medium added with relatively low dosages (0, 25, 50, and 100 mg/L) of CeO2 NPs were investigated. Ce accumulated in the roots (up to 287.91 mg/kg dry weight) and translocated to the aerial parts (up to 2.78% at the highest CeO2 dosage), and ionomic analysis showed that CeO2 NPs interfered with potassium, molybdenum, and zinc. Unsupervised hierarchical clustering analysis from metabolomic profiles suggested a dose-dependent and tissue-specific metabolic reprogramming induced by NPs. The majority of differential metabolites belonged to flavonoids and other phenolics, nitrogen-containing low molecules (such as alkaloids and glucosinolates), lipids, and amino acids.


Assuntos
Cério/farmacologia , Phaseolus/efeitos dos fármacos , Metabolismo Secundário/efeitos dos fármacos , Aminoácidos/análise , Aminoácidos/metabolismo , Cério/análise , Flavonoides/análise , Flavonoides/metabolismo , Nanopartículas/análise , Phaseolus/química , Phaseolus/metabolismo , Fenóis/análise , Fenóis/metabolismo , Folhas de Planta/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/química , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo
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