Sources of parthenocarpy for Zucchini breeding: relationship with ethylene production and sensitivity

Parthenocarpy is becoming an essential trait for off-season greenhouse production of Zucchini squash. Given that winter conditions promote a reduction in the number of male flowers and in the activity of pollinators, the application of synthetic auxins is currently the most widespread method to induce fruit set. We have evaluated the parthenocarpic tendency of 48 long-fruited accessions of Cucurbita pepo spp. pepo, from morphotypes Zucchini, Vegetable marrow and Cocozelle, including 45 traditional cultivars and 3 commercial hybrids, with the goal of identifying new sources of parthenocarpy for breeding programs. After the first screening, 20 selected accessions were evaluated for the growth rate of unpollinated fruit. Twelve of the selected accessions identified as either strongly parthenocarpic or non-parthenocarpic, were compared for fruit rate growth, ethylene production and ethylene sensitivity. Apart from the three control hybrids, the fastest parthenocarpic fruit growth was observed in 'CpCAL112', 'CM-37', 'E-27', 'PI261610', and 'V-185'. The source of the parthenocarpy of some of these accessions differs from that of the hybrids as it was not associated with the conversion of female into bisexual flowers or with the so-called "fruits with attached flowers" syndrome, which is an undesirable trait in current parthenocarpic hybrids. The alternative sources of parthenocarpy may be of great importance in current Zucchini breeding programs. We also demonstrate that the parthenocarpy of these accessions is associated with downregulation of ethylene production in unpollinated fruits during the first days post anthesis (DPA). In non-parthenocarpic accessions, unpollinated fruits boosted ethylene production at 3 DPA, concomitantly with fruit abortion and senescence, while in parthenocarpic accessions, fruits produced little ethylene at 3 DPA. Therefore, ethylene production in ovaries/fruits at 3 DPA can be used as a marker to identify and select parthenocarpy in Zucchini squash. However, in the cultivars tested here, ethylene production and sensitivity in vegetative organs and in male flowers earlier than 3 PDA do not appear well associated with parthenocarpy.Martinez, C.; Manzano, S.; Megias, Z.; Garrido, D.; Picó Sirvent, MB.; Jamilena, M. (2014). Sources of parthenocarpy for Zucchini breeding: relationship with ethylene production and sensitivity. Euphytica. 200(3):349-362. doi:10.1007/s10681-014-1155-83493622003Byers R, Baker L, Dilley D, Sell H (1972) Chemical induction of perfect flowers on a gynoecious line of muskmelon, Cucumis melo L. HortSci 9:321–331Carbonell-Bejerano P, Urbez C, Granell A, Carbonell J, Perez-Amador MA (2011) Ethylene is involved in pistil fate by modulating the onset of ovule senescence and the GA-mediated fruit set in Arabidopsis. 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Ecological, genetic and evolutionary drivers of regional genetic differentiation in Arabidopsis thaliana

Background: Disentangling the drivers of genetic differentiation is one of the cornerstones in evolution. This is because genetic diversity, and the way in which it is partitioned within and among populations across space, is an important asset for the ability of populations to adapt and persist in changing environments. We tested three major hypotheses accounting for genetic differentiation—isolation-by-distance (IBD), isolation-by-environment (IBE) and isolation-by-resistance (IBR)—in the annual plant Arabidopsis thaliana across the Iberian Peninsula, the region with the largest genomic diversity. To that end, we sampled, genotyped with genome-wide SNPs, and analyzed 1772 individuals from 278 populations distributed across the Iberian Peninsula. Results: IBD, and to a lesser extent IBE, were the most important drivers of genetic differentiation in A. thaliana. In other words, dispersal limitation, genetic drift, and to a lesser extent local adaptation to environmental gradients, accounted for the within- and among-population distribution of genetic diversity. Analyses applied to the four Iberian genetic clusters, which represent the joint outcome of the long demographic and adaptive history of the species in the region, showed similar results except for one cluster, in which IBR (a function of landscape heterogeneity) was the most important driver of genetic differentiation. Using spatial hierarchical Bayesian models, we found that precipitation seasonality and topsoil pH chiefly accounted for the geographic distribution of genetic diversity in Iberian A. thaliana. Conclusions: Overall, the interplay between the influence of precipitation seasonality on genetic diversity and the effect of restricted dispersal and genetic drift on genetic differentiation emerges as the major forces underlying the evolutionary trajectory of Iberian A. thaliana

Simulation of gauge transformations on systems of ultracold atoms

We show that gauge transformations can be simulated on systems of ultracold atoms. We discuss observables that are invariant under these gauge transformations and compute them using a tensor network ansatz that escapes the phase problem. We determine that the Mott-insulator-to-superfluid critical point is monotonically shifted as the induced magnetic flux increases. This result is stable against the inclusion of a small amount of entanglement in the variational ansatz.Comment: 14 pages, 6 figure

Novel intravesical bacterial immunotherapy induces rejection of BCG-unresponsive established bladder tumors

Background Intravesical BCG is the gold-standard therapy for non-muscle invasive bladder cancer (NMIBC); however, it still fails in a significant proportion of patients, so improved treatment options are urgently needed. Methods Here, we compared BCG antitumoral efficacy with another live attenuated mycobacteria, MTBVAC, in an orthotopic mouse model of bladder cancer (BC). We aimed to identify both bacterial and host immunological factors to understand the antitumoral mechanisms behind effective bacterial immunotherapy for BC. Results We found that the expression of the BCG-absent proteins ESAT6/CFP10 by MTBVAC was determinant in mediating bladder colonization by the bacteria, which correlated with augmented antitumoral efficacy. We further analyzed the mechanism of action of bacterial immunotherapy and found that it critically relied on the adaptive cytotoxic response. MTBVAC enhanced both tumor antigen-specific CD4 + and CD8 + T-cell responses, in a process dependent on stimulation of type 1 conventional dendritic cells. Importantly, improved intravesical bacterial immunotherapy using MBTVAC induced eradication of fully established bladder tumors, both as a monotherapy and specially in combination with the immune checkpoint inhibitor antiprogrammed cell death ligand 1 (anti PD-L1). Conclusion These results contribute to the understanding of the mechanisms behind successful bacterial immunotherapy against BC and characterize a novel therapeutic approach for BCG-unresponsive NMIBC cases. © Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ

Improving the batch-to-batch reproducibility in microbial cultures during recombinant protein production by guiding the process along a predefined total biomass profile

In industry Escherichia coli is the preferred host system for the heterologous biosynthesis of therapeutic proteins that do not need posttranslational modifications. In this report, the development of a robust high-cell-density fed-batch procedure for the efficient production of a therapeutic hormone is described. The strategy is to guide the process along a predefined profile of the total biomass that was derived from a given specific growth rate profile. This profile might have been built upon experience or derived from numerical process optimization. A surprisingly simple adaptive procedure correcting for deviations from the desired path was developed. In this way the batch-to-batch reproducibility can be drastically improved as compared to the process control strategies typically applied in industry. This applies not only to the biomass but, as the results clearly show, to the product titer also

Nonlinear dispersive waves in repulsive lattices

[EN] The propagation of nonlinear waves in a lattice of repelling particles is studied theoretically and experimentally. A simple experimental setup is proposed, consisting of an array of coupled magnetic dipoles. By driving harmonically the lattice at one boundary, we excite propagating waves and demonstrate different regimes of mode conversion into higher harmonics, strongly influenced by dispersion and discreteness. The phenomenon of acoustic dilatation of the chain is also predicted and discussed. The results are compared with the theoretical predictions of $\alpha$-FPU equation, describing a chain of masses connected by nonlinear quadratic springs and numerical simulations. The results can be extrapolated to other systems described by this equation.The work was supported by Spanish Ministry of Economy and Innovation (MINECO) and European Union FEDER through Project No. FIS2015- 65998-C2-2 and by Project No. AICO/2016/060 by Conselleria de Educacion, Investigacion, Cultura y Deporte de la Generalitat Valenciana. L.J.S.-C. gratefully acknowledge the support of PAID-01-14 at Universitat Politscnica de Valsncia. A. M. gratefully acknowledge to Generalitat Valenciana (Santiago Grisolia program).Mehrem, A.; Jimenez, N.; Salmerón-Contreras, LJ.; García-Andrés, FX.; García-Raffi, LM.; Picó Vila, R.; Sánchez Morcillo, VJ. (2017). Nonlinear dispersive waves in repulsive lattices. Physical Review E. 96(1). https://doi.org/10.1103/PhysRevE.96.012208S00220096

Optimal Matrix Product States for the Heisenberg Spin Chain

We present some exact results for the optimal Matrix Product State (MPS) approximation to the ground state of the infinite isotropic Heisenberg spin-1/2 chain. Our approach is based on the systematic use of Schmidt decompositions to reduce the problem of approximating for the ground state of a spin chain to an analytical minimization. This allows to show that results of standard simulations, e.g. density matrix renormalization group and infinite time evolving block decimation, do correspond to the result obtained by this minimization strategy and, thus, both methods deliver optimal MPS with the same energy but, otherwise, different properties. We also find that translational and rotational symmetries cannot be maintained simultaneously by the MPS ansatz of minimum energy and present explicit constructions for each case. Furthermore, we analyze symmetry restoration and quantify it to uncover new scaling relations. The method we propose can be extended to any translational invariant Hamiltonian.Comment: 10 pages, 3 figures; typos adde