SignificanceWe present identification of the luciferase and enzymes of the biosynthesis of a eukaryotic luciferin from fungi. Fungi possess a simple bioluminescent system, with luciferin being only two enzymatic steps from well-known metabolic pathways. The expression of genes from the fungal bioluminescent pathway is not toxic to eukaryotic cells, and the luciferase can be easily co-opted to bioimaging applications. With the fungal system being a genetically encodable bioluminescent system from eukaryotes, it is now possible to create artificially bioluminescent eukaryotes by expression of three genes. The fungal bioluminescent system represents an example of molecular evolution of a complex ecological trait and with molecular details reported in the paper, will allow additional research into ecological significance of fungal bioluminescence.

Autoluminescent plants that express a bacterial bioluminescence gene cluster 1 have not been widely adopted due to requisite expression in plastids and low light output. Alternatively, we have engineered tobacco lines expressing a fungal bioluminescent system 2 , which converts caffeic acid present in all plants into luciferin, and report self-sustained luminescence easily visible to the naked eye. Our findings might underpin development of a suite of imaging tools for plants.

No abstract

Avian influenza is a major viral disease in poultry. Antigenic variation of this virus hinders vaccine development. However, the extracellular domain of the virus-encoded M2 protein (peptide M2e) is nearly invariant in all influenza A strains, enabling the development of a broad-range vaccine against them. Antigen expression in transgenic plants is becoming a popular alternative to classical expression methods. Here we expressed M2e from avian influenza virus A/chicken/Kurgan/5/2005(H5N1) in nuclear-transformed duckweed plants for further development of avian influenza vaccine. The N-terminal fragment of M2, including M2e, was selected for expression. The M2e DNA sequence fused in-frame to the 5' end of β-glucuronidase was cloned into pBI121 under the control of CaMV 35S promoter. The resulting plasmid was successfully used for duckweed transformation, and western analysis with anti-β-glucuronidase and anti-M2e antibodies confirmed accumulation of the target protein (M130) in 17 independent transgenic lines. Quantitative ELISA of crude protein extracts from these lines showed M130-β-glucuronidase accumulation ranging from 0.09-0.97 mg/g FW (0.12-1.96 % of total soluble protein), equivalent to yields of up to 40 μg M2e/g plant FW. This relatively high yield holds promise for the development of a duckweed-based expression system to produce an edible vaccine against avian influenza.

The effects of different factors on the embryogenesis and plant regeneration from mature embryos of Russian spring and winter genotypes were studied. Embryogenic callus induction was achieved on MS medium supplemented with different concentrations of 2,4-D (2,4-dichlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) or Dicamba (3,6-dichloro-o-anisic acid). Although all auxins were able to induce callus from explants with high frequency (98-100%), Dicamba was more effective for the induction of embryogenic callus (21.8-38.3%). Maximum embryogenic callus formation and high number of regenerated plants were observed at 12 mg l )1 of Dicamba. The time exposure to Dicamba (7, 14, 21 and 28 days) had a significant effect on efficiency of somatic embryogenesis. When contact of explants with callus induction medium was increased from 7 to 21 days the rate of somatic embryogenesis and number of regenerated plants per embryogenic callus gradually increased from 13.0 to 38.4% and 3.6 to 8.0%, respectively. Supplement of additional auxins (indoleacetic acid (IAA), indolebutyric acid (IBA), and naphthaleneacetic acid (NAA)) to callus induction medium with Dicamba had a positive effect on the rate of embryogenic callus formation, while the average number of regenerated shoots was not affected. The best rate of somatic embryogenesis was observed at the addition of 0.5 mg l )1 IAA with Dicamba (61.0%). The optimum combination of Dicamba and IAA increased the efficiency of somatic embryogenesis and plant regeneration from seven spring and winter wheat genotypes, thought overall morphogenic capacity was still genotype dependent.

A tensor decomposition approach for the solution of high-dimensional, fully nonlinear Hamilton-Jacobi-Bellman equations arising in optimal feedback control of nonlinear dynamics is presented. The method combines a tensor train approximation for the value function together with a Newton-like iterative method for the solution of the resulting nonlinear system. The tensor approximation leads to a polynomial scaling with respect to the dimension, partially circumventing the curse of dimensionality. An analysis of the linear-quadratic case is presented. For nonlinear dynamics, the effectiveness of the high-dimensional control synthesis method is assessed in the optimal feedback stabilization of the Allen-Cahn and Fokker-Planck equations.

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.

No abstract