Journal of Basic Microbiology最新文献

A novel Gram-stain positive bacterial strain, GB16_1_BI, with 70.3% G+C content was isolated from rice roots cultivated in the Madhyamgram field station of Bose Institute, West Bengal, India. GB16_1_BI is a nonmotile, nitrate reducing, ammonium releasing and plant growth promoting bacteria. The average nucleotide identity-analysis of GB16_1_BI showed highest identity with Microbacterium enclense NIO-1002^T (ANIb: 82.55%; ANIm: 87.51%) and Microbacterium phycohabitans KSW2-29^T (ANIb: 82.53%; ANIm: 86.79%). Type strain genome server comparison of whole genome sequence of GB16_1_BI with genomes sequences for other species of the genus predicted that GB16_1_BI as a novel species with the digital DNA-DNA hybridization values of < 30% with its closest phylogenetic relatives. The 16S rRNA sequence of GB16_1_BI showed 98.72% similarity with Microbacterium proteolyticum RZ36^T, 98.42% similarity with Microbacterium phycohabitans KSW2-29^T and 98.43% with M. enclense NIO-1002^T. Whole cell fatty acid analyses showed iso-C16:0, anteiso-C17:0 and anteisoC15:0 as the predominant fatty acids. The strain was designated as Microbacterium bengalense sp. nov GB16_1_BIT (=MTCC 13245=JCM 37885).

Aphis gossypii Glover (Hemiptera: Aphididae) poses a major threat to okra cultivation, causing significant yield losses worldwide. This study evaluated the efficacy of the entomopathogenic fungus Lecanicillium fusisporum strain NBAIR-Vl8 against A. gossypii in both laboratory and field environments, along with Metarhizium anisopliae NBAIR-Ma4 and Beauveria bassiana NBAIR-Bb5a. L. fusisporum NBAIR-Vl8 exhibited high virulence, with an LC₅₀ of 4.22 × 10⁴ spores/mL and LT₅₀ and LT₉₀ values of 60.45 h and 86.97 h, respectively. Over 2 years of field trials, there were significant reductions in aphid (73.65%) and leafhopper, Amrasca biguttula biguttula (67.93%) populations and increased yield (6.64 q ha⁻¹) compared to untreated plots (3.98 q ha⁻¹). LC-MS/MS and GC-MS analyses of NBAIR-Vl8 identified important bioactive metabolites, including penitrem D, zwittermicin A, β-sitosterol, curcumin, and (1 R,2S)-naphthalene 1,2-oxide. To explore potential molecular targets, homology models of A. gossypii nicotinic acetylcholine receptor (nAChR) and chemosensory protein CSP8, as well as A. biguttula biguttula ribosomal protein L13 and tubulin beta chain, were developed and validated. Molecular docking using AutoDock Vina revealed that penitrem D had the highest binding affinities (−8.9 kcal/mol for nAChR), surpassing the commercial insecticide thiamethoxam (−5.4 kcal/mol for nAChR). β-sitosterol and curcumin also demonstrated strong interactions with CSP8 and structural proteins. These targets are essential for neurotransmission, olfaction, protein synthesis, and cytoskeletal integrity, indicating a multitarget mechanism of action of the drug. NBAIR-Vl8 shows significant biocontrol potential, supported by in vitro, field, and in silico evidence, highlighting its potential as a broad-spectrum microbial pesticide for integrated pest management.

Paramyrothecium roridum has recently emerged as a notable foliar pathogen of cotton in India, yet information on its population diversity remains limited. This study provides the first integrated assessment of the morpho-genetic diversity of P. roridum across traditional and non-traditional cotton-growing regions of Haryana. Thirty isolates collected from diseased cotton leaves exhibited clear phenotypic variability in colony appearance, sporodochial structures, growth patterns, and conidial dimensions, indicating considerable morphological plasticity within the species. ITS rRNA sequencing grouped all isolates into a single major clade with a small internal subgroup, reflecting overall genetic coherence with minor evolutionary divergence. Analysis of 544 nucleotide sites identified 20 segregating sites, demonstrating measurable polymorphism among isolates. Non-traditional cotton regions displayed greater genetic variability and more segregating sites than traditional areas, suggesting a broader genetic base and the influence of distinct ecological or agronomic selection pressures. Despite this variability, the low genetic differentiation coefficient indicated that all isolates constitute a largely panmictic population with unrestricted gene flow across cotton-growing zones. By combining morphological and molecular characterization, this study enhances understanding of P. roridum diversity, its dispersal potential, and evolutionary dynamics within Haryana. To the best of our knowledge, this is the first detailed investigation of P. roridum population structure in Haryana's cotton ecosystem.

Arsenic contamination in agriculture negatively impacts the normal growth and development of plants, limiting crop production. Although plant growth-promoting rhizobacteria (PGPR) can enhance plant growth under stress, the molecular mechanisms of induced systemic tolerance (IST) exerted by these bacteria remain unclear. Thus, this study was designed to isolate arsenic-stress-tolerant PGPR from the rice rhizosphere to evaluate its effectiveness in rice plant growth and to understand the molecular mechanisms of IST against arsenite (As^III) through jasmonic acid (JA) biosynthetic (OsAOS1), signaling (OsJAR1), and antioxidant (OsSOD-Cu/Zn, OsCATA, and OsAPX1) gene expression profiling. In this study, the arsenic-tolerant rhizobacterium RK027 was identified as Bacillus subtilis, exhibiting multiple PGP traits, including IAA, ammonia, and EPS production, phosphate solubilization, and ACCD activity, under both non-stressed and As^III-stressed conditions. The FT-IR analysis of EPS revealed the presence of functional groups that likely form As^III–EPS complexes, reducing As^III translocation. Rice seed priming with RK027 and subsequent plant inoculation exhibited significant improvements in morphophysiological and biochemical traits, including antioxidant activities, during the vegetative and reproductive phases under both conditions. The qRT-PCR analysis indicated that B. subtilis RK027 significantly upregulated OsAOS1 (38% and 25%) and OsJAR1 (35% and 30%), OsSOD-Cu/Zn (59% and 78%), OsCATA (40% and 18%), and OsAPX1 (30% and 25%) compared to non-inoculated stressed plants in vegetative and reproductive phases, respectively. These enhancements suggest that B. subtilis RK027 exerts IST by enhancing JA-biosynthesis and downstream JA-responsive antioxidant pathways under As^III-stress. Our findings highlight the potential of B. subtilis RK027 to improve rice plant health in arsenic-stressed environments.

Cyanobacteria are photosynthetic prokaryotes recognized for their varying pigment composition and capacity to adapt to different ecological situations. Even though they are significant, there aren't many studies comparing native cyanobacterial strains in terms of their ability to be used as biofertilizers. This study comparatively evaluated the physiological characteristics of seven cyanobacterial strains (Nostoc sp., Anabaena sp., Westiellopsis sp., Oscillatoria sp., Tolypothrix sp., Calothrix sp., and Phormidium sp.) isolated from paddy fields in different regions of Uttar Pradesh (Meerut, Muzaffarnagar, and Haridwar regions). The examined parameters included photosynthetic pigments- chlorophyll, carotenoids, phycobiliproteins-Phycocyanin (PC), Phycoerythrin (PE), and Allophycocyanin (APC), Total Soluble Protein (TSP), and carbohydrates. Cultures were cultivated in BG-11 medium, and samples were analyzed at 7th, 14th, 21st, and 28th days of incubation for examination via spectrophotometer. The findings indicated substantial interstrain differences. Anabaena sp. demonstrated the highest levels of chlorophyll, carotenoids, proteins, and carbohydrates on Day 14, while Tolypothrix sp. had the greatest concentrations of APC and PE. The strain-specific variations underscore the metabolic diversity of paddy field cyanobacteria. This thorough comparison of physiological data sheds light on the adaptation mechanisms of cyanobacteria and their potential uses as natural biofertilizers and in biotechnological applications.

Fusarium wilt disease is a significant challenge to the tomato crop, causing economic losses worldwide. The unwise use of chemical fungicides has raised concerns about food safety. Hence, biocontrol is a sustainable strategy for controlling Fusarium wilt disease. This study aimed to promote growth and manage Fusarium wilt disease in pea plants using two Bacillus strains (Bacillus aryabhattai strain Z-48 and Bacillus cereus strain Z-53) either alone or in a synthetic consortium. The application of the consortium of both Bacillus strains provided maximum protection against Fusarium wilt disease, showing the biocontrol effect of 54.3%. Under Fusarium disease stress, the consortium application increased shoot length, root length and dry biomass up to 88.6%, 31.1%, and 86.7% respectively, compared with the pathogen alone treatment. Likewise, the application of the Bacillus consortium significantly increased the time-course accumulation of defence-related enzymes, and photosynthetic pigments in Pea plants. Non-targeted metabolite profiling indicated extensive remodulations in the production of a wide array of metabolites upon application of the consortium (Z-48 + Z-53). The multivariate analysis showed strong relationships between treatments and different metabolites, including phenylalanine, ursolic acid, and glycerol-3-phosphocholine. The study demonstrates that this Bacillus consortium can be effectively used to develop a biocontrol-based formulation for farming applications.

Tomato (Solanum lycopersicum L.) is a major horticultural crop worldwide but remains highly vulnerable to soil-borne fungal pathogens that threaten greenhouse production. Increasing incidences of root rot and wilt have been observed in tomato nurseries and greenhouses in the Qassim and Riyadh regions of Saudi Arabia. This study aimed to identify the causal fungal agents and assess cultivar resistance under controlled conditions. Symptomatic root samples were collected, and pathogens were isolated, morphologically characterized, and confirmed through internal transcribed spacer (ITS) sequencing. Pathogenicity tests verified Fusarium oxysporum, Fusarium foetens, Ectophoma multirostrata, and Pygmaeomyces thomasii as causal agents of tomato root rot and wilt. Notably, E. multirostrata and P. thomasii were recorded for the first time as tomato root pathogens in Saudi Arabia. Four commercial tomato cultivars (Ace 55 VF, Marmande, Rio Grande, and Red Cherry) were evaluated for resistance. Disease incidence, severity, and growth parameters revealed significant variability among cultivars, with ‘Red Cherry’ and ‘Rio Grande’ showing enhanced resistance compared to more susceptible varieties. These results emphasize the novelty of detecting two previously unreported pathogens in Saudi Arabia and demonstrate the practical relevance of identifying resistant cultivars for field application. Overall, the study provides valuable insights supporting sustainable tomato production and offers a foundation for future resistance-breeding strategies.

Escherichia coli is considered a major extended-spectrum β-lactamases producer, of which CTX-M is the most common member. However, the different variants of this primary resistance-determinant make it challenging to detect by conventional PCR-based techniques. Therefore, in this study, we investigated the transcriptional response of 2 secondary resistance genes, repB and mtgA, under sub-inhibitory concentrations of oxy-imino cephalosporins in resistant isolates of E. coli harboring bla_CTX-M. The STRING database and Cytoscape software were used to identify the secondary resistance genes by gene network analysis. The cephalosporin-resistant isolate of E. coli co-harboring repB and mtgA, along with bla_CTX-M, was employed for the current study. The bla_CTX-M-carrying plasmid was successfully eliminated from the native-type isolate using 6% and 8% SDS treatment for 7 days. The plasmid was also transformed into a recipient strain, E. coli DH5α, by the heat-shock method. All three models were grown under sub-inhibitory stress of cephalosporins, and the transcriptional response of repB and mtgA was determined by quantitative real-time PCR. The study revealed that the transcriptional responses of both repB and mtgA were antibiotic-specific, which potentially can serve as a secondary resistance reporter for cephalosporin resistance in E. coli.