Comparative metagenomic analysis of rice soil samples revealed the diverse microbial population and biocontrol organisms against plant pathogenic fungus Magnaporthe oryzae.

Intensive cropping degrades soil quality and disrupts the soil microbiome. To understand the effect of rice monocropping on soil-microbiome, we used a comparative 16S rRNA metagenome sequencing method to analyze the diversity of soil microflora at the genomic level. Soil samples were obtained from five locations viz., Chamarajnagara, Davangere, Gangavathi, Mandya, and Hassan of Karnataka, India. Chemical analysis of soil samples from these locations revealed significant variations in pH (6.00-8.38), electrical conductivity (0.17-0.69 dS m-1), organic carbon (0.51-1.29%), available nitrogen (279-551 kg ha-1), phosphorous (57-715 kg ha-1) and available potassium (121-564 kg ha-1). The 16S metagenome analysis revealed that the microbial diversity in Gangavathi soil samples was lower than in other locations. The soil sample of Gangavathi showed a higher abundance of Proteobacteria (85.78%) than Mandya (27.18%). The Firmicutes were more abundant in Chamarajnagar samples (36.01%). Furthermore, the KEGG pathway study revealed enriched nitrogen, phosphorus, and potassium metabolism pathways in all soil samples. In terms of the distribution of beneficial microflora, the decomposers were more predominant than the nutrient recyclers such as nitrogen fixers, phosphorous mineralizers, and nitrifiers. Furthermore, we isolated culturable soil microbes and tested their antagonistic activity in vitro against a fungal pathogen of rice, Magnaporthe oryzae strain MG01. Six Bacillus sp. and two strains of Trichoderma harzianum showed higher antagonistic activity against MG01. Our findings indicate that metagenome sequencing can be used to investigate the diversity, distribution, and abundance of soil microflora in rice-growing areas. The knowledge gathered can be used to develop strategies for maintaining soil quality and crop conservation to increase crop productivity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02783-y.

Drug Repurposing Approaches: Existing Leads For Novel Threats And Drug Targets.

Drug Repurposing (DR) is an alternative to the traditional drug discovery process. It is cost and time effective, with high returns and low risk process that can tackle the increasing need for interventions for varied diseases and new outbreaks. Repurposing of old drugs for other diseases has gained a wider attention, as there have been several old drugs approved by FDA for new diseases. In the global emergency of COVID19 pandemic, this is one of the strategies implemented in repurposing of old anti-infective, anti-rheumatic and anti-thrombotic drugs. The goal of the current review is to elaborate the process of DR, its advantages, repurposed drugs for a plethora of disorders, and the evolution of related academic publications. Further, detailed are the computational approaches: literature mining and semantic inference, network-based drug repositioning, signature matching, retrospective clinical analysis, molecular docking and experimental phenotypic screening. We discuss the legal and economical potential barriers in DR, existent collaborative models and recommendations for overcoming these hurdles and leveraging the complete potential of DR in finding new indications.

Antioxidant profiling of Hippophae salicifolia growing in sacred forests of Sikkim, India.

Hippophae commonly known as sea-buckthorn, is a versatile plant with multipurpose uses including the control of soil erosion, biological nitrogen fixation and medicinal properties. In India, two species of sea-buckthorn; namely, Hippophae salicifolia D. Don and Hippophae rhamnoides L., are very common. H. salicifolia has a shrub-to-tree habit and is restricted to the Himalayan region, whereas H. rhamnoides is bushy, growing at higher altitude in India, and widely distributed in Europe and Asia. In this study, aqueous, methanol and acetone extracts of various parts of female and male plants of H. salicifolia were evaluated for total antioxidant activity, phenolic and flavonoid contents, and correlations were made. The total phenolic and flavonoid content in all the samples ranged from 99±32 to 1459±53mg gallic acid equivalent g-1, 135±12 to 707±62mg quercetin equivalent g-1 of dry extract, respectively. The highest free radical (DPPH) scavenging activity was found in methanol extracts of female bark and male leaf. Methanol extracts of male bark and male leaf showed maximum H2O2 activity at a concentration of 1mgmL-1. Antioxidant activity (FRAP method) ranged from 0.021 to 1.041 at concentrations ranging from 20 to 200µgmL-1 with a reducing capacity of extracts as water>methanol>acetone. Strong correlation (P<0.05) was observed between DPPH scavenging activity and total phenolic content from all the extracts under study.