RESUMO
Salt affected cotton rhizospheric soil was explored for multi-stress resistance microbes to obtain 46 rhizobacteria. Of these, seven strains strongly inhibited the growth of phytopathogenic fungus Rhizoctonia solani by virtue of antifungal compound 2,4-diacetylphloroglucinol (DAPG) production. These seven strains demonstrated an array of plant growth-promoting activities as follows: (i) production of indole-3-acetic acid, ammonia, siderophore; (ii) solubilisation of phosphate, while two isolates showed Zn solubilisation. The phenetic and 16S ribotyping revealed affiliation of all the isolates to Pseudomonas guariconensis and presence of phlD gene marker for DAPG production. Among the seven isolates, strain VDA8 showed the highest DAPG production (0.16 µg ml-1) in liquid synthetic medium under aerobic conditions at 28 °C. Furthermore, sucrose, peptone, sodium hydrogen phosphate, ZnSO4, pH 8.0, and NaCl (1%) were observed as the best carbon, nitrogen, phosphate, trace element, pH, and salt concentration, respectively for maximum production of DAPG by strain VDA8 (3.62 ± 0.04 µg ml-1). The strain VDA8 was further assessed for wheat (Triticum aestivum) growth promotion by seed biopriming under laboratory (plate assay) and field condition in alkaline saline soil with pH 8.5. The field scale (324 m2) trials demonstrated 28.6% enhanced grain production compared to control demonstrating the newly isolated Pseudomonas sp. as multi-potent bioinoculant.
RESUMO
The pandemic of Severe Acute Respiratory Syndrome Coronavirus-2 has affected millions of people worldwide with common symptoms of fever, cough, and respiratory complications. The pandemic has posed a huge challenge to emergency health services due to unavailability of potent therapeutic drugs. The proteins associated with the viral pathogenesis has been identified as suitable targets for drug design and warrants effective drug discovery to abate COVID-19. The papain-like protease (PLpro), nucleocapsid (N), main protease (Mpro) and non-structural protein (nsp12) of SARS-CoV-2, key component of processing of viral polyproteins, transcription, assembly and replication. On this streak, present study evaluated the interaction of ligand 2,4-diacetylphloroglucinol (DAPG) with viral proteins using molecular docking with (i) AutoDock 4.2.6 and (ii) AutoDock Vina followed by molecular dynamic simulation studies of protein-ligand complex configuration. The analysis revealed that PLpro (3E9S) and N (4J3K) protein corresponds to the highest docking score and therefore, selected for molecular dynamics simulation study (100 ns). The study comprised analysis of parameters: (i) RMSD and RMSF, (ii) radius of gyration- which indicated interaction of protein entities with ligand supported steadiness of the complex, (iii) Coulombic and Lennard-Jones interactions, which played a significant role in complex stability. DAPG showed a good number of H-bonds with PLpro and MM-PBSA binding energy when compared to the N protein. This study showed DAPG as a potential bioactive molecule to act as an inhibitor for the PLpro thereby, DAPG can be used as potential inhibitor against SARS-CoV-2 and is potential drug candidate against COVID-19. Supplementary Information: The online version contains supplementary material available at 10.1007/s11756-021-00979-4.
