| Abstrakt: |
Assam lemon (Citrus limon) is an indigenous plant of Assam known for its high concentration of ascorbic acid and reduction in cholesterol. Current study was aimed at studying the presence of endophytic bacteria in Assam lemon and exploring its potential in the production of secondary metabolites capable of inhibiting pathogens in vitro. Endophytic bacterium VITLTMJ4 produced bioactive compounds which effectively inhibited Escherichia coli, Bacillus cereus, Staphylococcus aureusand Pseudomonas aeruginosawith a zone size of 17.33, 15.66, 24.33 and 11.33 mm respectively in chloroform extract. The extract was purified using Solid Phase Extraction (SPE) column and Ultra Performance Liquid Chromatography (UPLC). A peak with a retention time at 8.082 min confirmed the presence of lead molecule which was further identified to be Pyrrolo[1,2-α] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl)-(PPDHMP) by Gas Chromatography Mass Spectrometry (GC-MS) with a peak at 19th minute and functional groups such as CC, N-H and CO obtained in Fourier-transform infrared spectroscopy (FT-IR) confirmed the compound. The 16S rRNA gene sequencing revealed the evolutionary distance of the effective strain to be closely related to Bacillussp. and scanning electron micrographs showed the resemblance of VITLTMJ4 to rod shaped morphology. Non-toxic nature of the bioactive compounds was confirmed by seed germination assay where the seeds of Vigna radiata, Vigna mungoand Cajanus cajanshowed growth pattern better than the solvent control. Current research is the first of its kind to our knowledge where endophytic bacteria has been obtained from Assam lemon. |
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