The plant growth-promoting fungus, Penicillium simplicissimum GP17-2, was evaluated for its ability to induce resistance against Cucumber mosaic virus (CMV) in Arabidopsis thaliana and tobacco plants. Treatment with barley grain inoculum (BGI) of GP17-2 significantly enhanced fresh weight, dry weight and leaf number of A. thaliana and tobacco plants 6 weeks after planting. Two weeks after CMV inoculation, all plants treated with BGI of GP17-2 or its culture filtrate (CF) showed a significant reduction in disease severity compared with non-treated control plants, which exhibited severe mosaic symptoms by the end of the experiment. The enzyme-linked immunosorbent assay (ELISA) demonstrated that CMV accumulation was significantly reduced in plants treated with GP17-2 or its CF relative to control plants. Based on RT-PCR, plants treated with GP17-2 (BGI or CF) also exhibited increased expression of regulatory and defence genes involved in the SA and JA ⁄ ET signalling pathways. These results suggested that multiple defence pathways in A. thaliana and tobacco were involved in GP17-2-mediated resistance to CMV, although neither the transgenic NahG line, nor the npr1, jar1 or ein3 mutants disrupted the response in A. thaliana. This is the first report to demonstrate the induction of systemic resistance against CMV by GP17-2 or its CF.

Trichoderma asperellum SKT-1 is a microbial pesticide that is very effective against various diseases. Our study was undertaken to evaluate T. asperellum SKT-1 for induction of resistance against yellow strain of Cucumber mosaic virus (CMV-Y) in Arabidopsis plants. Disease severity was rated at 2 weeks post inoculation (WPI). CMV titre in Arabidopsis leaves was determined by indirect enzyme-linked immunosorbent assay (ELISA) at 2 WPI. Our results demonstrated that among all Arabidopsis plants treated with barley grain inoculum (BGI) of SKT-1 NahG and npr1 plants showed no significant reduction in disease severity and CMV titre as compared with control plants. In contrast, disease severity and CMV titre were significantly reduced in all Arabidopsis plants treated with culture filtrate (CF) of SKT-1 as compared with control plants. RT-PCR results showed increased expression levels of SA-inducible genes, but not JA/ET-inducible genes, in leaves of BGI treated plants. Moreover, expression levels of SA-and JA/ETinducible genes were increased in leaves of CF treated plants. In conclusion, BGI treatment induced systemic resistance against CMV through SA signaling cascade in Arabidopsis plants. While, treatment with CF of SKT-1 mediated the expression of a majority of the various pathogen related genes, which led to the increased defense mechanism against CMV infection.

No abstract

New seven complexes of N 1 ,N 6 -bis((2-hydroxynaphthalin-1-yl)methinyl)) adipohydrazone (H 2 L) with MnCl 2 •4H 2 O, CoCl 2 •6H 2 O, NiCl 2 •6H 2 O, CuCl 2 •2H 2 O, Cu(NO 3 ) 2 •3H 2 O, CuSO 4 •5H 2 O, and Cu(OAc) 2 •2H 2 O have beenprepared and characterized by the aid of elemental and thermal analyses, spectra (FT-IR, 1 H NMR, MS, UV-Vis, ESR, X-ray powder diffraction), molar conductance and magnetic moment measurements. The XRD results unambiguously confirmed the nano-sized particles of the complexes. The results showed that H 2 L behaves as dibasic tetra-dentate ligand towards the metal ions of interest. The low molar conductance values revealed the non-electrolytic nature for the chelates. The magnetic moment data, UV-Vis and ESR spectra denoted the formation of octahedral geometries for Mn(II) and Ni(II) complexes, whereas Co(II), Cu(II) complexes exhibited tetrahedral arrangement. The activation parameters for the thermal decomposition stages were calculated from TGA curves using Coats-Redfern and Horowitz-Metzger methods. The obtained data were confirmed by 3-D molecular modeling of the ligand and some complexes. The investigated compounds were screened for their antimicrobial activities against different types of organisms and antitumor activities towards human liver Carcinoma (HEPG2) cell to access their potential chemotherapeutic use. The free ligand (H 2 L) exhibited a weak inhibition of cell viability with IC 50 of 11.80 μg/ml, complexes 4, 6 and 7 showed a moderate activity with IC 50 of 5.56, 7.71 and 5.67 μg/ml, whereas complexes 1, 2, 3, and 5 displayed a strong anticancer activity with IC 50 of 4.65, 3.97, 3.30 and 4.84 μg/ml, compared with IC 50 value of 4.73 μg/ml for the doxorubicin (standard cytotoxin drug).

No abstract

An effective medium designated phosphate separately autoclaved Reasoner’s 2A supplemented with cycloheximide and tobramycin (PSR2A-C/T) has been developed for the isolation of Flavobacterium and Chryseobacterium strains from the plant rhizosphere. It consists of Reasoner’s 2A agar (R2A) prepared by autoclaving phosphate and agar separately and supplementing with 50 mg L−1 cycloheximide and 1 mg L−1 tobramycin. A comparison was made among the following nine media: PSR2A-C/T, PSR2A-C/T supplemented with NaCl, R2A agar, R2A agar supplemented with cycloheximide and tobramycin, 1/4-strength tryptic soy agar (TSA), 1/10-strength TSA, soil-extract agar, Schaedler anaerobe agar (SAA), and SAA supplemented with gramicidin, for the recovery of Flavobacterium and Chryseobacterium strains from the Welsh onion rhizosphere. Flavobacterium strains were only isolated on PSR2A-C/T, and the recovery rate of Chryseobacterium strains was higher from PSR2A-C/T than from the eight other media. In order to confirm the effectiveness of PSR2A-C/T, bacteria were isolated from onion rhizosphere soil with this medium. Flavobacterium and Chryseobacterium strains were successfully isolated from this sample at a similar rate to that from the Welsh onion rhizosphere.

No abstract

The systemic expressions of certain defense-related genes in cucumber plants induced by culture filtrate (CF) of the plant growth-promoting fungus (PGPF), Penicillium simplicissimum GP17-2, and challenging with Sio 2 nanoparticles against Papaya ring spot virus (PRSV) and its vector the green peach aphid Myzus persicae were investigated. CF and Sio 2 were topically applied to cucumber plants by soil drench method. Results showed that the severity of PRSV and its accumulation in cucumber leaves were significantly reduced in all treated cucumber plants compared with the control. The expression of pathogenesis-related genes showed strong activations of peroxidases (POX) and phenylalanineammonia lyase (PAL) genes and moderate expression of PR-1 one day after inoculation, while, six days after inoculation a high activation of PAL and PR-1 genes and moderate activation of POX gene were detected. No expression was detected in plants infected with PRSV alone without any treatments. These results suggested that CF and Sio 2 treatments mediated the expression of the majority of various pathogen-related genes, which may contribute to the increased defense mechanism against PRSV infection in cucumber.