The IBR5 phosphatase promotes Arabidopsis auxin responses through a novel mechanism distinct from TIR1-mediated repressor degradation

<p>Abstract</p> <p>Background</p> <p>In Arabidopsis, INDOLE-3-BUTYRIC ACID RESPONSE5 (IBR5), a putative dual-specificity protein phosphatase, is a positive regulator of auxin response. Mutations in <it>IBR5 </it>result in decreased plant height, defective vascular development, increased leaf serration, fewer lateral roots, and resistance to the phytohormones auxin and abscisic acid. However, the pathways through which IBR5 influences auxin responses are not fully understood.</p> <p>Results</p> <p>We analyzed double mutants of <it>ibr5 </it>with other mutants that dampen auxin responses and found that combining <it>ibr5 </it>with an auxin receptor mutant, <it>tir1</it>, enhanced auxin resistance relative to either parent. Like other auxin-response mutants, auxin-responsive reporter accumulation was reduced in <it>ibr5</it>. Unlike other auxin-resistant mutants, the Aux/IAA repressor reporter protein AXR3NT-GUS was not stabilized in <it>ibr5</it>. Similarly, the Aux/IAA repressor IAA28 was less abundant in <it>ibr5 </it>than in wild type. <it>ibr5 </it>defects were not fully rescued by overexpression of a mutant form of IBR5 lacking the catalytic cysteine residue.</p> <p>Conclusion</p> <p>Our genetic and molecular evidence suggests that IBR5 is a phosphatase that promotes auxin responses, including auxin-inducible transcription, differently than the TIR1 auxin receptor and without destabilizing Aux/IAA repressor proteins. Our data are consistent with the possibility that auxin-responsive transcription can be modulated downstream of TIR1-mediated repressor degradation.</p

Sequence determinants of in cell condensate morphology, dynamics, and oligomerization as measured by number and brightness analysis

BACKGROUND: Biomolecular condensates are non-stoichiometric assemblies that are characterized by their capacity to spatially concentrate biomolecules and play a key role in cellular organization. Proteins that drive the formation of biomolecular condensates frequently contain oligomerization domains and intrinsically disordered regions (IDRs), both of which can contribute multivalent interactions that drive higher-order assembly. Our understanding of the relative and temporal contribution of oligomerization domains and IDRs to the material properties of in vivo biomolecular condensates is limited. Similarly, the spatial and temporal dependence of protein oligomeric state inside condensates has been largely unexplored in vivo. METHODS: In this study, we combined quantitative microscopy with number and brightness analysis to investigate the aging, material properties, and protein oligomeric state of biomolecular condensates in vivo. Our work is focused on condensates formed by AUXIN RESPONSE FACTOR 19 (ARF19), a transcription factor integral to the auxin signaling pathway in plants. ARF19 contains a large central glutamine-rich IDR and a C-terminal Phox Bem1 (PB1) oligomerization domain and forms cytoplasmic condensates. RESULTS: Our results reveal that the IDR amino acid composition can influence the morphology and material properties of ARF19 condensates. In contrast the distribution of oligomeric species within condensates appears insensitive to the IDR composition. In addition, we identified a relationship between the abundance of higher- and lower-order oligomers within individual condensates and their apparent fluidity. CONCLUSIONS: IDR amino acid composition affects condensate morphology and material properties. In ARF condensates, altering the amino acid composition of the IDR did not greatly affect the oligomeric state of proteins within the condensate. Video Abstract

Componentes del amor y bienestar psicológico en estudiantes de una Universidad Privada de Trujillo

RESUMEN En la presente investigación se exploró la relación entre Componentes del amor y el Bienestar psicológico, llevándose a cabo un Diseño de estudio Correlacional, cuya muestra de tipo probabilística estuvo conformada por 125 estudiantes universitarios entre 20 y 24 años de edad de la ciudad de Trujillo y se utilizaron para su medición La Escala Triangular del amor de Sternberg y la Escala de Bienestar Psicológico de Ryff, adaptado por Van Dierendonck. Los resultados evidencian que se encuentra correlación negativa y significativa (r=-.17, p<.05) entre el componente Intimidad y la dimensión autonomía, asimismo se correlaciona positiva y altamente significativa el mismo componente con la dimensión crecimiento personal (r=.28, p<.01); en lo que respecta al segundo componente (Pasión) se correlaciona de manera negativa y significativamente (r=-.19, p<.05) con la dimensión dominio del entorno, empero se correlaciona de forma positiva y altamente significativa (r=.25, p<.01)con la dimensión crecimiento personal; además en lo que respecta al tercer componente (Compromiso) se evidencia correlación positiva y significativa (r=.20, p<.05) con la dimensión dominio del entorno, no obstante correlación negativa y altamente significativa (r=-.24, p<01) con la dimensión crecimiento personal. En lo concerniente a los resultados descriptivos se observa que el componente de amor con tendencia de medio a alto en la muestra de estudio es Intimidad (52.8% y 29.6%); y finalmente en lo concerniente a bienestar psicológico todas las dimensiones presentan una tendencia de nivel medio; excepto Propósito en la vida, cuyo puntaje se ubicó en un nivel de medio a bajo (60.0% y 26.4%). PALABRAS CLAVE: componentes del amor, bienestar psicológico, relación de pareja.ABSTRACT The present research explored the relationship between Components of Love and Psychological Well-Being, carrying out a correlational study design, whose sample of probabilistic type was formed by 125 university students between 20 and 24 years old from Trujillo city and were used for measurement of Sternberg’s Triangular Scale of Love and the Ryff Psychological Well-Being Scale adapted by Van Dierendonck. The results show that there is a negative and significant correlation (r=-.17, p<.05) between the Intimacy component and the Autonomy dimension, and the same component is correlated positively and highly significant with the Personal Growth dimension (r=.28, p<.01), with respect to the second component Passion is negatively and significantly correlated (r=-.19, p<.05) with the dimension Domain of the Environment, however is correlated in a positive way and highly significant (r=.25, p<.01) with the Personal Growth dimension. In addition to the third component (Commitment) evidence positive and significant correlation (r=.20, p<01) with the dimension Domain of the Environment, however negative and highly significant correlation (r=-.24, p<01) with the Personal Growth dimension. Regarding to the descriptive results it is observed that the love component with tendency medium to high in the study sample is Intimacy (52.8% and 29.6%); and finally with respect to Psychological Well-Being all the dimensions present a mediumlevel tendency, except Purpose in life whose score was placed in a level of medium to low (60.0% and 26.4%). KEYWORDS: components of love, psychological wellbeing, relationship

Regulation of AUXIN RESPONSE FACTOR condensation and nucleo-cytoplasmic partitioning

Auxin critically regulates plant growth and development. Auxin-driven transcriptional responses are mediated through the AUXIN RESPONSE FACTOR (ARF) family of transcription factors. ARF protein condensation attenuates ARF activity, resulting in dramatic shifts in the auxin transcriptional landscape. Here, we perform a forward genetics screen for ARF hypercondensation, identifying an F-box protein, which we named AUXIN RESPONSE FACTOR F-BOX1 (AFF1). Functional characterization of SC

What is quantitative plant biology?

Quantitative plant biology is an interdisciplinary field that builds on a long history of biomathematics and biophysics. Today, thanks to high spatiotemporal resolution tools and computational modelling, it sets a new standard in plant science. Acquired data, whether molecular, geometric or mechanical, are quantified, statistically assessed and integrated at multiple scales and across fields. They feed testable predictions that, in turn, guide further experimental tests. Quantitative features such as variability, noise, robustness, delays or feedback loops are included to account for the inner dynamics of plants and their interactions with the environment. Here, we present the main features of this ongoing revolution, through new questions around signalling networks, tissue topology, shape plasticity, biomechanics, bioenergetics, ecology and engineering. In the end, quantitative plant biology allows us to question and better understand our interactions with plants. In turn, this field opens the door to transdisciplinary projects with the society, notably through citizen science.Peer reviewe

The Formation and Evolution of Virgo Cluster Galaxies - II. Stellar Populations

We use a combination of deep optical and near-infrared light profiles for a morphologically diverse sample of Virgo cluster galaxies to study the radially-resolved stellar populations of cluster galaxies over a wide range of galaxy structure. We find that, in the median, the age gradients of Virgo galaxies are either flat (lenticulars and Sa-Sb spirals) or positive (ellipticals, Sbc+Sc spirals, gas-rich dwarfs, and irregulars), while all galaxy types have a negative median metallicity gradient. Comparison of the galaxy stellar population diagnostics (age, metallicity, and gradients thereof) against structural and environmental parameters also reveals that the ages of gas-rich systems depend mainly on their atomic gas deficiencies. Conversely, the metallicities of Virgo gas-poor galaxies depend on their concentrations, luminosities, and surface brightnesses. The stellar population gradients of all Virgo galaxies exhibit no dependence on either their structure or environment. We interpret these stellar population data for Virgo galaxies in the context of popular formation and evolution scenarios, and suggest that gas-poor giants grew hierarchically (through dissipative starbursts), gas-poor dwarfs have descended from at least two different production channels (e.g., environmental transformation and merging), while spirals formed inside-out, but with star formation in the outskirts of a significant fraction of the population having been quenched due to ram pressure stripping. (Abridged)Comment: 54 pages, 16 figures, 3 tables, re-submitted to MNRAS (edited to reflect the referee's suggestions

Interplay of Auxin and Cytokinin in Lateral Root Development

The spacing and distribution of lateral roots are critical determinants of plant root system architecture. In addition to providing anchorage, lateral roots explore the soil to acquire water and nutrients. Over the past several decades, we have deepened our understanding of the regulatory mechanisms governing lateral root formation and development. In this review, we summarize these recent advances and provide an overview of how auxin and cytokinin coordinate the regulation of lateral root formation and development

Auxin perception and downstream events

Auxin responses have been arbitrarily divided into two categories: genomic and non-genomic effects. Genomic effects are largely mediated by SCFTIR1/AFB-Aux/IAA auxin receptor complexes whereas it has been postulated that AUXIN BINDING PROTEIN 1 (ABP1) controls the non-genomic effects. However, the roles of ABP1 in auxin signaling and plant development were recently called into question. In this paper, we present recent progress in understanding the SCFTIR1/AFB-Aux/IAA pathway. In more detail, we discuss the current understanding of ABP1 research and provide an updated view of ABP1-related genetic materials. Further, we propose a model in which auxin efflux carriers may play a role in auxin perception and we briefly describe recent insight on processes downstream of auxin perception

Up in the air: Untethered Factors of Auxin Response [version 1; referees: 5 approved]

As a prominent regulator of plant growth and development, the hormone auxin plays an essential role in controlling cell division and expansion. Auxin-responsive gene transcription is mediated through the TRANSPORT INHIBITOR RESPONSE1/AUXIN SIGNALING F-BOX (TIR1/AFB) pathway. Roles for TIR1/AFB pathway components in auxin response are understood best, but additional factors implicated in auxin responses require more study. The function of these factors, including S-Phase Kinase-Associated Protein 2A (SKP2A), SMALL AUXIN UP RNAs (SAURs), INDOLE 3-BUTYRIC ACID RESPONSE5 (IBR5), and AUXIN BINDING PROTEIN1 (ABP1), has remained largely obscure. Recent advances have begun to clarify roles for these factors in auxin response while also raising additional questions to be answered

The Arabidopsis PLEIOTROPIC DRUG RESISTANCE8/ABCG36 ATP Binding Cassette Transporter Modulates Sensitivity to the Auxin Precursor Indole-3-Butyric Acid[C][W]

Plants have developed numerous mechanisms to store hormones in inactive but readily available states, enabling rapid responses to environmental changes. The phytohormone auxin has a number of storage precursors, including indole-3-butyric acid (IBA), which is apparently shortened to active indole-3-acetic acid (IAA) in peroxisomes by a process similar to fatty acid β-oxidation. Whereas metabolism of auxin precursors is beginning to be understood, the biological significance of the various precursors is virtually unknown. We identified an Arabidopsis thaliana mutant that specifically restores IBA, but not IAA, responsiveness to auxin signaling mutants. This mutant is defective in PLEIOTROPIC DRUG RESISTANCE8 (PDR8)/PENETRATION3/ABCG36, a plasma membrane–localized ATP binding cassette transporter that has established roles in pathogen responses and cadmium transport. We found that pdr8 mutants display defects in efflux of the auxin precursor IBA and developmental defects in root hair and cotyledon expansion that reveal previously unknown roles for IBA-derived IAA in plant growth and development. Our results are consistent with the possibility that limiting accumulation of the IAA precursor IBA via PDR8-promoted efflux contributes to auxin homeostasis