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1.
Plant Sci ; 312: 111036, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34620440

RESUMO

Like in mammals, the plant immune system has evolved to perceive damage. Damaged-associated molecular patterns (DAMPs) are endogenous signals generated in wounded or infected tissue after pathogen or insect attack. Although extracellular DNA (eDNA) is a DAMP signal that induces immune responses, plant responses after eDNA perception remain largely unknown. Here, we report that signaling defenses but not direct defense responses are induced after eDNA applications enhancing broad-range plant protection. A screening of defense signaling and hormone biosynthesis marker genes revealed that OXI1, CML37 and MPK3 are relevant eDNA-Induced Resistance markers (eDNA-IR). Additionally, we observed that eDNA from several Arabidopsis ecotypes and other phylogenetically distant plants such as citrus, bean and, more surprisingly, a monocotyledonous plant such as maize upregulates eDNA-IR marker genes. Using 3,3'-Diaminobenzidine (DAB) and aniline blue staining methods, we observed that H2O2 but not callose was strongly accumulated following self-eDNA treatments. Finally, eDNA resulted in effective induced resistance in Arabidopsis against the pathogens Hyaloperonospora arabidopsidis, Pseudomonas syringae, and Botrytis cinerea and against aphid infestation, reducing the number of nymphs and moving forms. Hence, the unspecificity of DNA origin and the wide range of insects to which eDNA can protect opens many questions about the mechanisms behind eDNA-IR.


Assuntos
Arabidopsis/genética , DNA/farmacologia , Resistência à Doença/genética , Resistência à Doença/imunologia , Imunidade Vegetal/genética , Transdução de Sinais/genética , Zea mays/genética , Arabidopsis/imunologia , Arabidopsis/microbiologia , Brassica/genética , Brassica/imunologia , Brassica/microbiologia , Citrus/genética , Citrus/imunologia , Citrus/microbiologia , Produtos Agrícolas/genética , Produtos Agrícolas/imunologia , Produtos Agrícolas/microbiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Phaseolus/genética , Phaseolus/imunologia , Phaseolus/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Solanum/genética , Solanum/imunologia , Solanum/microbiologia , Spinacia oleracea/genética , Spinacia oleracea/imunologia , Spinacia oleracea/microbiologia , Zea mays/imunologia , Zea mays/microbiologia
2.
Int J Mol Sci ; 22(18)2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34576026

RESUMO

Quorum sensing (QS) is a microbial cell-cell communication mechanism and plays an important role in bacterial infections. QS-mediated bacterial infections can be blocked through quorum quenching (QQ), which hampers signal accumulation, recognition, and communication. The pathogenicity of numerous bacteria, including Xanthomonas campestris pv. campestris (Xcc), is regulated by diffusible signal factor (DSF), a well-known fatty acid signaling molecule of QS. Cupriavidus pinatubonensis HN-2 could substantially attenuate the infection of XCC through QQ by degrading DSF. The QQ mechanism in strain HN-2, on the other hand, is yet to be known. To understand the molecular mechanism of QQ in strain HN-2, we used whole-genome sequencing and comparative genomics studies. We discovered that the fadT gene encodes acyl-CoA dehydrogenase as a novel QQ enzyme. The results of site-directed mutagenesis demonstrated the requirement of fadT gene for DSF degradation in strain HN-2. Purified FadT exhibited high enzymatic activity and outstanding stability over a broad pH and temperature range with maximal activity at pH 7.0 and 35 °C. No cofactors were required for FadT enzyme activity. The enzyme showed a strong ability to degrade DSF. Furthermore, the expression of fadT in Xcc results in a significant reduction in the pathogenicity in host plants, such as Chinese cabbage, radish, and pakchoi. Taken together, our results identified a novel DSF-degrading enzyme, FadT, in C. pinatubonensis HN-2, which suggests its potential use in the biological control of DSF-mediated pathogens.


Assuntos
Acil-CoA Desidrogenase/genética , Infecções Bacterianas/genética , Ácidos Graxos/genética , Doenças das Plantas/genética , Xanthomonas campestris/genética , Acil-CoA Desidrogenase/química , Acil-CoA Desidrogenase/isolamento & purificação , Infecções Bacterianas/microbiologia , Brassica/crescimento & desenvolvimento , Brassica/microbiologia , Comunicação Celular/genética , Ácidos Graxos/metabolismo , Regulação Enzimológica da Expressão Gênica , Genoma Bacteriano/genética , Genômica , Mutagênese Sítio-Dirigida , Doenças das Plantas/microbiologia , Percepção de Quorum/genética , Raphanus/genética , Raphanus/microbiologia , Transdução de Sinais/genética , Fatores de Virulência/genética , Sequenciamento Completo do Genoma , Xanthomonas campestris/enzimologia
3.
Molecules ; 26(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34361746

RESUMO

New agricultural strategies aim to reduce the use of pesticides due to their damage to the environment and humans, and the caused resistance to pathogens. Therefore, alternative sources of antifungal compounds from plants are under investigation lately. Extracts from plants have a wide composition of chemical compounds which may complicate the development of pathogen resistance. Botrytis cinerea, causing grey mould, is an important horticultural and ornamental pathogen, responsible for the relevant yield and quality losses. B. cinerea isolated from a different plant host may differ in the sensitivity to antifungal substances from plants. Assessing the importance of research covering a wide range of pathogens for the rapid development of biopesticides, this study aims to determine the sensitivity of the B. cinerea isolate complex (10 strains) to plant extracts, describe morphological changes caused by the extract treatment, and detect differences between the sensitivity of different plant host isolates. The results showed the highest sensitivity of the B. cinerea isolates complex to cinnamon extract, and the lowest to laurel extract. In contrast, laurel extract caused the most changes of morphological attributes in the isolates. Five B. cinerea isolates from plant hosts of raspberry, cabbage, apple, bell pepper, and rose were grouped statistically according to their sensitivity to laurel extract. Meanwhile, the bell pepper isolate separated from the isolate complex based on its sensitivity to clove extract, and the strawberry and apple isolates based on their sensitivity to cinnamon extract.


Assuntos
Antifúngicos/farmacologia , Agentes de Controle Biológico/farmacologia , Botrytis/efeitos dos fármacos , Cinnamomum zeylanicum/química , Hifas/efeitos dos fármacos , Doenças das Plantas/prevenção & controle , Antifúngicos/isolamento & purificação , Agentes de Controle Biológico/isolamento & purificação , Botrytis/crescimento & desenvolvimento , Botrytis/isolamento & purificação , Brassica/microbiologia , Capsicum/microbiologia , Cinnamomum camphora/química , Fragaria/microbiologia , Humanos , Hifas/crescimento & desenvolvimento , Hifas/isolamento & purificação , Malus/microbiologia , Testes de Sensibilidade Microbiana , Doenças das Plantas/microbiologia , Extratos Vegetais/química , Syzygium/química , Vitis/microbiologia
4.
Food Microbiol ; 100: 103868, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34416967

RESUMO

Kimchi is one of the primary sources of high sodium content in the Korean diet. Low-sodium kimchi is commercially manufactured to minimize the health effects of high salt. We investigated the influence of lactic acid bacteria (LAB) as starter culture in combination with 1% or 2.5% salt on the survival of pathogenic Escherichia coli and physicochemical properties of kimchi during fermentation at 10 °C and 25 °C. Among ten strains of LAB isolated from kimchi, Leuconostoc mesenteroides (KCTC 13374) and Lactobacillus plantarum (KCTC 33133) exhibited antimicrobial activities against pathogenic E. coli (EPEC, ETEC, and E. coli O157:H7) and strong tolerance to low pH (2 and 3) and 0.3% bile salts. Thus, L. mesenteroides and L. plantarum were used as starter cultures for kimchi that contained 1% and 2.5% salt. All pathogenic E. coli strains survived in kimchi regardless of starter cultures or salt concentration for over 15 days at 10 °C, but they died off within 4 days at 25 °C. Survival of pathogenic E. coli was better in naturally fermented kimchi (titratable acidity:0.65%) than kimchi fermented with starter cultures (titratable acidity:1.0%). At 10 °C, the average delta value of E. coli O157:H7 (16.15 d) was smaller than those of EPEC (20.76 d) and ETEC (20.20 d) in naturally fermented kimchi. Overall, survival ability of E. coli O157:H7 was lower than EPEC and ETEC, although differences were not significant. Reduced salt concentration from 2.5% to 1% in kimchi did not affect the growth of LAB and the fermentation period. Pathogenic E. coli died at a faster rate in kimchi fermented with starter cultures and 1% salt than in naturally fermented kimchi with 2.5% salt.


Assuntos
Brassica/microbiologia , Escherichia coli Enteropatogênica/crescimento & desenvolvimento , Escherichia coli Enterotoxigênica/crescimento & desenvolvimento , Escherichia coli O157/crescimento & desenvolvimento , Alimentos e Bebidas Fermentados/microbiologia , Lactobacillales/metabolismo , Cloreto de Sódio/metabolismo , Antibiose , Brassica/química , Contagem de Colônia Microbiana , Escherichia coli Enteropatogênica/fisiologia , Escherichia coli Enterotoxigênica/fisiologia , Escherichia coli O157/fisiologia , Alimentos e Bebidas Fermentados/análise , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Cloreto de Sódio/análise
5.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34073109

RESUMO

Colletotrichum higginsianum is an important hemibiotrophic plant pathogen that causes crucifer anthracnose worldwide. To date, some hexose transporters have been identified in fungi. However, the functions of hexose transporters in virulence are not clear in hemibiotrophic phytopathogens. In this study, we identified and characterized a new hexose transporter gene named ChHxt6 from a T-DNA insertion pathogenicity-deficient mutant G256 in C. higginsianum. Expression profiling analysis revealed that six ChHxt genes, ChHxt1 to ChHxt6, exhibited specific expression patterns in different infection phases of C. higginsianum. The ChHxt1 to ChHxt6 were separately deleted using the principle of homologous recombination. ChHxt1 to ChHxt6 deletion mutants grew normally on PDA plates, but only the virulence of ChHxt4 and ChHxt6 deletion mutants was reduced. ChHxt4 was required for fungal infection in both biotrophic and necrotrophic stages, while ChHxt6 was important for formation of necrotrophic hyphae during infection. In addition, ChHxts were functional in uptake of different hexoses, but only ChHxt6-expressing cells could grow on all five hexoses, indicating that the ChHxt6 was a central hexose transporter and crucial for hexose uptake. Site-directed mutation of T169S and P221L positions revealed that these two positions were necessary for hexose transport, whereas only the mutation Thr169 caused reduced virulence and defect in formation of necrotrophic hyphae. Taken together, ChHxt6 might regulate fungal virulence by modulating the utilization of hexose.


Assuntos
Proteínas Fúngicas/fisiologia , Proteínas de Transporte de Monossacarídeos/metabolismo , Doenças das Plantas/microbiologia , Fatores de Virulência/metabolismo , Arabidopsis/microbiologia , Brassica/microbiologia , Colletotrichum/genética , Colletotrichum/metabolismo , Colletotrichum/patogenicidade , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Hexoses/metabolismo , Virulência
6.
Food Microbiol ; 99: 103805, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34119098

RESUMO

This study was done to develop a method to inactivate Escherichia coli O157:H7 on radish and cabbage seeds using simultaneous treatments with gaseous chlorine dioxide (ClO2) and heat at high relative humidity (RH) without decreasing seeds' viability. Gaseous ClO2 was spontaneously vaporized from a solution containing hydrochloric acid (HCl, 1 N) and sodium chlorite (NaClO2, 100,000 ppm). Using a sealed container (1.8 L), an equation (y = 5687×, R2 = 0.9948) based on the amount of gaseous ClO2 generated from HCl-NaClO2 solution at 60 °C and 85% RH was developed. When radish or cabbage seeds were exposed to gaseous ClO2 at concentrations up to 3,000 ppm for 120 min, germination rates did not significantly decrease (P > 0.05). When seeds inoculated with E. coli O157:H7 were treated with 2,000 or 3,000 ppm of gaseous ClO2 in an atmosphere with 85% RH at 60 °C, populations (6.8-6.9 log CFU/g) on both types of seeds were decreased to below the detection limit for enrichment (-0.5 log CFU/g) within 90 min. This study provides useful information for developing a decontamination method to control E. coli O157:H7 and perhaps other foodborne pathogens on plant seeds by simultaneous treatment with gaseous ClO2 and heat at high RH.


Assuntos
Brassica/crescimento & desenvolvimento , Compostos Clorados/farmacologia , Descontaminação/métodos , Desinfetantes/farmacologia , Escherichia coli O157/efeitos dos fármacos , Óxidos/farmacologia , Raphanus/crescimento & desenvolvimento , Sementes/microbiologia , Brassica/microbiologia , Cloro/farmacologia , Escherichia coli O157/crescimento & desenvolvimento , Germinação/efeitos dos fármacos , Temperatura Alta , Umidade , Viabilidade Microbiana/efeitos dos fármacos , Raphanus/microbiologia , Sementes/química , Sementes/crescimento & desenvolvimento
7.
J Exp Bot ; 72(18): 6524-6543, 2021 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-33993246

RESUMO

Quorum sensing (QS) helps the Xanthomonas group of phytopathogens to infect several crop plants. The vascular phytopathogen Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot disease on Brassicaceae leaves, where a typical v-shaped lesion spans both vascular and mesophyll regions with progressive leaf chlorosis. Recently, the role of QS has been elucidated during Xcc early infection stages. However, a detailed insight into the possible role of QS-regulated bacterial invasion in host chlorophagy during late infection stages remains elusive. In this study, using QS-responsive whole-cell bioreporters of Xcc, we present a detailed chronology of QS-facilitated Xcc colonization in the mesophyll region of cabbage (Brassica oleracea) leaves. We report that QS-enabled localization of Xcc to parenchymal chloroplasts triggers leaf chlorosis and promotion of systemic infection. Our results indicate that the QS response in the Xanthomonas group of vascular phytopathogens maximizes their population fitness across host tissues to trigger stage-specific host chlorophagy and establish a systemic infection.


Assuntos
Brassica , Doenças das Plantas/microbiologia , Percepção de Quorum , Xanthomonas campestris , Brassica/microbiologia , Folhas de Planta/microbiologia , Xanthomonas campestris/patogenicidade
8.
J Biosci Bioeng ; 132(1): 33-40, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33865692

RESUMO

Salt profoundly affects the physicochemical properties and microbial abundance of fermented foods such as suan cai, a popular traditional fermented food in China. It is vital to systematically investigate the effects of salt concentrations on fermented suan cai for high fermentation quality and large-scale production. We elucidated the effects of salt concentrations on Lactobacillus curvatus (LC-20) and suan cai during fermentation, and found that salt (0-1%) favoured an increase in LC-20 growth and a decrease in pH (salt: 0-2%). For suan cai fermentation, the results from sensory scoring judged 1% salt treatment the highest. Salt concentration also affected the nitrite content of the fermentation system with peak nitrite values in low salt treatments being significantly higher on the first day, and gradually decreasing to similar levels. After fermentation, the total titratable acid and lactic acid concentrations in the 0-1% treatments were higher (p < 0.05) than those in 2-5% treatments. The colony forming units of lactic acid bacteria increased initially and then decreased after 6 d of fermentation. At the phylum level, Firmicutes and Proteobacteria were predominant in all treatments, and at the genus level, Lactobacillus dominated the fermentation. Other lactic acid bacteria such as Lactococcus and Weissella were also detected. Quantitative PCR showed DNA concentration of LC-20 at 0.5-2% salt treatments were higher than that in other treatments and L. curvatus was the dominant microorganism during fermentation. Hence, we conclude that L. curvatus could be used for suan cai product at low salt concentrations.


Assuntos
Brassica/química , Brassica/microbiologia , Fermentação/efeitos dos fármacos , Alimentos e Bebidas Fermentados/microbiologia , Lactobacillus/efeitos dos fármacos , Lactobacillus/metabolismo , Cloreto de Sódio/farmacologia , Relação Dose-Resposta a Droga , Microbiologia de Alimentos
9.
J Biosci Bioeng ; 132(1): 25-32, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33867273

RESUMO

Most commercially circulating mushrooms are produced via cultivation using artificially produced mushroom substrates. However, after mushroom harvesting, the disposal of spent mushroom substrates (SMSs) is a serious problem for the mushroom industry owing to the need for a disposal site and the cost involved. Thus, in view of the possibility of recycling SMSs as a soil modifier, we examined the effect of soil mixed with SMSs on the infection of Arabidopsis leaves by Alternaria brassicicola, the causal agent of cabbage leaf spot. The mixing of SMSs used for Hypsizygus marmoreus, Pholiota microspora, Lyophyllum decastes, and Auricularia polytricha into culture soil suppressed the lesion formation caused by A. brassicicola. The defense responses of Arabidopsis were not induced by the culturing of these seedlings in soils containing SMSs. Suppressed lesion formation was observed after the seedlings were treated with volatiles emitted from SMSs that were incubated with soil for 7 days and used for H. marmoreus, P. microspora, L. decastes, A. polytricha, Lentinula edodes, and Cyclocybe cylindracea. The volatiles from the SMSs reduced the elongation of A. brassicicola hyphae. GC-MS analyses of extracts from the SMS containing soils led to the detection of various volatile compounds; among these, skatole, 2,4-di-tert-butylphenol, γ-dodecalactone, butyric acid, guaiacol, 6-amyl-2-pyrone, and 1-octen-3-ol were examined for inhibitory activity on A. brassicicola and found to suppress hyphae elongation. These findings indicate that the antifungal volatile compounds emitted by the SMSs suppress A. brassicicola infection.


Assuntos
Agaricales/química , Alternaria/fisiologia , Compostos Orgânicos Voláteis/farmacologia , Alternaria/efeitos dos fármacos , Arabidopsis/microbiologia , Brassica/microbiologia , Doenças das Plantas/microbiologia , Solo , Resíduos/análise
10.
Int J Mol Sci ; 22(8)2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33924035

RESUMO

The nucleotide-binding site-leucine-rich repeat (NBS-LRR) gene family is the largest group of plant disease resistance (R) genes widespread in response to viruses, bacteria, and fungi usually involved in effector triggered immunity (ETI). Forty members of the Chinese cabbage CC type NBS-LRR family were investigated in this study. Gene and protein characteristics, such as distributed locations on chromosomes and gene structures, were explored through comprehensive analysis. CC-NBS-LRR proteins were classified according to their conserved domains, and the phylogenetic relationships of CC-NBS-LRR proteins in Brassica rapa, Arabidopsis thaliana, and Oryza sativa were compared. Moreover, the roles of BrCC-NBS-LRR genes involved in pathogenesis-related defense were studied and analyzed. First, the expression profiles of BrCC-NBS-LRR genes were detected by inoculating with downy mildew and black rot pathogens. Second, sensitive and resistant Chinese cabbage inbred lines were screened by downy mildew and black rot. Finally, the differential expression levels of BrCC-NBS-LRR genes were monitored at 0, 1, 3, 6, 12 and 24 h for short and 0, 3, 5, 7, 10 and 14 days for long inoculation time. Our study provides information on BrCC-NBS-LRR genes for the investigation of the functions and mechanisms of CC-NBS-LRR genes in Chinese cabbage.


Assuntos
Brassica/metabolismo , Brassica/microbiologia , Doenças das Plantas/microbiologia , Arabidopsis/microbiologia , Resistência à Doença , Regulação da Expressão Gênica de Plantas , Oryza/microbiologia , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
11.
Food Microbiol ; 98: 103573, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33875193

RESUMO

Chinese Sichuan Paocai (CSP) is one of the world's best-known fermented vegetables with a large presence in the Chinese market. The dynamic microbial community is the main contributor to Paocai fermentation. However, little is known about the ecological distribution and functional importance of these community members. In this study, metatranscriptomics was used to comprehensively explore the active microbial community members and key transcripts with significant functions in the Paocai fermentation process. Enterobacter, Leuconostoc, and Lactobacillus dominated the three-fermentation stages (Pre-, Mid- and Lat-), respectively. Carbon metabolism was the most abundant pathway. GH (glycoside hydrolase) and GT (lycosyl transferase) were the two most highly expressed carbohydrate-active enzymes. The most highly differentially expressed genes were grouped in the biosynthesis of amino acids, followed by glycolysis. Meta-pathways in the Sichuan Paocai fermentation ecosystem were reconstructed, Lactobacillaceae and Enterobacteriaceae were the two most important metabolic contributors. In addition, the nrfA and nirB were two genes referred to distinct nitrite reductase enzymes and 9 specialized genes, such as eclo, ron and ent were expressed to produce autoinducer 2 (AI-2) kinase in response to population density. The present study revealed functional enzymes and meta-pathways of the active microbial communities, which provide a deeper understanding of their contribution to CSP products.


Assuntos
Brassica/microbiologia , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/metabolismo , Alimentos e Bebidas Fermentados/microbiologia , Lactobacillaceae/isolamento & purificação , Microbiota , Verduras/microbiologia , Brassica/metabolismo , China , Enterobacteriaceae/classificação , Enterobacteriaceae/genética , Fermentação , Microbiologia de Alimentos , Lactobacillaceae/classificação , Lactobacillaceae/genética , Lactobacillaceae/metabolismo , Metagenômica , Transcriptoma , Verduras/metabolismo
12.
Mol Plant Pathol ; 22(5): 618-624, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33650275

RESUMO

Transcription activator-like effectors (TALEs), which induce the expression of specific plant genes to promote infection, are the main pathogenic determinants of various Xanthomonas bacteria. However, investigation of TALEs from Xanthomonas campestris pv. campestris, which causes black rot disease of crucifers, received little attention. In this study, we used PCR-based amplification followed by SMRT amplicon sequencing to identify TALE genes in several X. campestris pv. campestris strains. Computational prediction in conjunction with quantitative reverse transcription PCR analysis was used to find their targets in the Brassica oleracea genome. Transcription factor ERF121, from the AP2/ERF family, was identified as target gene for the conserved TALEs from multiple X. campestris pv. campestris strains. Several members of this family from diverse plants were previously identified as targets of TALEs from different Xanthomonas species. We propose that TALE-dependent activation of AP2/ERF transcription factors promotes susceptibility to Xanthomonas through the misregulation of plant defence pathways.


Assuntos
Brassica/microbiologia , Doenças das Plantas/microbiologia , Efetores Semelhantes a Ativadores de Transcrição/metabolismo , Fatores de Transcrição/metabolismo , Xanthomonas campestris/genética , Brassica/imunologia , Doenças das Plantas/imunologia , Imunidade Vegetal , Efetores Semelhantes a Ativadores de Transcrição/genética , Fatores de Transcrição/genética , Xanthomonas campestris/fisiologia
13.
Planta ; 253(4): 80, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33742226

RESUMO

MAIN CONCLUSION: Chitinase family genes were involved in the response of Brassica oleracea to Fusarium wilt, powdery mildew, black spot and downy mildew. Abstract Chitinase, a category of pathogenesis-related proteins, is believed to play an important role in defending against external stress in plants. However, a comprehensive analysis of the chitin-binding gene family has not been reported to date in cabbage (Brassica oleracea L.), especially regarding the roles that chitinases play in response to various diseases. In this study, a total of 20 chitinase genes were identified using a genome-wide search method. Phylogenetic analysis was employed to classify these genes into two groups. The genes were distributed unevenly across six chromosomes in cabbage, and all of them contained few introns (≤ 2). The results of collinear analysis showed that the cabbage genome contained 1-5 copies of each chitinase gene (excluding Bol035470) identified in Arabidopsis. The heatmap of the chitinase gene family showed that these genes were expressed in various tissues and organs. Two genes (Bol023322 and Bol041024) were relatively highly expressed in all of the investigated tissues under normal conditions, exhibiting the expression characteristics of housekeeping genes. In addition, under four different stresses, namely, Fusarium wilt, powdery mildew, black spot and downy mildew, we detected 9, 5, 8 and 8 genes with different expression levels in different treatments, respectively. Our results may help to elucidate the roles played by chitinases in the responses of host plants to various diseases.


Assuntos
Brassica , Quitina/metabolismo , Genoma de Planta , Imunidade Vegetal , Proteínas de Plantas/genética , Brassica/genética , Brassica/microbiologia , Quitinases/genética , Regulação da Expressão Gênica de Plantas , Filogenia
14.
J Food Sci ; 86(3): 749-761, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33604898

RESUMO

The supercooling degree (SD), which refers to the difference between the ice nucleation temperature and freezing point of kimchi, varies depending on the type of kimchi, manufacturer, recipe, and manufacturing season. The aim of this study is to investigate the major influencing factors for the supercooled storage of kimchi and to analyze the possibility of supercooled storage for commercial kimchi. Pearson correlation analysis determined that, in commercial kimchi manufactured between March and July 2018, the SD of kimchi correlated to the number of aerobic bacteria (P < 0.01), however, was not associated with lactic acid bacteria. Moreover, the ice nucleation temperature of saline solution inoculated with aerobic bacteria was reduced from -3.03 ± 0.04 to -6.18 ± 0.11 °C by 10 kGy gamma ray sterilization. Meanwhile, the ice nucleation temperatures of 1.8 kg of commercial red cabbage kimchi and 500 g of white cabbage kimchi manufactured in February 2020 were -3.93 ± 0.06 °C and -3.57 ± 0.06 °C, respectively, and they could be stored at -2.5 °C for 12 weeks without freezing. Additionally, supercooled storage of kimchi at -2.5 °C caused a fermentation delay effect compared to control storage at 1 °C, considering the acidity and amount of lactic acid bacteria. Therefore, if the number of aerobic bacteria is controlled during the manufacturing process of kimchi, supercooled storage at temperatures below -2.5 °C may extend the shelf life of kimchi. PRACTICAL APPLICATION: We have shown that aerobic bacteria are the key influencing factor for ice nucleation of kimchi during supercooled storage. Aside from the initial sterilization process, fermentation of kimchi can also be delayed by lowering the storage temperature below -2.5 °C. Moreover, the method of direct cool refrigeration may have an industrial-level application.


Assuntos
Brassica , Temperatura Baixa , Fermentação , Alimentos e Bebidas Fermentados , Armazenamento de Alimentos/métodos , Bactérias Aeróbias , Brassica/microbiologia , Alimentos e Bebidas Fermentados/microbiologia , Microbiologia de Alimentos/métodos , Lactobacillales , Temperatura
15.
Sci Rep ; 11(1): 2781, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33531553

RESUMO

Several root-colonizing bacterial species can simultaneously promote plant growth and induce systemic resistance. How these rhizobacteria modulate plant metabolism to accommodate the carbon and energy demand from these two competing processes is largely unknown. Here, we show that strains of three Paraburkholderia species, P. graminis PHS1 (Pbg), P. hospita mHSR1 (Pbh), and P. terricola mHS1 (Pbt), upon colonization of the roots of two Broccoli cultivars led to cultivar-dependent increases in biomass, changes in primary and secondary metabolism and induced resistance against the bacterial leaf pathogen Xanthomonas campestris. Strains that promoted growth led to greater accumulation of soluble sugars in the shoot and particularly fructose levels showed an increase of up to 280-fold relative to the non-treated control plants. Similarly, a number of secondary metabolites constituting chemical and structural defense, including flavonoids, hydroxycinnamates, stilbenoids, coumarins and lignins, showed greater accumulation while other resource-competing metabolite pathways were depleted. High soluble sugar generation, efficient sugar utilization, and suppression or remobilization of resource-competing metabolites potentially contributed to curb the tradeoff between the carbon and energy demanding processes induced by Paraburkholderia-Broccoli interaction. Collectively, our results provide a comprehensive and integrated view of the temporal changes in plant metabolome associated with rhizobacteria-mediated plant growth promotion and induced resistance.


Assuntos
Brassica , Burkholderiaceae/metabolismo , Doenças das Plantas/prevenção & controle , Folhas de Planta/metabolismo , Raízes de Plantas , Brassica/metabolismo , Brassica/microbiologia , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Índice de Gravidade de Doença
16.
Planta ; 253(2): 25, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33404767

RESUMO

MAIN CONCLUSION: The presence of Bacillus cereus plays a key role in clubroot suppression and improves plant biomass in pak choi. B. cereus is reported for the first time as a novel biocontrol agent against clubroot. Plasmodiophora brassicae Woronin causes a devastating infectious disease known as clubroot that is damaging to cruciferous vegetables. This study aimed to isolate beneficial bacteria from the rhizosphere soil of pak choi (Brassica campestris sp. chinensis) and to evaluate the ability of the isolate to reduce the severity of clubroot. Strains obtained from the rhizosphere of symptomless pak choi were first selected on the basis of their germination inhibition rate and effects on the viability of P. brassicae resting spores. Eight bacterial isolates had inhibitory effects against the resting spores of clubroot causing pathogen. However, MZ-12 showed the highest inhibitory effect at 73.4%. Inoculation with MZ-12 enhanced the plant biomass relative to plants grown without MZ-12 as well as P. brassicae infected plants. Furthermore, enhanced antioxidant enzymatic activities were observed in clubroot-infected plants during bacterial association. Co-inoculation of the plant with both P. brassicae and MZ-12 resulted in a 64% reduction of gall formation in comparison to plants inoculated with P. brassicae only. Three applications of MZ-12 to plants infected with P. brassicae at 7, 14 and 21 days after seeding (DAS) were more effective than one application and repressed root hair infection. According to 16S rDNA sequence analysis, strain MZ-12 was identified as had a 100% sequence similarity with type strain Bacillus cereus. The findings of the present study will facilitate further investigation into biological mechanisms of cruciferous clubroot control.


Assuntos
Bacillus cereus , Brassica , Doenças das Plantas , Raízes de Plantas , Plasmodioforídeos , Bacillus cereus/fisiologia , Brassica/microbiologia , Brassica/parasitologia , Interações Microbianas , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Raízes de Plantas/microbiologia , Raízes de Plantas/parasitologia , Tumores de Planta/microbiologia , Tumores de Planta/parasitologia , Plasmodioforídeos/fisiologia
17.
Arch Microbiol ; 203(4): 1641-1647, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33432379

RESUMO

To investigate the molecular mechanism of Trichoderma L-amino acid oxidase (Th-LAAO) in protecting and in promoting growth of cabbage infected with Botrytis cinerea, a three-way interaction system was established. Cabbage leaves treated with purified Th-LAAO significantly constrained damaged leaf area caused by B. cinerea infection. In response to Th-LAAO treatment, the expression levels of genes involved in photosynthesis, such as ribulose-1,5-bisphosphate carboxylase oxygenase, Rubisco activase, and ATP synthase increased 2.54, 2.18, and 1.41 folds, respectively. The transcription levels of sucrose transport protein 1 increased 7.6 fold. As to the expression of defense-related genes, the transcription level of ascorbate peroxidase increased 1.46 fold. On the contrary, pathogenesis-related protein 1, chitinase, ß-1,3 glucanase, and glutathione S-transferase decreased significantly. Overall, the results indicated that Th-LAAO may stimulate CO2 fixation and sucrose transport and elicit host defense responses in cabbage against B. cinerea, and this elicitation of defense response is likely to contribute to induced systemic resistance of host plant.


Assuntos
Brassica , Resistência à Doença , L-Aminoácido Oxidase , Trichoderma , Botrytis/fisiologia , Brassica/efeitos dos fármacos , Brassica/genética , Brassica/microbiologia , Resistência à Doença/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas/genética , L-Aminoácido Oxidase/isolamento & purificação , L-Aminoácido Oxidase/farmacologia , Fotossíntese/efeitos dos fármacos , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/microbiologia , Trichoderma/química , Trichoderma/enzimologia
18.
J Food Sci ; 86(2): 334-342, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33483957

RESUMO

Consumption of nutrient-rich seaweeds and fermented nondairy foods represent fast growing trends among health-minded consumers. Assessment of lacto-fermented seaweed was performed to address these trends, and to offer shelf-life extension and product diversification for fresh kelps. The objectives were to evaluate the effects of kelp species and inclusion level on fermentation kinetics, physicochemical quality, safety, shelf-life, and consumer acceptability of a seaweed sauerkraut-style product. Six formulations with different inclusion levels (25, 50, and 75%) of shredded kelp (sugar kelp, SK or winged kelp, WK) were mixed with cabbage, 2% salt, and inoculated with Lactobacillus plantarum (approximately 106 CFU/g) and Leuconostoc mesenteroides (approximately 101 CFU/g). Products were processed in triplicate, fermented until a target pH of ≤4.6 was achieved, and sampled periodically for 60 days. Kelp species and inclusion level significantly affected most variables tested. The most rapid fermentation (3 days), as evidenced by pH decrease, lactic acid bacteria counts, and lactic acid levels, was noted in WK formulations. Some SK formulations took up to 14 days to achieve the target pH, and coliforms persisted to a greater extent in the SK formulations. Higher levels of kelp decreased the fermentation rate and concentration of fermentable sugars in the brine, but increased the total phenolic content and antioxidant activity of the sauerkrauts. Despite differences in instrumental color (L* a* b* ) and texture (shear force) among formulations, overall liking as rated by a consumer panel was not significantly affected by species or inclusion level. Results support the use of lacto-fermentation in the production of refrigeration-stable seaweed sauerkraut-style product. PRACTICAL APPLICATION: Health-conscious consumers are becoming increasingly interested in plant-based diets and fermented foods, and the development of novel seaweed sauerkraut-style products can help to meet these needs. This study demonstrated the successful production of a sauerkraut-style product formulated with up to 50% farm-raised kelp. Physical, chemical, microbiological, and consumer acceptability testing established lactic acid fermentation as a viable method for shelf life extension and value addition of fresh kelps. These results provide science-based information on an alternative processing method for cultivated seaweeds and can assist the industry in product diversification efforts.


Assuntos
Brassica/microbiologia , Fermentação , Kelp/microbiologia , Ácido Láctico/metabolismo , Sensação , Antioxidantes , Brassica/química , Fenômenos Químicos , Comportamento do Consumidor , Alimentos e Bebidas Fermentados/análise , Alimentos e Bebidas Fermentados/microbiologia , Microbiologia de Alimentos , Humanos , Concentração de Íons de Hidrogênio , Kelp/química , Lactobacillus plantarum/metabolismo , Leuconostoc mesenteroides/metabolismo , Sais
19.
J Food Sci ; 86(2): 505-512, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33415724

RESUMO

Cabbage Kimchi, a traditional Korean fermented food, has occasionally been related to acute gastroenteritis caused by human norovirus (HuNoV). The present study examined the inhibitory effects of electron beam (e-beam) irradiation (1, 3, 5, 7, and 10 kGy) on HuNoV GII.4 in suspension or cabbage Kimchi using reverse transcription quantitative polymerase chain reaction combined with immunomagnetic separation (IMS/RT-qPCR). In addition, physicochemical and sensorial analyses were conducted to assess any change in the quality of cabbage Kimchi following e-beam irradiation. Following e-beam irradiation at 1 to 10 kGy, HuNoV significantly decreased to 0.28 to 2.08 log10 copy number/mL in suspension (P < 0.05). HuNoV levels in cabbage Kimchi were also significantly reduced to 0.26 to 1.57 log10 copy number/mL following irradiation with 1 to 10 kGy (P < 0.05) compared to positive control (6.0 log10 copy number/mL). The D-values for 1 log10 reduction (90% inhibition) of HuNoV in suspension and cabbage Kimchi were 4.94 and 6.96 kGy of e-beam, respectively. The pH and acidity in the irradiated cabbage Kimchi were 4.41 to 4.58 and 0.61% to 0.71%, respectively, indicating that e-beam did not affect the optimal pH or acidity. Although a slight increase of greenness was observed in the leaf portion of cabbage Kimchi irradiated with 7 to 10 kGy of e-beam, this color change was minimal and went undetected by panelists in the sensorial evaluation. The five properties of sensorial quality assessed were no different in the irradiated Kimchi sample compared with the control sample (nonirradiated cabbage Kimchi). Therefore, this study suggests that ≥6.96 kGy of e-beam could be applied in the cabbage Kimchi industry to obtain >90% of HuNoV without affecting the quality. PRACTICAL APPLICATION: As the most representative food in Korea, Kimchi needs the sanitation technology that can inhibit viral infection. Our findings suggest that e-beam irradiation can be used to reduce HuNoV effectively in Kimchi without changes in sensorial quality.


Assuntos
Brassica/microbiologia , Alimentos e Bebidas Fermentados/virologia , Separação Imunomagnética , Norovirus/efeitos da radiação , Reação em Cadeia da Polimerase em Tempo Real , Inativação de Vírus/efeitos da radiação , Elétrons , Fermentação , Irradiação de Alimentos , Microbiologia de Alimentos , Humanos
20.
Arch Microbiol ; 203(3): 975-988, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33104821

RESUMO

The aim of the paper was to analyse changes in lactic acid bacteria (LAB) populations during spontaneous fermentation of green curly kale juice (Brasicca oleracea L. var. acephala L.) and to determine the probiotic potential of LAB isolates. The analyses revealed that changes in LAB populations were specific for spontaneously fermented vegetable juices. The initial microbiota, composed mostly of Leuconostoc mesenteroides bacteria, was gradually replaced by Lactobacillus species, mainly Lactobacillus plantarum, Lactobacillus sakei, and Lactobacillus coryniformis. Screening tests for the antimicrobial properties and antibiotic susceptibility of isolates allowed for the selection of 12 strains with desirable characteristics. L. plantarum isolates were characterized by the widest spectrum of antimicrobial interactions, both towards Gram-positive and Gram-negative bacteria. Also, L. plantarum strains exhibited the best growth abilities under low pH conditions, and at different NaCl and bile salt concentrations. All strains showed different levels of antibiotic sensitivity, although they were resistant to vancomycin and kanamycin. The present study has shown that bacterial isolates obtained from spontaneously fermented kale juice could constitute valuable probiotic starter cultures, which may be used in fermentation industry.


Assuntos
Brassica/microbiologia , Fermentação , Microbiologia de Alimentos , Sucos de Frutas e Vegetais/microbiologia , Microbiologia Industrial , Lactobacillus/fisiologia , Probióticos , Antibacterianos/farmacologia , Humanos , Lactobacillales/isolamento & purificação , Lactobacillus/efeitos dos fármacos , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/isolamento & purificação , Interações Microbianas
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