A Potential Biocontrol Agent Streptomycesviolaceusniger AC12AB for Managing Potato Common Scab

Potato common scab (PCS) is an economically important disease worldwide. In this study we demonstrated the possible role of Streptomyces violaceusniger AC12AB in controlling PCS. Isolates of Streptomyces scabies were obtained from CS infected tubers collected from Maine United States, which were confirmed by morphological and molecular analysis including 16S rRNA sequencing and RFLP analysis of amplified 16S-23S ITS. Pathogenicity assays related genes including txtAB, nec1, and tomA were also identified in all S. scabies strains through PCR reaction. An antagonistic bacterial strain was isolated from soil in Punjab and identified as S. violaceusniger AC12AB based on 16S rRNA sequencing analysis. Methanolic extract of S. violaceusniger AC12AB contained azalomycin RS-22A which was confirmed by 1H and 13C-NMR, 1H/1H-COSY, HMBC and HMQC techniques. S. violaceusniger AC12AB exhibited plant growth promotion attributes including Indole-3-acetic acid production with 17 μgmL-1 titers, siderophores production, nitrogen fixation and phosphates solubilization potential. When tubers were inoculated with S. violaceusniger AC12AB, significant (P < 0.05) PCS disease reduction up to 90% was observed in greenhouse and field trials, respectively. Likewise, S. violaceusniger AC12AB significantly (P < 0.05) increased potato crop up to 26.8% in field trial. Therefore, plant growth promoting S. violaceusniger AC12AB could provide a dual benefit by decreasing PCS disease severity and increasing potato yield as an effective and inexpensive alternative strategy to manage this disease

Molecular Characterization of Mercury Resistant Bacteria Isolated from Tannery Wastewater

Mercury resistant (HgR) bacteria were isolated from heavy metal polluted wastewater and soil, collected from the proximity of some tanneries from Kasur, Pakistan. Three out of 30 bacterial strains were screened out on the basis of resistance level against various concentrations of HgCl2. Bacterial isolates AZ-1, AZ-2 and AZ-3 showed resistance up to 40 μg/mL of HgCl2 and mercury sensitive (HgS) isolate ZA-15 was taken as a negative control. 16S rDNA ribotyping and phylogenetic analysis were performed for the characterization of isolates as Bacillus sp. AZ-1 (KT270477), B. cereus AZ-2 (KT270478), B. cereus AZ-3 (KT270479) and Enterobacter cloacae ZA-15 (KJ728671). Phylogenetic relationship on the basis of merA nucleotide sequence confirmed 51-100% homology with the corresponding region of the merA gene of already reported mercury resistant Gram-positive bacteria. Restriction fragment length polymorphism (RFLP) analysis was applied to the amplification products of 16S rRNA and merA genes and a specific restriction patterns was successfully obtained after treatment with different endonucleases. A small-scale reservoir of Luria Bertani (LB) medium supplemented with 30 μg/mL of HgCl2 was designed to check the detoxification ability of the selected strains. The results demonstrated 83% detoxification of mercury by both B. cereus AZ-2 and B. cereus AZ-3, and 76% detoxification by Bacillus sp. AZ-1 (p<0.05)

GC–MS characterisation and antibacterial activity evaluation of <i>Nigella sativa</i> oil against diverse strains of <i>Salmonella</i>

<div><p><i>Salmonella</i> resistance is becoming a worldwide serious health issue in these days; therefore, it is an urgent need to develop some alternative approaches to overcome this problem. Twenty bacterial strains were isolated and purified from different environmental sources and confirmed as <i>Salmonella</i> by morphological and biochemical analyses. Further confirmation was done by 16s rRNA sequencing. Antibiotic susceptibility test was performed by well diffusion assay against different concentrations of Ceftriaxone and Ciprofloxacin. The behaviour of both antibiotics was different against diverse strains of <i>Salmonella</i>. <i>Salmonella</i> strains resistant to both antibiotics were analysed for antibacterial activity of natural extracts of <i>Nigella sativa</i> (black seeds). <i>N</i>.<i> sativa</i> oil was found to be more effective against <i>Salmonella</i> species for which even Ceftriaxone and Ciprofloxacin were ineffective. Gas chromatography and mass spectrometry analysis of <i>N</i>.<i> sativa</i> oil was also accomplished, exhibiting 10 compounds including thymoquinone, <i>p</i>-cymene, <i>c</i><i>is</i>-carveol, thymol, α-phellandrene, α-pinene, β-pinene, <i>trans</i>-anethole, α-longipinene and longifolene.</p></div

Biological Control of Potato Common Scab With Rare Isatropolone C Compound Produced by Plant Growth Promoting Streptomyces A1RT

Potato is prone to many drastic diseases like potato common scab (CS). As no highly effective methods exist for managing CS, this study explored the possibility of using biological control. Ten bacterial strains were isolated from CS-infected potato tubers from four different locations of Punjab, Pakistan, and identified based on biochemical and molecular analysis. Analysis of 16s rDNA sequences amplified by PCR revealed the isolated bacterial strains to be Streptomyces scabies, S. turgidiscabies and S. stelliscabiei. Pathogenic islands were also confirmed among the isolates after identification of txtAB, nec1, and tomA genes with PCR amplification. One strain isolated from soil was antagonistic to the pathogenic Streptomyces spp., and determined to be Streptomyces A1RT on the basis of 16s rRNA sequencing. A methanolic extract of Streptomyces A1RT contained Isatropolone C, which was purified and structurally determined by 1H- and 13C-NMR, 1H/1H-COSY, HMQC, and HMBC techniques. Streptomyces A1RT also produced the plant growth hormone indole-3-acetic acid (IAA) with a titer of 26 μg ml-1 as confirmed by spectrophotometry and HPLC. In a greenhouse assay, disease severity index was established from 0 to 500. Average disease severity indexes were recorded as 63, 130.5, and 78 for Streptomyces scabies, S. turgidiscabies and S. stelliscabiei, respectively. When Streptomyces A1RT was applied in soil that contained one of these pathogenic isolates, the average disease severity indexes were significantly (P &lt; 0.05) reduced to 11.1, 5.6 and 8.4, respectively. A significant increase in tuber weight and shoot development was also observed with the tubers treated with Streptomyces A1RT. The use of the plant growth-promoting Streptomyces A1RT against potato CS thus provides an alternative strategy to control the disease without affecting environmental, plants, animals and human health

Data_Sheet_1_Biological Control of Potato Common Scab With Rare Isatropolone C Compound Produced by Plant Growth Promoting Streptomyces A1RT.DOCX

<p>Potato is prone to many drastic diseases like potato common scab (CS). As no highly effective methods exist for managing CS, this study explored the possibility of using biological control. Ten bacterial strains were isolated from CS-infected potato tubers from four different locations of Punjab, Pakistan, and identified based on biochemical and molecular analysis. Analysis of 16s rDNA sequences amplified by PCR revealed the isolated bacterial strains to be Streptomyces scabies, S. turgidiscabies and S. stelliscabiei. Pathogenic islands were also confirmed among the isolates after identification of txtAB, nec1, and tomA genes with PCR amplification. One strain isolated from soil was antagonistic to the pathogenic Streptomyces spp., and determined to be Streptomyces A1RT on the basis of 16s rRNA sequencing. A methanolic extract of Streptomyces A1RT contained Isatropolone C, which was purified and structurally determined by ¹H- and ¹³C-NMR, ¹H/¹H-COSY, HMQC, and HMBC techniques. Streptomyces A1RT also produced the plant growth hormone indole-3-acetic acid (IAA) with a titer of 26 μg ml^-1 as confirmed by spectrophotometry and HPLC. In a greenhouse assay, disease severity index was established from 0 to 500. Average disease severity indexes were recorded as 63, 130.5, and 78 for Streptomyces scabies, S. turgidiscabies and S. stelliscabiei, respectively. When Streptomyces A1RT was applied in soil that contained one of these pathogenic isolates, the average disease severity indexes were significantly (P < 0.05) reduced to 11.1, 5.6 and 8.4, respectively. A significant increase in tuber weight and shoot development was also observed with the tubers treated with Streptomyces A1RT. The use of the plant growth-promoting Streptomyces A1RT against potato CS thus provides an alternative strategy to control the disease without affecting environmental, plants, animals and human health.</p