Browsing by Author "Aquea, Felipe"

Now showing 1 - 7 of 7
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    Biochemical and molecular changes in response to aluminium-stress in highbush blueberry (Vaccinium corymbosum L.)
    (2011) Inostroza-Blancheteau, Claudio; Reyes-Diaz, Marjorie; Aquea, Felipe; Nunes-Nesi, Adriano; Alberdi, Miren; Arce-Johnson, Patricio
    Aluminium (Al) stress is an important factor limiting crop yields in acid soils. Despite this, very little is known about the mechanisms of resistance to this stress in woody plants. To understand the mechanisms of Al-toxicity and response in blueberries, we compared the impact of AI-stress in Al-resistant and AI-sensitive genotypes using Vaccinium corymbosum L. (Ericaceae) as a plant model. We investigated the effect of Al-stress on the physiological performance, oxidative metabolism and expression of genes that encode antioxidant enzymes in two V. corymbosum cultivars maintained hydroponically with AlCl3 (0 and 100 mu M). Microscopic analyses of AI-treated root tips suggested a higher degree of Al-induced morphological injury in Bluegold (sensitive genotype) compared to Brigitta (resistant genotype). Furthermore, the results indicated that Brigitta had a greater ability to control oxidative stress under Al-toxicity, as reflected by enhancement of several antioxidative and physiological properties (radical scavenging activity: RSA, superoxide dismutase: SOD and catalase: CAT; maximum quantum yield: Fv/Fm, effective quantum yield: 04)511, electron transport rate: ETR and non-photochemical quenching: NPQ). Finally, we analyzed the expression of genes homologous to GST and ALDH, which were identified in a global expression analysis. In the resistant genotype, the expression of these genes in response to Al-stress was greater in leaves than in roots. (C) 2011 Elsevier Masson SAS. All rights reserved.
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    Functional characterization of Citrus macrophylla BOR1 as a boron transporter
    (2013) Canon, Paola; Aquea, Felipe; Rodriguez-Hoces de la Guardia, Amparo; Arce-Johnson, Patricio
    Plants have evolved to develop an efficient system of boron uptake and transport using a range of efflux carriers named BOR proteins. In this work we isolated and characterized a boron transporter of citrus (Citrus macrophylla), which was named CmBOR1 for its high homology to AtBOR1. CmBOR1 has 4403bp and 12 exons. Its coding region has 2145bp and encodes for a protein of 714 amino acids. CmBOR1 possesses the molecular features of BORs such as an anion exchanger domain and the presence of 10 transmembrane domains. Functional analysis in yeast indicated that CmBOR1 has an efflux boron transporter activity, and transformants have increased tolerance to excess boron. CmBOR1 is expressed in leaves, stem and flowers and shows the greatest accumulation in roots. The transcript accumulation was significantly increased under boron deficiency conditions in shoots. In contrast, the accumulation of the transcript did not change in boron toxicity conditions. Finally, we observed that constitutive expression of CmBOR1 was able to increase tolerance to boron deficiency conditions in Arabidopsis thaliana, suggesting that CmBOR1 is a xylem loading boron transporter. Based on these results, it was determined that CmBOR1 encodes a boric acid/borate transporter involved in tolerance to boron deficiency in plants.
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    Identification of genes expressed during early somatic embryogenesis in Pinus radiata
    (2008) Aquea, Felipe; Arce-Johnson, Patricio
    Analysis of cDNA-AFLPs was used to study gene expression underlying the early embryogenic process in the gymnosperm Pinus radiata. Somatic embryogenesis in this species was used as a model as it resulted in the generation of a large number of embryos at defined stages of development. The gene expression patterns of three ernbryogenic stages were compared with non-embryogenic cells. Fifty transcript-derived fragments (TDFs) that are upregulated and 32 TDFs that are down-regulated in the embryogenic stages were selected, sequenced and their homologies sought in the databases. Expression of a selected subset of differentially expressed genes was confirmed by RT-PCR and their levels of expression were quantified. Of the 50 up-regulated TDFs, 16 are homologous to genes encoding either known or putative proteins in higher plants, 19 are homologous to conifer ESTs and 15 did not show significant matches. Of the down-regulated TDFs, 8 are homologous to genes encoding either known or putative proteins, 20 are homologous to conifer ESTs and 4 of them did not show significant matches in DNA or protein sequence database. The known up-regulated genes were similar to genes involved in cellular metabolism and in the stress response and the known down-regulated genes were similar to genes involved in proteolysis, cell wall modification and signaling pathways. Their putative individual function is briefly reviewed based on published information, and the potential roles of these genes in embryo development are discussed. (C) 2008 Elsevier Masson SAS. All rights reserved.
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    Isolation and molecular characterization of MYB60 in Solanum lycopersicum
    (2021) Rodríguez Hoces de la Guardia, Amparo Cecilia; Ugalde, María Beatriz; Lobos Díaz, Valeria Rocío; Lucina Romero-Romero, Jesús; Meyer Regueiro, Carlos José; Inostroza Blancheteau, Claudio; Reyes Diaz, Marjorie; Aquea, Felipe; Arce Johnson, Jorge Patricio
    Stomatal closure is a common adaptation response of plants to the onset of drought condition and its regulation is controlled by transcription factors. MYB60, a transcription factor involved in the regulation of light-induced stomatal opening, has been characterized in arabidopsis and grapevine. In this work, we studied the role of MYB60 homolog SIMYB60 in tomato plants. We identified, isolated, and sequenced the SIMYB60 coding sequence, and found domains and motifs characteristic of other MYB60 proteins. We determined that SlMYB60 is mainly expressed in leaves, and its expression is repressed by abscisic acid. Next, we isolated a putative promoter region containing regulatory elements responsible for guard cell expression and other putative regulatory elements related to ABA repression and vascular tissue expression. Protein localization assays demonstrated that SlMYB60 localizes to the nucleus. Finally, SlMYB60 is able to complement the mutant phenotype of atmyb60-1 in Arabidopsis. Together, these results indicate that SlMYB60 is the homologous gene in tomato and potentially offer a molecular target to improve crops.
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    RESISTANCE MECHANISMS OF ALUMINUM (Al3+) PHYTOTOXICITY IN CEREALS: PHYSIOLOGICAL, GENETIC AND MOLECULAR BASES
    (2008) Inostroza-Blancheteau, Claudio; Soto, Braulio; Ulloa, Pilar; Aquea, Felipe; Reyes-Diaz, Marjorie
    Aluminum (Al) toxicity is one of the main factors limiting crop productivity in acid soils around the world. In cereals, this problem can affect between 30 and 40% of crop yields. One way to reduce the toxic effect of Al is to neutralize the acidity with calcareous amendments. However, this practice is demanding and not very effective. An alternative is the search for genetic variability in the genome of cropping grasses and/or their wild relatives to resist Al. The development of biotechnology and molecular genetics approach has facilitated the understanding of the physiological, genetic and molecular bases in the process of ameliorating these species. This review presents the main physiological mechanisms of Al resistance and the genetic and molecular bases that explain the degree of resistance between different cereals species.
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    Synthetic seed production from somatic embryos of Pinus radiata
    (2008) Aquea, Felipe; Poupin, Maria Josefina; Matus, Jose Tomas; Gebauer, Marlene; Medina, Consuelo; Arce-Johnson, Patricio
    Pinus radiata is one of the most important forestry species in the southern hemisphere. This work describes the regeneration of this plant via somatic embryogenesis from immature zygotic embryos. To improve this process, somatic embryogenic cell suspensions were established in liquid media for the generation of material for embryo maturation. Each developmental stage of these suspensions was characterized by microscopy and their growth phases quantified. An alginate-containing medium was used as an encapsulation method for the somatic embryos that were then germinated as artificial seeds in vitro. The protocols described in this work are both useful and reliable for industrial purposes.
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    The photomorphogenic factors UV-B RECEPTOR 1, ELONGATED HYPOCOTYL 5, and HY5 HOMOLOGUE are part of the UV-B signalling pathway in grapevine and mediate flavonol accumulation in response to the environment
    (2016) Loyola, Rodrigo; Herrera, Daniela; Mas, Abraham; Wong, Darren Chern Jan; Hoell, Janine; Cavallini, Erika; Amato, Alessandra; Azuma, Akifumi; Ziegler, Tobias; Aquea, Felipe; Castellarin, Simone Diego; Bogs, Jochen; Tornielli, Giovanni Battista; Pena-Neira, Alvaro; Czemmel, Stefan; Antonio Alcalde, Jose; Tomas Matus, Jose; Arce-Johnson, Patricio
    By performing molecular studies coupled to radiation experiments and in silico systems analyses, we have ascertained the role of the grapevine UV-B receptor and two HY5 homologues in regulating flavonol synthesis.Grapevine (Vitis vinifera L.) is a species well known for its adaptation to radiation. However, photomorphogenic factors related to UV-B responses have not been molecularly characterized. We cloned and studied the role of UV-B RECEPTOR (UVR1), ELONGATED HYPOCOTYL 5 (HY5), and HY5 HOMOLOGUE (HYH) from V. vinifera. We performed gene functional characterizations, generated co-expression networks, and tested them in different environmental conditions. These genes complemented the Arabidopsis uvr8 and hy5 mutants in morphological and secondary metabolic responses to radiation. We combined microarray and RNA sequencing (RNA-seq) data with promoter inspections to identify HY5 and HYH putative target genes and their DNA binding preferences. Despite sharing a large set of common co-expressed genes, we found different hierarchies for HY5 and HYH depending on the organ and stress condition, reflecting both co-operative and partially redundant roles. New candidate UV-B gene markers were supported by the presence of HY5-binding sites. These included a set of flavonol-related genes that were up-regulated in a HY5 transient expression assay. We irradiated in vitro plantlets and fruits from old potted vines with high and low UV-B exposures and followed the accumulation of flavonols and changes in gene expression in comparison with non-irradiated conditions. UVR1, HY5, and HYH expression varied with organ, developmental stage, and type of radiation. Surprisingly, UVR1 expression was modulated by shading and temperature in berries, but not by UV-B radiation. We propose that the UV-B response machinery favours berry flavonol accumulation through the activation of HY5 and HYH at different developmental stages at both high and low UV-B exposures.