Reactive oxygen species generated in chloroplasts contribute to tobacco leaf infection by the necrotrophic fungus Botrytis cinerea

Reactive oxygen species (ROS) play fundamental roles in plant responses to pathogen infection, including modulation of cell death processes and defense-related gene expression. Cell death triggered as part of the hypersensitive response enhances resistance to biotrophic pathogens, but favors the virulence of necrotrophs. Even though the involvement of ROS in the orchestration of defense responses is well established, the relative contribution of specific subcellular ROS sources to plant resistance against microorganisms with different pathogenesis strategies is not completely known. The aim of this work was to investigate the role of chloroplastic ROS in plant defense against a typical necrotrophic fungus, Botrytis cinerea. For this purpose, we used transgenic Nicotiana tabacum (tobacco) lines expressing a plastid-targeted cyanobacterial flavodoxin (pfld lines), which accumulate lower chloroplastic ROS in response to different stresses. Tissue damage and fungal growth were significantly reduced in infected leaves of pfld plants, as compared with infected wild-type (WT) counterparts. ROS build-up triggered by Botrytis infection and associated with chloroplasts was significantly decreased (70–80%) in pfld leaves relative to the wild type. Phytoalexin accumulation and expression of pathogenesis-related genes were induced to a lower degree in pfld plants than in WT siblings. The impact of fungal infection on photosynthetic activity was also lower in pfld leaves. The results indicate that chloroplast-generated ROS play a major role in lesion development during Botrytis infection. This work demonstrates that the modulation of chloroplastic ROS levels by the expression of a heterologous antioxidant protein can provide a significant degree of protection against a canonical necrotrophic fungus.Fil: Rossi, Franco Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Krapp, Adriana del Rosario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Bisaro, Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; Argentina. The Queens University of Belfast; IrlandaFil: Maiale, Santiago Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Pieckenstain, Fernando Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Carrillo, Nestor Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; Argentin

Occurrence of scab disease of pecan caused by Cladosporium caryigenum in Argentina

Pecan (Carya illinoinensis) is a new crop in Argentina. The planted area is expanding quickly with around 4000 h in the Pampas region. In 2007 and 2008 typical scab symptoms on seedlings and mature trees were commonly observed in La Plata. A Cladosporium-like fungus was isolated on potato dextrose agar (PDA) from surface-sterilized pecan leaves collected from the Experimental Station of UNLP. Fungus' characteristics agree with a published description of Cladosporium caryigenum (Gottwald, 1982).Centro de Investigaciones en FitopatologíaFacultad de Ciencias Astronómicas y Geofísica

Occurrence of scab disease of pecan caused by Cladosporium caryigenum in Argentina

Pecan (Carya illinoinensis) is a new crop in Argentina. The planted area is expanding quickly with around 4000 h in the Pampas region. In 2007 and 2008 typical scab symptoms on seedlings and mature trees were commonly observed in La Plata. A Cladosporium-like fungus was isolated on potato dextrose agar (PDA) from surface-sterilized pecan leaves collected from the Experimental Station of UNLP. Fungus' characteristics agree with a published description of Cladosporium caryigenum (Gottwald, 1982).Centro de Investigaciones en FitopatologíaFacultad de Ciencias Astronómicas y Geofísica

Efectos fisiológicos por el uso de elicitores en tomate cultivado en suelo infestado con Nacobbus aberrans

La medición de respuestas fisiológicas de la planta frente a situaciones de estreses o prácticas que los mitiguen es útil para realizar evaluaciones no destructivas y diagnósticos tempranos. Este trabajo tuvo como objetivo estudiar el efecto fisiológico del uso de fitohormonas sobre tomate cultivado en suelo infestado con Nacobbus aberrans. El ensayo se condujo en un invernadero, en la EE (Estación Experimental) Julio Hirschhorn (La Plata, Buenos Aires). Tomate Elpida fue tratado por drench, 24 horas antes del trasplante con 1 ml de: ácido salicílico 0,5 x 10-4 M y 1,0 x 10-4 M, etileno 0,35 x 10-3 M y 0,70 x 10-3 M y ácido jasmónico 1,00 x 10-4 M y 1,00 x10-5 M, utilizando plantas sin tratar como testigo. Se registró intercambio de gases: asimilación neta de CO2, conductancia estomática, transpiración y eficiencia del uso del agua instantánea, temperatura foliar e índice de verdor. El diseño fue en bloques completos aleatorizados con 4 repeticiones. Se aplicó análisis de la varianza y prueba de Tukey. El intercambio gaseoso no fue modificado por los tratamientos. La temperatura foliar fue significativamente más baja con ácido salicílico 1,0 x 10-4 M, que incrementó el índice de verdor; variable que fue más baja en el testigo. El aumento de resistencia en tomate frente a N. aberrans tratado con ácido salicílico y la medición de variables fisiológicas para chequear la respuesta de la planta son posibilidades promisorias.Measurement of plant physiologicalresponse to stress or practices for itsalleviation is useful for non-destructiveevaluation and early diagnosis. The aim ofthis work was to study physiological effectof the use of phytohormones on tomatocrop in soil infested by Nacobbusaberrans. The essay was carried out undera greenhouse located in EE JulioHirschhorn (La Plata, Buenos Aires).Tomato Elpida was treated by drench, 24hours pre-transplanting with 1 ml of:salicilic acid 0.50 x 10-4 M and 1.00 x 10-4M, ethylen 0.35 x 10-3 M and 0.70 x 10-3M, jasmonic acid 1.00 x 10-4 M and 1.00 x10-5 M, using plants without treatment ascontrol. It was recorded gas exchange: CO2net assimilation rate, stomatalconductance, transpiration and instantwater use efficiency, leaf temperature andgreenness index. Statistical design was arandomized complete block with 4replications. Variance analysis and Tukeytest were applied. Gas exchange was notmodified by treatments. Leaf temperaturewas significant lesser with salicylic acid1.00 x 10-4 M, which increased thegreenness index; variable that was lower incontrol plants. Increasing resistance inktomato against N. aberrans by salicylicacid and the measurement of physiologicalvariables to check the response of the plantare promising possibilities.Fil: Martinez, Susana. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; ArgentinaFil: Garbi, Mariana. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; ArgentinaFil: Puig, Maria Lucrecia. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Maiale, Santiago Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin

Field and genetic evidence support the photosynthetic performance index (PIABS) as an indicator of rice grain yield

The effective increase of the rice breeding process for grain yield could be sustained by developing efficient tools to accelerate plant selection through the rapid determination of reliable predictors. Here, we have described different associations between grain yield and photosynthetic parameters simply and fast obtainable by a non-invasive technique in flag leaf during the anthesis stage. Among the analyzed photosynthetic parameters, the photosynthetic performance index (PIABS) stood out for its strong association with grain yield. A genome-wide association analysis determined in plants from a rice diversity panel at tillering stage indicated the presence of a quantitative trait locus on chromosome 9 characterized by a set of candidate chloroplastic genes with contrasting haplotypes for PIABS. An analysis of these haplotypes indicated a separation into two groups. One with haplotypes linked to high values of PIABS, which were associated almost exclusively with Japonica spp. subpopulations, and another with haplotypes linked to low values of PIABS, which were associated exclusively with Indica spp. subpopulations. Genotypes of the Japonica spp. subpopulations showed high values in panicle weight, a yield components parameter, compared with the Indica spp. subpopulations genotypes. The results of this work suggested that PIABS could be an early predictor of grain yield at the tillering stage in rice breeding processes.Fil: Rodriguez, Andres Alberto. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Vilas, Juan Manuel. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Sartore, Gustavo Daniel. Universidad Nacional de La Plata; ArgentinaFil: Bezus, Rodolfo. Universidad Nacional de La Plata; ArgentinaFil: Colazo, José Luis. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Maiale, Santiago Javier. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; Argentin

Occurrence of scab disease of pecan caused by Cladosporium caryigenum in Argentina

Pecan (Carya illinoinensis) is a new crop in Argentina. The planted area is expanding quickly with around 4000 h in the Pampas region. In 2007 and 2008 typical scab symptoms on seedlings and mature trees were commonly observed in La Plata. A Cladosporium-like fungus was isolated on potato dextrose agar (PDA) from surface-sterilized pecan leaves collected from the Experimental Station of UNLP. Fungus' characteristics agree with a published description of Cladosporium caryigenum (Gottwald, 1982).Centro de Investigaciones en FitopatologíaFacultad de Ciencias Astronómicas y Geofísica

Phenotypic plasticity with respect to salt stress response by Lotus glaber: The role of its AM fungal and rhizobial symbionts

Our hypothesis is that Lotus glaber (a glycophytic species, highly tolerant to saline-alkaline soils) displays a plastic root phenotypic response to soil salinity that may be influenced by mycorrhizal and rhizobial microorganisms. Uninoculated plants and plants colonised by Glomus intraradices or Mesorhizobium loti were exposed to either 150 or 0 mM NaCl. General plant growth and root architectural parameters (morphology and topology) were measured and phenotypic plasticity determined at the end of the salt treatment period. Two genotypes differing in their salt tolerance capacity were used in this study. G. intraradices and M. loti reduced the total biomass of non-salinised, sensitive plants, but they did not affect that of corresponding tolerant ones. Root morphology of sensitive plants was greatly affected by salinity, whereas mycorrhiza establishment counteracted salinity effects. Under both saline conditions, the external link length and the internal link length of mycorrhizal salt-sensitive plants were higher than those of uninoculated control and rhizobial treatments. The topological trend (TT) was strongly influenced by genotype x symbiosis interaction. Under non-saline conditions, nodulated root systems of the sensitive plant genotype had a more herringbone architecture than corresponding uninoculated ones. At 150 mM NaCl, nodulated root systems of tolerant plants were more dichotomous and those of the corresponding sensitive genotype more herringbone in architecture. Notwithstanding the absence of a link between TTs and variations in plant growth, it is possible to predict a dissimilar adaptation of plants with different TTs. Root colonisation by either symbiotic microorganisms reduced the level of root phenotypic plasticity in the sensitive plant genotype. We conclude that root plasticity could be part of the general mechanism of L. glaber salt tolerance only in the case of non-symbiotic plants.Fil: Echeverria, Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Scambato, Agustina Azul. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Sannazzaro, Analía Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Maiale, Santiago Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Ruiz, Oscar Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Menendez, Ana Bernardina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Occurrence of Phomopsis sp. causing cankers on pecan trees in Buenos Aires province, Argentina

Production of pecan (Carya illinoiensis) continues to increase in Argentina, due mainly to its nutritional qualities and sustained export demand. In April 2014, the presence of cankers on branches and twigs was observed on pecan trees in the province of Buenos Aires, where the incidence ranged from 10 to 50% of the surveyed plantations (Fig. 1). Fungal isolates with morphological characteristics similar to those of Phomopsis (Sutton, 1980) were collected from cankers on potato dextrose agar after seven days of incubation in a growth chamber at 25°C with a 12 h photoperiod. Colonies in their early stages were whitish cottony (Fig. 2). They contained numerous, globose, brown to black pycnidia of 346.1 ± 59.8 μm × 286.4 ± 55.6 μm (Fig. 3), alpha hyaline conidia, fusiform to ellipsoid in shape, bigutulate with an average size of 6.8 ± 1.0 μm × 2.0 ± 0.2 μm, and beta filiform hyaline conidia, hamate in shape with average size of 21.6 ± 3.9 μm × 1.0 ± 0.1 μm.Facultad de Ciencias Agrarias y Forestale

Chlorophyll a fluorescence analysis reveals divergent photosystem II responses to saline, alkaline and saline–alkaline stresses in the two Lotus japonicus model ecotypes MG20 and Gifu-129

Saline and alkaline stresses affect more than 10% of the World’s arable land, limiting agricultural production. Salt-induced stress may affect the photosystem II (PSII) function, altering fluorescence emission. Therefore, changes in fluorescence are used to quantify and analyze abiotic stress responses in plants. So far, no study has focused on the response of PSII to saline, alkaline and saline–alkaline stresses in the model legume Lotus japonicus. For the saline, alkaline and saline–alkaline treatments, plants of the L. japonicus ecotypes MG20 and Gifu-129 were cultivated in sand with nutrient solution, added with NaCl and NaHCO3 in different proportions. Growth, gas exchange, and chlorophyll a fluorescence transient kinetic and OJIP parameters were measured, and chlorophyll a and b were determined. The analysis of the kinetic of chlorophyll a fluorescence showed that NaCl-derived stress sources affect the photochemical events in PSII in both ecotypes, being this effect more evident under higher pH condition, whereas alkalinity per se has a mild or no effect on these events. The saline–alkaline stress induced a more severe effect on Gifu B-129, compared with Miyakojima MG20, whereas NaCl improved primary photochemistry in MG20. Our results allow us to accept the hypothesis that both ecotypes deploy differential responses under the three stressful treatments and that the saline–alkaline stress causes higher damage levels than saline and alkaline stresses alone in relation with structures and sub-processes of the PSII.Fil: Bordenave, César Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Rocco, Ruben Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Maiale, Santiago Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Campestre, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Ruiz, Oscar Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Rodriguez, Andres Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Menendez, Ana Bernardina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentin

Optimization of tissue culture conditions and in vitro and in planta transformation of the local variety of rice Don Justo FCAyF

El arroz (Oryza sativa L.) es uno de los cereales de mayor importancia económica debido a que provee alimento a más de la mitad de la población mundial. El mejoramiento de este cultivo mediante ingeniería genética requiere poner a punto procesos como el cultivo de tejidos y la transformación. En este trabajo se optimizaron los métodos de cultivo in vitro y transformación de la variedad local de alto rendimiento Don Justo FCAyF. Con respecto al cultivo de tejidos se determinó que la concentración óptima de 2,4D para la callogénesis fue de 3 mg.l-1 con un 42%. La regeneración de parte aérea mostró un 77% de eficiencia con una combinación de 4 mg.l-1 BAP y 0,8 mg.l-1 ANA. En relación a la transformación mediante Agrobacterium tumefaciens se obtuvieron diferentes porcentajes de eficiencia dependiendo del plásmido utilizado para transformar como también del explanto. En el caso de la transformación in vitro de callos embriogénicos se obtuvieron valores entre 14-29% dependiendo del plásmido. Mientras que el método in planta de transformación de embriones presentó una eficiencia entre 3-28%. En conclusión, en este trabajo se puso a punto los métodos de cultivo y transformación de una variedad local de arroz que facilitará el mejoramiento genético de la misma mediante distintas técnicas como transgénesis convencional o edición génica.Rice (Oryza sativa L.) is one of the most economically important cereals because it provides food for more than half of the world's population. Improving this crop through genetic engineering requires fine-tuning processes such as tissue culture and transformation. Here, we optimized tissue in vitro culture and transformation methods of the local premium cultivar Don Justo FCAyF. Regarding tissue culture, the optimal 2,4D concentration was 3 mg.l-1showing 42% of callogenesis. Shoot regeneration showed 77% efficiency using a combination of 4 mg.l-1 BAP and 0.8 mg.l-1 NAA. About Agrobacterium tumefaciens transformation we obtained variable results depending on the plasmid as well as the explant used. In the case of in vitro transformation of embryogenic calli, values between 14-29% were obtained depending on the plasmid. While, in planta methods of embryo transformation presented an efficiency between 3-28%. In conclusion, in this work the methods for tissue cultivation and Agrobacterium transformation of a local variety of rice were fine-tuned. These results will facilitate its genetic improvement through different techniques such as conventional transgenesis or gene editing.Facultad de Ciencias Agrarias y Forestale