Macrolactin A mediated biocontrol of Fusarium oxysporum and Rhizoctonia solani infestation on Amaranthus hypochondriacus by Bacillus subtilis BS-58.

Plant diseases are one of the main hurdles for successful crop production and sustainable agriculture development world-wide. Though several chemical measures are available to manage crop diseases, many of them have serious side effects on humans, animals and the environment. Therefore, the use of such chemicals must be limited by using effective and eco-friendly alternatives. In view of the same, we found a Bacillus subtilis BS-58 as a good antagonist towards the two most devastating phytopathogens, i.e., Fusarium oxysporum and Rhizoctonia solani. Both the pathogens attack several agricultural crops (including amaranth) and induce a variety of infections in them. The findings of scanning electron microscopy (SEM) in this study suggested that B. subtilis BS-58 could inhibit the growth of both the pathogenic fungi by various means such as perforation, cell wall lysis, and cytoplasmic disintegration in the fungal hyphae. Thin-layer chromatography, LC-MS and FT-IR data revealed the antifungal metabolite to be macrolactin A with a molecular weight of 402 Da. Presence of the mln gene in the bacterial genome further endorsed that the antifungal metabolite produced by BS-58 was macrolactin A. Pot trial conducted in the present study showed that seed treatment by BS-58 effectively reduced seedling mortality (54.00 and 43.76%) in amaranth, when grown in pathogen infested soil (F. oxysporum and R. solani, respectively), when compared to their respective negative controls. Data also revealed that the disease suppression ability of BS-58 was almost equivalent to the recommended fungicide, carbendazim. SEM analysis of roots of the seedlings recovered from pathogenic attack substantiated the hyphal disintegration by BS-58 and prevention of amaranth crop. The findings of this study conclude that macrolactin A produced by B. subtilis BS-58 is responsible for the inhibition of both the phytopathogens and the suppression of the diseases caused by them. Being native and target specific, such strains under suitable conditions, may result in ample production of antibiotic and better suppression of the disease.

The changing paradigm of rhizobial taxonomy and its systematic growth upto postgenomic technologies.

Rhizobia are a diazotrophic group of bacteria that are usually isolated form the nodules in roots, stem of leguminous plants and are able to form nodules in the host plant owing to the presence of symbiotic genes. The rhizobial community is highly diverse, and therefore, the taxonomy and genera-wise classification of rhizobia has been constantly changing since the last three decades. This is mainly due to technical advancements, and shifts in definitions, resulting in a changing paradigm of rhizobia taxonomy. Initially, the taxonomic definitions at the species and sub species level were based on phylogenetic analysis of 16S rRNA sequence, followed by polyphasic approach to have phenotypic, biochemical, and genetic analysis including multilocus sequence analysis. Rhizobia mainly belonging to α- and ß-proteobacteria, and recently new additions from γ-proteobacteria had been classified. Nowadays rhizobial taxonomy has been replaced by genome-based taxonomy that allows gaining more insights of genomic characteristics. These omics-technologies provide genome specific information that considers nodulation and symbiotic genes, along with molecular markers as taxonomic traits. Taxonomy based on complete genome sequence (genotaxonomy), average nucleotide identity, is now being considered as primary approach, resulting in an ongoing paradigm shift in rhizobial taxonomy. Also, pairwise whole-genome comparisons, phylogenomic analyses offer correlations between DNA and DNA re-association values that have delineated biologically important species. This review elaborates the present classification and taxonomy of rhizobia, vis-a-vis development of technical advancements, parameters and controversies associated with it, and describe the updated information on evolutionary lineages of rhizobia.

Diagnosis, prevention, and treatment of coronavirus disease: a review.

INTRODUCTION: Coronavirus disease (COVID-19) was first reported in Wuhan, China, in late December 2019 and subsequently, declared a pandemic. As of 3 June 2021, 172,493,290 individuals have acquired COVID-19 and 3,708,334 patients have died worldwide, according to the World Health Organization. AREAS COVERED: This review explores epidemiology; virology; pathogenesis; genomic variations; mode of transmission; clinical occurrence; diagnosis; and treatment with antiviral agents, antibiotics, and supportive therapies. It covers a nanotechnology-based treatment approach and emphasizes the importance of herbal and marine antiviral drugs. The review attempts to explain current advances in research, prevention, and control of COVID-19 spread through artificial intelligence and vaccine development status under cosmopolitan consideration. EXPERT OPINION: While COVID-19 research is advancing at full capacity, the discovery of drugs or vaccines that can fight the pandemic is necessary. Human survival in such a critical situation will be possible only with the development of strong immunity by opting for exercise, yoga, and consumption of hygienic food and beverages. Therefore, education about COVID-19 lethality and its impact on livelihood is important. The pandemic has also shown positive effects on the environment, such as a significant reduction in environmental pollution and global warming and improvement in river water quality.

Cyclic siloxane biosurfactant-producing Bacillus cereus BS14 biocontrols charcoal rot pathogen Macrophomina phaseolina and induces growth promotion in Vigna mungo L.

Rhizobacteria are vital component of soil-plant interfaces which helps in plant growth responses and disease management. Precisely, the role of biosurfactant production by rhizobacteria in biocontrol mechanisms is underscored. The current study explores the destructive effect of a biosurfactant-producing bacterium Bacillus cereus BS14 on fungal growth under in vitro experiments and showed in vivo reduction of disease severity in pulse crop Vigna mungo. In this study, B. cereus BS14 was observed as plant growth-promoting rhizobacterium (PGPR) based on abilities of production of phytohormone and HCN, phosphate solubilization and biocontrol of Macrophomina phaseolina. The purified biosurfactant from BS14 inhibited the fungal growth by arresting radially growing mycelia. Scanning electron microscope (SEM) study revealed deformities at cellular level in the mycelia of M. phaseolina. The biosurfactant of Bacillus BS14 was identified as cyclic siloxane in GC-MS spectroscopy and FT-IR spectroscopy analyses. In the pot trial studies, B. cereus BS14 proved its efficiency for the growth promotion of Vigna mungo and significantly reduced disease severity index. The present study concludes that biosurfactant of rhizobacterial origin and rhizobacteria can serve for biological control, improvement in crop production and agricultural sustainability. In future, it can be developed as biological control and biofertilizer formulations for legume crops, and commercialized for routine farming practices.

Insights of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) pandemic: a current review.

COVID-19, a pandemic of the 21st century caused by novel coronavirus SARS-CoV-2 was originated from China and shallowed world economy and human resource. The medical cures via herbal treatments, antiviral drugs, and vaccines still in progress, and studying rigorously. SARS-CoV-2 is more virulent than its ancestors due to evolution in the spike protein(s), mediates viral attachment to the host's membranes. The SARS-CoV-2 receptor-binding spike domain associates itself with human angiotensin-converting enzyme 2 (ACE-2) receptors. It causes respiratory ailments with irregularities in the hepatic, nervous, and gastrointestinal systems, as reported in humans suffering from COVID-19 and reviewed in the present article. There are several approaches, have been put forward by many countries under the world health organization (WHO) recommendations and some trial drugs were introduced for possible treatment of COVID-19, such as Lopinavir or Ritonavir, Arbidol, Chloroquine (CQ), Hydroxychloroquine (HCQ) and most important Remdesivir including other like Tocilizumab, Oritavancin, Chlorpromazine, Azithromycin, Baricitinib, etc. RT-PCR is the only and early detection test available besides the rapid test kit (serodiagnosis) used by a few countries due to unreasonable causes. Development of vaccine by several leader of pharmaceutical groups still under trial or waiting for approval for mass inoculation. Management strategies have been evolved by the recommendations of WHO, specifically important to control COVID-19 situations, in the pandemic era. This review will provide a comprehensive collection of studies to support future research and enhancement in our wisdom to combat COVID-19 pandemic and to serve humanity.

Combined effects of rhizo-competitive rhizosphere and non-rhizosphere Bacillus in plant growth promotion and yield improvement of Eleusine coracana (Ragi).

This study emphasizes the beneficial role of rhizo-competitive Bacillus spp. isolated from rhizospheric and non-rhizospheric soil in plant growth promotion and yield improvement via nitrogen fixation and biocontrol of Sclerotium rolfsii causing foot rot disease in Eleusine coracana (Ragi). The selection of potent rhizobacteria was based on plant-growth-promoting attributes using Venn set diagram and Bonitur scale. Bacillus pumilus MSTA8 and Bacillus amyloliquefaciens MSTD26 were selected because they were effective in root colonization, rhizosphere competence, and biofilm formation using root exudates of E. coracana L. rich with carbohydrates, proteins, and amino acids. The relative chemotaxis index of the isolates expressed the invasive behavior of the rhizosphere. During pot and field trials, the consortium of the rhizobacteria in a vermiculite carrier increased the grain yield by 37.87%, with a significant harvest index of 16.45. Soil analysis after the field trial revealed soil reclamation potentials to manage soil nutrition and fertility. Both indexes ensured crop protection and production in eco-safe ways and herald commercialization of Bacillus bio-inoculant for improvement in crop production and disease management of E. coracana.

Evaluation of Probiotic Potential and Safety Assessment of Lactobacillus pentosus MMP4 Isolated From Mare's Lactation.

Lactic acid bacteria isolated from indigenous milk of different animals were investigated for their efficacy, safety, and probiotic potential. The most potential isolate MMP4 was screened from mare's milk, which was further identified as Lactobacillus pentosus by using 16S rRNA gene sequencing and phylogeny. The probiotic potential of strain MMP4 was assessed by its ability to survive under acidic environment and in presence of bile salts along with the ability to inhibit food-borne as well as clinical pathogenic microorganisms such as Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Salmonella typhi. The phenol tolerance with cogent hydrophobicity to different hydrocarbons was demonstrated. Bile salt hydrolase activity of L. pentosus MMP4 was confirmed by detecting the Bsh gene by using colony PCR. The presence of Mub, Map, and EF-Tu genes involved in adhesion conferred the behavior of passage and adherence to gastrointestinal tract. Scanning electron microscopy of intestinal autopsy from albino mice revealed the attachment of bacterial cells on the mucus-lined intestinal walls against pathogens and further proved in vivo adhesion ability. The presence of intrinsic antibiotic resistance and lack of DNase, gelatinase, and hemolytic activity in MMP4 support its safety as probiotic traits. Thus, MMP4 bears an excellent and pragmatic properties for being used as probiotic and may be exploited in dairy industry.

Differential antagonistic responses of Bacillus pumilus MSUA3 against Rhizoctonia solani and Fusarium oxysporum causing fungal diseases in Fagopyrum esculentum Moench.

Chitinase and surfactin-mediated biocontrol of Rhizoctonia solani and Fusarium oxysporum causing wilt and root rot of Fagopyrum esculentum respectively has been studied in this communication. Bacillus pumilus MSUA3 as a potential bacterial strain strongly inhibited the growth of R. solani and F. oxysporum involving the chitinolytic enzymes and an antibiotic surfactin. Plant growth promoting attributes seem to be involved in plant growth promotion and yield attributes. The action of cell-free culture supernatant (CFCS) was found deleterious to F. oxysporum and R. solani even in the heat-treated (boiled/autoclaved) CFCS. The possible involvement of surfactin in disease control was revealed by colony PCR amplification of SrfA. Chitinolytic enzyme and antibiotic surfactin evidenced differential biocontrol of F. oxysporum and R. solani by B. pumilus MSUA3. A significant reduction in disease index under gnotobiotic conditions and productivity enhancement of F. esculentum using vermiculite-based bioformulation revealed B. pumilus MSUA3 as a successful potential biocontrol agent (BCA) and an efficient plant growth promoting rhizobacterium (PGPR) for disease management and productivity enhancement of buckwheat crop.

Termitarium-Inhabiting Bacillus spp. Enhanced Plant Growth and Bioactive Component in Turmeric (Curcuma longa L.).

Curcumin (diferuloyl methane) is the main bioactive component of turmeric (Curcuma longa L.) having remarkable multipotent medicinal and therapeutic applications. Two Bacilli isolated from termitarium soil and identified as Bacillus endophyticus TSH42 and Bacillus cereus TSH77 were used for bacterization of rhizome for raising C. longa ver. suguna for growth and enhancement. Both the strains showed remarkable PGP activities and also chemotactic in nature with high chemotactic index. Turmeric plants bacterized with strains B. endophyticus TSH42 and B. cereus TSH77 individually and in combination increased plant growth and turmeric production up to 18% in field trial in comparison to non-bacterized plants. High-performance liquid chromatography analysis was performed to determine the content of curcumin, which showed concentration of curcumin in un-inoculated turmeric as 3.66 g which increased by 13.6% (4.16 g) when combination of TSH42 and TSH77 was used.