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Frontiers in Microbiology 2023Pitaya canker, caused by , is one of the most important fungal diseases that cause significant losses in production. To replace chemical pesticides, the use of...
Pitaya canker, caused by , is one of the most important fungal diseases that cause significant losses in production. To replace chemical pesticides, the use of biocontrol strains to manage plant diseases has been the focus of research. In this study, the bacterial strain AF01, identified as , exhibited significant antifungal effects against and four other pitaya fungal pathogens. The strain AF01 produces 13 fusaricidins, which directly inhibit mycelial growth, spore germination and germ tube elongation by causing the membrane integrity and cell ultrastructure to incur irreversible damage. Pot experiment and yield test confirmed that AF01 provided preservative effects by reducing the disease index. In comparison to the untreated control groups, RNA-seq data showed that AF01 selectively blocked some transcription and translation processes and inhibited RNA and DNA structural dynamics, energy production and conversion, and signal transduction, particularly cell wall biosynthesis, changes in membrane permeability, and impairment of protein biosynthesis. Thus, AF01 could be potentially useful as a suitable biocontrol agent for pitaya canker.
PubMed: 37266020
DOI: 10.3389/fmicb.2023.1188722 -
Microbiology Spectrum Jun 2023Through screening of rhizobacteria, species that effectively suppress phytopathogens and/or promote plant growth are found. Genome sequencing is a crucial step in...
Through screening of rhizobacteria, species that effectively suppress phytopathogens and/or promote plant growth are found. Genome sequencing is a crucial step in obtaining a complete characterization of microorganisms for biotechnological applications. This study aimed to sequence the genomes of four rhizobacteria that differ in their inhibition of four root pathogens and in their interaction with chili pepper roots to identify the species and analyze differences in the biosynthetic gene clusters (BGCs) for antibiotic metabolites and to determine possible phenotype-genotype correlations. Results from sequencing and genome alignment identified two bacteria as Paenibacillus polymyxa, one as Kocuria polaris, and one that was previously sequenced as Bacillus velezensis. Analysis with antiSMASH and PRISM tools showed that 2A-2B, the strain with the best performance of referred characteristics, had 13 BGCs, including those related to surfactin, fengycin, and macrolactin, not shared with the other bacteria, whereas 2A-2A and 3A-25AI, with up to 31 BGCs, showed lower pathogen inhibition and plant hostility; showed the least antifungal capacity. and had the highest number of BGCs for nonribosomal peptides and polyketides. In conclusion, the 13 BGCs in the genome of 2A-2B that were not present in the other bacteria could explain its effective antifungal capacity and could also contribute to its friendly interaction with chili pepper roots. The high number of other BGCs for nonribosomal peptides and polyketide shared by the four bacteria contributed much less to phenotypic differences. To advance the characterization of a microorganism as a biocontrol agent against phytopathogens, it is highly recommended to analyze the potential of the profile of secondary metabolites as antibiotics that it produces to counteract pathogens. Some specific metabolites have positive impacts in plants. By analyzing sequenced genomes with bioinformatic tools, such as antiSMASH and PRISM, outstanding bacterial strains with high potential to inhibit phytopathogens and/or promote plant growth can be quickly selected to confirm and expand our knowledge of BGCs of great value in phytopathology.
Topics: Capsicum; Genome, Bacterial; Antifungal Agents; Plant Development; Bacteria; Anti-Bacterial Agents; Multigene Family
PubMed: 37222590
DOI: 10.1128/spectrum.03072-22 -
BioRxiv : the Preprint Server For... May 2023Engaging computational tools for protein design is gaining traction in the enzyme engineering community. However, current design and modeling algorithms have limited...
Engaging computational tools for protein design is gaining traction in the enzyme engineering community. However, current design and modeling algorithms have limited functionality predictive capacities for enzymes due to limitations of the dataset in terms of size and data quality. This study aims to expand training datasets for improved algorithm development with the addition of five rationally designed single-point enzyme variants. β-glucosidase B variants were modeled in Foldit Standalone and then produced and assayed for thermal stability and kinetic parameters. Functional parameters: thermal stability (T ) and Michaelis-Menten constants ( , K , and /K ) of five variants, V311D, Y166H, M221K, F248N, and Y166K, were added into the Design2Data database. As a case study, evaluation of this small mutant set finds mutational effect trends that both corroborate and contradict findings from larger studies examining the entire dataset.
PubMed: 37214998
DOI: 10.1101/2023.05.10.540081 -
Microorganisms Mar 2023Many farmers' incomes in developing countries depend on the cultivation of major crops grown in arid and semi-arid regions. The agricultural productivity of arid and...
Many farmers' incomes in developing countries depend on the cultivation of major crops grown in arid and semi-arid regions. The agricultural productivity of arid and semi-arid areas primarily relies on chemical fertilizers. The effectiveness of chemical fertilizers needs to improve by integration with other sources of nutrients. Plant growth-promoting bacteria can solubilize nutrients, increase plant nutrient uptake, and supplement chemical fertilizers. A pot experiment evaluated the promising plant growth-promoting bacterial strain's effectiveness in promoting cotton growth, antioxidant enzymes, yield, and nutrient uptake. Two phosphate solubilizing bacterial strains ( IA6 and IA7) and two zinc solubilizing bacterial strains ( sp. IA7 and IA20) were coated on cotton seeds in a single as well as co-inoculation treatments. These treatments were compared with uninoculated controls in the presence and absence of recommended chemical fertilizer doses. The results showed the co-inoculation combination of IA7 and IA20 significantly increased the number of bolls, seed cotton yield, lint yield, and antioxidants activities, including superoxide dismutase, guaiacol peroxidase, catalase, and peroxidase. Co-inoculation combination of IA6 and sp. IA16 promoted growth attributes, including shoot length, root length, shoot fresh weight, and root fresh weight. This co-inoculation combination also increased soil nutrient content. At the same time, IA7 + IA20 increased nutrient uptake by plant shoots and roots compared.
PubMed: 37110284
DOI: 10.3390/microorganisms11040861 -
Microorganisms Mar 2023Polymyxin-producing bacteria within the complex have broad-spectrum activities against fungi and bacteria. Their antibacterial activities against soft rot and...
Polymyxin-producing bacteria within the complex have broad-spectrum activities against fungi and bacteria. Their antibacterial activities against soft rot and phytopathogens containing multiple polymyxin-resistant genes were not clear. Here, we selected nine strains within the complex having broad-spectrum antagonistic activities against phytopathogenic fungi and a polymyxin-resistant strain causing stem and root rot disease of sweet potato and did antagonistic assays on nutrient agar and sweet potato tuber slices. These strains within the complex showed clear antagonistic activities against in vitro and in vivo. The most effective antagonistic strain ShX301 showed broad-spectrum antagonistic activities against all the test and strains, completely eliminated from sweet potato seed tubers, and promoted the growth of sweet potato seedlings. Cell-free culture filtrate of ShX301 inhibited growth, swimming motility, and biofilm formation and disrupted plasma membranes, releasing nucleic acids and proteins. Multiple lipopeptides produced by ShX301 may play a major role in the bactericidal and bacteriostatic actions. This study clarifies that the antimicrobial spectrum of polymyxin-producing bacteria within the complex includes the polymyxin-resistant and phytopathogens and strengthens the fact that bacteria within the complex have high probability of being effective biocontrol agents and plant growth promoters.
PubMed: 37110240
DOI: 10.3390/microorganisms11040817 -
Environmental Microbiome Mar 2023Verticillium wilt of olive (VWO), caused by Verticillium dahliae Kleb, is one of the most threatening diseases affecting olive cultivation. An integrated disease...
BACKGROUND
Verticillium wilt of olive (VWO), caused by Verticillium dahliae Kleb, is one of the most threatening diseases affecting olive cultivation. An integrated disease management strategy is recommended for the effective control of VWO. Within this framework, the use of biological control agents (BCAs) is a sustainable and environmentally friendly approach. No studies are available on the impact that the introduction of BCAs has on the resident microbiota of olive roots. Pseudomonas simiae PICF7 and Paenibacillus polymyxa PIC73 are two BCAs effective against VWO. We examined the effects of the introduction of these BCAs on the structure, composition and co-occurrence networks of the olive (cv. Picual) root-associated microbial communities. The consequences of the subsequent inoculation with V. dahliae on BCA-treated plants were also assessed.
RESULTS
Inoculation with any of the BCAs did not produce significant changes in the structure or the taxonomic composition of the 'Picual' root-associated microbiota. However, significant and distinctive alterations were observed in the topologies of the co-occurrence networks. The introduction of PIC73 provoked a diminution of positive interactions within the 'Picual' microbial community; instead, PICF7 inoculation increased the microbiota's compartmentalization. Upon pathogen inoculation, the network of PIC73-treated plants decreased the number of interactions and showed a switch of keystone species, including taxa belonging to minor abundant phyla (Chloroflexi and Planctomycetes). Conversely, the inoculation of V. dahliae in PICF7-treated plants significantly increased the complexity of the network and the number of links among their modules, suggestive of a more stable network. No changes in their keystone taxa were detected.
CONCLUSION
The absence of significant modifications on the structure and composition of the 'Picual' belowground microbiota due to the introduction of the tested BCAs underlines the low/null environmental impact of these rhizobacteria. These findings may have important practical consequences regarding future field applications of these BCAs. Furthermore, each BCA altered the interactions among the components of the olive belowground microbiota in idiosyncratic ways (i.e. PIC73 strongly modified the number of positive relations in the 'Picual' microbiota whereas PICF7 mostly affected the network stability). These modifications may provide clues on the biocontrol strategies used by these BCAs.
PubMed: 36949520
DOI: 10.1186/s40793-023-00480-2 -
Heliyon Mar 2023Barley scald is very important in temperate and wet regions worldwide and has become one of the most important foliar diseases. Before the development of recent... (Review)
Review
Barley scald is very important in temperate and wet regions worldwide and has become one of the most important foliar diseases. Before the development of recent technologies, several scientists had argued that is the causal agent of scald disease. However, the causal agent of this disease was revised and recognized as . Again recently, was suggested to be replaced as the causal agent of . The disease outbreak is depending on cool and frequent rainfall. Because of scald disease significance, numerous management practices have been advocated. Then, resistance materials, and mixing of resistant and susceptible cultivars have been used as the best management methods. Several studies have demonstrated that some cultivars and landraces of barley are resistant to scald disease during the seedling and adult growth stages. The first cultivar is "Atlas 46″ which was created from the cultivar "Turk". From biological method: , KaI245, and are very effective in treating this disease. Finally, as a last option, different fungicides have been suggested. Pathogenicity testing, seed treatments, tillage, cultivar mixtures, and biological control are all commonly overlooked in developing countries. Cultural practices such as times of fungicide application, appropriate time of sowing to scape disease, and tillage practices which are adopted for other diseases are greatly missed for scald disease. Then, we are intended to assess the various findings available on barley scald biology, taxonomy, and management.
PubMed: 36938428
DOI: 10.1016/j.heliyon.2023.e14315 -
Frontiers in Microbiology 2023Nitrogenase in some bacteria and archaea catalyzes conversion of N to ammonia. To reconstitute a nitrogenase biosynthetic pathway in a eukaryotic host is still a...
Nitrogenase in some bacteria and archaea catalyzes conversion of N to ammonia. To reconstitute a nitrogenase biosynthetic pathway in a eukaryotic host is still a challenge, since synthesis of nitrogenase requires a large number of (trogen ixation) genes. Viral 2A peptide mediated "cleavage" of polyprotein is one of strategies for multigene co-expression. Here, we show that cleavage efficiency of NifB-2A-NifH polyprotein linked by four different 2A peptides (P2A, T2A, E2A, and F2A) in ranges from ~50% to ~90%. The presence of a 2A tail in NifB, NifH, and NifD does not affect their activity. Western blotting shows that 9 Nif proteins (NifB, NifH, NifD, NifK, NifE, NifN, NifX, HesA, and NifV) from that are fused into two polyproteins 2A peptides are co-expressed in . . Expressed NifH from NifU and NifS and . NifH fusion linked 2A in . exhibits Fe protein activity.
PubMed: 36937264
DOI: 10.3389/fmicb.2023.1137355 -
Heliyon Mar 2023The rhizosphere microbes play a key role in plant nutrition and health. However, the interaction of beneficial microbes and (lobia) production remains poorly...
The rhizosphere microbes play a key role in plant nutrition and health. However, the interaction of beneficial microbes and (lobia) production remains poorly understood. Thus, we aimed to isolate and characterize the soil microbes from the rhizosphere and develop novel microbial consortia for enhancing lobia production. Fifty bacterial strains were isolated from the rhizosphere soil samples of lobia. Finally, five effective strains (e.g., sp. IESDJP-V1 and sp. IESDJP-V2, IESDJP-V3, IESDJP-V4, sp. IESDJP-V5) were identified and molecularly characterized by 16 S rDNA gene amplification. All selected strains showed positive plant growth promoting (PGP) properties in broth culture. Based on morphological, biochemical, and plant growth promoting activities, five effective isolated strains and two collected strains ( MTCC-4037 and BHUPSB17) were selected. The pot trials were conducted with seed inoculations of lobia var. Kashi Kanchan with thirty treatments and three replications. The treatment combination T3 ( sp. IESDJP-V2), T14 ( sp. IESDJP-V2 + ), T26 ( sp. IESDJP-V1+ IESDJP-V4 + ) and T27 (IESDJP-V1+ IESDJP-V5+ ) were recorded for enhancing plant growth attributes, yield, nutritional content like protein, total sugar, flavonoid and soil properties as compared to control and others. The effective treatments T3 ( sp.), T14 ( sp. IESDJP-V2 + ), T26 ( sp. IESDJP-V1+ IESDJP-V4 + ) and T27 (IESDJP-V1+ IESDJP-V5+ ) recorded as potential PGPR consortium for lobia production. The treatment of single ( sp.), duel (IESDJP-V2 + ) and triple combination (IESDJP-V1+ IESDJP-V4 + ) and (IESDJP-V1+ IESDJP-V5+ ) can be further used for developing effective indigenous consortium for lobia production under sustainable farming practices. These PGPR bio-inoculant will be cost-effective, environment-friendly and socially acceptable.
PubMed: 36895350
DOI: 10.1016/j.heliyon.2023.e13804 -
Toxins Feb 2023An antibiotic produced by 7F1 was studied. The 7F1 strain was isolated from the rhizosphere of a wheat field. Response surface methodology was used to optimize the...
An antibiotic produced by 7F1 was studied. The 7F1 strain was isolated from the rhizosphere of a wheat field. Response surface methodology was used to optimize the physicochemical parameters. The strain showed broad-spectrum activity against several plant pathogens. Identification of the strain was realized based on 16s rRNA gene and gene sequencing. The antibiotic was optimized by one-factor-at-a-time (OFAT) and response surface methodology (RSM) approaches. The suitable antibiotic production conditions were optimized using the one-factor-at-a-time method. The individual and interaction effects of three independent variables: culture temperature, initial pH, and culture time, were optimized by Box-Behnken design. The 16SrRNA gene sequence (1239 nucleotides) and gene (1111 nucleotides) were determined for strain 7F1 and shared the highest identities to those of . The results showed the optimal fermentation conditions for antibiotics produced by 7F1 were a culture temperature of 38 °C, initial pH of 8.0, and culture time of 8 h. The antibiotics produced by 7F1 include lipopeptides such as iturin A and surfactin. The results provide a theoretical basis for the development of bacteriostatic biological agents and the control of mycotoxins.
Topics: Paenibacillus polymyxa; Fusarium; Anti-Bacterial Agents; RNA, Ribosomal, 16S; Fermentation
PubMed: 36828452
DOI: 10.3390/toxins15020138