For a safe and sustainable environment, effective microbes as biocontrol agents are in high demand. We have isolated a new Bacillus velezensis strain DTU001, investigated its antifungal spectrum, sequenced its genome, and uncovered the production of lipopeptides in HPLC-HRMS analysis. To test the antifungal efficacy, extracts of B. velezensis DTU001 was tested against a range of twenty human or plant pathogenic fungi. We demonstrate that inhibitory potential of B. velezensis DTU001 against selected fungi is superior in comparison to single lipopeptide, either iturin or fengycin. The isolate showed analogous biofilm formation to other closely related Bacilli. To further support the biocontrol properties of the isolate, coculture with Candida albicans demonstrated that B. velezensis DTU001 exhibited excellent antiproliferation effect against C. albicans. In summary, the described isolate is a potential antifungal agent with a broad antifungal spectrum that might assist our aims to avoid hazardous pathogenic fungi and provide alternative to toxicity caused by chemicals.
Arthrobacter globiformis mrc11 was isolated from a Khangkhui cave deposit. Here, we report the draft genome sequence of this phylogenetically novel organism, which has a genome size of 4.89 Mb, a 65.9% GC content, and 4,657 predicted open reading frames that can be translated. This study will give insights into the mechanisms of the strain's antimicrobial activity.
Towards assessing the genetic diversity and occurrence of Trichoderma species from the Indian region of Indo-Burma Biodiversity hotspot, a total of 193 Trichoderma strains were isolated from cultivated soils of nine different districts of Manipur comprising 4 different agroclimatic zones. The isolates were grouped based on the morphological characteristics. ITS-RFLP of the rDNA region using three restriction digestion enzymes: Mob1, Taq1, and Hinf1, showed interspecific variations among 65 isolates of Trichoderma . Based on ITS sequence data, a total of 22 different types of representative Trichoderma species were reported and phylogenetic analysis showed 4 well-separated main clades in which T. harzianum was found to be the most prevalent spp. among all the Trichoderma spp. Combined molecular and phenotypic data leads to the development of a taxonomy of all the 22 different Trichoderma spp., which was reported for the first time from this unique region. All these species were found to produce different extrolites and enzymes responsible for the biocontrol activities against the harmful fungal phytopathogens that hamper in food production. This potential indigenous Trichoderma spp. can be targeted for the development of suitable bioformulation against soil and seedborne pathogens in sustainable agricultural practice.
In a natural ecosystem, the plant is in a symbiotic relationship with beneficial endophytes contributing huge impact on its host plant. Therefore, exploring beneficial endophytes and understanding its interaction is a prospective area of research. The present work aims to characterize the fungal endophytic communities associated with healthy maize and rice plants and to study the deterministic factors influencing plant growth and biocontrol properties against phytopathogens, viz, Pythium ultimum, Sclerotium oryzae, Rhizoctonia solani, and Pyricularia oryzae. A total of 123 endophytic fungi was isolated using the culture-dependent approach from different tissue parts of the plant. Most dominating fungal endophyte associated with both the crops belong to genus Fusarium, Sarocladium, Aspergillus, and Penicillium and their occurrence was not tissue specific. The isolates were screened for in vitro plant growth promotion, stress tolerance, disease suppressive mechanisms and based on the results, each culture from both the cereal crops was selected for further study. Acremonium sp. (ENF 31) and Penicillium simplicisssum (ENF22), isolated from maize and rice respectively could potentially inhibit the growth of all the tested pathogens with 46.47 ± 0.16 mm to 60.09 ± 0.04 mm range zone of inhibition for ENF31 and 35.48 ± 0.14 to 62.29 ± 0.15 mm for ENF22. Both significantly produce the defensive enzymes, ENF31 could tolerate a wide range of pH from 2 to 12, very important criteria, for studying plant growth in different soil types, especially acidic as it is widely prevalent here, making more land unsuitable for cultivation. ENF22 grows in pH range 3-12, with 10% salt tolerating ability, another factor of consideration. Study of root colonization during 7th to 30th days of growth phase reveals that ENF31 could colonize pleasantly in rice, though a maize origin, ranging from 1.02 to 1.21 log10 CFU/g root and in maize, it steadily colonizes ranging from 0.95 to 1.18 log10 CFU, while ENF22 could colonize from 0.98 to 1.24 Log10CFU/g root in rice and 1.01 to 1.24Log10CFU/g root in maize, just the reverse observed in Acremonium sp. Therefore, both the organism has the potency of a promising Bio-resource agent, that we must definitely explore to fill the gap in the agriculture industry.
Blast of rice (Oryza sativae L.) caused by Pyricularia oryzae is one of the most destructive disease in Manipur giving losses ranging from 60 to 100%. In the present investigation, biocontrol of this disease was attempted by isolating local strains of Pseudomonas fluorescens and Trichoderma spp. P. fluorescens B 24 gave maximum mycellial inhibition (77.5%) among the bacterial biocontrol and T. koningiopsis T 162 gave maximum inhibition of 46.25%. Seed germination, root and shoot length were enhanced by single treatment (B 24) in vitro conditions. Plant height was also increased by 5% in greenhouse and 12.02% in field trial with single application (B 24). However, greenhouse and field data revealed significant reduction in Blast incidence (5.1% and 3.4%), lesion number (35.53% and 58.72%) and size (18.86%, 16.39%) when applied in consortia (B 24+ T 162) as compared to single application (B 24) resulting in incidence of 6.7% and 3.92%, lesion number of 33.33% and 14.67%, size of 15.09% and 27.83% irrespective of greenhouse and field trial. The results indicated the effectiveness of combined application of P. fluorescens B 24 and T. koningiopsis T 162 for plant growth promotion and control of Blast of rice and therefore can be integrated for managing Blast of rice.
Stem rot of rice (Oryza sativae L.) caused by Sclerotium oryzae Catt. is found to occur frequently in Manipur infecting all cultivated lowland rice cultivars and become a major concern in rice production. Local strains of Pseudomanas fluorescens and Trichoderma collected from rice fields of Imphal East and Imphal West districts of Manipur were screened for their ability to control S. oryzae and production of different biocontrol mechanisms under laboratory conditions. Further, combined application of talc formulations of selected strains of P. fluorescens IE 62 and T. inhamatum (T 80) (based on in vitro antifungal activity, production of cell wall degrading enzymes and secondary metabolites) were assessed for their plant growth promotion and biocontrol ability under greenhouse and field conditions. Seed germination, root length, shoot length and plant height were enhanced by treatment with P. fluorescens IE 62 and T. inhamatum T 80 in vitro conditions as compared to single applications under greenhouse and field conditions. Field data revealed significant reduction in stem rot incidence, lesion number and size when applied in consortia. Percent reduction in lesion number and size were recorded as 35.15% & 26.14% when applied with P. fluorescens IE 62 alone and 51.63% & 14.43% with combined applications as compared to control plot indicating better biocontrol activity. The results indicated the effectiveness of combined application of local strains of P. fluorescens IE 62 and T. inhamatum T 80 resulting increased plant growth and control of S. oryzae and therefore can be used as potential bioagents for managing Stem rot disease in rice.
ABSTRACT For a safe and sustainable environment, effective microbes as biocontrol agents are in high demand. We have isolated a new Bacillus velezensis strain DTU001, investigated its antifungal spectrum, sequenced its genome, and uncovered the production of lipopeptides in HPLC-HRMS analysis. To test the antifungal efficacy, extracts of B. velezensis DTU001 was tested against a range of twenty human or plant pathogenic fungi. We demonstrate that inhibitory potential of B. velezensis DTU001 against selected fungi is superior in comparison to single lipopeptide, either iturin or fengycin. The isolate showed analogous biofilm formation to other closely related Bacilli . To further support the biocontrol properties of the isolate, coculture with Candida albicans demonstrated that B. velezensis DTU001 exhibited excellent antiproliferation effect against C. albicans . In summary, the described isolate is a potential antifungal agent with a broad antifungal spectrum that might assist our aims to avoid hazardous pathogenic fungi and provide alternative to toxicity caused by chemicals.
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