Person: Rexach, Jesús
Profesor/a Titular de Universidad
Universidad Pablo de Olavide
Fisiología, Anatomía y Biología Celular
Now showing 1 - 7 of 7
PublicationRole of ABA in the adaptive response of Arabidopsis plants to long-term boron toxicity treatment(Elsevier, 2023) Martínez-Mazón, Paula; Bahamonde, Cristina; Herrera-Rodríguez, M. Begoña; Fernández-Ocaña, Ana María; Rexach, Jesús; González-Fontes, Agustín; Camacho-Cristóbal, Juan J.Boron (B) toxicity causes impairments in several plant metabolic and physiological processes. Under conditions of excessive B availability, this micronutrient is passively transported through the transpiration stream and accumulates in leaves, causing the development of necrotic regions in leaf tips. Some plants have developed adaptive mechanisms to minimize the toxic effects of excessive B accumulation in their tissues. Thus, for instance, in Arabidopsis it has been described an ABA-dependent decrease in the transpiration rate that would restrict B accumulation in aerial plant tissues in response to short-term B toxicity, this effect being mediated by AtNCED3 (which encodes a key enzyme for ABA biosynthesis). The present work aimed to study the possible involvement of ABA in the adjustment of plant water balance and B homeostasis during the adaptive response of Arabidopsis to prolonged B toxicity. For this purpose, Arabidopsis wild-type and the ABA-deficient nced3-2 mutant plants were subjected to B toxicity for 7 days. We show that ABA-dependent stomatal closure is determinant for the adjustment of plant water relations under conditions of prolonged B toxicity. Results suggest that, in addition to the AtNCED3 gene, the AtNCED5 gene could also be involved in this ABA-dependent stomatal closure. Finally, our results also indicate the possible role of endogenous root ABA content in the mechanism of active efflux of B via BOR4 (efflux-type B transporter) from the root to the external environment under excess B conditions. PublicationLeaf Proteomic Analysis in Seedlings of Two Maize Landraces with Different Tolerance to Boron Toxicity(2023-06-15) Mamani-Huarcaya, Betty Maribel; Navarro-Gochicoa, María Teresa; Herrera-Rodríguez, María Begoña; Camacho-Cristóbal, Juan José; Ceacero, Carlos Juan; Fernández Cutire, Óscar; González-Fontes, Agustín; Rexach, JesúsBoron (B) toxicity is an important stressor that negatively affects maize yield and the quality of the produce. The excessive B content in agricultural lands is a growing problem due to the increase in arid and semi-arid areas because of climate change. Recently, two Peruvian maize landraces, Sama and Pachía, were physiologically characterized based on their tolerance to B toxicity, the former being more tolerant to B excess than Pachía. However, many aspects regarding the molecular mechanisms of these two maize landraces against B toxicity are still unknown. In this study, a leaf proteomic analysis of Sama and Pachía was performed. Out of a total of 2793 proteins identified, only 303 proteins were differentially accumulated. Functional analysis indicated that many of these proteins are involved in transcription and translation processes, amino acid metabolism, photosynthesis, carbohydrate metabolism, protein degradation, and protein stabilization and folding. Compared to Sama, Pachía had a higher number of differentially expressed proteins related to protein degradation, and transcription and translation processes under B toxicity conditions, which might reflect the greater protein damage caused by B toxicity in Pachía. Our results suggest that the higher tolerance to B toxicity of Sama can be attributed to more stable photosynthesis, which can prevent damage caused by stromal over-reduction under this stress condition. PublicationCharacterization of two Peruvian maize landraces differing in boron toxicity tolerance(Elsevier, 2022-06-06) Mamani-Huarcaya, Betty M; González-Fontes, Agustín; Navarro-Gochicoa, M. Teresa; Camacho-Cristóbal, Juan J.; Ceacero, Carlos J.; Herrera-Rodríguez, M. Begoña; Fernández Cutire, Oscar; Rexach, JesúsBoron (B) toxicity is a major agricultural problem that causes a considerable decrease in crop yield and quality. The soil in arid and semi-arid areas is often subjected to excessive B content. Southwestern Perú (department of Tacna) is characterized by high B levels in its agricultural land and irrigation water. This work analyzes the response of two local maize (Zea mays) landraces (Pachía and Sama) from Tacna to B toxicity. Both landraces were, therefore, grown in hydroponic media under control and B toxicity conditions, and after 10 days, seedlings were harvested and B content, B-transporter gene expressions, and several morphological and physiological parameters were determined. The leaf and root soluble B content was lower in Sama than in Pachía when both landraces were subjected to high B concentrations, which could be explained by its higher expression levels of B-efflux transporters. The capacity of Sama to maintain reduced levels of soluble B in its leaves and roots led to decreased leaf damage and higher photosynthetic and growth parameters under B toxicity conditions. These results support the proposal that Sama would perform better than Pachía under excessive B conditions, thus making it a more suitable landrace to be used in soils with toxic levels of B. PublicationCrosstalk of Cytokinin with Ethylene and Auxin for Cell Elongation Inhibition and Boron Transport in Arabidopsis Primary Root under Boron Deficiency(MDPI, 2022-09-08) Herrera-Rodríguez, María Begoña; Camacho-Cristóbal, Juan José; Barrero-Rodríguez, Rafael; Rexach, Jesús; Navarro-Gochicoa, María Teresa; González-Fontes, AgustínSeveral studies have shown the role of phytohormones in the regulation of root growth of Arabidopsis plants under boron (B) deficiency. Ethylene and auxin play an important role in the control of Arabidopsis primary root cell elongation under short-term B deprivation, whereas cytokinins regulate root growth inhibition under B deficiency by controlling meristem cell proliferation. In this work, we study the possible interaction among cytokinin, ethylene, and auxin in the primary root response to B-deprivation treatment, as well as their possible role in B uptake and transport. Wild type (WT) and two mutants related to auxin and ethylene (aux1 and acs11) Arabidopsis plants were grown in control (10 µM B) or B starvation (0 µM B) treatment, in the absence or presence of trans-zeatin, and their primary root growth was analyzed. The possible interaction between these hormones was also studied by analyzing AUX1 gene expression in the acs11 mutant and ACS11 gene expression in the aux1 mutant. The GUS reporter lines ARR5::GUS, IAA2::GUS, and EBS::GUS were used to observe changes in cytokinin, auxin, and ethylene levels in the root, respectively. The results of this work suggest that cytokinin inhibits root cell elongation under B deficiency through two different mechanisms: (i) an ethylene-dependent mechanism through increased expression of the ACS11 gene, which would lead to increased ethylene in the root, and (ii) an ethylene-independent mechanism through decreased expression of the AUX1 gene, which alters auxin signaling in the meristematic and elongation zones and stele. We also report that changes in the expression of several B transporters occur in response to auxin, ethylene, and cytokinin that may affect the plant B content. PublicationCaracterización fisiológica de tres razas de maíz peruano cultivadas con altos contenidos de boro(Universidad Nacional Jorge Basadre Grohmann, Tacna - Perú, 2020) Mamani-Huarcaya, Betty M; Luque-Zuñiga, Bret; Ceacero Ruiz, Carlos Juan; Rexach, Jesús; Fernández Cutire, ÓscarEl boro (B) es un nutriente esencial para un adecuado desarrollo de las plantas. En regiones áridas o semiáridas es frecuente encontrar suelos con elevado contenido de B. Este exceso de B desencadena problemas importantes de toxicidad en las plantas, que conducen a una reducción de su crecimiento y a una disminución de la fotosíntesis, entre otros efectos. El maíz es uno de los cultivos de mayor importancia en Perú. Muchas de las tierras de cultivo del sur del Perú presentan contenidos elevados de B. La selección de razas que sean tolerantes a estas condiciones es fundamental para obtener mejores rendimientos en las cosechas. El objetivo de este trabajo fue caracterizar la tolerancia al exceso de B de las razas de maíz Pachía, Lipe-Coruca y Sama, originarias de la región de Tacna (Perú). Para ello, se cultivaron estas razas de maíz en macetas con tierras con alto contenido de B (214 ppm), y fueron -1 regadas con aguas del río Sama cuya concentración de B fue de 14.63 mgL . Las razas Sama y Lipe-Coruca mostraron las mayores alturas con respecto al vástago. Además, la raza Sama presentó los más bajos contenidos foliares de B soluble e insoluble, y los mayores contenidos de clorofilas y carotenoides. En resumen, estos resultados sugieren que Sama es la raza más tolerante al exceso de B. Así, los menores contenidos de B y el mayor contenido de estos pigmentos de Sama permitirían una mejor adaptación al estrés generado por la acumulación de B en las tierras de cultivo. PublicationBoron Deficiency Increases Cytosolic Ca2+ Levels Mainly via Ca2+ Influx from the Apoplast in Arabidopsis thaliana Roots(MDPI, 2019) Quiles-Pando, Carlos; Navarro-Gochicoa, M. Teresa; Herrera Rodríguez, María Begoña; Camacho-Cristóbal, Juan José; González-Fontes, Agustín; Rexach, JesúsBoron (B) is a micronutrient for plant development, and its deficiency alters many physiological processes. However, the current knowledge on how plants are able to sense the B-starvation signal is still very limited. Recently, it has been reported that B deprivation induces an increase in cytosolic calcium concentration ([Ca2+]cyt) in Arabidopsis thaliana roots. The aim of this work was to research in Arabidopsis whether [Ca2+]cyt is restored to initial levels when B is resupplied and elucidate whether apoplastic Ca2+ is the major source for B-deficiency-induced rise in [Ca2+]cyt. The use of chemical compounds affecting Ca2+ homeostasis showed that the rise in root [Ca2+]cyt induced by B deficiency was predominantly owed to Ca2+ influx from the apoplast through plasma membrane Ca2+ channels in an IP3-independent manner. Furthermore, B resupply restored the root [Ca2+]cyt. Interestingly, expression levels of genes encoding Ca2+ transporters (ACA10, plasma membrane PIIB-type Ca2+-ATPase; and CAX3, vacuolar cation/proton exchanger) were upregulated by ethylene glycol tetraacetic acid (EGTA) and abscisic acid (ABA). The results pointed out that ACA10, and especially CAX3, would play a major role in the restoration of Ca2+ homeostasis after 24 h of B deficiency. PublicationPlant Response to Boron Deficiency and Boron Use Efficiency in Crop Plants(Elsevier, 2018) Camacho-Cristóbal, Juan José; Navarro-Gachicoa. María T.; Rexach, Jesús; González-Fontes, Agustín; Herrera Rodríguez, María BegoñaBoron (B) is an essential nutrient for vascular plants with a key role in the stabilization of the primary cell wall through the formation of borate esters with apiose residues of rhamnogalacturonan II. B limited availability in soil and irrigation water affects the yield and quality of crops, which produced significant economic losses. This fact highlights the importance of understanding not only the role of B in plants, but also the physiological and molecular responses and tolerance mechanisms to B deficiency. In recent years, several studies have contributed greatly to the knowledge of these subjects. This will allow the development of crop plants that more efficiently use B and, therefore, are more tolerant to B deficiency. In this chapter, all these aspects related to B are addressed in a comprehensive manner.