New report of endophytic bacterium Achromobacter xylosoxidans from root tissue of Musa spp.

BACKGROUND: Cavendish (AAA) banana plant (Musa spp.) worldwide cultivated crop harbors many endophytic bacteria. Endophytic bacteria are those that live inside plant tissues without producing any visible symptoms of infection. RESULTS: Endophytic bacterium (MRH 11), isolated from root tissue of Musa spp.was identified as Achromobacter xylosoxidans (ON955872) which showed positive effects in IAA production, phosphate solubilization, catalase production. A. xylosoxidans also showed in vitro antagonism against Curvularia lunata causing leaf spot disease of Cavendish (AAA) banana (G-9 variety). The GC-MS analysis of culture filtrate of A. xylosoxidans (ON955872) confirmed this finding. GC-MS analysis was carried by using two solvent etheyl acetate and chloroform and it showed several antifungal compounds. The identification of these bioactive secondary metabolites compounds was based on the peak area, retention time, molecular weight, molecular formula and antimicrobial actions. GC-MS analysis result revealed the presence of major components including Cyclododecane, 1-Octanol, Cetene, Diethyl phthalate. In vivo test to banana plants was carried out in separate field as well as in potted conditions. Appearance of leaf spots after foliar spray of spore of pathogen and reduction in leaf spots after application of bacterial suspension was found. CONCLUSION: The present study has highlighted the role of endophytic bacterium as antagonist to the pathogen Curvularia lunata.

Antimicrobial potential of a ponericin-like peptide isolated from Bombyx mori L. hemolymph in response to Pseudomonas aeruginosa infection.

The main effectors in the innate immune system of Bombyx mori L. are antimicrobial peptides (AMPs). Here, we infected B. mori with varied inoculum sizes of Pseudomonas aeruginosa ATCC 25668 cells to investigate changes in morpho-anatomical responses, physiological processes and AMP production. Ultraviolet-visible spectra revealed a sharp change in λmax from 278 to 285 nm (bathochromic shift) in the hemolymph of infected B. mori incubated for 24 h. Further, Fourier Transform InfraRed studies on the hemolymph extracted from the infected B. mori showed a peak at 1550 cm-1, indicating the presence of α-helical peptides. The peptide fraction was obtained through methanol, acetic acid and water mixture (90:1:9) extraction, followed by peptide purification using Reverse Phase High Performance Liquid Chromatography. The fraction exhibiting antibacterial properties was collected and characterized by Matrix-Assisted Laser Desorption/Ionization-Time of Flight. A linear α-helical peptide with flexible termini (LLKELWTKMKGAGKAVLGKIKGLL) was found, corresponding to a previously described peptide from ant venom and here denominated as Bm-ponericin-L1. The antibacterial activity of Bm-ponericin-L1 was determined against ESKAPE pathogens. Scanning electron microscopy confirmed the membrane disruption potential of Bm-ponericin-L1. Moreover, this peptide also showed promising antibiofilm activity. Finally, cell viability and hemolytic assays revealed that Bm-ponericin-L1 is non-toxic toward primary fibroblasts cell lines and red blood cells, respectively. This study opens up new perspectives toward an alternative approach to overcoming multiple-antibiotic-resistance by means of AMPs through invertebrates' infection with human pathogenic bacteria.

Draft Genome Sequence of Streptomyces sp. Strain PSAA01, Isolated from the Soil of Eastern Himalayan Foothills.

Streptomyces strains are powerhouses for a diverse range of secondary metabolites, including antibiotics, anticancer and immunosuppressive agents, and enzymes. Here, we report the genome sequence of Streptomyces sp. strain PSAA01, which was isolated from a soil sample taken in Manas National Park, Assam, India, in the eastern Himalayan foothills of India.