The impact of domestication and crop improvement on arbuscular mycorrhizal symbiosis in cereals: insights from genetics and genomics

The cereals (rice, maize, wheat, sorghum and the millets) provide over 50% of the world’s caloric intake, a value that rises to >80% in developing countries. Since domestication, cereals have been under artificial selection, largely directed towards higher yield. Throughout this process, cereals have maintained their capacity to interact with arbuscular mycorrhizal (AM) fungi, beneficial symbionts that associate with the roots of most terrestrial plants. It has been hypothesized that the shift from the wild to cultivation, and above all the last ~50 years of intensive breeding for high-input farming systems, has reduced the capacity of the major cereal crops to gain full benefit from AM interactions. Recent studies have shed further light on the molecular basis of establishment and functioning of AM symbiosis in cereals, providing insight into where the breeding process might have had an impact. Classic phytohormones, targets of artificial selection during the generation of Green Revolution semi-dwarf varieties, have emerged to be important regulators of AM symbiosis. Although there is still much to be learned about the mechanistic basis of variation in symbiotic outcome, these advances are providing an insight into the role of arbuscular mycorrhiza in agronomic systems

The spectral variability of FSRQs

The optical variability of 29 flat spectrum radio quasars in SDSS Stripe 82 region are investigated by using DR7 released multi-epoch data. All FSRQs show variations with overall amplitude ranging from 0.24 mag to 3.46 mag in different sources. About half of FSRQs show a bluer-when-brighter trend, which is commonly observed for blazars. However, only one source shows a redder-when-brighter trend, which implies it is rare in FSRQs. In this source, the thermal emission may likely be responsible for the spectral behavior.Comment: 4 pages, 1 figure, to be published in Journal of Astrophysics and Astronomy, as a proceeding paper of the conference "Multiwavelength Variability of Blazars", Guangzhou, China, September 22-24, 201

The genetic architecture of host response reveals the importance of arbuscular mycorrhizae to maize cultivation.

Arbuscular mycorrhizal fungi (AMF) are ubiquitous in cultivated soils, forming symbiotic relationships with the roots of major crop species. Studies in controlled conditions have demonstrated the potential of AMF to enhance the growth of host plants. However, it is difficult to estimate the actual benefit in the field, not least because of the lack of suitable AMF-free controls. Here we implement a novel strategy using the selective incorporation of AMF-resistance into a genetic mapping population to evaluate maize response to AMF. We found AMF to account for about one-third of the grain production in a medium input field, as well as to affect the relative performance of different plant genotypes. Characterization of the genetic architecture of the host response indicated a trade-off between mycorrhizal dependence and benefit. We identified several QTL linked to host benefit, supporting the feasibility of breeding crops to maximize profit from symbiosis with AMF

Glutamate receptor-like channels are essential for chemotaxis and reproduction in mosses

The deposited article version is a "Accelerated Article Preview" provided by Nature Publishing Group, and it contains attached the supplementary materials within the pdf.». This publication hasn't any creative commons license associated.Glutamate receptors are well characterized channels that mediate cell-to-cell communication during neurotransmission in animals. Nevertheless, information regarding their functional role in organisms without nervous systems is still limited. In plants, Glutamate Receptor-like (GLR) genes have been implicated in defence against pathogens, reproduction, control of stomata aperture and light signal transduction(1-5). However, the numerous GLR genes present in angiosperm genomes (20 to 70)(6) has prevented the observation of strong phenotypes in loss-of-function mutants. Here, we show that in the moss Physcomitrella patens, a basal land plant, mutation of GLR genes cause sperm failure in targeting the female reproductive organs. In addition, we show that GLR genes encode non-selective Ca(2+) permeable channels that can regulate cytoplasmic Ca(2+) and are needed to induce the expression of a BELL1-like transcription factor essential for zygote development. Our work reveals novel functions for GLRs in sperm chemotaxis and transcriptional regulation. Sperm chemotaxis is essential for fertilization in both animals and early land plants like bryophytes and pteridophytes. Therefore, our results are suggestive that ionotropic glutamate receptors may have been conserved throughout plant evolution to mediate cell-to-cell communication during sexual reproduction.Phillips University; Oxford University; University of Marburg; University of Muenster; MarieCurie ITN-Plant Origins grant: (FP7-PEOPLE-ITN-2008); FCT grants: (BEX-BCM/0376/2012; PTDC/BIA-PLA/4018/2012); NSF-US grant: (MCB 1616437/2016).info:eu-repo/semantics/acceptedVersio

Masa muscular y valores espirométricos en el equipo de atletismo de fondo de la BUAP

Introduction. Spirometry is a test to assess respiratory function and its evaluation in athletes is useful, since physical abilities are essential for good sports performance. Muscle mass (MM) may be a determining factor that would explain the variability of spirometry results in athletes. For these reasons, the objective of the study is to associate MM and its distribution with spirometric values ​​in the BUAP Athletics team. Materials and methods. Sample: 25 athletes from the BUAP men's track and field team. Anthropometric evaluation: through Bioelectrical Impedance to obtain MM, from the trunk (MMtr) and from the lower extremities (MMei). Assessment of lung function: through forced spirometry obtaining: forced vital capacity (FVC), forced expiratory volume at the first second (FEV1), peak flow and Tiffenau index. Results. A positive correlation was found between all the spirometric variables and those of the MM, with the MMei having the highest correlation, the strongest correlations with PEF and FEV1 with respect to the MMei (0.664 and 0.865 respectively). Conclusions. The distribution of MM has a significant influence on the respiratory function of athletes and it is the MMei that has the greatest association with spirometric values ​​(FEV1 and PEF). Introducción. La espirometría es una prueba para valorar la función respiratoria y su evaluación en atletas resulta útil, ya que las capacidades físicas son esenciales para un buen desempeño deportivo. La masa muscular (MM) pueden ser factor determinante que explicaría la variabilidad de los resultados de la espirometría en atletas. Por estas razones el objetivo del estudio es asociar la MM y su distribución con valores espirométricos en el equipo de Atletismo de fondo de la BUAP. Materiales y Métodos.  Muestra: 25 deportistas del equipo masculino de atletismo de fondo de la BUAP. Evaluación antropométrica: a través de Impedancia Bioeléctrica para obtener MM, del tronco (MMtr) y de las extremidades inferiores (MMei). Valoración de la función pulmonar: a través de espirometría forzada obteniendo: capacidad vital forzada (CVF), volumen espiratorio forzado al primer segundo (VEF1), pico flujo e Índice de Tiffenau. Resultados. Se encontró correlación positiva entre todas las variables espirométricas y las de la MM, siendo la MMei la que mayor correlación presento, siendo las correlaciones más fuertes con PEF y VEF1 respecto a la MMei (0.664 y 0.865 respectivamente). Conclusiones. La distribución de la MM tiene influencia significativa en la función respiratoria de los atletas y es la MMei la que tiene mayor asociación con valores espirométricos (VEF1 y el PEF)

A Very High-Order Accurate Staggered Finite Volume Scheme for the Stationary Incompressible Navier–Stokes and Euler Equations on Unstructured Meshes

International audienceWe propose a sixth-order staggered finite volume scheme based on polynomial reconstructions to achieve high accurate numerical solutions for the incompressible Navier-Stokes and Euler equations. The scheme is equipped with a fixed-point algorithm with solution relaxation to speed-up the convergence and reduce the computation time. Numerical tests are provided to assess the effectiveness of the method to achieve up to sixth-order con-2 Ricardo Costa et al. vergence rates. Simulations for the benchmark lid-driven cavity problem are also provided to highlight the benefit of the proposed high-order scheme