Assessment of resistance to rice tungro disease in popular rice varieties in India by introgression of a transgene against Rice tungro bacilliform virus.

Rice crops in South and Southeast Asian countries suffer critical yield losses due to rice tungro disease caused by joint infection with rice tungro bacilliform virus (RTBV) and rice tungro spherical virus (RTSV). Previously, for generating RNA interference-based transgenic resistance against tungro viruses, RTBV ORF IV was used as a transgene to develop RTBV resistance in a popular high-yielding scented rice variety. The transgene from this line was then introgressed into five popular high-yielding but tungro-susceptible rice varieties by marker-assisted backcross breeding with a view to combine the resistant trait with the agronomic traits. The present work includes a resistance assay of the BC3F5 lines of these varieties under glasshouse conditions. Out of a total of 28 lines tested, each consisting of 12 individual plants, eight lines showed significant amelioration in height reduction and 100- to 1000-fold reduction in RTBV titers. The RNAi-mediated resistance was clearly manifested by the presence of virus-derived small RNA (vsRNA) specific for RTBV ORF IV in the transgenic backcrossed lines.

Evaluation of virus resistance and agronomic performance of rice cultivar ASD 16 after transfer of transgene against Rice tungro bacilliform virus by backcross breeding.

Severe losses of rice yield in south and southeast Asia are caused by Rice tungro disease (RTD) induced by mixed infection of Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV). In order to develop transgene-based resistance against RTBV, one of its genes, ORF IV, was used to generate transgenic resistance based on RNA-interference in the easily transformed rice variety Pusa Basmati-1, and the transgene was subsequently introgressed to rice variety ASD 16, a variety popular in southern India, using transgene marker-assisted selection. Here, we report the evaluation of BC3F4 and BC3F5 generation rice plants for resistance to RTBV as well as for agronomic traits under glasshouse conditions. The BC3F4 and BC3F5 generation rice plants tested showed variable levels of resistance, which was manifested by an average of twofold amelioration in height reduction, 1.5-fold decrease in the reduction in chlorophyll content, and 100- to 10,000-fold reduction in the titers of RTBV, but no reduction of RTSV titers, in three backcrossed lines when compared with the ASD 16 parent. Agronomic traits of some of the backcrossed lines recorded substantial improvements when compared with the ASD 16 parental line after inoculation by RTBV and RTSV. This work represents an important step in transferring RTD resistance to a susceptible popular rice variety, hence enhancing its yield in areas threatened by the disease.

Synthesis, spectral (IR, UV-Vis and variable temperature NMR) characterization and crystal structure of (N-benzyl-N-furfuryldithicarbamato-S,S')(thiocyanato-N)(triphenylphosphine)nickel(II).

Planar (N-benzyl-N-furfuryldithiocarbamato-S,S')(thiocyanato-N)(triphenylphospine)nickel(II), [Ni(bfdtc)(NCS)(PPh3)], (1) was prepared from bis(N-benzyl-N-furfuryldithiocarbamato-S,S')nickel(II), [Ni(bfdtc)2], (2) and characterized by elemental analysis, cyclic voltammetry, electronic, IR and variable temperature (1)H and (13)C NMR spectra. For complex 1, the thioureide vCN value is shifted to higher wavenumber compared to 2 and N(13)CS2 carbon signal observed for 1 is additionally shielded compared to the parent complex 2, suggesting increased strength of the thioureide bond due to the presence of the π-accepting phosphine. In the room temperature (13)C NMR spectrum of 1, two pseudo doublets are observed in the aliphatic region. Variable temperature (13)C NMR spectral studies suggest that the fast thiocyanate exchange appears to be responsible for the appearance of pseudo doublets. Single crystal X-ray structural analysis of 1 and 2 confirm the presence of four coordinated nickel in a distorted square planar arrangement with the NiS2PN and NiS4 chromophores, respectively. The NiS bonds are symmetric in 2 (2.1914(14) and 2.2073(13)Å). But significant asymmetry in NiS bond distances was observed in 1 (2.2202(8)Å and 2.1841Å). This observation clearly supports the less effective trans effect of SCN(-) over PPh3. Cyclic voltammetric studies revealed easier reduction of nickel(II) to nickel(I) in complex 1 compared to 2.

Bis(µ-N-benzyl-N-furfuryldithio-carbamato)-1:2κS,S':S';2:1κS,S':S'-bis-[(N-benzyl-N-furfuryldithio-carbamato-κS,S')cadmium].

In the centrosymmetric title compound, [Cd(2)(C(13)H(12)NOS(2))(4)], pairs of dithio-carbamate ligands exhibit different structural functions. Each of the terminal ligands is bidentately coordinated to one Cd(II) atom and forms a planar four-membered CS(2)Cd chelate ring, whereas pairs of the tridentate bridging ligands link two neighbouring Cd(II) atoms, forming extended eight-membered C(2)S(4)Cd(2) tricyclic units whose geometry can be approximated by a chair conformation. The coordination polyhedron of the Cd(II) atoms is a distorted square-pyramid. The five-membered furan ring and the benzene ring are disordered over two sets of sites with an occupancy ratio of 0.62 (8):0.38 (8).

cis-Bis(4-methyl-piperazine-1-carbo-dithio-ato-κS,S')bis-(pyridine-κN)cadmium.

In the title complex, [Cd(C(6)H(11)N(2)S(2))(2)(C(5)H(5)N)(2)], the Cd(II) ion is hexa-coordinated by two N atoms from two pyridine ligands and by four S atoms from two dithio-carbamate ligands in a distorted octa-hedral geometry. The Cd(II) ion lies on a twofold axis. The piperazine ring is in chair conformation and its least-squares plane makes a dihedral angle of 81.4 (1)° with that of the pyridine ring.

(1,2,3,4-Tetra-hydro-isoquinoline-2-carbo-dithio-ato-κS,S')(thio-cyanato-κN)(tri-phenyl-phosphane)nickel(II).

The Ni(II) atom in the mononuclear title compound, [Ni(C(10)H(10)NS(2))(NCS)(C(18)H(15)P)], exists within a S(2)PN donor set that defines a distorted square-planar geometry. A significant asymmetry in the Ni-S bond lengths support the less effective trans effect of SCN(-) over PPh(3).