Hablando de sexo en plantas: ¡Vamos al grano!

In plants, development and sexual reproduction are key steps for the generation of the next generation and for the genetic recombination resulting from the meiotic process to take place. In addition, it should not be forgotten that in many cases the production of many species of agricultural interest exploits the partial or final result of the reproductive process, as flowers, the complete fruit or the seed are often collected. Higher plants have been evolving towards the generation of increasingly reduced gametophytic (haploid) phases, which include the embryonic sac and the pollen grain as the expression of the female and male gametophytes respectively. Understanding the physiology of the pollen grain is one of the most exciting issues in reproductive biologyEn las plantas, el desarrollo y la reproducción sexual son pasos clave para la obtención de la generación siguiente y para que tenga lugar la recombinación genética resultante del proceso meiótico. Además, no hay que olvidar que en muchos casos la producción de muchas especies de interés agrícola explota el resultado parcial o final del proceso reproductivo, ya que con frecuencia se recolectan las flores, el fruto completo o la semilla. Las plantas supe- riores han ido evolucionando hacia la generación de fases gametofíticas (haploides) cada vez más reducidas, que incluyen el saco embrionario y el grano de polen como expresión de los gametofitos femenino y masculino respectivamente. La comprensión de la fisiología del grano de polen es una de las cuestiones más apasionantes de la biología reproductiv

Application of X-Ray microanalysis, diffraction and cytochemical techniques in the study of the structure and chemical composition of inclusions in Olea europaea leaves

4 páginas, 11 figuras.-- Trabajo presentado al EMAG-MICRO 89 celebrado en Londres (Inglaterra) en Septiembre de 1989.Two types of inclusions have been found in mesophyll cells oÍ leaves of Olea eurooaea. The first type is located in the vacuole, and the application of X-Ray microanalysis, X-Ray diffraction and cytochemical techniques shown that these inclusions are composed of calcium oxalate. The second type of inclusion is intranuclear and its proteic nature is demonstrated by means of light microscopy stains. These crystal structures are probably well ordered in three dimensions.Peer reviewe

Current overview of S-nitrosoglutathione (GSNO) in higher plants

S-nitrosoglutathione is a nitric oxide-derived molecule, generated by the interaction of nitric oxide (NO) with reduced glutathione (GSH) in a process called S-nitrosylation (Figure 1). The reaction appears to take place either through the formation of N2O3 or the addition of NO to a glutathionyl radical formed during this reaction (Broniowska et al., 2013). GSNO is regarded as an intracellular NO reservoir as well as a vehicle of NO throughout the cell, which enables NO biological activity to expand. GSNO is also considered to be the most abundant low-molecular-mass (LMM) S-nitrosothiol (SNO). This family includes other molecules such as S-nitrosocysteine (CySNO) and S-nitrosocysteinylglycine (GlyCySNO), which have been the subject of less study in the field of plant research. There is another group of SNOs called high-molecular mass (HMM) SNOs which are produced by NO binding to sulfhydryl (-SH) groups present in specific cysteine residues of proteins. Figure 1 shows a simple model of GSNO metabolism and its interactions with other molecules in cells where different reactions including S-nitrosylation, S-transnitrosation, and S-glutathionylation are involved (Hogg, 2002; Martínez-Ruiz and Lamas, 2007). In plants, research has focused on the importance of total SNOs in specific stress situations (Feechan et al., 2005; Chaki et al., 2011a) and on the identification of the potential protein targets of S-nitrosylation as this kind of post-translational modification can alter the function of the affected proteins (Astier et al., 2012). Initial studies in this area exogenously applied GSNO in order to identify the pool of potential protein candidates (Lindermayr et al., 2005). However, less attention has been paid to the abundance, distribution, and modulation of endogenous GSNO under natural and stress conditions. In this article, we will provide a current overview of GSNO in higher plants. [EN]Work in our laboratories is supported by ERDF-cofinanced grants from the Ministry of Science and Innovation (BIO2012-33904 and BFU2011-22779)Peer reviewe

The use of in situ hybridisation and immunocytochemistry to characterise coiled bodies in plant meiocytes

2 páginas, 2 figuras.-- Trabajo presentado a la XI European Conference on Electron Microscopy- EUREM11 celebrada en Dublín (Irlanda) del 26 al 30 de Agosto de 1996.This study was supported by project DGICYT PB92-0079-CO3-O3.Peer reviewe

Patterns of ROS Accumulation in the Stigmas of Angiosperms and Visions into Their Multi-Functionality in Plant Reproduction

Accumulation of reactive oxygen species (ROS) in the stigma of several plant species has been investigated. Four developmental stages (unopened flower buds, recently opened flowers, dehiscent anthers, and flowers after fertilization) were analyzed by confocal laser scanning microscopy using the ROS-specific probe DCFH2-DA. In all plants scrutinized, the presence of ROS in the stigmas was detected at higher levels during those developmental phases considered “receptive” to pollen interaction. In addition, these molecules were also present at early (unopened flower) or later (post-fertilization) stages, by following differential patterns depending on the different species. The biological significance of the presence ROS may differ between these stages, including defense functions, signaling and senescence. Pollen-stigma signaling is likely involved in the different mechanisms of self-incompatibility in these plants. The study also register a general decrease in the presence of ROS in the stigmas upon pollination, when NO is supposedly produced in an active manner by pollen grains. Finally, the distribution of ROS in primitive Angiosperms of the genus Magnolia was determined. The production of such chemical species in these plants was several orders of magnitude higher than in the remaining species evoking a massive displacement toward the defense function. This might indicate that signaling functions of ROS/NO in the stigma evolved later, as fine tune likely involved in specialized interactions like self-incompatibility.This study was supported by the following European Regional Development Fund co-financed grants: MCINN BFU2011-22779, RTC-2015-4181-2, CSIC-201540E065, CICE (Junta de Andalucía) P2010-CVI15767, P2010-AGR6274, P2011-CVI-7487, and the MINECO/CSIC agreement RECUPERA 2020.Peer reviewedPeer Reviewe

Preliminary characterization of ssps (Seed Storage Proteins) in Argania spinosa L.

4 páginas, 2 figuras, 1 tabla.-- Comunicación presentada al 3rd International SMBBM Congress, IUBMB Special Meeting & 6th FASBMB Congress, celebrado en Marrakech (Marruecos) del 20 al 24 de Abril de 2009.SSPs (Seed Storage Proteins) of the 11S type have been preliminary characterized in the seeds of the argan tree, an endemic species from Morocco. Protein extracts from mature seeds were prepared by using different solutions in order to assess the solubility of the major protein forms. SSPs of the 11S type were classified as albumins according to the further SDS-PAGE analysis of these extracts. The combination of both reducing- and non-reducing conditions for the SDS-PAGE analysis, together with immunoblot experiments allowed us to determine the presence of three precursor forms of these proteins (pro1, pro2 and pro3), which are composed of six individual peptides (p1 to p6) in different combinations.This work was funded by Spanish BFU2004-00601/BFI and BFU2008-00629 projects. M. Allach thanks the research bursary granted by UNESCO/L´ORÉAL and L´ORÉAL Morocco.Peer reviewe

NADPH Oxidase-Dependent Superoxide Production in Plant Reproductive Tissues

In the life cycle of a flowering plant, the male gametophyte (pollen grain) produced in the anther reaches the stigmatic surface and initiates the pollen–pistil interaction, an important step in plant reproduction, which ultimately leads to the delivery of two sperm cells to the female gametophyte (embryo sac) inside the ovule. The pollen tube undergoes a strictly apical expansion characterized by a high growth rate, whose targeting should be tightly regulated. A continuous exchange of signals therefore takes place between the haploid pollen and diploid tissue of the pistil until fertilization. In compatible interactions, theses processes result in double fertilization to form a zygote (2n) and the triploid endosperm. Among the large number of signaling mechanisms involved, the redox network appears to be particularly important. Respiratory burst oxidase homologs (Rbohs) are superoxide-producing enzymes involved in a broad range of processes in plant physiology. In this study, we review the latest findings on understanding Rboh activity in sexual plant reproduction, with a particular focus on the male gametophyte from the anther development stages to the crowning point of fertilization. Rboh isoforms have been identified in both the male and female gametophyte and have proven to be tightly regulated. Their role at crucial points such as proper growth of pollen tube, self-incompatibility response and eventual fertilization is discussed. [EN]European Regional Development Fund (ERDF) co-financed grants: BFU2008-006292, BFU2011-22779, CSIC-201540E065, and RECUPERA2020-3.1.4.Peer reviewe

Expression profiling and localization of wall polysaccharides in the olive pollen during in vitro germination

1 página.-- Comunicación oral presentada en la XVIII Reunión de la Sociedad Española de Fisiología Vegetal (SEFV).-- Sesión Temática 2: Crecimiento y desarrollo.-- S2-O2.This work was supported by the Andalusian Regional Government (project P06-AGR-01791). C. Suarez thanks the MEC for providing FPI grant funding.Peer reviewe

Proteínas de almacenamiento tipo 11S en semillas de olivo (Olea europaea L.). Caracterización mediante técnicas de proteómica

6 páginas, 3 figuras, 1 tabla.-- Trabajo presentado al Simposium Científico–Técnico EXPOLIVA 2007.Los tejidos de reserva de la semilla del olivo acumulan grandes cantidades de proteínas de almacenamiento en forma de cuerpos proteicos. En este trabajo se analizaron extractos proteicos de cotiledón y endospermo mediante electroforesis bidimensional (2-D). Dichas técnicas permitieron detectar el carácter básico de los péptidos p1 y p2, así como el carácter ácido de p3, p4 y p5. La espectrometría de masas de diversos spot aislados, indicó una homología relevante con la subunidad básica de las leguminas de tipo 11S. También se detectó la presencia de diversas isoformas, algunas posiblemente resultantes de modificaciones postranscripcionales. La abundancia de estas proteínas en las semillas maduras de olivo hace que dicho material pueda ser considerado una fuente nitrogenada de posible uso como complemento en nutrición animal. Otras utilidades relevantes podrían explotar un posible carácter discriminatorio entre variedades para el desarrollo de programas de mejora genética en olivo actualmente en curso.Este trabajo fue financiado gracias a los proyectos AGL2003-00719 y MEC BFU2004- 00601/BFI. Los autores agradecen al Consejo Superior de Investigaciones Científicas (CSIC) la concesión de una beca predoctoral (I3P-CSIC 2002).Peer reviewe

Internalization of the anti-carcinogenic IBB1, a major Bowman-Birk isoinhibitor from soybean (Glycine max), in HT29 colon cancer cells

Proceedings of the I Congress PIIISA celebrado en la Estación Experimental del Zaidín (Granada), en mayo de 2013.Protease inhibitors of the Bowman-Birk type, a major protease inhibitor family in legume seeds, which inhibit potently trypsin- and chymotrypsin-like proteases, are currently being investigated as colorectal chemopreventive agents. Although the therapeutic target/s and the action mechanism/s of Bowman-Birk inhibitors (BBI) have not yet been elucidated, the emerging evidence suggests that BBI exert their chemopreventive properties via protease inhibition; in this sense, serine proteases should be considered as primary targets in early stages of carcinogenesis. In this work, we have demonstrated that IBB1, a major protease inhibitor of the Bowman-Birk family in soybean (Glycine max), exerts anti-proliferative effect in human colorectal HT29 cancer cells at concentrations higher than 15 μM, in a dose dependent manner. By using confocal microscopy, we have demonstrated that IBB1 is taken up by HT29 colon cancer cells in a time-dependent manner, being the bulk of the internalized protease inhibitor localized in the cytoplasm where might interact with their potential therapeutic target/s.This work was supported by ERDF-co-financed grants AGL2011-26353 (Spanish Ministry of Economy and Competitiveness) and PE2010-CVI-5767 (Junta de Andalucía).Peer reviewe