Morphological diversity among local and introduced maize (Zea mays L.) varieties in Haiti for yield improvement

Maize, the cereal with the largest production in the world, is a staple crop in many developing countries includingHaiti. Even if Haiti is the second maize consumer in the Caribbean region, its national yield is low and alleged ofaflatoxin contamination. In order to increase grain yield, three introduced and two local maize varieties (theseused as comparative control) were evaluated. Three field trials were carried out at Torbeck and Morne Briller (Port-Salut) during different growing seasons. Experiments were designed in a three-replicate randomized block. Eachexperimental plot was 3.50 m per 10.5 m with a gross area of 36.75 m2 and 40 000 plants/ha densities. The trialswere carried out according to local agricultural practices. The results revealed that the introduced varieties hada smaller yield than the local ones. Moreover, all varieties showed some aflatoxin content below the EuropeanUnion limit (5μg/Kg). Statistical analyses showed a strong and direct correlation between yield and ear weightand an inverse correlation between yield and male and female flowering day after sowing. The broad phenotypicdiversity suggested a rich reserve of alleles to exploit in a breeding program focused to improve food security inHaiti

Fine-tune control of targeted RNAi efficacy by plant artificial small RNAs

[EN] Eukaryotic RNA interference (RNAi) results in gene silencing upon the sequence-specific degradation of target transcripts by complementary small RNAs (sRNAs). In plants, RNAi-based tools have been optimized for high efficacy and high specificity, and are extensively used in gene function studies and for crop improvement. However, efficient methods for finely adjusting the degree of induced silencing are missing. Here, we present two different strategies based on artificial sRNAs for fine-tuning targeted RNAi efficacy in plants. First, the degree of silencing induced by synthetic-trans-acting small interfering RNAs (syn-tasiRNAs) can be adjusted by modifying the precursor position from which the syn-tasiRNA is expressed. The accumulation and efficacy of Arabidopsis TAS1c-based syn-tasiRNAs progressively decrease as the syn-tasiRNA is expressed from positions more distal to the trigger miR173 target site. And second, syn-tasiRNA activity can also be tweaked by modifying the degree of base-pairing between the 3' end of the syn-tasiRNA and the 5' end of the target RNA. Both strategies were used to finely modulate the degree of silencing of endogenous and exogenous target genes in Arabidopsis thaliana and Nicotiana benthamiana. New high-throughput syn-tasiRNA vectors were developed and functionally analyzed, and should facilitate the precise control of gene expression in multiple plant species.Ministerio de Ciencia, Innovacion y Universidades (MCIU); Agencia Estatal de Investigacion (AEI); Fondo Europeo de Desarrollo Regional (FEDER) [RTI2018-095118-A-100; RYC-2017-21648 to A.C.; BIO2017-83184-R to J.-A.D.]. Funding for open access charge: MCIU; AEI; FEDER [RTI2018-095118-A-100].López-Dolz, L.; Spada, M.; Daròs, J.; Carbonell, A. (2020). Fine-tune control of targeted RNAi efficacy by plant artificial small RNAs. Nucleic Acids Research. 48(11):6234-6250. https://doi.org/10.1093/nar/gkaa343S62346250481

Amplified singlet oxygen generation in metallated-porphyrin doped conjugated polymer nanoparticles

We report on the mechanism and efficiencies of singlet oxygen O2(1Δg) generation of nanoparticles (NP) of the conjugated polymer (CP) poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) doped with platinum octaethylporphyrin (PtOEP) suspended in water. A detailed study of the photophysics of these NP, using stationary and time-resolved absorption and emission techniques, indicates that O2(1Δg) is generated by the triplet excited state of F8BT and not by that of PtOEP, as previously observed for other porphyrin doped CP NP. O2(1Δg) quantum yields (ΦΔ) were measured by quantifying the characteristic phosphorescence of O2(1Δg) in the NIR region (∼1268 nm). It was found that incorporation of relatively small amounts of PtOEP to F8BT NP results in a significant increase of ΦΔ. NP containing 10% PtOEP (w/w) show a ΦΔ ∼ 0.24, which is 3 times larger than that observed for undoped F8BT NP, and larger than the reported for most water-soluble porphyrins. ΦΔ were also calculated from the oxidation rates (v0) of 3-[10-(2-carboxyethyl)anthracen-9-yl]propanoic acid (ADPA), a well-known chemical O2(1Δg) trap. Unexpectedly, this method was found to significantly overestimate the ΦΔ values due to the adsorption of ADPA on the surface of NP. The ADPA/NP adsorption process was characterized using a simple adsorption model yielding an (average) equilibrium constant of ∼8 × 103 M−1 and an (average) number of NP-binding sites of ∼14000. These results necessarily caution about the use of ADPA as a probe to evaluate ΦΔ in these NP systems. In addition, the interaction of F8BT NP with other anionic, cationic and zwitterionic dyes (dissolved in water) was studied. It was found that even at nano-molar concentrations all the dyes efficiently adsorb on the NP surface. This general and simple self-assembly strategy can be used to prepare superficially-dye-doped CP NP with potentially interesting technological applications.Fil: Spada, Ramiro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Macor, Lorena Paola. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hernández, Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ponzio, Rodrigo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Ibarra, Luis Exequiel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; ArgentinaFil: Lorente, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Chesta, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Palacios, Rodrigo Emiliano. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Furanosic forms of sugars: conformational equilibrium of methyl beta-D-ribofuranoside

The investigation of an isolated ribofuranose unit in the gas phase reveals the intrinsic conformational landscape of the biologically active sugar form.We report the rotational spectra of two conformers of methyl b-D-ribofuranoside in a supersonic jet expansion. Both conformers adopt a near twisted (3T2) ring conformation with the methoxy and hydroxymethyl substituents involved in various intramolecular hydrogen bonds.MINECO-FEDER CTQ2015-68148-C2-

Modern biotechnological approaches toward sustainable viticulture

Conventional breeding does not allow the introgression of single traits without compromising the genetic background that characterize an elite cultivar. The exploitation of the new molecular techniques known as genome editing and cisgenesis make possible to modify or transfer single genes preserving all the characteristics selected with difficulty by breeders over a long-time span. To date, 27 QTLs have been associated with downy mildew disease resistance (Rpv1-Rpv27) and many of these have been employed in breeding programs for the introgression in genotypes of interest. Just in case of Rpv1 and Rpv3, however, the underlying genes have been identified and characterized. In both cases nucleotide-binding leucine rich repeat (NB-LRR) genes are present, codifying for receptors that act as cytoplasmic pathogen sensors, triggering a signal transduction pathway for cell-death mediated defense at the infection site. One of the biggest drawbacks of traditional genetic engineered plants is represented by the presence of transgenes (often selection markers), usually perceived as unsafe by consumers. The cisgenic approach aims at circumventing this problem avoiding the presence of exogenous DNA, introducing only the desired trait by using native genes from Vitis species, interfertile with V. vinifera. Adopting this strategy, the already characterized resistance genes RPV3 and/or RPV1 will be introduced in some elite Vitis vinifera varieties, highly appreciated by the wine industry. The outcomes will reduce the agrochemicals needs and the risks associated with their use, increasing the profitability of the vineyard and consumers\u2019 appreciation. Flower tissues of Glera, Sangiovese and Pinot Nero have been collected from field and fruit cuttings grown plants and from fruiting cuttings and used as explants for the induction of somatic embryos. PCR products of candidate genes, including native promoter and terminator, will be cloned in a suitable vector and transformed into competent E.coli. The gene sequences will be then isolated by PCR and cloned into a binary vector engineered with an inducible excision system. Transient expression assays will be used to evaluate the efficacy of the candidate genes into the different genetic backgrounds of the selected cultivars. The gene construct will be used for the transformation of grapevine embryogenic calli through A. tumefaciens infection. Infected calli will be transferred on selective media for the induction and germination of somatic embryos . Regenerated plantlets will hence be checked for the presence and expression of candidate genes. For the removal of exogenous sequences, chemical or thermal induction of the excision system will be used. Absence of Agrobacterium and backbone sequences will also be checked by PCR on transformants. Resistance and susceptibility to downy mildew will be tested on available material of interest by leaf disc bioassay or whole leaves inoculation of in-vitro and/or acclimatisedacclimatized plantlets

Curation of a reference database of COI sequences for insect identification through DNA metabarcoding: COins

DNA metabarcoding is a widespread approach for the molecular identification of organisms. While the associated wet-lab and data processing procedures are well established and highly efficient, the reference databases for taxonomic assignment can be implemented to improve the accuracy of identifications. Insects are among the organisms for which DNA-based identification is most commonly used; yet, a DNA-metabarcoding reference database specifically curated for their species identification using software requiring local databases is lacking. Here, we present COins, a database of 5' region cytochrome c oxidase subunit I sequences (COI-5P) of insects that includes over 532 000 representative sequences of >106 000 species specifically formatted for the QIIME2 software platform. Through a combination of automated and manually curated steps, we developed this database starting from all COI sequences available in the Barcode of Life Data System for insects, focusing on sequences that comply with several standards, including a species-level identification. COins was validated on previously published DNA-metabarcoding sequences data (bulk samples from Malaise traps) and its efficiency compared with other publicly available reference databases (not specific for insects). COins can allow an increase of up to 30% of species-level identifications and thus can represent a valuable resource for the taxonomic assignment of insects' DNA-metabarcoding data, especially when species-level identification is needed https://doi.org/10.6084/m9.figshare.19130465.v1

Physico-Chemical Features of Undoped and Fe/Cu-Doped Na0.67MnO2-Layered Cathodes for Sodium Batteries

Na0.67MnO2 (NMO) stands out among the layered cathode materials used for sodium batteries due to its high-capacity values, low cost, and environmental friendliness. Unfortunately, many drawbacks arise during cycling, but nanostructure tailoring and doping can help to mitigate them. Our aim was to synthesize undoped and Cu- or Fe-doped NMO samples via the sol-gel route, with a different cooling step to room temperature, i.e., in a natural way or via quenching. The formation of a mixture of polymorphs was observed, as well as differences in the external morphology of the powders' grains. The use of spectroscopic techniques, Mössbauer spectroscopy for the Fe-doped samples and Electron paramagnetic resonance, allowed us to gain insights into the oxidation states of transition metals and to make suggestions about the magnetic ordering, as well as on the possible presence of magnetic impurities. Cyclic voltammetry and galvanostatic cycling results were interpreted on the basis of the spectroscopic data: the introduction of substituents, in general, worsens the capacity values, due to the decrease in the P2 amount and the introduction of structural distortions. The structural stability of the samples in air as a function of time was also analyzed via X-ray diffraction, demonstrating the positive effect of Cu presence