Spike fertility and duration of stem elongation as promising traits to improve potential grain number (and yield): Variation in modern Argentinean wheats

The identification of physiological traits that determine grain number (and yield) in modern cultivars, and the possible tradeoffs among them, may help to detect promising traits for breeding to increase yield potential. High-yielding Argentinean wheat (Triticum aestivum L.) cultivars were grown under irrigated and highinput conditions during two seasons to study (i) yield and grain number m-2 (GN) as a result of stover biomass at harvest (SH) and harvest index (HI); and (ii) spike dry weight at anthesis (SDWa; g m-2) and spike fertility index (SFI; grain number per gram of spike chaffor non-grain spike biomass). Duration of the stem elongation phase (SEP; first node detectable to anthesis) was analyzed as an alternative to increase SDWa. The HI was highly associated with yield differences between cultivars for both years, independently of stem height. In contrast, SH did not vary among cultivars in either season (P > 0.05). The GN determined yield differences between cultivars and was highly associated with SFIand SDWa for both years and cycles. Some cultivars with the same anthesis date showed stable variation for duration of the SEP between years (despite the year × cultivar interaction observed). As the SFIand duration of the SEP were not related, it seems promising to increase GN in a cultivar with high SFIthrough an increased duration of the SEP (which may yield higher SWDa) or vice versa.Fil: González, Fernanda Gabriela. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Pergamino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Terrile, Ignacio Ismael. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Pergamino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Falcón, M. O.. Universidad de Buenos Aires. Facultad de Agronomía; Argentin

Nitric oxide mediates vesicle trafficking of pin2 auxin transporter in Arabidopsis

Auxin is transported from cell to cell with strict directionality by uptake and efflux carrier proteins. The PIN efflux transporters exhibit polar plasma membrane (PM) localization and determine the direction and rate of intracellular auxin flow. The localization of PIN proteins is maintained by endocytosis and recycling through vesicle trafficking in a process termed constitutive cycling. Auxin itself has been shown to inhibit PIN2 endocytosis and promote PIN2 PM localization. It has been also demonstrated that SCF TIR1/AFBs complex is involved in endocytosis, recycling and PM accumulation of PIN2.Recently, it has been described that TIR1 auxin receptor is regulated by NO through S-nitrosylation. In order to study the TIR1-AFB-mediated auxin signaling pathway and its regulation by NO in the control of PIN2 localization, pharmacological and functional approaches were carried out. We presented evidence that NO affect PIN2 endocytosis. The mechanism underlying this regulation is discussed. Las auxinas se distribuyen polarmente a lo largo de la planta, por medio de transportadores específicos de influjo y eflujo. La familia de transportadores de eflujo PIN se localiza en la membrana plasmática y determina la dirección y tasa de flujo de esta hormona. Para PIN1 y PIN2, dicha localización es regulada por endocitosis y tráfico vesicular intracelular. A su vez, las auxinas inhiben la endocitosis de PIN2, promoviendo su localización en la membrana. Se ha demostrado la participación de la vía SCF TIR1/AFBs en los procesos de endocitosis, reciclado y acumulación en la membrana de las proteínas PIN. Asimismo, la vía de transducción de señales iniciada por la unión de las auxinas al receptor TIR1 se encuentra regulada por óxido nítrico (NO) mediante la S-nitrosilación de dicha proteína. Con el objetivo de profundizar el estudio de la vía de señalización por auxinas mediada por el complejo SCF TIR1/AFBs y su regulación por NO, se abordaron complementariamente los enfoques farmacológicos y de genómica funcional. Las evidencias indican que el NO afecta la endocitosis de PIN2. Se discutirán los mecanismos que subyacen en dicha regulación.Fil: Vazquez, Maria Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Colman, Silvana Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Terrile, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Otegui, M.. University of Wisconsin; Estados UnidosFil: Casalongue, Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Paris, Ramiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; Argentina51 Annual Meeting Argentine Society for Biochemistry and Molecular BiologyMar del PlataArgentinaSociedad Argentina de Investigación en Bioquímica y Biología Molecula

The Circumstellar Disk of HD 141569 Imaged with NICMOS

Coronagraphic imaging with the Near Infrared Camera and Multi Object Spectrometer on the Hubble Space Telescope reveals a large, ~400 AU (4'') radius, circumstellar disk around the Herbig Ae/Be star HD 141569. A reflected light image at 1.1 micron shows the disk oriented at a position angle of 356 +/- 5 deg and inclined to our line of sight by 51 +/- 3 deg; the intrinsic scattering function of the dust in the disk makes the side inclined toward us, the eastern side, brighter. The disk flux density peaks 185 AU (1.''85) from the star and falls off to both larger and smaller radii. A region of depleted material, or a gap, in the disk is centered 250 AU from the star. The dynamical effect of one or more planets may be necessary to explain this morphology.Comment: 4 pages, LaTeX with emulateapj.sty and epsfig.sty, 4 postscript figures, Accepted to ApJ Letter

MiR393 regulation of auxin signaling and redox-related components during acclimation to salinity in Arabidopsis

One of the most striking aspects of plant plasticity is the modulation of development in response to environmental changes. Plant growth and development largely depend on the phytohormone auxin that exerts its function through a partially redundant family of F-box receptors, the TIR1-AFBs. We have previously reported that the Arabidopsis double mutant tir1 afb2 is more tolerant to salt stress than wild-type plants and we hypothesized that down-regulation of auxin signaling might be part of Arabidopsis acclimation to salinity. In this work, we show that NaCl-mediated salt stress induces miR393 expression by enhancing the transcription of AtMIR393A and leads to a concomitant reduction in the levels of the TIR1 and AFB2 receptors. Consequently, NaCl triggers stabilization of Aux/IAA repressors leading to down-regulation of auxin signaling. Further, we report that miR393 is likely involved in repression of lateral root (LR) initiation, emergence and elongation during salinity, since the mir393ab mutant shows reduced inhibition of emergent and mature LR number and length upon NaCl-treatment. Additionally, mir393ab mutant plants have increased levels of reactive oxygen species (ROS) in LRs, and reduced ascorbate peroxidase (APX) enzymatic activity compared with wild-type plants during salinity. Thus, miR393 regulation of the TIR1 and AFB2 receptors could be a critical checkpoint between auxin signaling and specfic redoxassociated components in order to coordinate tissue and time-specific growth responses and tolerance during acclimation to salinity in Arabidopsis.Instituto de Fisiología Vegeta

A Candidate Substellar Companion to HR 7329

We present the discovery of a candidate substellar companion from a survey of nearby, young stars with the NICMOS coronagraph on the Hubble Space Telescope. The H ~ 12 mag object was discovered approximately 4" from the young A0V star HR 7329. Using follow-up spectroscopy from STIS, we derive a spectral type between M7V and M8V with an effective temperature of ~ 2600 K. We estimate that the probability of a chance alignment with a foreground dwarf star of this nature is ~ 10^(-8) and therefore suggest the object (HR 7329B) is physically associated with HR 7329 with a projected separation of 200 AU. Current brown dwarf cooling models indicate a mass of less than 50 Jupiter masses for HR 7329B based on age estimates of < 30 Myr for HR7329A.Comment: 8 pages LATEX, 5 ps figures, accepted for Ap

Urban food waste for soil amendment? Analysis and characterisation of waste-based compost for soil fertility management in agroecological horticultural production systems in the city of Rosario, Argentina

Urban and peri-urban lands can be an important source of food production for localised and sustainable food systems, however, their soils can be of poor quality, degraded or damaged by anthropic activities, and little is known about their suitability or safety. This paper aims to contribute to this knowledge gap by assessing the soil remediation capacity and qualities of different types of compost made from urban and peri-urban organic wastes for agroecological food production. Prepared over the course of 2021, and used in 2022 for food growing, five different composts were observed and analysed, in two different farms in the city of Rosario, Argentina. Four raw materials generated largely by local industries were used to make the composts: chicken manure, rumen (cow’s stomachs), brewer’s bagasse (byproducts of the beer industry) and urban leaves collected from the municipality waste collection. These were mixed in different proportions (all reaching the 20–30 C/N ratio, typical of quality compost) to produce viable growing substrates where radishes and lettuces were grown. The aim of the study was to assess the possibility, quality and limitations to use locally available organic inputs for soil fertility management in agroecological farming, in the context of urbanisation and to assess pathways to develop closed-cycle agroecological agriculture at metropolitan level. Natural manure substrates (raw and composted) were analysed, as well as crops grown and fertilised with each of the substrates. The attributes and limiting factors of each substrate and their response to local soil conditions were compared and physicochemical, biochemical, and microbiological analyses were performed, including among others, the study of microbial biomass, biological activity, biophytotoxicity, pH, aerobic heterotrophs, nitrogen fixation, and the presence of antibiotics, agrochemicals and heavy metals. The results of the analyses show that all the composted materials improved the physical, chemical and biological properties. However, in some cases, pollutants were present even after composting. Analysis carried out on the vegetables generally indicate undetectable levels or levels below the admissible limits, demonstrating the filtering capacity of the different composts and the soil

Distribution of endogenous NO regulates early gravitropic response and PIN2 localization in arabidopsis roots

High-resolution and automated image analysis of individual roots demonstrated that endogenous nitric oxide (NO) contribute significantly to gravitropism of Arabidopsis roots. Lowering of endogenous NO concentrations strongly reduced and even reversed gravitropism, resulting in upward bending, without affecting root growth rate. Notably, the asymmetric accumulation of NOalong the upper and lower sides of roots correlated with a positive gravitropic response. Detection of NO by the specific DAF-FM DA fluorescent probe revealed that NO was higher at the lower side of horizontally-oriented roots returning to initial values 2h after the onset of gravistimulation. We demonstrate that NO promotes plasma membrane re-localization of PIN2 in epidermal cells, which is required during the early root gravitropic response. The dynamic and asymmetric localization of both auxin and NO is critical to regulate auxin polar transport during gravitropism. Our results collectively suggest that, although auxin and NO crosstalk occurs at different levels of regulation, they converge in the regulation of PIN2 membrane trafficking in gravistimulated roots, supporting the notion that a temporally and spatially coordinated network of signal molecules could participate in the early phases of auxin polar transport during gravitropism.Fil: Paris, Ramiro. Universidad Nacional de Mar del Plata; ArgentinaFil: Vazquez, María M.. Universidad Nacional de Mar del Plata; ArgentinaFil: Graziano, Magdalena. Universidad Nacional de Mar del Plata; ArgentinaFil: Terrile, Maria Cecilia. Universidad Nacional de Mar del Plata; ArgentinaFil: Miller, Nathan D.. University Of Wisconsin-madison; Estados UnidosFil: Spalding, Edgar P.. University Of Wisconsin-madison; Estados UnidosFil: Otegui, Marisa S.. University Of Wisconsin-madison;Fil: Casalongue, Claudia. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; Argentin

Teste de aceitabilidade de brotos de soja da cultivar BRS 216.

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Produção de brotos de soja da cultivar BRS 216.

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