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Microbiological Research
Urban & Fischer Verlag DmbH & Co.
Microbiological Research

Urban & Fischer Verlag DmbH & Co.

0944-5013

Microbiological Research/Journal Microbiological ResearchSCIEIAHCI
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    Trichoderma: Potential bio-resource for the management of tomato root rot diseases in Africa

    Olowe O.M.Akanmu A.O.Babalola O.O.Nicola L....
    14页
    查看更多>>摘要:? 2022Trichoderma spp. are among the front-line microorganisms commonly employed in novel biotechnology applications. They have been well-proven as biopesticides, biofertilizers, and biostimulants for managing plants against biotic and abiotic stresses. They are instrumental in managing plant diseases of economic importance, such as tomato root rot. However, this group of fungi has not been well-exploited en-mass in developing countries, while the use of bioagents in-lieu of chemical pesticides is still not a common practice in many African countries. Africa contributes 11.8% to global tomato production. Unfortunately, more than half of the actual product is lost due to diseases. The root rot of tomatoes predominantly caused by soil-borne fungal pathogens are among significant problems of tomato cultivation in Africa. Here, we review the constraints of tomato root rot in Africa and the roles of Trichoderma in repositioning the crop for optimum productivity. We gave a comprehensive overview of the economic importance, root rot epidemiology, and how to circumvent it through gene pool to resistant tomato and employ Trichoderma's biological control potentials. Furthermore, this review gives an overview of the mechanisms of action of Trichoderma, gaps in the advocacy, adoption, commercialization, and regulation of Trichoderma as biocontrol agents of tomato rot diseases in Africa.

    Fungal endophytes in Fraxinus excelsior petioles and their in vitro antagonistic potential against the ash dieback pathogen Hymenoscyphus fraxineus

    Bilanski P.Kowalski T.
    20页
    查看更多>>摘要:? 2022 Elsevier GmbHFungal endophytes were isolated from 250 asymptomatic leaf petioles of Fraxinus excelsior collected from trees showing symptoms of ash dieback in five forest sites in southern Poland. Fungal isolations yielded 1646 colonies representing 97 taxa, including 92 Ascomycota and 5 Basidiomycota species. The most common Ascomycota comprised Nemania serpens (38.0 % of colonized petioles), Diaporthe eres (33.6 %), Venturia fraxini (26.4 %), Diaporthe sp. 1 (20.4 %), Alternaria sp. 1 (14.8 %), Colletotrichum acutatum (14.8 %), Nemania diffusa (14.0 %), Colletotrichum gloeosporioides (12.4 %) and Colletotrichum sp. (12.4 %). The occurrence of all these taxa except Alternaria sp. 1 was significantly different between the studied forest sites. Two yeast species, Vishniacozyma foliicola (4.8 %) and Cystobasidium pinicola (2.8 %), dominated among the Basidiomycota endophytes detected. All the fungal endophytes were tested in dual culture antagonistic assays against two strains of Hymenoscyphus fraxineus, resulting in the development of four interaction types. The interactions included the physical contact of co-partners’ mycelia (41.8 %), development of an inhibition zone (47.4 %), growth of endophyte mycelia over H. fraxineus colonies (9.3 %) and growth of H. fraxineus mycelia over endophyte colonies (1.5 %). The strongest antibiotic activity against H. fraxineus, measured by the width of the inhibition zone, was observed for Cytospora pruinosa, Fusarium lateritium, Phoma sp. 2, Pleosporales sp. 2 and Thielavia basicola. A variety of morphophysiological deformations of H. fraxineus hyphae were observed under endophyte pressure: spiral twist of the hyphae, formation of cytoplasmic extrusions, development of torulose hyphae and excessive lateral branching of the hyphae. The strongest antagonistic effects, coupled with the potential to overgrow H. fraxineus colonies, was shown by Clonostachys rosea, Nemania diffusa, N. serpens, Peniophora cinerea, Rosellinia corticium and Xylaria polymorpha. Some of these species were able to attack H. fraxineus hyphae in a mycoparasitic manner. The antagonistic activities included the physical penetration of H. fraxineus hyphae, dissolution of hyphal cell walls, disappearance of pigmentation, disintegration of hyphae and degradation of other fungal structures. In contrast, one of the most commonly detected endophytes in ash leaves, Venturia fraxini, did not show in vitro antagonistic potential against H. fraxineus. Finally, we discuss the potential of the detected fungal endophytes to combat H. fraxineus invasion, the cause of ash decline in Europe.

    Identification of long non-coding RNAs in Verticillium dahliae following inoculation of cotton

    Li R.Xue H.-S.Zhang D.-D.Wang D....
    12页
    查看更多>>摘要:? 2022Long non-coding RNAs (lncRNAs) play important roles in diverse biological processes. However, these functions have not been assessed in Verticillium dahliae, a soil-borne fungal pathogen that causes devastating wilt diseases in many crops. The discovery and identity of novel lncRNAs and their association with virulence may contribute to an increased understanding of the regulation of virulence in V. dahliae. Here, we identified a total of 352 lncRNAs in V. dahliae. The lncRNAs were transcribed from all V. dahliae chromosomes, typically with shorter open reading frames, lower GC content, and fewer exons than protein-coding genes. In addition, 308 protein-coding genes located within 10 kb upstream and 10 kb downstream of lncRNAs were identified as neighboring genes, and which were considered as potential targets of lncRNA. These neighboring genes encode products involved in development, stress responses, and pathogenicity of V. dahliae, such as transcription factors (TF), kinase, and members of the secretome. Furthermore, 47 lncRNAs were significantly differentially expressed in V. dahliae following inoculation of susceptible cotton (Gossyoiumhisutum) cultivar Junmian No.1, suggesting that lncRNAs may be involved in the regulation of virulence in V. dahliae. Moreover, correlations in expression patterns between lncRNA and their neighboring genes were detected. Expression of lncRNA012077 and its neighboring gene was up-regulated 6 h following inoculation of cotton, while the expression of lncRNA007722 was down-regulated at 6 h but up-regulated at 24 h, in a pattern opposite to that of its neighboring gene. Overexpression of lncRNA012077 in wild-type strain (Vd991) enhanced its virulence on cotton while overexpression of lncRNA009491 reduced virulence. Identification of novel lncRNAs and their association with virulence may provide new targets for disease control.

    Anti-CRISPR proteins as a therapeutic agent against drug-resistant bacteria

    Vyas P.Harish
    13页
    查看更多>>摘要:? 2022 Elsevier GmbHThe continuous deployment of various antibiotics to treat multiple serious bacterial infections leads to multidrug resistance among the bacterial population. It has failed the standard treatment strategies through different antibacterial agents and serves as a significant threat to public health worldwide at devastating levels. The discovery of anti-CRISPR proteins catches the interest of researchers around the world as a promising therapeutic agent against drug-resistant bacteria. Anti-CRISPR proteins are known to inhibit bacterial CRISPR-Cas defense systems in multiple possible ways. The CRISPR-Cas nucleoprotein assembly provides adaptive immunity in bacteria against diverse categories of phage infections. Parallelly, phages also try to break the CRISPR-Cas barrier by producing anti-CRISPR proteins, leading to growth inhibition and bacterial lysis. This review begins with a brief description of the bacterial CRISPR-Cas system, followed by a detailed portrayal of anti-CRISPR proteins, including their discovery and evolution, mechanism of action, regulation of expression, and potential applications in the healthcare sector as an alternative therapeutic strategy to combat severe bacterial infections.

    Genome-wide lone strand adenine methylation in Deinococcus radiodurans R1: Regulation of gene expression through DR0643-dependent adenine methylation

    Joshi S.Deobagkar D.D.Basu B.Ghosh P....
    15页
    查看更多>>摘要:? 2022 Elsevier GmbHDNA methylation is a covalent modification of adenine or cytosine in the genome of an organism and is found in diverse microbes including the radiation resistant bacterium Deinococcus radiodurans R1. Although earlier findings have confirmed repression or de-repression of certain genes in adenine methyltransferase (DR_0643/Dam1DR) deficient D. radiodurans mutant however, the overall regulatory aspects of Dam1DR-mediated adenine methylation remain mostly unexplored. In the present study, we compared the genome-wide methylome and the corresponding transcriptome of D. radiodurans WT and Δdam1 mutant to explore the correlation between methylation and gene expression. In D. radiodurans, deletion of DR_0643 ORF (Δdam1) led to hypomethylation of 512 genes resulting in differential expression of 168 genes (99 genes are upregulated and 69 genes are downregulated). The modification patterns deduced for Dam1DR (DR_0643) and Dam2DR (DR_2267) were non-palindromic and atypical. Moreover, we observed methylation at opportunistic sites that show adenine methylation only in D. radiodurans Δdam1 and not in D. radiodurans WT. Correlation between the methylome and transcriptome suggests that hypomethylation at Dam1DR specific sites had both negative as well as a positive effects on gene expression. Pathways such as amino acid metabolism, transport, oxidative phosphorylation, quorum sensing, signal transduction, two-component system, glycolysis/gluconeogenesis, TCA cycle, glyoxylate and dicarboxylate metabolism were modulated by Dam1DR-mediated adenine methylation in D. radiodurans. Processes such as DNA repair, recombination, ATPase and transmembrane transporter activity were enriched when Dam1DR mutant was subjected to radiation stress. We further evaluated the molecular interactions and mode of binding between Dam1DR protein and S-adenosyl methionine using molecular docking followed by MD simulation. To get a better insight into the methylation mechanism, the Dam1DR-SAM complex was also docked with a DNA molecule to elucidate DNA-Dam1DR structural interaction during methyl-group transfer reaction. In summary, our work presents comprehensive and integrative approaches to investigate both functional and structural aspects of DNA adenine methyltransferase (Dam1DR) in D. radiodurans biology.

    Identification and characterization of a central replication origin of the mega-plasmid pSCATT of Streptomyces cattleya

    Li P.Zhang J.Deng Z.Ou H.-Y....
    5页
    查看更多>>摘要:? 2022 Elsevier GmbHStreptomyces linear plasmids often contain an internal replication origin. In this study, a new replication origin was identified and confirmed in the 1.8-Mb plasmid pSCATT of Streptomyces cattleya DSM46488. The real-time qPCR results indicated that the copy number of pSCATT was one copy per chromosome. The identified replication origin oriC1-II was found to locate in the central region of pSCATT and was 2 kb in size. This replication origin consists of a protein-coding gene SCATT_p08010 with an unknown function and the upstream non-coding sequence. Deletion or disruption analysis of SCATT_p08010 or the upstream non-coding sequence revealed that both SCATT_p08010 and the non-coding sequence were essential for replication. However, the identified replication origin was shown to endow the plasmid with the ability to replicate in a circular model but not in a linear model in S. lividans. Interestingly, the knockout of the replication origin did not result in the curing of pSCATT, indicating that there might be other replication origins present in the mega-plasmid. The experimental validation of the central replication origin oriC1-II might be helpful for the investigation of the replication mechanism of the mega-plasmid and the genome evolution of Streptomyces.

    The menaquinone pathway is important for susceptibility of Staphylococcus aureus to the antibiotic adjuvant, cannabidiol

    Wassmann C.S.Rolsted A.P.Lyngsie M.C.Torres-Puig S....
    11页
    查看更多>>摘要:? 2022 The AuthorsEmergence of antibiotic resistant bacteria is evolving at an alarming pace; therefore, we must start turning to alternative approaches. One of these, could be the use of antibiotic adjuvants that enhances the effect of antibiotics towards resistant bacteria. A novel antibiotic adjuvant is cannabidiol (CBD), which we have previously shown can enhance the effect of bacitracin (BAC). BAC targets cell wall synthesis by inhibiting dephosphorylation of the lipid carrier undecaprenyl pyrophosphate prior to recycling across the membrane. However, the mechanism underlying this CBD mediated potentiation of BAC has remained unknown. To explore this, we examined resistance to CBD in Staphylococcus aureus through daily exposures to CBD. By subsequent whole genome sequencing, we observed multiple genes to be mutated, including the farE/farR system encoding a fatty acid efflux pump (FarE) and its regulator (FarR). Importantly, recreation of mutations in these genes showed decreased susceptibility towards the combination of CBD and BAC. Furthermore, we searched the Nebraska Transposon Mutant Library for CBD susceptible strains and identified menH encoding a protein participating in menaquinone biosynthesis. Strains containing deletions in this and other menaquinone related genes showed increased susceptibility towards CBD, while addition of exogenous menaquinone reversed the effect and reduced susceptible towards CBD. These results suggest that CBD potentiates BAC by redirecting the isoprenoid precursor isopentenyl pyrophosphate towards production of menaquinone rather than the lipid carrier undecaprenyl pyrophosphate, which dephosphorylation is inhibited by BAC. This in turn might decrease the level of undecaprenyl pyrophosphate thus enhancing the effect of BAC. Our study illustrates how antibiotic adjuvants may apply to enhance efficacy of antimicrobial compounds.

    Diaporthe/Phomopsis longicolla degrades an array of bisphenol analogues with secreted laccase

    Baluyot J.C.Ghimire L.B.Joson S.E.A.Obusan M.C.M....
    9页
    查看更多>>摘要:? 2022 Elsevier GmbHWith recent initiatives to ban bisphenol A (BPA) in certain commercial products, manufacturers shifted to the production and use of BPA analogues. However, some of these BPA alternatives still possess endocrine disruptive activities. Many fungal enzymes are known to biodegrade phenolic compounds, such as BPA. However, the activity of these enzymes on BPA analogues remains unexplored. This study reports a secreted laccase from the endophytic fungus Diaporthe longicolla capable of degrading an impressive range of bisphenol analogues. The secreted crude enzymes are optimally active at pH 5 from 39 °C to 60 °C, efficiently degrading BPA as well as BPA analogues BPB, BPC, BPE and BPF. A purified form of laccase was identified from the crude fungal extract using FPLC and peptide sequencing. Furthermore, BPA induced the expression of this D. longicolla laccase gene. Overall, this paper demonstrated that the crude laccase enzyme from D. longicolla metabolizes BPA and select analogues, implicating the potential role of this fungus to remove environmental bisphenols.

    Fecal microbiota transplantation as tool to study the interrelation between microbiota composition and miRNA expression

    Wortelboer K.Winkelmeijer M.van Riel N.Levin E....
    7页
    查看更多>>摘要:? 2022 The Author(s)The intestinal gut microbiota is important for human metabolism and immunity and can be influenced by many host factors. A recently emerged host factor is secreted microRNA (miRNA). Previously, it has been shown that secreted miRNAs can influence the growth of certain bacteria and conversely, that shifts in the microbiota can alter the composition of secreted miRNAs. Here, we sought to further investigate the interaction between the gut microbiota and secreted miRNAs by the use of fecal microbiota transplantation (FMT). Subjects with the metabolic syndrome received either an autologous (n = 4) or allogenic (n = 14) FMT. Fecal samples were collected at baseline and 6 weeks after FMT, from which the microbiome and miRNA composition were determined via 16S rRNA sequencing and miRNA sequencing, respectively. We observed a significant correlation between the fecal miRNA expression and microbiota composition, both before and after FMT. Our results suggest that the FMT-induced shift in microbiota altered the fecal miRNA profile, indicated by correlations between differentially abundant microbes and miRNAs. This idea of a shift in miRNA composition driven by changes in the microbiota was further strengthened by the absence of a direct effect of specific miRNAs on the growth of specific bacterial strains.

    Acquiring novel chemicals by overexpression of a transcription factor DibT in the dibenzodioxocinone biosynthetic cluster in Pestalotiopsis microspora

    Liu Y.Fu Y.Zhou M.Hao X....
    7页
    查看更多>>摘要:? 2022 Elsevier GmbHThe endophytic fungus Pestalotiopsis microspora has drawn attention due to its production of dibenzodioxocinones which are a new class of inhibitors of cholesterol ester transfer protein (CETP). Previous studies showed that the pks8 gene cluster is responsible for the biosynthesis of dibenzodioxocinones in P. microspora. Disrupting the gene encoding a transcription factor DibT, which contains a zinc-finger functional domain, led to a significant decrease in the production of dibenzodioxocinones. To further investigate the function of DibT in the expression of pks8 cluster, we constructed dibT-overexpressing strains and found that all genes in the pks8 cluster were upregulated and the yields of dibenzodioxocinones were significantly increased. Moreover, function of DibT was required for the expression of most PKS genes outside of pks8 clusters, i.e., 43 out of 48 defined PKS genes, and boosted pigmentation of the mycelium and conidia. Still, we identified a new dibenzodioxocinone, 1′,2′-dimethyl-3′-formyl- 1′,2′-dehydropenicillide (6) and a previously known, but conditionally synthesized dibenzodioxocinone, 3′-methoxy-1′,2′-dehydropenicillide (4) from the overexpression strains. Our results show that DibT was the key transcription factor in the expression of pks8 cluster and still has a wide effect on the expression of PKS genes in the genome. This work provides information for the regulation of dibenzodioxocinone biosynthesis and may be helpful for the development of new CETP inhibitors.