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1.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445145

RESUMO

The main goal of growing plants under various photoperiods is to optimize photosynthesis for using the effect of day length that often acts on plants in combination with biotic and/or abiotic stresses. In this study, Brassica juncea plants were grown under four different day-length regimes, namely., 8 h day/16 h night, 12 h day/12 h night, 16 h day/8 h night, and continuous light, and were infected with a necrotrophic fungus Alternaria brassicicola. The development of necroses on B. juncea leaves was strongly influenced by leaf position and day length. The largest necroses were formed on plants grown under a 16 h day/8 h night photoperiod at 72 h post-inoculation (hpi). The implemented day-length regimes had a great impact on leaf morphology in response to A. brassicicola infection. They also influenced the chlorophyll and carotenoid contents and photosynthesis efficiency. Both the 1st (the oldest) and 3rd infected leaves showed significantly higher minimal fluorescence (F0) compared to the control leaves. Significantly lower values of other investigated chlorophyll a fluorescence parameters, e.g., maximum quantum yield of photosystem II (Fv/Fm) and non-photochemical quenching (NPQ), were observed in both infected leaves compared to the control, especially at 72 hpi. The oldest infected leaf, of approximately 30% of the B. juncea plants, grown under long-day and continuous light conditions showed a 'green island' phenotype in the form of a green ring surrounding an area of necrosis at 48 hpi. This phenomenon was also reflected in changes in the chloroplast's ultrastructure and accelerated senescence (yellowing) in the form of expanding chlorosis. Further research should investigate the mechanism and physiological aspects of 'green islands' formation in this pathosystem.


Assuntos
Alternaria/patogenicidade , Mostardeira/microbiologia , Mostardeira/fisiologia , Necrose/microbiologia , Necrose/patologia , Fotossíntese/fisiologia , Doenças das Plantas/microbiologia , Carotenoides/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Fluorescência , Mostardeira/metabolismo , Necrose/metabolismo , Fotoperíodo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia
2.
Artigo em Inglês | MEDLINE | ID: mdl-34382928

RESUMO

A novel genistein-producing actinobacterial strain, designated strain CRPJ-33T, was isolated from the healthy leaves of a medicinal plant Xanthium sibiricum collected from Hunan Province, PR China. 16S rRNA gene sequence analysis indicated strain CRPJ-33T belonged to the genus Streptomyces and had 99.7, 99.0, 98.9, 98.9, 98.8 and 98.7% sequence similarities to Streptomyces zhihengii YIM T102T, Streptomyces eurocidicus NRRL B-1676T, Streptomyces xanthochromogenes NRRL B-5410T, Streptomyces michiganensis NBRC 12797T, Streptomyces mauvecolor LMG 20100T and Streptomyces lavendofoliae NBRC 12882T, respectively. Phylogenetic analysis of 16S rRNA gene sequences showed that strain CRPJ-33T was most closely related to S. zhihengii YIM T102T. However, digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between them were much less than the recommended threshold values. Furthermore, differential comparisons of the phenotypic characteristics were enough to distinguish strain CRPJ-33T from S. zhihengii YIM T102T. Meanwhile, the ANI and dDDH values or MLSA distances between strain CRPJ-33T and other type strains, which exhibited ≥98.7 % 16S rRNA gene sequence similarities to strain CRPJ-33T, were far away from the recommended threshold values. Based on these results, it is thought that strain CRPJ-33T should represent a novel species of the genus Streptomyces, for which the name Streptomyces genisteinicus sp. nov. is proposed. The type strain is CRPJ-33T (=MCCC 1K04965T=JCM 34526T). In addition, the phenotypic, chemotaxonomic and genotypic characteristics, as well as phylogenetic information revealed that the type strains of S. xanthochromogenes and S. michiganensis should belong to same genomic species. Consequently, it is proposed that S. michiganensis is a heterotypic synonym of S. xanthochromogenes for which an emended description is given.


Assuntos
Genisteína/metabolismo , Filogenia , Streptomyces , Xanthium/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Folhas de Planta/microbiologia , Plantas Medicinais/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Streptomyces/classificação , Streptomyces/isolamento & purificação
3.
Artigo em Inglês | MEDLINE | ID: mdl-34424837

RESUMO

Three phytopathogenic bacterial strains (Pc19-1T, Pc19-2 and Pc19-3) were isolated from seedlings displaying water-soaked, dark brown-to-black, necrotic lesions on pepper (Capsicum annuum) leaves in Georgia, USA. Upon isolation on King's medium B, light cream-coloured colonies were observed and a diffusible fluorescent pigment was visible under ultraviolet light. Analysis of their 16S rRNA gene sequences showed that they belonged to the genus Pseudomonas, with the highest similarity to Pseudomonas cichorii ATCC 10857T (99.7 %). The fatty acid analysis revealed that the majority of the fatty acids were summed feature 3 (C16  :  1 ω7c/C16  :  1 ω6c), C16  :  0 and summed feature 8 (C18  :  1 ω7c/C18  :  1 ω6c). Phylogenomic analyses based on whole genome sequences demonstrated that the pepper strains belonged to the Pseudomonas syringae complex with P. cichorii as their closest neighbour, and formed a separate monophyletic clade from other species. Between the pepper strains and P. cichorii, the average nucleotide identity values were 91.3 %. Furthermore, the digital DNA-DNA hybridization values of the pepper strains when compared to their closest relatives, including P. cichorii, were 45.2 % or less. In addition, biochemical and physiological features were examined in this study and the results indicate that the pepper strains represent a novel Pseudomonas species. Therefore, we propose a new species Pseudomonas capsici sp. nov., with Pc19-1T (=CFBP 8884T=LMG 32209T) as the type strain. The DNA G+C content of the strain Pc19-1T is 58.4 mol%.


Assuntos
Capsicum/microbiologia , Filogenia , Pseudomonas , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Georgia , Hibridização de Ácido Nucleico , Folhas de Planta/microbiologia , Pseudomonas/classificação , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
4.
Molecules ; 26(14)2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34299537

RESUMO

Microbial natural products are an invaluable resource for the biotechnological industry. Genome mining studies have highlighted the huge biosynthetic potential of fungi, which is underexploited by standard fermentation conditions. Epigenetic effectors and/or cultivation-based approaches have successfully been applied to activate cryptic biosynthetic pathways in order to produce the chemical diversity suggested in available fungal genomes. The addition of Suberoylanilide Hydroxamic Acid to fermentation processes was evaluated to assess its effect on the metabolomic diversity of a taxonomically diverse fungal population. Here, metabolomic methodologies were implemented to identify changes in secondary metabolite profiles to determine the best fermentation conditions. The results confirmed previously described effects of the epigenetic modifier on the metabolism of a population of 232 wide diverse South Africa fungal strains cultured in different fermentation media where the induction of differential metabolites was observed. Furthermore, one solid-state fermentation (BRFT medium), two classic successful liquid fermentation media (LSFM and YES) and two new liquid media formulations (MCKX and SMK-II) were compared to identify the most productive conditions for the different populations of taxonomic subgroups.


Assuntos
Epigênese Genética/genética , Fungos/genética , Folhas de Planta/microbiologia , Produtos Biológicos/metabolismo , Vias Biossintéticas/genética , Biotecnologia/métodos , Meios de Cultura/metabolismo , Fermentação/genética , Genoma Fúngico/genética , Metabolômica/métodos , África do Sul
5.
Nat Microbiol ; 6(7): 852-864, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34194036

RESUMO

The plant microbiota consists of a multitude of microorganisms that can affect plant health and fitness. However, it is currently unclear how the plant shapes its leaf microbiota and what role the plant immune system plays in this process. Here, we evaluated Arabidopsis thaliana mutants with defects in different parts of the immune system for an altered bacterial community assembly using a gnotobiotic system. While higher-order mutants in receptors that recognize microbial features and in defence hormone signalling showed substantial microbial community alterations, the absence of the plant NADPH oxidase RBOHD caused the most pronounced change in the composition of the leaf microbiota. The rbohD knockout resulted in an enrichment of specific bacteria. Among these, we identified Xanthomonas strains as opportunistic pathogens that colonized wild-type plants asymptomatically but caused disease in rbohD knockout plants. Strain dropout experiments revealed that the lack of RBOHD unlocks the pathogenicity of individual microbiota members driving dysbiosis in rbohD knockout plants. For full protection, healthy plants require both a functional immune system and a microbial community. Our results show that the NADPH oxidase RBOHD is essential for microbiota homeostasis and emphasizes the importance of the plant immune system in controlling the leaf microbiota.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/microbiologia , Homeostase , Microbiota , NADPH Oxidases/metabolismo , Arabidopsis/enzimologia , Arabidopsis/imunologia , Proteínas de Arabidopsis/genética , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/patogenicidade , Fenômenos Fisiológicos Bacterianos , Genótipo , NADPH Oxidases/genética , Fenótipo , Imunidade Vegetal/genética , Folhas de Planta/enzimologia , Folhas de Planta/imunologia , Folhas de Planta/microbiologia
6.
Artigo em Inglês | MEDLINE | ID: mdl-34313583

RESUMO

In the present study, four bacterial strains, two (S-713T and 406) isolated from faecal samples of Tibetan antelopes and the other two (S-531T and 1598) from leaves of dandelion collected on the Qinghai-Tibet Plateau of PR China, were analysed using a polyphasic approach. All four isolates were aerobic, rod-shaped, non-motile, oxidase-negative, Gram-stain-positive and catalase-positive. According to four phylogenetic trees, strain pairs S-713T/406 and S-531T/1598 form two independent branches belonging to the genus Nocardioides, and are closest to Nocardioides lianchengensis, Nocardioides dokdonensis, Nocardioides salarius, Nocardioides marinisabuli, Nocardioides psychrotolerans and Nocardioides szechwanensis. Although sharing MK8-(H4) as their major isoprenoid quinone, strains S-713T and S-531T contained C18 : 1 ω9c (24.64 and 16.34 %) and iso-C16 : 0 (9.74 and 29.38 %), respectively, as their main fatty acids, with remarkable differences in their biochemical profiles but only slight ones in their optimal growth conditions. The chromosomes of strains S-713T and S-531T were 4 207 844 bp (G+C content, 73.0 mol%) and 4 809 817 bp (G+C content, 72.5 mol%), respectively. Collectively, the two strain pairs represent two separate novel species of the genus Nocardioides, for which the names Nocardioides dongkuii sp. nov. and Nocardioides lijunqiniae sp. nov. are proposed, with S-713T (=JCM 33698T=CGMCC 4.7660T) and S-531T (=JCM 33468T=CGMCC 4.7659T) as the respective type strains.


Assuntos
Antílopes/microbiologia , Nocardioides/classificação , Filogenia , Taraxacum/microbiologia , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Fezes/microbiologia , Nocardioides/isolamento & purificação , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Folhas de Planta/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tibet , Vitamina K 2/análogos & derivados , Vitamina K 2/química
7.
Int J Mol Sci ; 22(12)2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34208600

RESUMO

Coumarins belong to a group of secondary metabolites well known for their high biological activities including antibacterial and antifungal properties. Recently, an important role of coumarins in plant resistance to pathogens and their release into the rhizosphere upon pathogen infection was discovered. It is also well documented that coumarins play a crucial role in the Arabidopsis thaliana growth under Fe-limited conditions. However, the mechanisms underlying interplay between plant resistance, accumulation of coumarins and Fe status, remain largely unknown. In this work, we investigated the effect of both mentioned factors on the disease severity using the model system of Arabidopsis/Dickeya spp. molecular interactions. We evaluated the disease symptoms in Arabidopsis plants, wild-type Col-0 and its mutants defective in coumarin accumulation, grown in hydroponic cultures with contrasting Fe regimes and in soil mixes. Under all tested conditions, Arabidopsis plants inoculated with Dickeya solani IFB0099 strain developed more severe disease symptoms compared to lines inoculated with Dickeya dadantii 3937. We also showed that the expression of genes encoding plant stress markers were strongly affected by D. solani IFB0099 infection. Interestingly, the response of plants to D. dadantii 3937 infection was genotype-dependent in Fe-deficient hydroponic solution.


Assuntos
Cumarínicos/metabolismo , Dickeya/fisiologia , Resistência à Doença , Ferro/metabolismo , Doenças das Plantas/microbiologia , Plantas/metabolismo , Plantas/microbiologia , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Suscetibilidade a Doenças , Hidroponia , Folhas de Planta/microbiologia , Estresse Fisiológico
8.
Plant Sci ; 310: 110982, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34315598

RESUMO

The spotted leaf lesion mimic trait simulates cell death in a plant responding to pathogen infection. Some spotted leaf genes are recessive, while others are dominant. A small number of plants with a lesion mimic phenotype appeared in a segregating population obtained by crossing two normal green wheat strains, XN509 and N07216. Here, we clarified the genetic model and its breeding value. Phenotyping of the consecutive progeny populations over six cropping seasons showed that the spotted leaf lesion mimic phenotype was controlled by a dominant gene designated TaSpl1, which was inhibited by two other dominant genes, designated TaSpl1-I1 and TaSpl1-I2. Using bulked segregant analysis RNA-seq (BSR-Seq) and newly developed KASP-PCR markers, the TaSpl1 and TaSpl1-I1 loci in N07216 were mapped to the end of chromosomes 3DS and 3BS, respectively. Plants with the spotted phenotype showed lower levels of stripe rust and powdery mildew than those with the normal green phenotype. Compared with normal leaves, the differentially expressed genes in spotted leaves were significantly enriched in plant-pathogen interaction and endocytosis pathways. There were no differences in the yield parameters of the F5 and F6 sister lines, N13039S with TaSpl1 and N13039 N without TaSpl1. These results provide a greater understanding of spotted leaf phenotyping and the breeding value of the lesion mimic allele in developing disease-resistance varieties.


Assuntos
Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Triticum/metabolismo , Triticum/microbiologia , Morte Celular/genética , Morte Celular/fisiologia , Resistência à Doença/fisiologia , Endocitose/fisiologia
9.
Int J Mol Sci ; 22(11)2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34200345

RESUMO

Efficient accumulation of flavonoids is important for increased tolerance to biotic stress. Although several plant defense mechanisms are known, the roles of many pathways, proteins, and secondary metabolites in stress tolerance are unknown. We generated a flavanone 3-hydroxylase (F3H) overexpressor rice line and inoculated Xanthomonas Oryzae pv. oryzae and compared the control and wildtype inoculated plants. In addition to promoting plant growth and developmental maintenance, the overexpression of F3H increased the accumulation of flavonoids and increased tolerance to bacterial leaf blight (BLB) stress. Moreover, leaf lesion length was higher in the infected wildtype plants compared with infected transgenics. Kaempferol and quercetin, which scavenge reactive oxygen species, overaccumulated in transgenic lines compared with wildtypes in response to pathogenic infection, detected by scanning electron microscopy and spectrophotometry. The induction of F3H altered the antioxidant system and reduced the levels of glutathione peroxidase activity and malondialdehyde (MDA) contents in the transgenic lines compared with the wildtypes. Downstream gene regulation analysis showed that the expression of F3H increased the regulation of flavonol synthase (FLS), dihydroflavonol 4-reductase (DFR), and slender rice mutant (SLR1) during BLB stress. The analysis of SA and JA signaling revealed an antagonistic interaction between both hormones and that F3H induction significantly promoted SA and inhibited JA accumulation in the transgenic lines. SA-dependent nonexpressor pathogenesis-related (NPR1) and Xa1 showed significant upregulation in the infected transgenic lines compared with the infected control and wildtype lines. Thus, the overexpression of F3H was essential for increasing BLB stress tolerance.


Assuntos
Antioxidantes/metabolismo , Resistência à Doença/imunologia , Flavonoides/metabolismo , Hormônios/metabolismo , Oxigenases de Função Mista/metabolismo , Oryza/imunologia , Doenças das Plantas/imunologia , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas , Oxigenases de Função Mista/genética , Oryza/genética , Oryza/metabolismo , Oryza/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Folhas de Planta/genética , Folhas de Planta/imunologia , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/imunologia , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/microbiologia , Estresse Fisiológico , Xanthomonas/fisiologia
10.
Molecules ; 26(14)2021 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-34299533

RESUMO

Grapevine is susceptible to fungal diseases generally controlled by numerous chemical fungicides. Elicitors of plant defence are a way of reducing the use of these chemicals, but still provide inconsistent efficiency. Easy-to-analyse markers of grapevine responses to elicitors are needed to determine the best conditions for their efficiency and position them in protection strategies. We previously reported that the elicitor sulphated laminarin induced the emission of volatile organic compounds (VOCs) by grapevine leaves. The present study was conducted to characterise and compare VOC emissions in response to other elicitors. Bastid® was first used to test the conditions of VOC collection and analysis. Using SBSE-GC-MS, we detected several VOCs, including the sesquiterpene α-farnesene, in a time-dependent manner. This was correlated with the induction of farnesene synthase gene expression, in parallel with stilbene synthesis (another defence response), and associated to resistance against downy mildew. The other elicitors (Redeli®, Romeo®, Bion®, chitosan, and an oligogalacturonide) induced VOC emission, but with qualitative and quantitative differences. VOC emission thus constitutes a response of grapevine to elicitors of various chemical structures. Therefore, VOC analysis is relevant for studying the impact of environmental factors on grapevine defence responses and optimising the performance of elicitors in vineyards.


Assuntos
Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Vitis/microbiologia , Compostos Orgânicos Voláteis/análise , Fungicidas Industriais/análise , Cromatografia Gasosa-Espectrometria de Massas , Folhas de Planta/química , Sesquiterpenos/análise , Vitis/química
11.
Int J Mol Sci ; 22(10)2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-34069750

RESUMO

Botrytis cinerea can attack over 500 genera of vascular plants and is considered the second phytopathogen in the 'top ten' for its economic importance. Traditional fungicides can be ineffective and with increasing fungicide resistance, new sustainable technologies are required. Lately, RNA interference-based fungicides are emerging for their potential uses in crop protection. Therefore, we assessed the potential of this innovative approach targeting the MAP kinase Bmp3 in B. cinerea, a gene involved in saprophytic growth, response to low osmolarity, conidiation, surface sensing, host penetration and lesion formation. After performing a prediction analysis of small interfering RNAs, a 427 nucleotides long dsRNA was selected as construct. We tested the effect of topical applications of dsRNA construct both in vitro by a fungal growth assay in microtiter plates and in vivo on detached lettuce leaves artificially inoculated. In both cases, topical applications of dsRNA led to gene knockdown with a delay in conidial germination, an evident growth retardation and a strong reduction of necrotic lesions on leaves. These results correlated with a strongly reduced expression of Bmp3 gene. In accordance to these findings, the Bmp3 gene could be a promising target for the development of an RNAi-based fungicide against B. cinerea.


Assuntos
Proteína Morfogenética Óssea 3/genética , Botrytis/genética , Proteína Morfogenética Óssea 3/metabolismo , Botrytis/metabolismo , Botrytis/patogenicidade , Fungicidas Industriais/metabolismo , Alface/genética , Alface/microbiologia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , RNA de Cadeia Dupla/metabolismo , RNA de Cadeia Dupla/farmacologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/farmacologia , Virulência
12.
Int J Mol Sci ; 22(9)2021 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-34066822

RESUMO

Melampsora larici-populina causes serious poplar foliar diseases called rust worldwide. Salicylic acid (SA) and jasmonic acid (JA) are important phytohormones that are related to plant defence responses. To investigate the transcriptome profiles of SA- and JA-related genes involved in poplar rust interaction, two tolerant poplars and one intolerant poplar were selected for this study. Weighted gene coexpression network analysis (WGCNA) was applied to characterize the changes in the transcriptome profiles and contents of SA and JA after infection with the virulent E4 race of M. larici-populina. In response to infection with the E4 race of M. larici-populina, tolerant symptoms were correlated with the expression of genes related to SA and JA biosynthesis, the levels of SA and JA, and the expression of defence-related genes downstream of SA and JA. Tolerant poplars could promptly regulate the occurrence of defence responses by activating or inhibiting SA or JA pathways in a timely manner, including regulating the expression of genes related to programmed cell death, such as Kunitz-type trypsin inhibitor (KTI), to limit the growth of E4 and protect themselves. WGCNA suggested that KTI might be regulated by a Cytochrome P450 family (CYP) gene. Some CYPs should play an important role in both JA- and SA-related pathways. In contrast, in intolerant poplar, the inhibition of SA-related defence signalling through increasing JA levels in the early stage led to continued inhibition of a large number of plant-pathogen interaction-related and signalling-related genes, including NBS-LRRs, EDS1, NDR1, WRKYs, and PRs. Therefore, timely activation or inhibition of the SA or JA pathways is the key difference between tolerant and intolerant poplars.


Assuntos
Basidiomycota/fisiologia , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Doenças das Plantas/microbiologia , Populus/genética , Populus/microbiologia , Ácido Salicílico/farmacologia , Transcriptoma/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Genes de Plantas , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Interações Hospedeiro-Patógeno/genética , Modelos Biológicos , Folhas de Planta/genética , Folhas de Planta/microbiologia , Populus/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transcriptoma/efeitos dos fármacos
13.
Int J Mol Sci ; 22(11)2021 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-34067363

RESUMO

Grapevine downy mildew, caused by the biotrophic oomycete Plasmopara viticola, is one of the most severe and devastating diseases in viticulture. Unravelling the grapevine defence mechanisms is crucial to develop sustainable disease control measures. Here we provide new insights concerning fatty acid's (FA) desaturation, a fundamental process in lipid remodelling and signalling. Previously, we have provided evidence that lipid signalling is essential in the establishment of the incompatible interaction between grapevine and Plasmopara viticola. In the first hours after pathogen challenge, jasmonic acid (JA) accumulation, activation of its biosynthetic pathway and an accumulation of its precursor, the polyunsaturated α-linolenic acid (C18:3), were observed in the leaves of the tolerant genotype, Regent. This work was aimed at a better comprehension of the desaturation processes occurring after inoculation. We characterised, for the first time in Vitis vinifera, the gene family of the FA desaturases and evaluated their involvement in Regent response to Plasmopara viticola. Upon pathogen challenge, an up-regulation of the expression of plastidial FA desaturases genes was observed, resulting in a higher content of polyunsaturated fatty acids (PUFAs) of chloroplast lipids. This study highlights FA desaturases as key players in membrane remodelling and signalling in grapevine defence towards biotrophic pathogens.


Assuntos
Resistência à Doença/genética , Ácidos Graxos Dessaturases/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Vitis/genética , Vitis/microbiologia , Vias Biossintéticas/genética , Cloroplastos/genética , Ciclopentanos/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Genótipo , Lipídeos/genética , Oomicetos/patogenicidade , Oxilipinas/metabolismo , Peronospora/patogenicidade , Folhas de Planta/genética , Folhas de Planta/microbiologia
14.
Int J Mol Sci ; 22(9)2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34067069

RESUMO

Banana (Musa spp.), one of the most important fruits worldwide, is generally cold sensitive. In this study, by using the cold-sensitive banana variety Tianbaojiao (Musa acuminate) as the study material, we investigated the effects of Piriformospora indica on banana cold resistance. Seedlings with and without fungus colonization were subjected to 4 °C cold treatment. The changes in plant phenotypes, some physiological and biochemical parameters, chlorophyll fluorescence parameters, and the expression of eight cold-responsive genes in banana leaves before and after cold treatment were measured. Results demonstrated that P. indica colonization reduced the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2) but increased the activities of superoxide dismutase (SOD) and catalase (CAT) and the contents of soluble sugar (SS) and proline. Noteworthily, the CAT activity and SS content in the leaves of P. indica-colonized banana were significant (p < 0.05). After 24 h cold treatment, the decline in maximum photochemistry efficiency of photosystem II (Fv/Fm), photochemical quenching coefficient (qP), efficient quantum yield [Y(II)], and photosynthetic electron transport rate (ETR) in the leaves of P. indica-colonized banana was found to be lower than in the non-inoculated controls (p < 0.05). Moreover, although the difference was not significant, P. indica colonization increased the photochemical conversion efficiency and electron transport rate and alleviated the damage to the photosynthetic reaction center of banana leaves under cold treatment to some extent. Additionally, the expression of the most cold-responsive genes in banana leaves was significantly induced by P. indica during cold stress (p < 0.05). It was concluded that P. indica confers banana with enhanced cold resistance by stimulating antioxidant capacity, SS accumulation, and the expression of cold-responsive genes in leaves. The results obtained from this study are helpful for understanding the P. indica-induced cold resistance in banana.


Assuntos
Basidiomycota/fisiologia , Temperatura Baixa , Resistência à Doença , Endófitos/fisiologia , Musa/enzimologia , Basidiomycota/crescimento & desenvolvimento , Catalase/metabolismo , Clorofila/metabolismo , Contagem de Colônia Microbiana , Eletrólitos/metabolismo , Fluorescência , Regulação da Expressão Gênica de Plantas , Musa/genética , Musa/microbiologia , Peroxidase/metabolismo , Fenótipo , Folhas de Planta/enzimologia , Folhas de Planta/microbiologia , Folhas de Planta/fisiologia , Superóxido Dismutase/metabolismo
15.
Int J Mol Sci ; 22(9)2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34067160

RESUMO

Puccinia striiformis f. sp. tritici (Pst) is an important pathogen of wheat (Triticum aestivum L.) stripe rust, and the effector protein secreted by haustoria is a very important component involved in the pathogenic process. Although the candidate effector proteins secreted by Pst haustoria have been predicted to be abundant, few have been functionally validated. Our study confirmed that chitin and flg22 could be used as elicitors of the pathogenic-associated molecular pattern-triggered immune (PTI) reaction in wheat leaves and that TaPr-1-14 could be used as a marker gene to detect the PTI reaction. In addition, the experimental results were consistent in wheat protoplasts. A rapid and efficient method for screening and identifying the effector proteins of Pst was established by using the wheat protoplast transient expression system. Thirty-nine Pst haustorial effector genes were successfully cloned and screened for expression in the protoplast. We identified three haustorial effector proteins, PSEC2, PSEC17, and PSEC45, that may inhibit the response of wheat to PTI. These proteins are localized in the somatic cytoplasm and nucleus of wheat protoplasts and are highly expressed during the infection and parasitism of wheat.


Assuntos
Proteínas Fúngicas/metabolismo , Imunidade , Padrões Moleculares Associados a Patógenos/metabolismo , Protoplastos/microbiologia , Puccinia/fisiologia , Triticum/imunologia , Triticum/microbiologia , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Quitina/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Imunidade/efeitos dos fármacos , Doenças das Plantas/microbiologia , Imunidade Vegetal/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/imunologia , Folhas de Planta/microbiologia , Protoplastos/efeitos dos fármacos , Puccinia/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Reprodutibilidade dos Testes , Frações Subcelulares/efeitos dos fármacos , Frações Subcelulares/metabolismo , Transcrição Genética/efeitos dos fármacos , Triticum/efeitos dos fármacos , Triticum/genética
16.
Int J Mol Sci ; 22(10)2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-34068175

RESUMO

Low phosphorus (P) availability is a major limiting factor for potatoes. P fertilizer is applied to enhance P availability; however, it may become toxic when plants accumulate at high concentrations. Therefore, it is necessary to gain more knowledge of the morphological and biochemical processes associated with P deficiency and toxicity for potatoes, as well as to explore an alternative approach to ameliorate the P deficiency condition. A comprehensive study was conducted (I) to assess plant morphology, mineral allocation, and metabolites of potatoes in response to P deficiency and toxicity; and (II) to evaluate the potency of plant growth-promoting rhizobacteria (PGPR) in improving plant biomass, P uptake, and metabolites at low P levels. The results revealed a reduction in plant height and biomass by 60-80% under P deficiency compared to P optimum. P deficiency and toxicity conditions also altered the mineral concentration and allocation in plants due to nutrient imbalance. The stress induced by both P deficiency and toxicity was evident from an accumulation of proline and total free amino acids in young leaves and roots. Furthermore, root metabolite profiling revealed that P deficiency reduced sugars by 50-80% and organic acids by 20-90%, but increased amino acids by 1.5-14.8 times. However, the effect of P toxicity on metabolic changes in roots was less pronounced. Under P deficiency, PGPR significantly improved the root and shoot biomass, total root length, and root surface area by 32-45%. This finding suggests the potency of PGPR inoculation to increase potato plant tolerance under P deficiency.


Assuntos
Fósforo/metabolismo , Desenvolvimento Vegetal , Rhizobiaceae/fisiologia , Solanum tuberosum/anatomia & histologia , Solanum tuberosum/metabolismo , Estresse Fisiológico , Folhas de Planta/anatomia & histologia , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Solanum tuberosum/crescimento & desenvolvimento , Solanum tuberosum/microbiologia
17.
Food Microbiol ; 99: 103820, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34119105

RESUMO

Sub-Saharan region is often characterized by food and nutrition insecurity especially "hidden hunger" which results from inadequate micronutrients in diets. African indigenous leafy vegetables (AILVs) can represent a valid food source of micronutrients, but they often go to waste resulting in post-harvest losses. In an attempt to prolong AILVs shelf-life while enhancing their nutritional quality, fermentation was studied from a microbiological and nutritional point of view. Pumpkin leaves (Cucurbita sp.) were spontaneously fermented using the submerged method with 3% NaCl and 3% sucrose. Controls were set up, consisting of leaves with no additions. During fermentation, samples of both treatments were taken at 0, 24, 48, 72 and 168 h to monitor pH and characterize the microbial population through culture-based and molecular-based analyses. Variations between fresh and treated leaves in B-group vitamins, carotenoids, polyphenols, and phytic acid were evaluated. Data revealed that the treatment with addition of NaCl and sucrose hindered the growth of undesired microorganisms; in controls, unwanted microorganisms dominated the bacterial community until 168 h, while in treated samples Lactobacillaceae predominated. Furthermore, the content in folate, ß-carotene and lutein increased in treated leaves compared to the fresh ones, while phytic acid diminished indicating an amelioration in the nutritional value of the final product. Thus, fermentation could help in preserving Cucurbita sp. leaves, avoiding contamination of spoilage microorganisms and enhancing the nutritional values.


Assuntos
Cucurbita/química , Alimentos e Bebidas Fermentados/análise , Folhas de Planta/química , Verduras/química , Carotenoides/análise , Carotenoides/metabolismo , Cucurbita/microbiologia , Fermentação , Alimentos e Bebidas Fermentados/microbiologia , Segurança Alimentar , Lactobacillaceae/metabolismo , Valor Nutritivo , Folhas de Planta/microbiologia , Verduras/microbiologia , Vitaminas/análise , Vitaminas/metabolismo
18.
Food Microbiol ; 99: 103825, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34119110

RESUMO

This study aimed to investigate the effect of different growth temperatures on the resistance of Escherichia coli O157:H7 and Salmonella Typhimurium to low-energy X-ray irradiation. Irradiation of contaminated phosphate-buffered saline with 0.6 kGy X-ray decreased the counts of E. coli O157:H7 cultured at 37 °C to below the detection limit (<1.0 colony-forming unit (CFU)/mL) and those of E. coli O157:H7 cultured at 25 and 15 °C by 4.82 and 4.45 log CFU/mL, respectively. The viable counts of S. Typhimurium cultured at 37, 25, and 15 °C in phosphate-buffered saline decreased by 3.56, 3.08, and 2.75 log CFU/mL, respectively, after irradiation with 0.6 kGy X-ray. Irradiation of contaminated lettuce with 0.4 kGy decreased the counts of E. coli O157:H7 cultured at 37, 25, and 15 °C by 3.97, 3.45, and 3.10 log CFU/cm2, respectively, and those of S. Typhimurium by 4.41, 3.84, and 3.40 log CFU/cm2, respectively. Growth temperature influenced pathogen resistance to X-ray irradiation by modulating cellular membrane and DNA integrity, intracellular enzyme activity, and efflux pump function. The results of this study suggest that the stress resistance status of pathogenic bacteria cultured at different growth temperatures should be considered for the application of X-ray irradiation for fresh produce sterilization.


Assuntos
Escherichia coli O157/crescimento & desenvolvimento , Escherichia coli O157/efeitos da radiação , Alface/microbiologia , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/efeitos da radiação , Contagem de Colônia Microbiana , Contaminação de Alimentos/prevenção & controle , Irradiação de Alimentos , Folhas de Planta/microbiologia , Temperatura , Raios X
19.
Arch Microbiol ; 203(7): 3851-3867, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34013420

RESUMO

Piper longum (also known as Indian long pepper) is widely used in Ayurvedic, Siddha and Unani medicine systems. The principle bioactive compound of this plant is piperine, which mainly accumulates in the fruits called spikes. The report of piperine production by endophytic microbes isolated from Piper sp., motivated us to investigate the endophytic microbial diversity associated with the spikes vis-à-vis leaves (which contain negligible levels of piperine). This is the first report to use metagenomics approach to unravel the endophytic microbial diversity in P. longum. Our results indicate that 2, 56, 631 bacterial OTUs and 1090 fungal OTUs were picked cumulatively from both the tissues. Although bacterial and fungal endophytes occupy the same niche, remarkable differences exist in their diversity and abundance. For instance, the most abundant bacterial genera in spikes were Nocardioides and Pseudonocardia (Phylum Actinobacteria; reported to produce bioactive compounds); while, in leaves were Larkinella and Hymenobacter (Phylum Bacteriodetes). Likewise, the fungal endophytes, Periconia, Cladosporium and Coniothyrium (which have been earlier reported to produce commercially important metabolites including piperine), were also present in high abundance in spikes, in comparison to leaves. Further, the results of PICRUSt analysis reveal the high metabolic potential of spike-associated bacteria for secondary metabolism, namely biosynthesis of alkaloids (including pyridine/piperidine), terpenes, flavonoids and antibiotics. Therefore, our findings indicate that the endophytes abundant or unique in spikes could be explored for bioprospecting of novel/commercially important metabolites; an approach that has both ecological and economical benefits.


Assuntos
Bioprospecção , Piper , RNA Ribossômico 16S , Bactérias/classificação , Bactérias/genética , DNA Espaçador Ribossômico/genética , Endófitos/química , Endófitos/genética , Fungos/química , Fungos/classificação , Fungos/genética , Piper/química , Piper/genética , Piper/microbiologia , Folhas de Planta/genética , Folhas de Planta/microbiologia , RNA Ribossômico 16S/genética
20.
Arch Virol ; 166(8): 2315-2319, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34028604

RESUMO

A putative polymycovirus tentatively named "Setosphaeria turcica polymycovirus 1" (StPmV1) was discovered in the phytopathogenic fungus Setosphaeria turcica. StPmV1 has a genome comprising five double-stranded RNAs (dsRNAs). dsRNA1, 2, and 3 each encode a protein sharing significant similarity but lower than 64% sequence identity to the corresponding proteins of other polymycoviruses. dsRNA4 and 5 each encode a protein with a sequence that is not conserved among polymycoviruses. However, the protein encoded by dsRNA4 is rich in proline (P), alanine (A), and serine (S) residues, which is a feature shared by the so-called PAS-rich proteins encoded by all polymycoviruses. Phylogeny reconstruction using the RNA-dependent RNA polymerase (RdRp) sequences of accepted or putative polymycoviruses revealed that StPmV1 is most closely related to Plasmopara viticola lesion associated polymycovirus 1 (PvaPolymyco1), a putative polymycovirus recovered from the phytopathogenic oomycetes Plasmopara viticola. These data suggest that StPmV1 may represent a novel species of the genus Polymycovirus, family Polymycoviridae. To our knowledge, this is the first polymycovirus reported from S. turcica.


Assuntos
Ascomicetos/virologia , Micovírus/classificação , RNA de Cadeia Dupla/genética , Sequenciamento Completo do Genoma/métodos , Composição de Bases , Micovírus/genética , Micovírus/isolamento & purificação , Tamanho do Genoma , Fases de Leitura Aberta , Filogenia , Folhas de Planta/microbiologia , RNA Fúngico/genética , Zea mays/microbiologia
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