A MYB/ZML complex regulates wound-induced lignin genes in maize

Lignin is an essential polymer in vascular plants that plays key structural roles in vessels and fibers. Lignification is induced by external inputs such as wounding, but the molecular mechanisms that link this stress to lignification remain largely unknown. In this work, we provide evidence that three maize (Zea mays) lignin repressors, MYB11, MYB31, and MYB42, participate in wound-induced lignification by interacting with ZML2, a protein belonging to the TIFY family. We determined that the three R2R3-MYB factors and ZML2 bind in vivo to AC-rich and GAT(A/C) cis-elements, respectively, present in a set of lignin genes. In particular, we show that MYB11 and ZML2 bind simultaneously to the AC-rich and GAT(A/C) cis-elements present in the promoter of the caffeic acid O-methyl transferase (comt) gene. We show that, like the R2R3-MYB factors, ZML2 also acts as a transcriptional repressor. We found that upon wounding and methyl jasmonate treatments, MYB11 and ZML2 proteins are degraded and comt transcription is induced. Based on these results, we propose a molecular regulatory mechanism involving a MYB/ZML complex in which wound-induced lignification can be achieved by the derepression of a set of lignin genes.Research in D.C.-R.'s laboratory was supported by a grant from the Spanish Ministry of Science and Education (AGL2011-30545-C02-01), the “Xarxa de Referència de Biotecnologia” (XarBa) from the Autonomous Government of Catalonia, the CONSOLIDER-INGENIO program (CSD2007-00036) from the Spanish Ministry of Science and Innovation, and the SGR programs (SGR2009-GRC703). Research in M.P.'s laboratory was supported by two grants from the Spanish Ministry of Science and Education (BIO2009-13044-C02-01 and BIO2012-31860), the framework of the XarBa, and the SGR programs (SGR2009-GRC626) from the Autonomous Government of Catalonia. Research in R.S.'s laboratory was supported by grants from the Ministry of Science and Innovation to R.S. (BIO2013-44407). M.P. and R.S. received financial support from the CONSOLIDER-INGENIO program (CSD2007-00057-B) from the Spanish Ministerio de Ciencia e Innovación. Research in the W.S. laboratory is supported by grants from the Ministry of Science and Technology and Academia Sinica. Research in phenylpropanoid gene regulation in the laboratories of E.G. and J.G. was supported by a grant from the National Science Foundation (IOS-1125620). I.-C.V.-B. was supported by a Spanish FPI Fellowship (BES-2007-17316). J.E.S.-H. was supported by the Department of Innovation, Universities and Enterprise of the Generalitatde Catalunya, the European Social Fund FI Fellowship (AGAUR: FI-2006, Resolució EDU/3600/2006; FI-2008, Resolució IUE/2658/2007 and BE-DGR2010), and CRAG.Peer reviewe

An Inventory of Nutrient-Responsive Genes in Arabidopsis Root Hairs

Root hairs, single cell extensions of root epidermal cells that are critically involved in the acquisition of mineral nutrients, have proven to be an excellent model system for studying plant cell growth. More recently, omics-based systems biology approaches have extended the model function of root hairs towards functional genomic studies. While such studies are extremely useful to decipher the complex mechanisms underlying root hair morphogenesis, their importance for the performance and fitness of the plant puts root hairs in the spotlight of research aimed at elucidating aspects with more practical implications. Here, we mined transcriptomic and proteomic surveys to catalog genes that are preferentially expressed in root hairs and responsive to nutritional signals. We refer to this group of genes as the root hair trophomorphome. Our analysis shows that the activity of genes within the trophomorphome is regulated at both the transcriptional and post-transcriptional level with the mode of regulation being related to the function of the gene product. A core set of proteins functioning in cell wall modification and protein transport was defined as the backbone of the trophomorphome. In addition, our study shows that homeostasis of reactive oxygen species and redox regulation plays a key role in root hair trophomorphogenesis

El proceso de escritura con un programa que reconoce la voz y con un procesador de textos: una experiencia con estudiantes de sexto grado

En este artículo se describen y comparan las estrategias de planeación, producción y revisión que utilizó un grupo de estudiantes de sexto grado (15 escritores competentes y 14 con dificultades de escritura) para escribir una serie de textos narrativos, expositivos y epistolares, la mitad con un programa de reconocimiento de voz y la otra mitad con un procesador de textos. En una Escala de Observación, tres profesores de español y literatura registraron las conductas o acciones que llevaron a cabo los estudiantes durante el proceso de composición con ambas herramientas. El conocimiento derivado de este estudio puede sustentar el diseño de propuestas didácticas que aprovechen de manera óptima el potencial de estas tecnologías para mejorar las habilidades de escritura

Protein and antibody purification followed by immunoprecipitation of MYB and GATA zinc finger-type maize proteins with magnetic beads

Co-immunoprecipitation (Co-IP) is a widely used and powerful approach for studying protein-protein interactions in vivo. Here, we describe a protocol for antibody purification and immobilization followed by immunoprecipitation from plant tissue extracts using magnetic beads. The protocol has been used to detect regulators in the Zea mays phenylpropanoid pathway. The protocol is amenable to a variety of downstream assays, including western blotting and mass spectrometry. For complete details on the use and execution of this protocol, please refer to Vélez-Bermúdez et al. (2015).David Caparrós-Ruiz was supported by the Spanish project AGL2014-58126-R funded by the Ministerio de Economía y Competitividad /AEI and European Regional Development Fund (FEDER). This work was also supported by the SGR programs (SGR2009-GRC703 and 2017SGR710) from the Secretaria d'Universitats i Recerca del Departament d'Empresa i Coneixement de la Generalitat de Catalunya and by the CERCA Programme/Generalitat de Catalunya. We also acknowledge financial support from “Severo Ochoa Programme for Centres of Excellence in R&D” SEV-2015-0533 and CEX2019-000902-S both funded by MCIN/AEI/10.13039/501100011033. I.C.V.-B. was supported by a Ministry of Science and Technology Fellowship (104-2811-12-001-025) and Academia Sinica Postdoctoral Fellowship (L004). J.E.S.-H. was supported by Academia Sinica Postdoctoral Fellowship (L004). Work in the Schmidt laboratory is supported by Academia Sinica and the Ministry of Science and Technology, Taiwan.Peer reviewe

AtMYB7, a new player in the regulation of UV-sunscreens in Arabidopsis thaliana

The phenylpropanoid metabolic pathway provides a wide variety of essential compounds for plants. Together with sinapate esters, in Brassicaceae species, flavonoids play an important role in protecting plants against UV irradiation. In this work we have characterized Arabidopsis thaliana AtMYB7, the closest homolog of AtMYB4 and AtMYB32, described as repressors of different branches of phenylpropanoid metabolism. The characterization of atmyb7 plants revealed an induction of several genes involved in flavonol biosynthesis and an increased amount of these compounds. In addition, AtMYB7 gene expression is repressed by AtMYB4. As a consequence, the atmyb4 mutant plants present a reduction of flavonol contents, indicating once more that AtMYB7 represses flavonol biosynthesis. Our results also show that AtMYB7 gene expression is induced by salt stress. Induction assays indicated that AtMYB7 represses several genes of the flavonoid pathway, DFR and UGT being early targets of this transcription factor. The results obtained indicate that AtMYB7 is a repressor of flavonol biosynthesis and also led us to propose AtMYB4 and AtMYB7 as part of the regulatory mechanism controlling the balance of the main A. thaliana UV-sunscreens.This work was supported by the Spanish ‘Ministerio de Economía y Competitividad’ [AGL2011-30545-C02-01 to D.C.-R.]; the Spanish Ministerio de Ciencia e Innovación [CONSOLIDER-INGENIO program (CSD2007-00036)]; Autonomous Government of Catalonia [grant AGAUR (2008FI-B 00399) to J.E.S.-H.]; CRAG [a contract to J.E.S.-H.]. This work was carried out within the framework of the ‘Xarxa de Referència de Biotecnologia’ (XarBa) from the Autonomous Government of Catalonia.Peer reviewe

BES1 regulates the localization of the brassinosteroid receptor BRL3 within the provascular tissue of the Arabidopsis primary root

Brassinosteroid (BR) hormones are important regulators of plant growth and development. Recent studies revealed the cell-specific role of BRs in vascular and stem cell development by the action of cell-specific BR receptor complexes and downstream signaling components in Arabidopsis thaliana. Despite the importance of spatiotemporal regulation of hormone signaling in the control of plant vascular development, the mechanisms that confer cellular specificity to BR receptors within the vascular cells are not yet understood. The present work shows that BRI1-like receptor genes 1 and 3 (BRL1 and BRL3) are differently regulated by BRs. By using promoter deletion constructs of BRL1 and BRL3 fused to GFP/GUS (green fluorescent protein/β-glucuronidase) reporters in Arabidopsis, analysis of their cell-specific expression and regulation by BRs in the root apex has been carried out. We found that BRL3 expression is finely modulated by BRs in different root cell types, whereas the location of BRL1 appears to be independent of this hormone. Physiological and genetic analysis show a BR-dependent expression of BRL3 in the root meristem. In particular, BRL3 expression requires active BES1, a central transcriptional effector within the BRI1 pathway. ChIP analysis showed that BES1 directly binds to the BRRE present in the BRL3 promoter region, modulating its transcription in different subsets of cells of the root apex. Overall our study reveals the existence of a cell-specific negative feedback loop from BRI1-mediated BES1 transcription factor to BRL3 in phloem cells, while contributing to a general understanding of the spatial control of steroid signaling in plant development

BES1 regulates the localization of the brassinosteroid receptor BRL3 within the provascular tissue of the Arabidopsis primary root

Brassinosteroid (BR) hormones are important regulators of plant growth and development. Recent studies revealed the cell-specific role of BRs in vascular and stem cell development by the action of cell-specific BR receptor complexes and downstream signaling components in Arabidopsis thaliana. Despite the importance of spatiotemporal regulation of hormone signaling in the control of plant vascular development, the mechanisms that confer cellular specificity to BR receptors within the vascular cells are not yet understood. The present work shows that BRI1-like receptor genes 1 and 3 (BRL1 and BRL3) are differently regulated by BRs. By using promoter deletion constructs of BRL1 and BRL3 fused to GFP/GUS (green fluorescent protein/β-glucuronidase) reporters in Arabidopsis, analysis of their cell-specific expression and regulation by BRs in the root apex has been carried out. We found that BRL3 expression is finely modulated by BRs in different root cell types, whereas the location of BRL1 appears to be independent of this hormone. Physiological and genetic analysis show a BR-dependent expression of BRL3 in the root meristem. In particular, BRL3 expression requires active BES1, a central transcriptional effector within the BRI1 pathway. ChIP analysis showed that BES1 directly binds to the BRRE present in the BRL3 promoter region, modulating its transcription in different subsets of cells of the root apex. Overall our study reveals the existence of a cell-specific negative feedback loop from BRI1-mediated BES1 transcription factor to BRL3 in phloem cells, while contributing to a general understanding of the spatial control of steroid signaling in plant development

BES1 regulates the localization of the brassinosteroid receptor BRL3 within the provascular tissue of the Arabidopsis primary root

Brassinosteroid (BR) hormones are important regulators of plant growth and development. Recent studies revealed the cell-specific role of BRs in vascular and stem cell development by the action of cell-specific BR receptor complexes and downstream signaling components in Arabidopsis thaliana. Despite the importance of spatiotemporal regulation of hormone signaling in the control of plant vascular development, the mechanisms that confer cellular specificity to BR receptors within the vascular cells are not yet understood. The present work shows that BRI1-like receptor genes 1 and 3 (BRL1 and BRL3) are differently regulated by BRs. By using promoter deletion constructs of BRL1 and BRL3 fused to GFP/GUS (green fluorescent protein/β-glucuronidase) reporters in Arabidopsis, analysis of their cell-specific expression and regulation by BRs in the root apex has been carried out. We found that BRL3 expression is finely modulated by BRs in different root cell types, whereas the location of BRL1 appears to be independent of this hormone. Physiological and genetic analysis show a BR-dependent expression of BRL3 in the root meristem. In particular, BRL3 expression requires active BES1, a central transcriptional effector within the BRI1 pathway. ChIP analysis showed that BES1 directly binds to the BRRE present in the BRL3 promoter region, modulating its transcription in different subsets of cells of the root apex. Overall our study reveals the existence of a cell-specific negative feedback loop from BRI1-mediated BES1 transcription factor to BRL3 in phloem cells, while contributing to a general understanding of the spatial control of steroid signaling in plant development

A MYB/ZML Complex Regulates Wound-Induced Lignin Genes in Maize

Lignin is an essential polymer in vascular plants that plays key structural roles in vessels and fibers. Lignification is induced by external inputs such as wounding, but the molecular mechanisms that link this stress to lignification remain largely unknown. In this work, we provide evidence that three maize (Zea mays) lignin repressors, MYB11, MYB31, and MYB42, participate in wound-induced lignification by interacting with ZML2, a protein belonging to the TIFY family. We determined that the three R2R3-MYB factors and ZML2 bind in vivo to AC-rich and GAT(A/C) cis-elements, respectively, present in a set of lignin genes. In particular, we show that MYB11 and ZML2 bind simultaneously to the AC-rich and GAT(A/C) cis-elements present in the promoter of the caffeic acid O-methyl transferase (comt) gene. We show that, like the R2R3-MYB factors, ZML2 also acts as a transcriptional repressor. We found that upon wounding and methyl jasmonate treatments, MYB11 and ZML2 proteins are degraded and comt transcription is induced. Based on these results, we propose a molecular regulatory mechanism involving a MYB/ZML complex in which wound-induced lignification can be achieved by the derepression of a set of lignin genes

Volumen 18 Número 1

Revista seriada del Instituto Humboldt en asocio con el Invemar, el Instituto de Ciencias Naturales (ICN) y el Missouri Botanical Garden, como una estrategia para ampliar la base del conocimiento de uno de los países con mayor diversidad biológica del mundo. Inicia como una publicación de listados de especies pero en 2005 amplía su espectro temático hacia la sistemática y la biogeografía. En 2010, a propósito del Año Internacional de la Biodiversidad y en pro del conocimiento, la conservación y el uso sostenible de la biodiversidad, se abre a un público más amplio, considerando trabajos inéditos de investigación sobre botánica, zoología, ecología, biología, limnología, pesquerías, conservación, manejo de recursos y uso de la biodiversidad, con buena aceptación por parte de la comunidad científica y académica. En 2013, en asocio con el SiB Colombia y con el apoyo de la GBIF, se institucionaliza la inclusión de Artículos de Datos (Data Papers) en Biota Colombiana