Genes encoding transcription factors TaDREB5 and TaNFYC-A7 are differentially expressed in leaves of bread wheat in response to drought, dehydration and ABA

Two groups of six spring bread wheat varieties with either high or low grain yield under the dry conditions of Central and Northern Kazakhstan were selected for analysis. Experiments were set up with the selected wheat varieties in controlled environments as follows: (1) slowly progressing drought imposed on plants in soil, (2) rapid dehydration of whole plants grown in hydroponics, (3) dehydration of detached leaves, and (4) ABA treatment of whole plants grown in hydroponics. Representatives of two different families of transcription factors (TFs), TaDREB5 and TaNFYC-A7, were found to be linked to yield-under-drought using polymorphic Amplifluor-like SNP marker assays. qRT-PCR revealed differing patterns of expression of these genes in the leaves of plants subjected to the above treatments. Under drought, TaDREB5 was significantly up-regulated in leaves of all high-yielding varieties tested and down-regulated in all low-yielding varieties, and the level of expression was independent of treatment type. In contrast, TaNFYC-A7 expression levels showed different responses in the high- and low-yield groups of wheat varieties. TaNFYC-A7 expression under dehydration (treatments 2 and 3) was higher than under drought (treatment 1) in all high-yielding varieties tested, while in all low-yielding varieties the opposite pattern was observed: the expression levels of this gene under drought were higher than under dehydration. Rapid dehydration of detached leaves and intact wheat plants grown in hydroponics produced similar changes in gene expression. ABA treatment of whole plants caused rapid stomatal closure and a rise in the transcript level of both genes during the first 30 min, which decreased 6 h after treatment. At this time-point, expression of TaNFYC-A7 was again significantly up-regulated compared to untreated controls, while TaDREB5 returned to its initial level of expression. These findings reveal significant differences in the transcriptional regulation of two drought-responsive and ABA-dependent TFs under slowly developing drought and rapid dehydration of wheat plants. The results obtained suggest that correlation between grain yield in dry conditions and TaNFYC-A7 expression levels in the examined wheat varieties is dependent on the length of drought development and/or strength of drought; while in the case of TaDREB5, no such dependence is observed.Lyudmila Zotova, Akhylbek Kurishbayev, Satyvaldy Jatayev, Gulmira Khassanova, Askar Zhubatkanov, Dauren Serikbay, Sergey Sereda, Tatiana Sereda, Vladimir Shvidchenko, Sergiy Lopato, Colin Jenkins, Kathleen Soole, Peter Langridge, and Yuri Shavruko

Effective Method for Obtaining the Hydrosols of Detonation Nanodiamond with Particle Size < 4 nm

Detonation nanodiamond is a commercially available synthetic diamond that is obtained from the carbon of explosives. It is known that the average particle size of detonation nanodiamond is 4–6 nm. However, it is possible to separate smaller particles. Here we suggest a new approach for the effective separation of detonation nanodiamond particles by centrifugation of a “hydrosol/glycerol” system. The method allows for the production of the detonation nanodiamond hydrosol with a very sharp distribution in size, where more than 85% of particles have a size ranging 1–4 nm. The result is supported by transmission electron microscopy, atomic force microscopy, and dynamic light scattering

Composite proton-conducting membranes with nanodiamonds

A new approach was applied to improve the proton conductivity mechanism in perfluorinated membranes for hydrogen fuel cells. The composite short-side chain membranes were modified with functionalized diamond nanoparticles. Carboxylated nanodiamonds embedded in the polymer matrix provide an increase in conductivity at a moderate nanodiamond content, while the mechanical strength of the membranes remains high. The casting method of membranes preparation from solutions in N,N-dimethylformamide allowed saving the general channel structure in membranes at the presence of nanodiamonds, in agreement with neutron scattering data. We propose the formation of additional areas of conductivity, formed controllably, due to nanodiamond particles associated with polymer chains, on the surface of which accelerated diffusion of protons through the hopping Grotthus mechanism from the centers of proton adsorption proceeds with the transition to proton-conducting channels of the matrix covered with sulfonic groups

Electrochemical Properties and Structure of Membranes from Perfluorinated Copolymers Modified with Nanodiamonds

In this study, we aimed to design and research proton-conducting membranes based on Aquivion®-type material that had been modified with detonation nanodiamonds (particle size 4–5 nm, 0.25–5.0 wt. %). These nanodiamonds carried different functional groups (H, OH, COOH, F) that provided the hydrophilicity of the diamond surface with positive or negative potential, or that strengthened the hydrophobicity of the diamonds. These variations in diamond properties allowed us to find ways to improve the composite structure so as to achieve better ion conductivity. For this purpose, we prepared three series of membrane films by first casting solutions of perfluorinated Aquivion®-type copolymers with short side chains mixed with diamonds dispersed on solid substrates. Then, we removed the solvent and the membranes were structurally stabilized during thermal treatment and transformed into their final form with –SO3H ionic groups. We found that the diamonds with a hydrogen-saturated surface, with a positive charge in aqueous media, contributed to the increase in proton conductivity of membranes to a greater rate. Meanwhile, a more developed conducting diamond-copolymer interface was formed due to electrostatic attraction to the sulfonic acid groups of the copolymer than in the case of diamonds grafted with negatively charged carboxyls, similar to sulfonic groups of the copolymer. The modification of membranes with fluorinated diamonds led to a 5-fold decrease in the conductivity of the composite, even when only a fraction of diamonds of 1 wt. % were used, which was explained by the disruption in the connectivity of ion channels during the interaction of such diamonds mainly with fluorocarbon chains of the copolymer. We discussed the specifics of the mechanism of conductivity in composites with various diamonds in connection with structural data obtained in neutron scattering experiments on dry membranes, as well as ideas about the formation of cylindrical micelles with central ion channels and shells composed of hydrophobic copolymer chains. Finally, the characteristics of the network of ion channels in the composites were found depending on the type and amount of introduced diamonds, and correlations between the structure and conductivity of the membranes were established

Improving PFSA Membranes Using Sulfonated Nanodiamonds

Aquivion®-type perfluorosulfonic acid membranes with a polytetrafluoroethylene backbone and short side chains with sulfonic acid groups at the ends have great prospects for operating in hydrogen fuel cells. To improve the conducting properties of membranes, various types of nanofillers can be used. We prepared compositional Aquivion®-type membranes with embedded detonation nanodiamond particles. Nanodiamonds were chemically modified with sulfonic acid groups to increase the entire amount of ionogenic groups involved in the proton conductivity mechanism in compositional membranes. We demonstrated the rise of proton conductivity at 0.5–2 wt.% of sulfonated nanodiamonds in membranes, which was accompanied by good mechanical properties. The basic structural elements, conducting channels in membranes, were not destroyed in the presence of nanodiamonds, as follows from small-angle neutron scattering data. The prepared compositional membranes can be used in hydrogen fuel cells to achieve improved performance