Expression analysis of defense-related genes in cucumber (Cucumis sativus L.) against Phytophthora melonis.

Phytophthora melonis is one of the most destructive cucumber disease, causing severe economic losses in the globe. Despite intense research efforts made in the past years, no permanent cure currently exists for this disease. With the aim to understand the molecular mechanisms of defense against P. melonis, root collars and leaves of four cucumber genotypes consisting of resistant Ramezz; moderately resistant Baby, and very susceptible Mini 6-23 and Extrem, were monitored for quantitative gene expression analysis of the five antifungal and/or anti-oomycete genes (CsWRKY20, CsLecRK6.1, PR3, PR1-1a and LOX1), at three points after inoculation with P. melonis. The gene expression analysis indicated, P. melonis strongly enhanced the expression of these genes after inoculation, in both the leaves and root collars. Further, not only the transcript levels of these genes were significantly higher in resistant and moderately resistance genotypes, but also the time point of the highest relative expression ratio for the five genes was different in the four cucumber genotypes. CsWRKY20 and PR3 showed the maximum expression in Ramezz at 48 h post inoculation (hpi) while CsLecRK6.1, and LOX1 showed the highest expression at 72 hpi. In addition, PR1-1a showed the maximum expression in the Baby at 72 hpi. Root collars responded faster than leaves, and some responses were more strongly up-regulated in root collars than in leaves. The genes found to be involved in disease resistance in two different organs of cucumber after pathogen infection. The results suggest that increased expression of these genes led to activation of defense pathways, and could be responsible for a reduced P. melonis colonization capacity in Ramezz and Baby. Overall, this work represents a valuable resource for future functional genomics studies to unravel molecular mechanisms of Cucumis sativus-P. melonis interaction.

Sonochemical synthesis and characterization of three nano zinc(II) coordination polymers; Precursors for preparation of zinc(II) oxide nanoparticles.

Nanostructures of three Zinc(II) coordination polymers, [Zn(NNO)2(H2O)4]n (1), [Zn(PNNO)2(H2O)2]n (2) and [Zn(H2O)6]·(INNO)2 (3) {NNO: Nicotinic acid N-oxide, PNNO: Picolinic acid N-oxide and INNO: Isonicotinic acid N-oxide}, have been synthesized by a sonochemical process and reaction of ligands with Zn(CH3COO)2. The Zinc(II) oxide nano-particles have been synthesized from thermolysis of [Zn(NNO)2(H2O)4]n (1), [Zn(PNNO)2(H2O)2]n (2) and [Zn(H2O)6]·(INNO)2 (3) at two different methods (with surfactant and without surfactant) and two temperatures (200 and 600°C). The ZnO nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Comparison of the SEM images of ZnO nano-particles at two different methods and temperatures shows that higher temperature results in an increasing of agglomeration and thus small and spherical ZnO particles with good separation were produced by thermolysis of compounds at 200°C and by use of surfactant.

Highly efficient syntheses of nano mixed-anions lead(II) thiocyanate/nitrate and lead(II) thiocyanate coordination polymers by sonochemical process.

Nanostructures of the three-dimensional coordination polymers with the ligand 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh), [Pb(4-bpdh)(NO3)(µ-NCS)]n (1) and [Pb(4-bpdh)(µ-NCS)2]n (2), have been synthesized by a sonochemical process at different concentrations and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. The solid state structural transformations of nano-compounds 1, 2 by anion-replacement processes under mechanochemical reaction, have been verified by IR and PXRD measurements. The SEM images showed that morphology change occurs on nanostructures during solid state anion-replacements.

Solid state and sonochemical syntheses of nano lead(II) chloride and bromide coordination polymers from its nitrate analog via mechanochemical crystal to crystal transformations.

Reversible crystal-to-crystal transformations of 3D lead(II) coordination polymers with the ligand 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh), from nitrate analoge [Pb(4-bpdh)(NO3)2(H2O)]n (1) to [Pb(4-bpdh)(NO3)(Br)]n (2), [Pb(4-bpdh)(Br)2]n (3), [Pb(4-bpdh)(NO3)(Cl)]n (4) and [Pb(4-bpdh)(Cl)2]n (5) by solid state anion-replacement processes under mechanochemical reactions, have been studied. The reversible solid state structural transformations of compounds 1-5, by anion-replacement processes under mechanochemical reaction, have been verified by PXRD measurements. Nanoparticles of compounds were synthesized by sonochemical process and characterized by scanning electron microscopy (SEM), powder X-ray diffraction, IR spectroscopy and elemental analyses. The SEM images showed that morphology change occurs during solid state anion-replacements of nanocrystals.

Mechanochemical solid state anion-exchange of lead(II) coordination polymers via an intermediate coordination polymer; new precursors for the preparation of PbBr2/Pb3O2Br2, PbBr(OH) and PbO nanoparticles.

The reversible crystal-to-crystal transformations of a 1D lead(II) coordination polymer with the ligand 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh), from [Pb(4-bpdh)Br2]n () to intermediate [Pb(4-bpdh)(Br)(NO3)]n () and [Pb(4-bpdh)(NO3)2(H2O)]n () by a solid state anion-replacement processes under mechanochemical reactions, have been studied. The reversible solid state structural transformation of compound to compound and then by anion replacement have been verified by PXRD and IR measurements. PbBr2, PbBr(OH), Pb3O2Br2 and PbO nanoparticles were obtained by the thermal decomposition of compounds , and in oleic acid at 180 °C in an air atmosphere, respectively. These nanoparticles were characterized by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM).