Mineral stress affects the cell wall composition of grapevine (Vitis vinifera L.) callus

Versão provisória aceite p. publicação na Plant Science (ISSN 0168-9452)em 19-01-2013Grapevine (Vitis vinifera L.) is one of the most economically important fruit crops in the world. Deficit in nitrogen, phosphorus and sulfur nutrition impairs essential metabolic pathways. The influence of mineral stress in the composition of the plant cell wall (CW) has received residual attention. Using grapevine callus as a model system, 6-weeks deficiency of those elements caused a significant decrease in growth. Callus CWs were analyzed by Fourier transform infrared spectroscopy (FT-IR), by quantification of CW components and by immunolocalization of CW epitopes with monoclonal antibodies. PCA analysis of FT-IR data suggested changes in the main components of the CW in response to individual mineral stress. Decreased cellulose, modifications in pectin methyl esterification and increase of structural proteins were among the events disclosed by FT-IR analysis. Chemical analyses supported some of the assumptions and further disclosed an increase in lignin content under nitrogen deficiency, suggesting a compensation of cellulose by lignin. Moreover, polysaccharides of callus under mineral deficiency showed to be more tightly bonded to the CW, probably due to a more extensive cross-linking of the cellulose-hemicellulose network. Our work showed that mineral stress impacts the CW at different extents according to the withdrawn mineral element, and that the modifications in a given CW component are compensated by the synthesis and/or alternative linking between polymers. The overall results here described for the first time pinpoint the CW of Vitis callus different strategies to overcome mineral stress, depending on how essential they are to cell growth and plant development

Fourier transform mid infrared spectroscopy applications for monitoring the structural plasticity of plant cell walls

[EN] Fourier transform mid-infrared (FT-MIR) spectroscopy has been extensively used as a potent, fast and non-destructive procedure for analyzing cell wall architectures, with the capacity to provide abundant information about their polymers, functional groups, and in muro entanglement. In conjunction with multivariate analyses, this method has proved to be a valuable tool for tracking alterations in cell walls. The present review examines recent progress in the use of FT-MIR spectroscopy to monitor cell wall changes occurring in muro as a result of various factors, such as growth and development processes, genetic modifications, exposition or habituation to cellulose biosynthesis inhibitors and responses to other abiotic or biotic stresses, as well as its biotechnological applicationsSIThe authors thank Antonio Encina, Penélope García-Angulo, and María de Castro for their helpful scientific discussion, and to Denise Phelps for the English revision of the manuscrip

Production of Encecalin in Cell Cultures and Hairy Roots of Helianthella quinquenervis (Hook.) A. Gray

Plant cell and organ cultures of Helianthella quinquenervis, a medicinal plant whose roots are used by the Tarahumara Indians of Chihuahua, Mexico, to relieve several ailments, were established to identify and quantify some chromenes with biological activity, such as encecalin, and to evaluate their potential for biotechnological production. Gas chromatography-mass spectrometry (GC-MS) analysis corroborated the presence of quantifiable amounts of encecalin in H. quinquenervis cell cultures (callus and cell suspensions). In addition, hairy roots were obtained through three transformation protocols (prick, 45-s sonication and co-culture), using wild type Agrobacterium rhizogenes A4. After three months, cocultivation achieved the highest percentage of transformation (66%), and a comparable production (FW) of encecalin (110 g/g) than the sonication assay (120 g/g), both giving far higher yields than the prick assay (19 g/g). Stable integration of rolC and aux1 genes in the transformed roots was confirmed by polymerase chain reaction (PCR). Hairy roots from cocultivation (six months-old) accumulated as much as 1086 g/g (FW) of encecalin, over three times higher than the cell suspension cultures. The production of encecalin varied with growth kinetics, being higher at the stationary phase. This is the first report of encecalin production in hairy roots of H. quinquenervis, demonstrating the potential for a future biotechnological production of chromenes

Cellulose Biosynthesis Inhibitors: Comparative Effect on Bean Cell Cultures

The variety of bioassays developed to evaluate different inhibition responses for cellulose biosynthesis inhibitors makes it difficult to compare the results obtained. This work aims (i) to test a single inhibitory assay for comparing active concentrations of a set of putative cellulose biosynthesis inhibitors and (ii) to characterize their effect on cell wall polysaccharides biosynthesis following a short-term exposure. For the first aim, dose-response curves for inhibition of dry-weight increase following a 30 days exposure of bean callus-cultured cells to these inhibitors were obtained. The compound concentration capable of inhibiting dry weight increase by 50% compared to control (I50) ranged from subnanomolar (CGA 325′615) to nanomolar (AE F150944, flupoxam, triazofenamide and oxaziclomefone) and micromolar (dichlobenil, quinclorac and compound 1) concentrations. In order to gain a better understanding of the effect of the putative inhibitors on cell wall polysaccharides biosynthesis, the [14C]glucose incorporation into cell wall fractions was determined after a 20 h exposure of cell suspensions to each inhibitor at their I50 value. All the inhibitors tested decreased glucose incorporation into cellulose with the exception of quinclorac, which increased it. In some herbicide treatments, reduction in the incorporation into cellulose was accompanied by an increase in the incorporation into other fractions. In order to appreciate the effect of the inhibitors on cell wall partitioning, a cluster and Principal Component Analysis (PCA) based on the relative contribution of [14C]glucose incorporation into the different cell wall fractions were performed, and three groups of compounds were identified. The first group included quinclorac, which increased glucose incorporation into cellulose; the second group consisted of compound 1, CGA 325′615, oxaziclomefone and AE F150944, which decreased the relative glucose incorporation into cellulose but increased it into tightly-bound cellulose fractions; and the third group, comprising flupoxam, triazofenamide and dichlobenil, decreased the relative glucose incorporation into cellulose and increased it into a pectin rich fraction

Elucidating compositional factors of maize cell walls contributing to stalk strength and lodging resistance

Lodging is one of the causes of maize (Zea mays L.) production losses worldwide and, at least, the resistance to stalk lodging has been positively correlated with stalk strength. In order to elucidate the putative relationship between cell wall, stalk strength and lodging resistance, twelve maize inbreds varying in rind penetration strength and lodging resistance were characterized for cell wall composition and structure. Stepwise multiple regression indicates that H lignin subunits confer a greater rind penetration strength. Besides, the predictive model for lodging showed that a high ferulic acid content increases the resistance to lodging, whereas those of diferulates decrease it. These outcomes highlight that the strength and lodging susceptibility of maize stems may be conditioned by structural features of cell wall rather than by the net amount of cellulose, hemicelluloses and lignin. The results presented here provide biotechnological targets in breeding programs aimed at improving lodging in maize.This work was funded by Projects AGL2014−58126-R and RTC-2016−5816-2 from the Spanish Ministry of Science, Innovation and Universities. This work was also supported by the CERCA Program and the SGR program (SGR-710) from the Generalitat de Catalunya. We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa Program for Centres of Excellence in R&D” 2016–2019 (SEV‐2015‐0533)”. Alba Manga-Robles’s contract was granted by the Junta de Castilla y León and the Fondo Social Europeo through “Sistema Nacional de Garantía Juvenil” Program, Universidad de León and Junta de Castilla y León predoctoral Programs. Rogelio Santiago acknowledges a postdoctoral contract “Ramón y Cajal” financed by the Ministry of Economy and Competitiveness of Spain (RYC-2012-10603).Peer reviewe

Unraveling the biochemical and molecular networks involved in maize cell habituation to the cellulose biosynthesis inhibitor dichlobenil

The biochemical and molecular processes involved in the habituation of maize cells to growth in the presence of the cellulose biosynthesis inhibitor dichlobenil (DCB) were investigated. DCB affects the synthesis of cellulose both in active and stationary growth phases and alters the expression of several CesA genes. Of these, ZmCesA5 and ZmCesA7 seem to play a major role in habituating cells to growth in the presence of DCB. As a consequence of the reduction in cellulose, the expression of several genes involved in the synthesis of hydroxycinnamates is increased, resulting in cell walls with higher levels of ferulic and p-coumaric acids. A proteomic analysis revealed that habituation to DCB is linked to modifications in several metabolic pathways. Finally, habituated cells present a reduction in glutathione S-transferase detoxifying activity and antioxidant activities. Plant cell adaptation to the disturbance of such a crucial process as cellulose biosynthesis requires changes in several metabolic networks, in order to modify cell wall architecture and metabolism, and survive in the presence of the inhibitor. Some of these modifications are described in this paper.This work was supported by the Spanish Ministry of Science and Innovation (CGL2008-02470/BOS and AGL2008-05157) program as well as the CONSOLIDER-INGENIO (CSD2007-00036) program. H.-M. was financed by a PhD grant from the Spanish Ministry of Science and Innovation's FPU program. This research was carried out within the framework of the ‘Xarxa de Referència de Biotecnologia’ (XarBa) of the Autonomous Government of Catalonia.Peer reviewe

Complicaciones de la cirugía craneofacial en tumores de base craneal anterior

Introducción. Los recientes avances en radiología, técnica microquirúrgica y de reconstrucción han permitido que la cirugía craneofacial (CCF) se haya convertido en el tratamiento de elección de la patología tumoral de fosa craneal anterior. A pesar de esto, continua asociándose a una incidencia de complicaciones considerable (24-56%). Objetivos. Revisión, análisis y manejo de las complicaciones de la CCF en una serie de 41 pacientes. Material y métodos. 41 pacientes diagnosticados de patología tumoral infiltrativa de base craneal anterior, fueron intervenidos mediante CCF, entre 1990 y 2002. La extensión tumoral fue valorada en todos los casos con TC y RMN de la región craneo-facial. Tras determinar el volumen y extensión tumoral se diseñó un tratamiento quirúrgico radical, con el objetivo de conseguir una resección tumoral "en bloque". Resultados. El 63.4% de los pacientes eran varones con una mediana de edad de 57 años (18-73). La histología más frecuente de los tumores fue carcinoma escamoso y la localización habitual fue en los senos paranasales en el 78% (32 de 41 casos). En el 85.4% de los pacientes se realizó una craneotomía bifrontal basal y en el 14.6% restante craneotomía frontoorbitaria unilateral, en un sólo colgajo óseo. El área de resección facial incluía: etmoidectomía (60.9%), etmoido-esfenoidectomía (24.3%), maxilectomía unilateral (39%) y exenteración orbitaria (14.6%). Para la reconstrucción se utilizó: colgajo pediculado pericraneal (100%), colgajos locales (34.1%), colgajos libres microvascularizados (21.9%) e injerto óseo autólogo (19.5%). 20 pacientes (48.7%) presentaron complicaciones postoperatorias, entre las que destacan, como complicaciones mayores la fístula de LCR (12.1%) y la meningitis (7.3%). La mortalidad global fue del 7.3%. Conclusiones. La CCF continua asociándose a una elevada tasa de complicaciones, en general de tipo infeccioso. El perfeccionamiento de las técnicas de reconstrucción permitirán reducir la incidencia de las complicaciones más frecuentes y peligrosas

Production of Encecalin in Cell Cultures and Hairy Roots of Helianthella quinquenervis (Hook.) A. Gray

Plant cell and organ cultures of Helianthella quinquenervis, a medicinal plant whose roots are used by the Tarahumara Indians of Chihuahua, Mexico, to relieve several ailments, were established to identify and quantify some chromenes with biological activity, such as encecalin, and to evaluate their potential for biotechnological production. Gas chromatography–mass spectrometry (GC-MS) analysis corroborated the presence of quantifiable amounts of encecalin in H. quinquenervis cell cultures (callus and cell suspensions). In addition, hairy roots were obtained through three transformation protocols (prick, 45-s sonication and co-culture), using wild type Agrobacterium rhizogenes A4. After three months, cocultivation achieved the highest percentage of transformation (66%), and a comparable production (FW) of encecalin (110 μg/g) than the sonication assay (120 μg/g), both giving far higher yields than the prick assay (19 μg/g). Stable integration of rolC and aux1 genes in the transformed roots was confirmed by polymerase chain reaction (PCR). Hairy roots from cocultivation (six months-old) accumulated as much as 1086 μg/g (FW) of encecalin, over three times higher than the cell suspension cultures. The production of encecalin varied with growth kinetics, being higher at the stationary phase. This is the first report of encecalin production in hairy roots of H. quinquenervis, demonstrating the potential for a future biotechnological production of chromenes

Characterization of structural cell wall polysaccharides in cattail (Typha latifolia): Evaluation as potential biofuel feedstock

Second generation bioethanol produced from lignocellulosic biomass is attracting attention as an alternative energy source. In this study, a detailed knowledge of the composition and structure of common cattail (Typha latifolia L.) cell wall polysaccharides, obtained from stem or leaves, has been conducted using a wide set of techniques to evaluate this species as a potential bioethanol feedstock. Our results showed that common cattail cellulose content was high for plants in the order Poales and was accompanied by a small amount of cross-linked polysaccharides. A high degree of arabinose-substitution in xylans, a high syringyl/guaiacyl ratio in lignin and a low level of cell wall crystallinity could yield a good performance for lignocellulose saccharification. These results identify common cattail as a promising plant for use as potential bioethanol feedstock. To the best of our knowledge, this is the first in-depth analysis to be conducted of lignocellulosic material from common cattail.This study was supported by the Spanish Ministry of Economy and Competitiveness (AGL2014-58126-R and SEV-2015-0533 from the Severo Ochoa Programme for Centres of Excellence in R&D 2016–2019) and by CERCA Programme/Generalitat de Catalunya, and the Suport a Grups de Recerca Programme (SGR2014-1434) from the Autonomous Government of Catalonia. Romina Martínez-Rubio received funding through a PhD grant from the Spanish Ministry of Science and Innovation FPU program.Peer reviewe