Rice is one of the major staple food crops in the world and an excellent model system for studying monocotyledonous plants. Diseases caused by nematodes in rice are well documented and among them, root-knot nematode (RKN), Meloidogyne graminicola, causes extensive yield decline. It is therefore necessary to identify novel sources of natural resistance to RKN in rice and to investigate the rice-RKN interaction in detail to understand the basal plant defence mechanisms and nematode manipulation of the host physiology. To this end, six different cultivars of rice were initially screened for RKN infection and development; Pusa 1121 and Vandana were found to be most susceptible and resistant to RKN infection, respectively. In order to investigate the role of major hormoneregulated plant defence pathways in compatible/incompatible rice-RKN interaction, some wellidentified marker genes involved in salicylate/jasmonate/ethylene pathway were evaluated for their differential expression through qRT-PCR. In general, our study shows a remarkable discrepancy in the expression pattern of those genes between compatible and incompatible rice-RKN interaction. As most information on the molecular interplay between plants and nematodes were generated on dicotyledonous plants, the current study will strengthen our basic understanding of plant-nematode interaction in the monocot crops, which will aid in defining future strategies for best plant health measures.Plant-parasitic nematodes (PPNs) have proved to be one of the most difficult to manage and stubborn pest of agricultural crops. PPNs display a wide variety of interactions with their hosts. Most advanced of them are sedentary endoparasites, which induce a specialized feeding cell in the host tissue. These feeding structures are believed to serve as the singular nutrient source for the nematode development and reproduction. A plethora of nematode effector proteins have been identified which interact with the several plant proteins to initiate and maintain the feeding cell and usurps innate host defence 1,2 .Being one of the major staple food crop, and a promising model monocotyledonous plant, rice (Oryza sativa L.) has garnered considerable attention from the nematologists studying the physiological and molecular interaction between rice and PPNs. Root-knot nematode (RKN), Meloidogyne graminicola is emerging as a serious bottleneck in rice-wheat cropping system of Indo-Gangetic plains and is causing substantial yield losses in all the rice growing belts of South-east Asia. The infective second-stage juvenile (J2) penetrates the rice root behind the root tip zone, traverses the vascular tissue and induces a typical feeding cell, known as the giant cell (GC). Cells surrounding the GC are hypertrophied to render the formation of macroscopic hook-like galls on the root system 3-5 .To date, almost all grown O. sativa cultivars tested are known to be susceptible to RKN infection, while the non-cultivated African relatives, O. glaberrima and O. longistaminata are reported to be resista...

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Four novel copper(II) complexes of the composition [CuLX] where L = 2,6-bis(benzimidazole-2yl)pyridine, X = dipyridophenazine (L1), 1,10-phenanthroline (L2), hydroxyproline (L3) and 2,6-pyridine dicarboxylic acid (L4) were synthesized and characterized by using elemental analysis, FT-IR, UV–vis, ESI-MS, molar conductance and magnetic susceptibility measurements. The complexes [CuLL1](NO3)2 [1], [CuLL2](NO3)2 [2], [CuLL3](NO3) [3] and [CuLL4] (NO3) [4] are stable at room temperature. In DMSO the complexes [1] and [2] are 1:2 electrolytes, [3] and [4] are 1:1 electrolytes. Based on elemental and spectral studies five coordinated geometry is assigned to all the four complexes. The interaction of four copper ion complexes with calf thymus DNA were carried out by UV-vis titrations, fluorescence spectroscopy, thermal melting and viscosity measurements .The binding constant (K(b)) of the above four metal complexes were determined as 5.43 × 10(4) M(-1), 2.56 × 10(4) M(-1), 1.21 × 10(4) M(-1) and 1.57 × 10(4) M(-1) respectively. Quenching studies of the four complexes indicates that these complexes strongly bind to DNA, out of all complex 1 is binding more strongly. Viscosity measurements indicate the binding mode of complexes with CT DNA by intercalation through groove. Thermal melting studies also support intercalative binding. The nuclease activity of the above metal complexes shows that 1, 2 and 3 complexes cleave DNA through redox chemistry.

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