Genome-wide association study reveals novel genomic regions governing agronomic and grain quality traits and superior allelic combinations for Basmati rice improvement

BackgroundBasmati is a speciality segment in the rice genepool characterised by explicit grain quality. For the want of suitable populations, genome-wide association study (GWAS) in Basmati rice has not been attempted.MaterialsTo address this gap, we have performed a GWAS on a panel of 172 elite Basmati multiparent population comprising of potential restorers and maintainers. Phenotypic data was generated for various agronomic and grain quality traits across seven different environments during two consecutive crop seasons. Based on the observed phenotypic variation, three agronomic traits namely, days to fifty per cent flowering, plant height and panicle length, and three grain quality traits namely, kernel length before cooking, length breadth ratio and kernel length after cooking were subjected to GWAS. Genotyped with 80K SNP array, the population was subjected to principal component analysis to stratify the underlying substructure and subjected to the association analysis using Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK) model.ResultsWe identified 32 unique MTAs including 11 robust MTAs for the agronomic traits and 25 unique MTAs including two robust MTAs for the grain quality traits. Six out of 13 robust MTAs were novel. By genome annotation, six candidate genes associated with the robust MTAs were identified. Further analysis of the allelic combinations of the robust MTAs enabled the identification of superior allelic combinations in the population. This information was utilized in selecting 77 elite Basmati rice genotypes from the panel.ConclusionThis is the first ever GWAS study in Basmati rice which could generate valuable information usable for further breeding through marker assisted selection, including enhancing of heterosis

Expression of Trichoderma reesei β-Mannanase in Tobacco Chloroplasts and Its Utilization in Lignocellulosic Woody Biomass Hydrolysis

Lignocellulosic ethanol offers a promising alternative to conventional fossil fuels. One among the major limitations in the lignocellulosic biomass hydrolysis is unavailability of efficient and environmentally biomass degrading technologies. Plant-based production of these enzymes on large scale offers a cost-effective solution. Cellulases, hemicellulases including mannanases and other accessory enzymes are required for conversion of lignocellulosic biomass into fermentable sugars. β-mannanase catalyzes endo-hydrolysis of the mannan backbone, a major constituent of woody biomass. In this study, the man1 gene encoding β-mannanase was isolated from Trichoderma reesei and expressed via the chloroplast genome. PCR and Southern hybridization analysis confirmed site-specific transgene integration into the tobacco chloroplast genomes and homoplasmy. Transplastomic plants were fertile and set viable seeds. Germination of seeds in the selection medium showed inheritance of transgenes into the progeny without any Mendelian segregation. Expression of endo-β-mannanase for the first time in plants facilitated its characterization for use in enhanced lignocellulosic biomass hydrolysis. Gel diffusion assay for endo-β-mannanase showed the zone of clearance confirming functionality of chloroplast-derived mannanase. Endo-β-mannanase expression levels reached up to 25 units per gram of leaf (fresh weight). Chloroplast-derived mannanase had higher temperature stability (40°C to 70°C) and wider pH optima (pH 3.0 to 7.0) than E.coli enzyme extracts. Plant crude extracts showed 6–7 fold higher enzyme activity than E.coli extracts due to the formation of disulfide bonds in chloroplasts, thereby facilitating their direct utilization in enzyme cocktails without any purification. Chloroplast-derived mannanase when added to the enzyme cocktail containing a combination of different plant-derived enzymes yielded 20% more glucose equivalents from pinewood than the cocktail without mannanase. Our results demonstrate that chloroplast-derived mannanase is an important component of enzymatic cocktail for woody biomass hydrolysis and should provide a cost-effective solution for its diverse applications in the biofuel, paper, oil, pharmaceutical, coffee and detergent industries

Synthesis and characterization of greenish-blue light emitting lithium-boron complex for organic light emitting-diode applications

A lithium-boron complex. lithium tetra (2-methyl 8-hydroxy quinolinato) boron (LiBqm(4)), which emits greenish-blue light has been synthesized by the reaction of LiBH4 with 2-methyl 8-hydroxyquinoline in a molecular weight ratio of 1:4. and Used for organic light emitting diodes (OLEDs) Fabrication. The complex has been characterized by optical absorption, Fourier Transform Infrared (FTIR), photoluminescence (PL) and electroluminescence (EL) spectroscopic methods. The thermo-gravimetric analysis (TGA) suggests that the material is quite thermally stable LIP to 380 degrees C. An optical band gap of 3.15 eV using the well-known Tauc relation and an exciton binding energy of 0.69 eV has been evaluated. OLEDs have been fabricated in ITO/N,N'-di-(3-methyl-phenyl)-N,N'diphenyl-4,4'diaminobiphenyl(TPD)/LiBqm(4)/Al configuration. PL and EL peaks exist at 503 nm. I-V characteristic of device reveals that at higher voltages the current follows I proportional to V-III law, where m > 1

Synthesis and characterization of greenish-blue light emitting lithium-boron complex for organic light emitting diode applications

357-361A lithium-boron complex, lithium tetra (2-methyl 8-hydroxy quinolinato) boron (LiBqm4), which emits greenish-blue light has been synthesized by the reaction of LiBH4 with 2-methyl 8-hydroxyquinoline in a molecular weight ratio of 1:4, and used for organic light emitting diodes (OLEDs) fabrication. The complex has been characterized by optical absorption, Fourier Transform Infrared (FTIR), photoluminescence (PL) and electroluminescence (EL) spectroscopic methods. The thermo-gravimetric analysis (TGA) suggests that the material is quite thermally stable up to 380oC. An optical band gap of 3.15 eV using the well-known Tauc relation and an exciton binding energy of 0.69 eV has been evaluated. OLEDs have been fabricated in ITO/N,N′-di-(3-methyl-phenyl)-N,N′diphenyl-4,4′diaminobiphenyl(TPD)/LiBqm4/Al configuration. PL and EL peaks exist at 503 nm. I-V characteristic of device reveals that at higher voltages the current follows I ⍺ Vm law, where m > 1

Bright-blue organic electroluminescent device based on bis (2-methyl 8-quinolinolato) (triphenyl siloxy) aluminium

522-526An organic-luminescent material bis (2-methyl 8-quinolinolato) (triphenyl siloxy) aluminium (III) (SAlq) was synthesized and its electrical and optical properties were studied. The material exhibited high photoluminescence (PL) and electroluminescence (EL). Photoluminescence (PL) spectra recorded at room temperature revealed a broad blue emission peak at 490 nm along with a shoulder at 448 nm. The material was characterized by UV-visible, photoluminescence, electroluminescence and IR spectroscopic methods. The thermal stability of the material was determined using Thermo Gravimetric Analysis (TGA), which suggests that the material is thermally stable up to 300 oC. Using the Tauc relation and the absorbance cut-off wavelength at 410 nm, the optical band gap of the material was evaluated to be 3.1 eV. OLEDs were fabricated in the configuration ITO/TPD/SAlq/LiF/Al. The CIE chromaticity was also studied and the coordinates were found to be independent of operating voltage. The devices show typical non-linear diode I-V characteristics under forward bias with the threshold voltage of 5 V

Blue electroluminescence in organic semiconductors

793-805Light emitting diodes based on organic materials are of considerable interest owing to their attractive characteristics and potential applications in flat panel displays. This paper focuses on some important blue light emitting organic materials. Particularly the attention has been paid to the absorption, photoluminescence (PL), electroluminescence (EL) spectra, current-voltage (1-V) and luminescence-voltage <span style="mso-bidi-font-family:Arial; mso-bidi-language:HI">(L- V) characteristics of blue light emitting organic semiconductors, as well as those of the para-hexaphenyl (PHP). Syntheses of some important blue light emitting materials have also been discussed. Para hexaphenyl (PHP), which was synthesized by the conventional Kovacic method, is one of the important blue light emitting π-conjugated oligomers. OLEDs fabricated, using PHP as an emitter, TPD and PBD as the hole transport layer and electron transport layer respectively, gave efficient blue electroluminescence. The photoluminescence (PL) and electrolurninescence (EL) of PHP occur at 423 nm, indicating PHP as an excellent blue emitter. This oligomer showed strong absorption peaks at 297 and 318 nm. The devices showed non-linear electrical properties and bright electroluminescence with low turn on voltages (9V). Some of our most recent work in the development of a variety of blue light emitting devices has been included and discussed in detail. </span

Electrochemical and optical studies of conjugated polymers for three primary colours

921-925The Cyclic Voltammetry investigation and optical properties of some of the commonly used conjugated polymers for the fabrication of organic LEDs, like poly [2-methoxy 5- (2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly [2,3-bis (2-ethylhexyloxy)1,4-phenylenevinylene] (BEH-PPV) and poly[(9,9'-di(2'-ethylhexyl) fluoren-2,7-yleneethynylene] (PFE) for three principal emission colours red, green and blue, respectively have been reported. Both oxidation and reduction potentials of polymers were determined under the same experimental conditions to estimate the ionization potential (Ip: energy of Highest Occupied Molecular Orbital) and electron affinity (Ea: energy of Lowest Unoccupied Molecular Orbital). The optical band gaps of the polymers were obtained from their optical absorption spectra. A comparative study of the electrochemical and optical bandgap of the polymers has been made. The photoluminescence (PL) of the polymers has also been studied

Blue organic light emitting diode based on lithium tetra-(8-hydroxy-quinolinato) boron complex

56-59Blue electro-luminescent materials are essential for the development of full colour display. The synthesis and characterization of blue emitter lithium tetra-(8-hydroxy-quinolinato) boron complex for organic light emitting diode (OLED) applications have been reported. The boron complex was synthesized by the reaction of lithium borohydride with 8-hydroxyquinoline at room temperature and shows absorption cut-off wavelength at 410 nm and bright blue photoluminescence (PL) with a peak wavelength at 485 nm. The electro-luminescence (EL) and I-V characteristics of bilayer OLED are also reported. The results show that boron complexes have a great potential for the blue emitters for OLED applications.</b

Blue-green emission from organic light emitting diodes based on aluminum complex

321-324Bluish-green emission from double layer organic light emitting diode (OLED), based on an aluminium complex, bis-(2-methyl 8-hydroxyquinoline) aluminium hydroxide (Almq2OH), as an emissive material and N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (TPD), as hole transport material with an electro-luminescence maximum at 506 nm, has been reported. The good thermal stability, good performance for the OLED applications, and a noticeable blue shift in the electroluminescence, in comparison to Alq3, make this Al complex a good contender for OLED applications for light emission in the blue-green region. It was also found that the devices based on this material have a slightly higher turn-on voltage than similar Alq3 devices. This can be attributed to the higher energy-gap of the material. The photoluminescence and electroluminescence spectra are reported and a shift of 9 nm in peaks is observed. The current-voltage characteristics of the device have also been studied