Plant growth promoting rhizobacteria (PGPR) are the rhizosphere bacteria that may be utilized to augment plant growth and suppress plant diseases. The objectives of this study were to identify and characterize PGPR indigenous to cucumber rhizosphere in Bangladesh, and to evaluate their ability to suppress Phytophthora crown rot in cucumber. A total of 66 isolates were isolated, out of which 10 (PPB1, PPB2, PPB3, PPB4, PPB5, PPB8, PPB9, PPB10, PPB11, and PPB12) were selected based on their in vitro plant growth promoting attributes and antagonism of phytopathogens. Phylogenetic analysis of 16S rRNA sequences identified these isolates as new strains of Pseudomonas stutzeri, Bacillus subtilis, Stenotrophomonas maltophilia, and Bacillus amyloliquefaciens. The selected isolates produced high levels (26.78–51.28 μg mL-1) of indole-3-acetic acid, while significant acetylene reduction activities (1.79–4.9 μmole C2H4 mg-1 protein h-1) were observed in eight isolates. Cucumber plants grown from seeds that were treated with these PGPR strains displayed significantly higher levels of germination, seedling vigour, growth, and N content in root and shoot tissue compared to non-treated control plants. All selected isolates were able to successfully colonize the cucumber roots. Moreover, treating cucumber seeds with these isolates significantly suppressed Phytophthora crown rot caused by Phytophthora capsici, and characteristic morphological alterations in P. capsici hyphae that grew toward PGPR colonies were observed. Since these PGPR inoculants exhibited multiple traits beneficial to the host plants, they may be applied in the development of new, safe, and effective seed treatments as an alternative to chemical fungicides.

Paper and paper products are widely used without any antimicrobial efficacy in our everyday lives and thus can act as potential transporters of many diseases. Herein, we introduce antimicrobial activity to cellulose paper by presenting a tailored mussel-inspired strategy for the sustainable immobilization of silver nanoparticles (AgNPs), which are well-known for the effectiveness in preventing annexation and proliferation of microbes on materials surfaces. First, we functionalized the cellulose paper with succinic acid that eventually reacted with dopamine to give dopamine-modified paper. The dopamine molecules possess excellent adhesion and strong coordination with metal substrates through catechol groups offering a potentially robust interface between AgNPs and the organic structure of the paper. Next, AgNPs were deposited onto the paper by simply immersing dopamine-modified paper in a silver salt solution to accomplish the antimicrobial properties. Field emission scanning electron microscopic study of the synthesized antimicrobial papers confirmed that the loading of AgNPs was time-dependent, and the average size of the nanoparticles was in the range of 50–60 nm after 8 h of deposition time. The paper decorated with AgNPs showed excellent antimicrobial activity against highly virulent and multiple antibiotic resistant Gram-positive and Gram-negative pathogenic bacteria as well as against some extremely virulent fungal phytopathogens.

Inhibition ability of gluconates for fresh water corrosion of mild steel changed with metal cations were investigated by immersion tests and electrochemical impedance spectroscopy (EIS) tests. The results of the tests showed that the inhibition ability of gluconates was enhanced by metal cations that have large "corrosion inhibitory effect of cation, Y", in model fresh water. Surface analysis showed that gluconate ligands and metal cations that have large Y can bond on mild steel and that they form a protective film on the steel. EIS analysis with an equivalent circuit suggested that metal cations that have large Y would reduce the area of defects in the protective film of gluconates.

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The corrosion characteristics of SUS304 exposed to 0.5 M Claqueous solution containing 14 different metal cations were studied with immersion tests, surface analysis and 15 electrochemical tests. The mechanism of corrosion with metal cations was clarified by the 16 XPS analysis results together with the hard and soft acid and base (HSAB) concept and the 17 passive films structure. It is supposed that metal cations with large hardness make a layer by 18 chemical bonding with the passive films. The passive films are protected by the metal cation 19 layer from Clattack, and consequently corrosion reactions are inhibited.

The plant pathogen Phytophthora cinnamon the causal agent of disease in numerous species, is a major threat to natural vegetation and has economic impacts in agriculture. The pathogen principally invades the root system, which, in susceptible species, is rapidly colonised and functionally destroyed. Few species are resistant, however, where resistance is expressed the pathogen is restricted to small, localised lesions. The molecular mechanisms that underpin this response in resistant species are not well understood. Lomandra longifolia, an Australian native species, is highly resistant to P. cinnamomi. In an earlier study, we showed induction of resistance-related components such as callose, lignin and hydrogen peroxide (H O ) in L. longifolia roots that had been inoculated with P. cinnamomi. Here, in order to further identify, during the very early stages of infection, the molecular components and regulatory networks that may trigger resistance, a comprehensive root transcriptome analysis was performed using next generation sequencing. Overall, 18 cDNA libraries were produced generating 52.8 GB 126 base pair reads, which were de novo assembled into contigs. Differentially expressed genes (DEGs) were identified allowing the identification of infection-responsive candidate genes that were putatively related to resistance, and from this set ten were selected for qRT-PCR to validate the RNA-Seq expression value. Further analysis of individual candidates revealed that many were involved in PAMP-triggered immunity (PTI; pattern recognition receptors, glutathione S-transferase, callose synthases, pathogenesis-related protein-1, mitogen activated protein kinases) and effector-triggered immunity (ETI) (NBS-LRR, signalling genes, transcription factors and anti-pathogenic compound synthase genes). As these candidate genes or mediated components activate different defence signalling systems, they may have potential for investigation of novel approaches to disease control and in transgenic approaches for improvement, in susceptible species, of resistance to P. cinnamomi.

Enterococcus faecalis is associated with streptococcosis like infection in fish. A whole-genome sequence study was conducted to investigate the virulence factor and antibiotic-resistance genes in three fish pathogenic E. faecalis. Genomic DNA was extracted from three strains of E. faecalis isolated from streptococcosis infected Nile tilapia (strains BF1B1 and BFFF11) and Thai sarpunti (strain BFPS6). The whole genome sequences of these three strains were performed using a MiSeq sequencer (Illumina, Inc.). All three strains conserved 69 virulence factor such as genes associated with protection against oxidative stress, bacterial cell wall synthesis, gelatinase toxin, multiple biofilm-associated genes and capsule producing genes. Moreover, 39 antibiotic-resistance genes against sixteen major groups of antibiotics were identified in the genome sequences of all three strains. The most commonly used antibiotic Tetracycline resistance genes were found only in BFPS6 strain, whereas, Bacteriocin synthesis genes were identified in both BFFF11 and BFPS6 strain. Phylogenetic analysis revealed that strains BF1B1 and BFFF1 form a different cluster than BFPS6. This is one of the first whole-genome sequence study of fish pathogenic E. faecalis, unfold new information on the virulence factor and Antibiotic resistance genes linked to pathogenicity in fish.