Explore the vast range of titles available.

Jasmonates are plant hormones that are involved in the regulation of different aspects of plant life, wherein their functions and molecular mechanisms of action in wheat are still poorly studied. With the aim of gaining more insights into the role of jasmonic acid (JA) in wheat growth, development, and responses to environmental stresses, we have generated transgenic bread wheat plants overexpressing Arabidopsis 12-OXOPHYTODIENOATE REDUCTASE 3 (AtOPR3), one of the key genes of the JA biosynthesis pathway. Analysis of transgenic plants showed that AtOPR3 overexpression affects wheat development, including germination, growth, flowering time, senescence, and alters tolerance to environmental stresses. Transgenic wheat plants with high AtOPR3 expression levels have increased basal levels of JA, and up-regulated expression of ALLENE OXIDE SYNTHASE, a jasmonate biosynthesis pathway gene that is known to be regulated by a positive feedback loop that maintains and boosts JA levels. Transgenic wheat plants with high AtOPR3 expression levels are characterized by delayed germination, slower growth, late flowering and senescence, and improved tolerance to short-term freezing. The work demonstrates that genetic modification of the jasmonate pathway is a suitable tool for the modulation of developmental traits and stress responses in wheat.

We propose algorithms for the solution of high-dimensional symmetrical positive definite (SPD) linear systems with the matrix and the right-hand side given and the solution sought in a low-rank format. Similarly to density matrix renormalization group (DMRG) algorithms, our methods optimize the components of the tensor product format subsequently. To improve the convergence, we expand the search space by an inexact gradient direction. We prove the geometrical convergence and estimate the convergence rate of the proposed methods utilizing the analysis of the steepest descent algorithm. The complexity of the presented algorithms is linear in the mode size and dimension, and the demonstrated convergence is comparable to or even better than the one of the DMRG algorithm. In the numerical experiment we show that the proposed methods are also efficient for non-SPD systems, for example, those arising from the chemical master equation describing the gene regulatory model at the mesoscopic scale.

Autoluminescent plants engineered to express a bacterial bioluminescence gene cluster in plastids have not been widely adopted because of low light output. We engineered tobacco plants with a fungal bioluminescence system that converts caffeic acid (present in all plants) into luciferin and report self-sustained luminescence that is visible to the naked eye. Our findings could underpin development of a suite of imaging tools for plants.Luminescence is engineered in whole plants, without an exogenous substrate, using a fungal gene cluster.

In light of recent climate change, with its rising temperatures and precipitation changes, we are facing the need to increase the valuable crop’s tolerance against unfavorable environmental conditions. Emmer wheat is a cereal crop with high nutritional value. We investigated the possibility of improving the stress tolerance of emmer wheat by activating the synthesis of the stress hormone jasmonate by overexpressing two genes of the jasmonate biosynthetic pathway from Arabidopsis thaliana, ALLENE OXIDE SYNTHASE (AtAOS) and OXOPHYTODIENOATE REDUCTASE 3 (AtOPR3). Analyses of jasmonates in intact and mechanically wounded leaves of non-transgenic and transgenic plants showed that the overexpression of each of the two genes resulted in increased wounding-induced levels of jasmonic acid and jasmonate-isoleucine. Against all expectations, the overexpression of AtAOS, encoding a chloroplast-localized enzyme, does not lead to an increased level of the chloroplast-formed 12-oxo-phytodienoic acid (OPDA), suggesting an effective conversion of OPDA to downstream products in wounded emmer wheat leaves. Transgenic plants overexpressing AtAOS or AtOPR3 with increased jasmonate levels show a similar phenotype, manifested by shortening of the first and second leaves and elongation of the fourth leaf, as well as increased tolerance to osmotic stress induced by the presence of the polyethylene glycol (PEG) 6000.

The transformation protocol based on the dual selection approach (fluorescent protein and herbicide resistance) has been applied here to produce transgenic plants of two cereal species, emmer wheat and bread wheat, with the goal of activating the synthesis of the stress hormone jasmonates by overexpressing ALLENE OXIDE SYNTHASE from Arabidopsis thaliana (AtAOS) and bread wheat (TaAOS) and OXOPHYTODIENOATE REDUCTASE 3 from A. thaliana (AtOPR3) under the strong constitutive promoter (ZmUbi1), either individually or both genes simultaneously. The delivery of the expression cassette encoding AOS was found to affect morphogenesis in both wheat species negatively. The effect of transgene expression on the accumulation of individual jasmonates in hexaploid and tetraploid wheat was observed. Among the introduced genes, overexpression of TaAOS was the most successful in increasing stress-inducible phytohormone levels in transgenic plants, resulting in higher accumulations of JA and JA-Ile in emmer wheat and 12-OPDA in bread wheat. In general, overexpression of AOS, alone or together with AtOPR3, negatively affected leaf lamina length and grain numbers per spike in both wheat species. Double (AtAOS + AtOPR3) transgenic wheat plants were characterized by significantly reduced plant height and seed numbers, especially in emmer wheat, where several primary plants failed to produce seeds.

We propose an algorithm for solution of high-dimensional evolutionary equations (ODEs and discretized time-dependent PDEs) in the Tensor Train (TT) decomposition, assuming that the solution and the right-hand side of the ODE admit such a decomposition with a low storage. A linear ODE, discretized via one-step or Chebyshev differentiation schemes, turns into a large linear system. The tensor decomposition allows to solve this system for several time points simultaneously using an extension of the Alternating Least Squares algorithm. This method computes a reduced TT model of the solution, but in contrast to traditional offline-online reduction schemes, solving the original large problem is never required. Instead, the method solves a sequence of reduced Galerkin problems, which can be set up efficiently due to the TT decomposition of the right-hand side. The reduced system allows a fast estimation of the time discretization error, and hence adaptation of the time steps. Besides, conservation laws can be preserved exactly in the reduced model by expanding the approximation subspace with the generating vectors of the linear invariants and correction of the Euclidean norm. In numerical experiments with the transport and the chemical master equations, we demonstrate that the new method is faster than traditional time stepping and stochastic simulation algorithms, whereas the invariants are preserved up to the machine precision irrespectively of the TT approximation accuracy.

Chrysanthemum is a vegetative propagated culture in which viral transmission with planting material is important for its production. Chrysanthemum virus B (CVB) belongs to the viruses that strike this plant culture. Chrysanthemum virus B is found everywhere where chrysanthemum is cultivated. Damage to plants by CVB often leads to a complete loss of floral yield. Chrysanthemum (Chrysanthemum morifolium Ramat cv. White Snowdon) was transformed via Agrobacterium-mediated DNA delivery with the aim of improving resistance to CVB infection. Transformation vectors contain the nucleotide sequence of CVB coat proteins (CP) in sense, antisense, and double sense orientation. The transformative vectors also invert repeats of CVB coat protein gene fragments for the induction of RNA-interference. The transgenic chrysanthemum plants were successfully obtained. The integration of the target sequences in plant genomes was confirmed by polymerase chain reaction (PCR) and Southern blot analyses. Chrysanthemum lines were transformed with antisense, sense, and double sense CVB CP sequences, as well as with hairpin RNA-interference constructs that were assayed for resistance to CVB. Infection of transgenic plants by CVB through the grafting of infected scions shows resistance only among plants with carried double sense (16.7%) and hairpin (12.5%) constructs. The plants transformed by sense and double sense sequences were observed and classified as tolerant.

The relevance of the work is caused by the need to develop the environmentally friendly heat-generating devices for disposal liquid technological wastes. The main aim of the research is to optimize the constructive implementation of technical solutions for disposal liquid hydrocarbon wastes. Using the software package «Ansys Multiphysics» the authors have simulated the combustion front at various flow conditions and measured reaction rate, temperature and components concentrations in the combustion zone. The results of the investigation have shown that the proposed technical solution has a number of features.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Chrysanthemum is one of the most important commercial cut flowers in the world. Early-flowering cultivars are required to produce quality chrysanthemum flowers with a lower cost of production. To shorten the vegetative growth phase of chrysanthemum, three AP1-like genes from Asteraceae were constitutively overexpressed in 80 independent transgenic chrysanthemum lines. All lines were characterized by PCR and RT-PCR and demonstrated that overexpression of compositae AP1-homologs in transgenic chrysanthemum under long-day conditions had no effect on plant development compared to non-transgenic controls. Conversely, under short-day conditions, transgenic plants commenced bud initiation 2 wk earlier than non-transgenic chrysanthemum plants. Subsequently, transgenic chrysanthemum flowers showed color earlier and resulted in full opening of inflorescences 3 wk prior to non-transgenic control plants. These results open new possibilities for genetic improvement and breeding of chrysanthemum cultivars.