Molecular characterization of Fusarium oxysporum f. sp. ciceri causing wilt of chickpea

Thirty isolates of Fusarium oxysporum f. sp. ciceri were isolated from rhizosphere soil of chickpea from different locations in Northern India. The amount of genetic variation was evaluated by polymerase chain reaction (PCR) amplification with a set of 40 RAPD primers and 2 IGS primers. Less than 10% of the amplified fragments in each case were polymorphic. Genetic similarity between each of the isolates was calculated and results indicate that there was little genetic variability among the isolates collected from the different locations. At the 0.75 similarity index the isolates divides into three groups. Isolates Foc-A18, Foc-A19, Foc-A20 forming a similar group and far different from other isolates.Key words: Fusarium oxysporum f. sp. ciceri, Fusarium wilt of chickpea, RAPD, ITS, IGS

Isolation of endophytic fungi from South African plants, and screening for their antimicrobial and extracellular enzymatic activities and presence of type I polyketide synthases

Endophytes are bacteria or fungi which live inside the host plant and participate in many biological processes without causing disease or other adverse effects. Endophytes are recognised as a rich source of secondary metabolites with potentially useful pharmacological properties. Many South African medicinal plants are highly under-investigated sources of potentially useful endophytic microbes. In this report six endophytic fungi were obtained from the leaves, stems and roots of South African medicinal plants which are known for their traditional uses and pharmacological properties. The endophytic fungi were isolated from Cotyledon orbiculata L., Psychotria zombamontana (Kuntze) Petit, Tecomaria capensis (Thunb.) Lindl., Catha edulis (Vahl) Endl. and Melianthus comosus Vahl. The crude extracts of the isolated endophytic fungi were investigated for their antimicrobial potential, extracellular enzymatic activity and phosphate solubilization. Additionally, the present study used genetic screening to assess the ability of the endophytic fungi to synthesize bioactive compounds, indicated by the presence of the polyketide synthase type 1 (PKS 1) gene. In preliminary microbial inhibition screening the fungal extracts had promising antifungal activity against Cryptococcus neoformans and Candida albicans. Furthermore, the endophytic fungus Talaromyces funiculosus displayed extracellular enzymatic activity, namely xylanase and cellulase. Five fungal strains demonstrated ability to solubilize phosphate and three strains demonstrated the presence of polyketide synthase type 1 (PKS 1) gene. It is worth considering further investigation of their bioactive secondary metabolites.The University of Pretoria, South Africahttp://www.elsevier.com/locate/sajb2022-04-16hj2021Paraclinical Science

<em>In vitro</em> evaluation of antimicrobial activities and antibiotic susceptibility profiling of culturable actinobacteria from fresh water streams

665-673Actinobacteria are major producers of antibiotics, industrially significant enzymes and many pharmaceutically important biologically active compounds. Twenty two actinobacterial strains were isolated from fresh water stream sediment samples of Murlen National Park, Mizoram, India. The actinobacterial strains were screened against antifungal pathogens (Fusarium oxysporum, Fusarium udum, Fusarium proliferatum, Fusarium oxysporum ciceri and Fusarium graminearum), and antibacterial activities against five bacterial pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Micrococcus luteus, Bacillus subtilis and Escherichia coli) and a yeast pathogen Candida albicans. All strains showed antibacterial activity against E. coli and F. proliferatum. Based on the results of antagonistic, antibacterial and anti-yeast, two most potent strains Kocuria sp. and Streptomyces intermidus were further evaluated for their antibiotics susceptibility activity against 21 different antibiotics. Kocuria sp. showed resistance to 10 antibiotics whereas Streptomyces intermidus was resistance to 15 antibiotics. Modular genes Polyketide Synthase (PKS II) and Nonribosomal Peptide Synthetase (NRPS) were also detected in these two strains, which might be responsible for the production of secondary metabolites. Two volatile compounds, Di-N-octyl phthalate and 1-Bromo-3, 7-Dimethyloctane were identified from the extract of Streptomyces intermidus BPSWAC29 strain using Gas chromatography Mass spectrometry (GC-MS). This study highlights the promise of discovering novel actinobacteria with antimicrobial activity from underexplored niche biotopes such as fresh water stream sediments

Molecular characterization of Fusarium oxysporum f. sp. ciceri causing wilt of chickpea

Thirty isolates of Fusarium oxysporum f. sp. ciceri were isolated from rhizosphere soil of chickpea from different locations in Northern India. The amount of genetic variation was evaluated by polymerase chain reaction (PCR) amplification with a set of 40 RAPD primers and 2 IGS primers. Less than 10% of the amplified fragments in each case were polymorphic. Genetic similarity between each of the isolates was calculated and results indicate that there was little genetic variability among the isolates collected from the different locations. At the 0.75 similarity index the isolates divides into three groups. Isolates Foc-A18, Foc-A19, Foc-A20 forming a similar group and far different from other isolates

Rhizospheric bacterial community of endemic rhododendron arboreum sm. ssp. delavayi along eastern himalayan slope in tawang

Information on rhizosphere microbiome of endemic plants from high mountain ecosystems against those of cultivated plantations is inadequate. Comparative bacterial profiles of endemic medicinal plant Rhododendron arboreum Sm. subsp. delavayi rhizosphere pertaining to four altitudinal zonation Pankang Thang (PTSO), Nagula, Y-junction and Bum La (Indo-China border; in triplicates each) along cold adapted Eastern slope of Himalayan Tawang region, India is described here. Significant differences in DGGE profile between below ground bulk vs. rhizospheric community profile associated with the plant was identified. Tagged 16S amplicon sequencing from PTSO (3912 m) to Burn La (4509 m), revealed that soil pH, total nitrogen (TN), organic matter (OM) significantly influenced the underlying bacterial community structure at different altitudes. The relative abundance of Acidobacteria was inversely related to pH, as opposed to TN which was positively correlated to Acidobacteria and Proteobacteria abundance. TN was also the significant predictor for less abundant taxonomic groups Chioroflexi, Gemmatimonadetes. and Nitrospirae. Bum La soil harbored less bacterial diversity compared to other sites at lower altitudes. The most abundant phyla at 3% genetic difference were Acidobacteria, Actinobacteria, and Proteobacteria amongst others. Analysis of similarity indicated greater similarity within lower altitudinal than higher altitudinal group (ANOSIM, R = 0.287, p = 0.02). Constraining the ordination with the edaphic factor explained 83.13% of variation. Unique phylotypes of Bradyrhizobium and uncultured Rhizobiales were found in significant proportions at the four regions. With over 1% relative abundance Actinobacteria (42.6%), Acidobacteria (24.02%), Proteobacteria (16.00%), AD3 (9.23%), WPS-2 (5.1%), and Chloroflexi (1.48%) dominated the core microbiome

Epigenetic manipulation for secondary metabolite activation in endophytic fungi: current progress and future directions

ABSTRACTFungal endophytes have emerged as a promising source of secondary metabolites with significant potential for various applications in the field of biomedicine. The biosynthetic gene clusters of endophytic fungi are responsible for encoding several enzymes and transcriptional factors that are involved in the biosynthesis of secondary metabolites. The investigation of fungal metabolic potential at genetic level faces certain challenges, including the synthesis of appropriate amounts of chemicals, and loss of the ability of fungal endophytes to produce secondary metabolites in an artificial culture medium. Therefore, there is a need to delve deeper into the field of fungal genomics and transcriptomics to explore the potential of fungal endophytes in generating secondary metabolites governed by biosynthetic gene clusters. The silent biosynthetic gene clusters can be activated by modulating the chromatin structure using chemical compounds. Epigenetic modification plays a significant role by inducing cryptic gene responsible for the production of secondary metabolites using DNA methyl transferase and histone deacetylase. CRISPR-Cas9-based genome editing emerges an effective tool to enhance the production of desired metabolites by modulating gene expression. This review primarily focuses on the significance of epigenetic elicitors and their capacity to boost the production of secondary metabolites from endophytes. This article holds the potential to rejuvenate the drug discovery pipeline by introducing new chemical compounds

Pharmacological potential of Bidens pilosa L. and determination of bioactive compounds using UHPLC-QqQLIT-MS/MS and GC/MS

Abstract Background Research of natural products from traditionally used medicinal plants to fight against the human ailments is fetching attention of researchers worldwide. Bidens pilosa Linn. var. Radiata (Asteraceae) is well known for its folkloric medicinal use against various diseases from many decades. Mizoram, North East India, has high plant diversity and the use of this plant as herbal medicine is deep rooted in the local tribes. The present study was executed to understand the pharmacological potential of B. pilosa leaves extract. Methods The antimicrobial potential was determined using agar well diffusion and broth microdilution method against bacterial and yeast pathogens. Cytotoxicity was evaluated using MTT and apoptotic DNA fragmentation assays. Further, the antioxidant ability of the extract was analysed using DPPH and ABTS free radical scavenging assay. Mosquitocidal activity was evaluated against third in-star larvae of C. quinquefasciatus using dose response and time response larvicidal bioassay. Additionally, the major phenolic and volatile compounds were determined using UHPLC-QqQLIT-MS/MS and GC/MS respectively. Results We found that the extract showed highest antimicrobial activity against E. coli (MIC 80 μg/mL and IC50 110.04 μg/mL) and showed significant cytotoxicity against human epidermoid carcinoma (KB-3-1) cells with IC50 values of 99.56 μg/mL among the tested cancer cell lines. The IC50 values for scavenging DPPH and ABTS was 80.45 μg/mL and 171.6 μg/mL respectively. The extract also showed the high phenolics (72 μg GAE/mg extract) and flavonoids (123.3 μg Quercetin /mg extract). Lastly, five bioactive and six volatile compounds were detected using UHPLC-QqQLIT-MS/MS and GC-MS respectively which may be responsible for the plant’s bioactivities. An anticancerous compound, Paclitaxel was detected and quantified for the first time from B. pilosa leaves extract, which further showed the anticancerous potential of the tested extract. Conclusion On the basis of the present investigation, we propose that the leaf extract of B. pilosa might be a good candidate for the search of efficient environment friendly natural bioactive agent and pharmaceutically important compounds