Lipo-Chitooligosaccharides (LCOs) as Elicitors of the Enzymatic Activities Related to ROS Scavenging to Alleviate Oxidative Stress Generated in Tomato Plants under Stress by UV-B Radiation

Exposure to ultraviolet-B (UV-B) radiation can lead to oxidative damage in plants, increasing reactive oxygen species (ROS) production. To overcome ROS burst, plants have antioxidant mechanisms related to ROS scavenging which can be improved by elicitation with biological agents or derived molecules (elicitors), as they can trigger a physiological alert state called “priming”. This work describes the effects of lipo-chitooligosaccharides (LCOs) treatment applied to tomato plants under UV-B stress. The LCOs used in the study are produced by three species of the genus Ensifer (formerly Sinorhizobium) (SinCEU-1, SinCEU-2, and SinCEU-3) were assayed on tomato plants under UV-B stress. LCOs were able to significantly increase most of the enzymatic activities related to ROS scavenging while non-enzymatic antioxidants were not modified. This response was associated with a lower oxidative stress, according to malondialdehyde (MDA) levels and the higher antioxidant capacity of the plants. Furthermore, the photosynthetic efficiency of LCOs-treated plants indicated a better physiological state than the control plants. Therefore, although more studies and deepening of certain aspects are necessary, LCOs have shown great potential to protect plants from high UV-B radiation conditions

Functional diversity of rhizosphere microorganisms from different genotypes of Arabidopsis thaliana

Activity and functional diversity of rhizosphere bacterial communities and fungal composition were studied in order to assess the effects of different genotypes (N8035, N224 and N8637) of Arabidopsis thaliana on these communities growing in different soils. Genotype effect and soil effect were studied independently. Also, the interactions between both factors (genotypes and soils) were considered. The activity was determined by thymidine and leucine incorporation analysis, and Biolog ECO plates were used to study bacterial functional diversity. Additionally, fungi groups (genera and/or species) were studied in the different rhizospheres. Statistical differences on thymidine incorporation between plant genotypes were only found in two of the soils. In addition, functional diversity (measured by Shanonn-Weaver index), showed statistical differences only in soil 1 for line N8035 (line B) vs . the other lines. Redundancy analysis (RDA) performed with Biolog data indicated and important effect of soil type, but also an effect of genotype since line N8035 (line B) was separated from the other lines within each soil in the RDA ordination, in spite of genotypic differences between them were minimum. Furthermore, carboxylic acids and amino acids were found to be the Biolog plate substrates with more influence in samples ordination in the Redundancy Analysis (RDA). However, fungi seem to be less labile to plant selection than bacteria probably due to a lower turn-over time of fungi than bacteria coupled with the short phenology of Arabidopsis . In this paper, plant-soil-micro-organism relationships in the rhizosphere were studied, and the complex interactions between them were highlighted. More studies are necessary to go deep in these interactions and to be able to asses the impact of genetically modified plants

Priming fingerprint induced by Bacillus amyloliquefaciens QV15, a common pattern in Arabidopsis thaliana and in field-grown blackberry

The aim of this study is focused on determining the Bacillus amyloliquefaciens QV15 priming fingerprint in two different plant species, Arabidopsis and blackberry as a crop of agronomic interest, associated with protection upon pathogen challenge. To achieve this goal, Arabidopsis thaliana plants were challenged with Pseudomonas syringae DC3000 under controlled conditions, and field-grown blackberries were challenged by a powdery Mildew outbreak, finding plant protection in plants treated with QV15, in both conditions. Changes in ROS scavenging enzymes’ activity, defense-related enzymes’ activity and gene expression were evaluated in both plant species, before and after pathogen challenge, revealing the ability of this strain to prime both. As a result of this analysis, the priming fingerprint induced by QV15 was defined by a decrease in ROS scavenging enzymes’ activity in pre- and post-challenged plants, an increase in glucanase and chitinase activity after pathogen challenge, significantly increasing the expression of PR1, indicating a salicylic acid (SA)-mediated pathway activation. These results suggest an excellent potential of B. amyloliquefaciens QV15 to protect different plant species against different pathogens in field conditions

Priming fingerprint induced by <i>Bacillus amyloliquefaciens</i> QV15, a common pattern in <i>Arabidopsis thaliana</i> and in field-grown blackberry

<p>The aim of this study is focused on determining the <i>Bacillus amyloliquefaciens</i> QV15 priming fingerprint in two different plant species, <i>Arabidopsis</i> and blackberry as a crop of agronomic interest, associated with protection upon pathogen challenge. To achieve this goal, <i>Arabidopsis thaliana</i> plants were challenged with <i>Pseudomonas syringae</i> DC3000 under controlled conditions, and field-grown blackberries were challenged by a powdery Mildew outbreak, finding plant protection in plants treated with QV15, in both conditions. Changes in ROS scavenging enzymes’ activity, defense-related enzymes’ activity and gene expression were evaluated in both plant species, before and after pathogen challenge, revealing the ability of this strain to prime both. As a result of this analysis, the priming fingerprint induced by QV15 was defined by a decrease in ROS scavenging enzymes’ activity in pre- and post-challenged plants, an increase in glucanase and chitinase activity after pathogen challenge, significantly increasing the expression of <i>PR1</i>, indicating a salicylic acid (SA)-mediated pathway activation. These results suggest an excellent potential of <i>B. amyloliquefaciens</i> QV15 to protect different plant species against different pathogens in field conditions.</p

Anales de Edafología y Agrobiología Tomo 44 Número 7-8

l. Suelos. Física Nuevo método para estimar la evapotranspiración potencial y el déficit de precipitación. Fórmulas para Salamanca y Zamora, por F. de Pablo, A. Egido, L. J. Rivas y J. Garmendia.-- Estudio climatológico del Valle del Guadalquivir mediante un modelo vectorial (Análisis de componentes generalizado), por R. Roman y M. C. Navarro. l. Suelos. Química Alfisoles de los Montes de Toledo. III. Perfil ultic palexeralf. Estudio mineralógico de la fracción arcilla por difracción de Rayos X y espectroscopia infrarroja, por P. Recio y M. T. García-González.-- Alfisoles de los Montes de Toledo. IV. Perfil ultic palexeralf. Estudio mineralógico de la fracción arcilla por métodos térmicos de análisis. Determinaciones analíticas elementales, por P. Recio y M. T. García-González.-- Determinación de la actividad fosfatasa en suelos gallegos. Precisiones al método de Sarathchandra y Perrot, por Ma C. Trasar Cepeda, F. Gil Sotres y F. Guitián Ojea.--Contribución al estudio de la movilización de nitrógeno en ecosistemas del centro de España, por A. García-Villaraco y F. Velasco de Pedro-- Movilización y fijación biológica de cationes en ecosistemas forestales. l. Dinámica del Ca y Mg en los horizontales superficiales del suelo, por A. García-Vilaraco.-- Electromelioration of saline-alkali soils • a review, by L. L. Somanil.-- Suelos.-Biologfa Efectos de la deforestación sobre los suelos de la comarca de Antequera (Málaga).lll. Análisis y evaluación, por R. Delgado Calvo-Flores, G. Barceló y J. Párraga.-- l. Suelos-Génesis, Clasificación y Cartografía Los xerumbrepts bajo matorral de alta montaña de la vertiente sur de Sierra Nevada (Granada), por G. Delgado Calvo-Flores, J. Párraga Martínez, E. Serrano Molina y R. Delgado Calvo-Flores.-- Aplicación de un análisis multivariante a los suelos de la Alfaguara (Sierra de Alfacar• Granada), por l. García Fernández, M. Simón Torres, A. Polo Sánchez.-- l. Suelos. Fertilidad Presence and characterization of micrococcus luteus in a bare soil, by M. A. Sagardoy.-- Soil managements and use of 15 N-Labelled fertilizer for weat in semiarid Argentina. 2, por R. A. Rosell, R. M. Martínez y K. Ch. Sommer.-- Contribución al conocimiento de la utilización del agua del suelo por las especies fores• tales (Quercus robus y Pinus pinaster) bajo clima templado húmedo, por A. Paz González y F. Díaz-Fierros Viqueira.-- Fertilizer and foliar sampling trials in two stages of development of the flower bud in the rose 'Mercedes', by C. E. Alvarez, M. Fernández, V. García and A. E. Carracedo.-- Poder fertilizante de los lodos residuales: efecto sobre el contenido total y disponibilidad de Fe, Mn, Cu, Co y Ni, por M. L. Andrade Couce, A. M ateos Beato y F. Guitián Ojea.-- Adición de lodos residuales a un suelo ácido : influencia sobre el contenido total, disponi• bilidad y absorción por el cultivo, de Zn, Pb, Cr y Cd, por M. L.Andrade Couce, M. Bao Iglesias y F. Guitián Ojea.—II. Biología Vegetal.-Nutrición Estudio comparativo de metodologías de control nutricional en plantas de pimiento cul• tivadas en invernadero bajo sistema de riego localizado, por C. F. Alcaraz, M. •A. Martínez-Cañadas, F. Martínez-Sánchez y F. Sevilla. II. Biología Vegetal. Fisiología Inducción y cultivo de callos procedentes de explantes de hipocotilo, cotiledon y ra• dicula de Erysimum scoparium, por J. F. Pérez Francés, F. Valdés, A. J. Carmona y A. C. Blesa.-- Biología Vegetal. Agrobiologfa Diversidad florística y heterogeneidad ambiental en una dehesa de Sierra Morena, por T. Marañón Arana.-- Trabajo recapitulativo Revisión monográfica de la aplicación de técnicas de microanálisis de Rayos-X en Viología Vegetal, por J. M. Pozuelo y M. R. de Felipe. BibliografíaPeer reviewe