Conceptions of Infant Education teachers about their initial and permanent professional training: a collective case study

Esta investigación se plantea para dar respuesta al hecho de que la formación inicial y permanente del profesorado de Educación Infantil es una de las menos abordadas en el panorama de los abundantes estudios sobre formación del profesorado. Con el objetivo de acceder a las concepciones de estos docentes sobre la formación inicial y permanente que han recibido, y aproximarnos a la valoración que hacen de la repercusión de ambas en su ejercicio profesional, se ha diseñado esta investigación cualitativa. El procedimiento elegido ha sido el estudio de caso colectivo. El instrumento empleado ha sido una entrevista clínica semiestructurada que ha permitido conocer y comprender con amplitud la particularidad de cada uno de los casos estudiados a través de un análisis de contenido. Además, se ha realizado otro análisis para establecer redes semánticas entre las categorías establecidas que ha permitido establecer comparaciones en busca de puntos comunes y de disensión entre ellos. Los resultados muestran que el profesorado comparte la creencia de que es necesario mejorar la formación inicial porque es excesivamente teórica; la formación permanente debe realizarse en el centro para facilitar la conciliación y adecuarla a cada contexto. Los docentes de Educación Infantil participantes en nuestra investigación no están muy satisfechos con la formación inicial y permanente que han recibido porque la consideran poco aplicable a su ejercicio.I+D+i: Proyecto de investigación “Canon de lecturas, prácticas de educación literaria y valores de la ciudadanía europea: claves axiológicas y propuestas para la igualdad de género y la multiculturalidad (EDUCALIT)Ministerio de Economía y Competitividad (PID2019-105913RB-I00)Trabajo derivado del proyecto I+D+I PID2019-105913RB-I00 financiado por MCIN/ AEI /10.13039/50110001103

Contributions of argumentative discourse analysis to the understanding of teachers' thinking: a case study of oral language teaching in early childhood education

Este trabajo se ha realizado dentro del periodo del Proyecto PID2019-105913RB-I00 financiado por MCIN/ AEI/10.13039/501100011033.En este trabajo se presenta una investigación de corte etnográfico sobre la enseñanza de la lengua oral en la Educación Infantil diseñada como un estudio de casos. El objetivo primordial es acceder a las representaciones y a los saberes teóricos y prácticos sobre la didáctica de las destrezas orales de los docentes de esta etapa a través del análisis del discurso argumentativo que despliegan al dar cuenta de sus decisiones y actuaciones. El instrumento utilizado ha sido una entrevista clínica semiestructurada, sobre la que se han realizado dos tipos de estudios: uno centrado en la sistematización de las categorías y metacategorías presentes en el contenido de las declaraciones, y otro que ha profundizado en los mecanismos discursivos empleados. Los resultados destacan que este profesorado cree que su formación no es suficiente para hacer una enseñanza más completa de las habilidades orales y que el trabajo sobre estas que se hace en Educación Infantil se pierde en Primaria por falta de coordinación. Las conclusiones apuntan a la necesidad de mejorar la formación de estos docentes en lo relativo a la epistemología de la competencia oral y su didáctica, así como de impulsar más investigaciones que orienten la innovación en este ámbito.This paper presents an ethnographic research on the teaching of oral language in early childhood education designed as a case study. The main objective is to gain access to the representations and theoretical and practical knowledge about the teaching of oral skills of teachers at this stage through the analysis of the argumentative discourse they display when giving an account of their decisions and actions. The instrument used was a semi-structured clinical interview, on which two types of study were carried out: one focused on the systematisation of the categories and meta-categories present in the content of the statements, and the other looked in depth at the discursive mechanisms employed. The results highlight the fact that these teachers believe that their training is not sufficient for a more complete teaching of oral skills and that the work done on these skills in pre-school education is lost in primary education due to a lack of coordination. The conclusions point to the need to improve the training of these teachers in relation to the epistemology of oral competence and its didactics, as well as to promote more research to guide innovation in this area.MCIN/ AEI/10.13039/501100011033, PID2019-105913RB-I0

Pre-School Spanish Teachers’ Training on Oral Language Teaching: A Comparative Study

La Educación Infantil en España es una etapa educativa estructurada en dos ciclos con un objetivo primordial: desarrollar la competencia en comunicación lingüística. Por ello se ha de proporcionar una correcta preparación de los docentes al respecto para garantizar una labor educativa de calidad. El objeto de esta investigación es realizar una revisión de los planes actuales de la titulación de Grado de Maestro de Educación Infantil en las universidades públicas de España (curso 2015/2016), y de esta forma evidenciar si es necesario aumentar la presencia de materias de lengua oral, así como los contenidos teóricos y prácticos de esta. La metodología utilizada posee un carácter cuantitativo y la principal técnica de recogida de datos es la revisión de documentos oficiales. Se trata, en suma, de un estudio descriptivo e informativo. Los resultados indican que existe una disparidad notable entre los contenidos de lengua oral en las diferentes universidades públicas de España.Pre-School in Spain is an educational stage structured in two cycles with a primary goal: to develop competence in linguistic communication. Therefore it’s to provide accurate preparation of teachers about educational work to ensure quality. The purpose of this research is to review current plans of the degree of Master Degree Infant Education, pre-school, in public universities in Spain (course 2015/2016) and thus show whether it’s necessary to increase the presence of substances of oral language. The methodology has a quantitative character and the main technique used is to review official documents also this study is descriptive and informative. The results show that there is a significant disparity between the contents of oral language in different public universities in Spain

Formación sobre didáctica de la lengua oral de los docentes de Educación Infantil: Un estudio comparativo

Resumen:La Educación Infantil en España es una etapa educativa estructurada en dos ciclos con un objetivo primordial: desarrollar la competencia en comunicación lingüística. Por ello se ha de proporcionar una correcta preparación de los docentes al respecto para garantizar una labor educativa de calidad. El objeto de esta investigación es realizar una revisión de los planes actuales de la titulación de Grado de Maestro de Educación Infantil en las universidades públicas de España (curso 2015/2016), y de esta forma evidenciar si es necesario aumentar la presencia de materias de lengua oral, así como los contenidos teóricos y prácticos de esta. La metodología utilizada posee un carácter cuantitativo y la principal técnica de recogida de datos es la revisión de documentos oficiales. Se trata, en suma, de un estudio descriptivo e informativo. Los resultados indican que existe una disparidad notable entre los contenidos de lengua oral en las diferentes universidades públicas de España.AbstractPre-School in Spain is an educational stage structured in two cycles with a primary goal: to develop competence in linguistic communication. Therefore it’s to provide accurate preparation of teachers about educational work to ensure quality. The purpose of this research is to review current plans of the degree of Master Degree Infant Education, pre-school, in public universities in Spain (course 2015/2016) and thus show whether it’s necessary to increase the presence of substances of oral language. The methodology has a quantitative character and the main technique used is to review official documents also this study is descriptive and informative. The results show that there is a significant disparity between the contents of oral language in different public universities in Spain

In vitro antagonistic activity of Trichoderma harzianum against Fusarium sudanense causing seedling Blight and seed rot on wheat

[EN] Fusarium sudanense is a novel fungus recently isolated from asymptomatic samples of wheat grains in Argentina. The fungus caused symptoms of seedling blight and seed rot on wheat after artificial inoculations. It is known that the production of mycotoxins by pathogens belonging to the Fusarium genus is harmful to human and animal health. Moreover, the warm and humid conditions that are favorable for growth and mycotoxin production of these species put the Argentinian wheat production area at a high risk of mycotoxin contamination with this novel pathogen. The aim of this work was to evaluate the antagonistic effect of Trichoderma harzianum against F. sudanense under in vitro tests at different environmental conditions. Fungi were screened in dual culture at different water activities (alpha(w)) (0.995, 0.98, 0.95, and 0.90) and temperatures (25 and 15 degrees C). The growth rate of the fungi, interaction types, and dominance index were evaluated. Also, the interaction between T. harzianum and F. sudanense was examined by light and cryo-scanning microscopy. T. harzianum suppressed the growth of F. sudanense at 0.995, 0.98, and 0.95 alpha(w) at 25 degrees C and 0.995 and 0.98 alpha(w) at 15 degrees C. Macroscopic study revealed different interaction types between F. sudanense and T. harzianum on dual culture. Dominance on contact where the colonies of T. harzianum overgrew the pathogen was the most common interaction type determined. The competitive capacity of T. harzianum was diminished by decreasing the temperature and alpha(w). At 0.95 alpha(w) and 15 degrees C, both fungi grew slowly, and interaction type "A" was assigned. Microscopic analysis from the interaction zone of dual cultures revealed an attachment of T. harzianum to the F. sudanense hyphae, penetration with or without formation of appressorium-like structures, coiling, plasmolysis, and a veil formation. According to our results, T. harzianum demonstrated capability to antagonize F. sudanense and could be a promising biocontrol agent.This work was supported by the Escuela Tecnica Superior de Ingenieria Agronomica y del Medio Natural (ETSIANM), UPV, Spain, and by Facultad de Ciencias Agrarias y Forestales of the Universidad Nacional de La Plata (grant no. 11A 296), Argentina.Larran, S.; Santamarina Siurana, MP.; Rosello Caselles, J.; Simón, MR.; Perelló, A. (2020). In vitro antagonistic activity of Trichoderma harzianum against Fusarium sudanense causing seedling Blight and seed rot on wheat. ACS Omega. 5(36):23276-23283. https://doi.org/10.1021/acsomega.0c03090S2327623283536Arnold, A. E. (2007). Understanding the diversity of foliar endophytic fungi: progress, challenges, and frontiers. Fungal Biology Reviews, 21(2-3), 51-66. doi:10.1016/j.fbr.2007.05.003Porras-Alfaro, A., & Bayman, P. (2011). Hidden Fungi, Emergent Properties: Endophytes and Microbiomes. Annual Review of Phytopathology, 49(1), 291-315. doi:10.1146/annurev-phyto-080508-081831Keswani, C., Singh, H. B., Hermosa, R., García-Estrada, C., Caradus, J., He, Y.-W., … Sansinenea, E. (2019). Antimicrobial secondary metabolites from agriculturally important fungi as next biocontrol agents. Applied Microbiology and Biotechnology, 103(23-24), 9287-9303. doi:10.1007/s00253-019-10209-2Mesa Vanegas, A. M., Calle Osorno, J., & Marín Pavas, D. A. (2020). Metabolitos secundarios en Trichoderma spp. y sus aplicaciones biotecnológicas agrícolas. Actualidades Biológicas, 41(111). doi:10.17533/udea.acbi.v41n111a02Moussa, T. A. A., Al-Zahrani, H. S., Kadasa, N. M. S., Ahmed, S. A., de Hoog, G. S., & Al-Hatmi, A. M. S. (2017). Two new species of the Fusarium fujikuroi species complex isolated from the natural environment. Antonie van Leeuwenhoek, 110(6), 819-832. doi:10.1007/s10482-017-0855-1Larran, S., Santamarina Siurana, M. P., Roselló Caselles, J., Simón, M. R., & Perelló, A. (2020). Fusarium sudanense, endophytic fungus causing typical symptoms of seedling blight and seed rot on wheat. Journal of King Saud University - Science, 32(1), 468-474. doi:10.1016/j.jksus.2018.07.005Larran, S. Estudio de la micobiota endofítica asociada al trigo y soja y su significancia en la interacción con patógenos fúngicos; Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata. 2016 http://sedici.unlp.edu.ar/handle/10915/54499.Shi, W., Tan, Y., Wang, S., Gardiner, D., De Saeger, S., Liao, Y., … Wu, A. (2016). Mycotoxigenic Potentials of Fusarium Species in Various Culture Matrices Revealed by Mycotoxin Profiling. Toxins, 9(1), 6. doi:10.3390/toxins9010006Bockus, W. W., Bowden, R. L., Hunger, R. M., Morrill, W. L., Murray, T. D., & Smiley, R. W. (Eds.). (2010). Compendium of Wheat Diseases and Pests, Third Edition. doi:10.1094/9780890546604Leslie, J. F., & Summerell, B. A. (Eds.). (2006). The Fusarium Laboratory Manual. doi:10.1002/9780470278376Perincherry, L., Lalak-Kańczugowska, J., & Stępień, Ł. (2019). Fusarium-Produced Mycotoxins in Plant-Pathogen Interactions. Toxins, 11(11), 664. doi:10.3390/toxins11110664Edwards, J., Auer, D., de Alwis, S.-K., Summerell, B., Aoki, T., Proctor, R. H., … O’Donnell, K. (2016). Fusarium agapanthi sp. nov., a novel bikaverin and fusarubin-producing leaf and stem spot pathogen of Agapanthus praecox (African lily) from Australia and Italy. Mycologia, 108(5), 981-992. doi:10.3852/15-333Andrade, J. F., & Satorre, E. H. (2015). Single and double crop systems in the Argentine Pampas: Environmental determinants of annual grain yield. Field Crops Research, 177, 137-147. doi:10.1016/j.fcr.2015.03.008Ortega, L. M., Dinolfo, M. I., Astoreca, A. L., Alberione, E. J., Stenglein, S. A., & Alconada, T. M. (2015). Molecular and mycotoxin characterization of Fusarium graminearum isolates obtained from wheat at a single field in Argentina. Mycological Progress, 15(1). doi:10.1007/s11557-015-1147-7Perelló, A. E., & Dal Bello, G. M. (2011). Suppression of tan spot and plant growth promotion of wheat by synthetic and biological inducers under field conditions. Annals of Applied Biology, 158(3), 267-274. doi:10.1111/j.1744-7348.2011.00460.xHarman, G. E., Petzoldt, R., Comis, A., & Chen, J. (2004). Interactions Between Trichoderma harzianum Strain T22 and Maize Inbred Line Mo17 and Effects of These Interactions on Diseases Caused by Pythium ultimum and Colletotrichum graminicola. Phytopathology®, 94(2), 147-153. doi:10.1094/phyto.2004.94.2.147Perelló, A., Lampugnani, G., Abramoff, C., Slusarenko, A., & Bello, G. D. (2016). Suppression of seed-borneAlternaria arborescensand growth enhancement of wheat with biorational fungicides. International Journal of Pest Management, 63(2), 157-165. doi:10.1080/09670874.2016.1252478Sempere, F., & Santamarina, M. P. (2009). Antagonistic interactions between fungal rice pathogenFusarium Verticillioides (Sacc.) Nirenberg andTrichoderma harzianum Rifai. Annals of Microbiology, 59(2), 259-266. doi:10.1007/bf03178326SAMAPUNDO, S., DEVLIEHGERE, F., DE MEULENAER, B., & DEBEVERE, J. (2005). Effect of Water Activity and Temperature on Growth and the Relationship between Fumonisin Production and the Radial Growth of Fusarium verticillioides and Fusarium proliferatum on Corn. Journal of Food Protection, 68(5), 1054-1059. doi:10.4315/0362-028x-68.5.1054Sempere Ferre, F., & Santamarina, M. P. (2010). Efficacy of Trichoderma harzianum in suppression of Fusarium culmorum. Annals of Microbiology, 60(2), 335-340. doi:10.1007/s13213-010-0047-yLlorens, A., Mateo, R., Hinojo, M. J., Valle-Algarra, F. M., & Jiménez, M. (2004). Influence of environmental factors on the biosynthesis of type B trichothecenes by isolates of Fusarium spp. from Spanish crops. International Journal of Food Microbiology, 94(1), 43-54. doi:10.1016/j.ijfoodmicro.2003.12.017Magan, N., & Medina, A. (2016). Integrating gene expression, ecology and mycotoxin production by Fusarium and Aspergillus species in relation to interacting environmental factors. World Mycotoxin Journal, 9(5), 673-684. doi:10.3920/wmj2016.2076Pilar Santamarina, M., & Roselló, J. (2006). Influence of temperature and water activity on the antagonism of Trichoderma harzianum to Verticillium and Rhizoctonia. Crop Protection, 25(10), 1130-1134. doi:10.1016/j.cropro.2006.02.006Prasad, R. D., Rangeshwaran, R., Hegde, S. V., & Anuroop, C. P. (2002). Effect of soil and seed application of Trichoderma harzianum on pigeonpea wilt caused by Fusarium udum under field conditions. Crop Protection, 21(4), 293-297. doi:10.1016/s0261-2194(01)00100-4Perello, A. E., Monaco, C. I., Moreno, M. V., Cordo, C. A., & Simon, M. R. (2006). The effect ofTrichoderma harzianumandT. koningiion the control of tan spot(Pyrenophora tritici-repentis) and leaf blotch (Mycosphaerella graminicola) of wheat under field conditions in Argentina. Biocontrol Science and Technology, 16(8), 803-813. doi:10.1080/09583150600700099Larran, S., Simón, M. R., Moreno, M. V., Siurana, M. P. S., & Perelló, A. (2016). Endophytes from wheat as biocontrol agents against tan spot disease. Biological Control, 92, 17-23. doi:10.1016/j.biocontrol.2015.09.002Nakkeeran, S., Renukadevi, P., & Aiyanathan, K. E. A. (2016). Exploring the Potential of Trichoderma for the Management of Seed and Soil-Borne Diseases of Crops. Integrated Pest Management of Tropical Vegetable Crops, 77-130. doi:10.1007/978-94-024-0924-6_4Magan, N., & Lacey, J. (1984). Effect of water activity, temperature and substrate on interactions between field and storage fungi. Transactions of the British Mycological Society, 82(1), 83-93. doi:10.1016/s0007-1536(84)80214-4Sinclair, J. B. (1991). Latent Infection of Soybean Plants and Seeds by Fungi. Plant Disease, 75(3), 220. doi:10.1094/pd-75-0220Verhoeff, K. (1974). Latent Infections by Fungi. Annual Review of Phytopathology, 12(1), 99-110. doi:10.1146/annurev.py.12.090174.000531Sempere, F., & Santamarina, M. P. (2011). Cryo-scanning electron microscopy and light microscopy for the study of fungi interactions. Microscopy Research and Technique, 74(3), 207-211. doi:10.1002/jemt.2089

Chemodiversity of wild populations of aromatic plants as source of valuable essential oil profiles. A study on Thymus vulgaris L. from Valencia (Spain)

[EN] Chemodiversity of wild populations of aromatic plants is a valuable source of essential oils, whose composition may be suitable for specific purposes according their biological activity. Furthermore, knowing the intrapopulational variability based on individual analysis has allowed characterizing atypical profiles, which can reach high levels of active compounds. Obviously, it requires the treatment of a high number of individual samples. In this work, a methodology to characterize T. vulgaris profiles in an area of recognized biodiversity was proposed and applied. After Thin Layer Chromatography (TLC) screening data of 85 individual samples, 7 groups, and 13 individuals were classified. Then, 20 samples were subjected to GC/MS and GC/FID analysis, respectively. These data were subjected to Hierarchical Agglomerative, Discriminant Analysis and ANOVA, which finally highlighted five profiles: (1) based on the camphane skeleton (camphene, camphor and borneol), (2) rich in the oxygenated sesquiterpenic fraction, (3) rich in 1,8-cineole, with appreciable amounts of camphor and borneol (typical chemotype from Eastern Iberian Peninsula), (4) camphor and terpinen-4-ol as major compounds, and (5) linalool chemotype. It should be noted that the percentages of the main compounds in these groups were higher than some of those described in the literature for similar chemotypes. In summary, the preliminary screening by TLC, grouping individuals with similar profiles, allowed establishing a quick first approximation to the chemodiversity of T. vulgaris in the studied area. Furthermore, the analysis of unclassified and potentially atypical individuals has also provided valuable information to establish the final profiles.Llorens Molina, JA.; Vacas, S.; Burgals Royo, E.; Santamarina Siurana, MP.; Verdeguer Sancho, MM. (2020). Chemodiversity of wild populations of aromatic plants as source of valuable essential oil profiles. A study on Thymus vulgaris L. from Valencia (Spain). Natural Volatiles and Essential Oils. 7(3):29-50. https://doi.org/10.37929/nveo.722313S29507

Antifungal films based on starch-gelatin blend, containing essential oils

[EN] The antimicrobial activity of essential oils (EO) is very well-known and it has been reported that incorporating them into edible films based on biopolymers extends the food's shelf-life. In this study, cinnamon, clove and oregano EO, at 25% with respect to the polymer, were incorporated into glycerol plasticized starch-gelatin blend films (ratio 1:1) in order to elucidate their effect on the physical (barrier, mechanical and optical), structural and antifungal properties of the films. Whereas EOs exhibited no significant effect on tensile behavior in the case of casting films conditioned at 53% relative humidity and 25 degrees C, the EO compounds did significantly reduce the water vapor and oxygen permeability of the films. Likewise, the EOs increased the films' transparency but reduced their gloss. Despite the fact that about 60% of the incorporated EOs were lost during the film drying step, they exhibited antifungal activity against the two tested fungal species, Colletotrichum gloesporoides (CG) and Fusarium oxysporum (FOG), as revealed by the in vitro agar diffusion method. (C) 2016 Elsevier Ltd. All rights reserved.The authors acknowledge the financial support provided by the Ministerio de Economia y Competitividad-Spanish Government (AGL2013-42989-R).Acosta-Davila, SC.; Chiralt, A.; Santamarina Siurana, MP.; Rosello Caselles, J.; González Martínez, MC.; Cháfer Nácher, MT. (2016). Antifungal films based on starch-gelatin blend, containing essential oils. Food Hydrocolloids. 61:233-240. doi:10.1016/j.foodhyd.2016.05.008S2332406

Endophytic Trichoderma strains increase soya bean growth and promote charcoal rot control

Charcoal rot, caused by Macrophomina phaseolina (Tassi) Goid., is one of the world's most serious diseases because it reduces yield and seed quality. Nowadays, biological control is an environment-friendly option for controlling plant diseases. The goals of this study were to (i) test eight endophytic Trichoderma spp. strains as biocontrol agents against M. phaseolina and (ii) further investigate two selected strains showing good behaviour against the pathogen. Pathogen-antagonist interactions were studied in dual culture, and the morphological alterations of M. phaseolina mycelia in the interaction zone were examined by light microscopy. Trichoderma strains were applied to soya bean seeds by a seed coating technique. Their bioprotective effects were assessed by in vitro and in vivo assays to evaluate radicle length, the germination percentage and the presence of typical charcoal rot symptoms in seedlings. Two Trichoderma strains were selected and they were molecularly identified as T. harzianum species complex. Their antagonistic ability against M. phaseolina was evaluated under different water availability conditions. The mechanisms used by these two endophytic strains against the pathogen were evaluated by cryo-scanning electron microscopy. The results showed that all eight Trichoderma strains successfully performed biocontrol activity against M. phaseolina by reducing colony growth and causing morphological alterations in the mycelia of M. phaseolina. All endophytes improved seed germination and radicle length, and reduced typical symptoms and disease progression on seedlings. Water availability in the medium impacted on fungal growth. At 0.995 ɑw, all the fungi grew more and faster. At 0.95 ɑw M. phaseolina grew more than the Trichoderma strains, while the pathogen grew slightly more at 0.98 ɑw than the Trichoderma strains. However, both selected Trichoderma strains grew larger and faster than the pathogen at 0.995 ɑw. The mechanisms involved in pathogen control revealed by the light and cryo-scanning microscopy studies included competition for nutrients or space and direct mycoparasitism. All the endophytic Trichoderma strains were antagonistic against M. phaseolina, however our study allowed us to select two Trichoderma strains with good potential to be included for charcoal rot management.Fil: Larran, Silvina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; ArgentinaFil: Simon, Maria Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; ArgentinaFil: Santamarina, María Pilar. Universidad Politécnica de Valencia; EspañaFil: Roselló Caselles, Josefa. Universidad Politécnica de Valencia; EspañaFil: Consolo, Verónica Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas. Centro de Estudios de Biodiversidad y Biotecnología; ArgentinaFil: Perello, Analia Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; Argentin

Fusarium sudanense, endophytic fungus causing typical symptoms of seedling blight and seed rot on wheat

An endophytic fungus isolated from healthy wheat seeds cultivar Klein Yarará in Buenos Aires Province, Argentina, was initially identified as belonging to the Fusarium fujikuroi species complex based on morphological and cultural characteristics. The fungus role in pathogenicity was investigated by artificial inoculation of wheat seeds. Symptoms evaluated 7 and 14 days after inoculation showed that the fungus was pathogenic on seed and seedlings causing symptoms as seed decay, seedling blight and seed rot. The fungus was re-isolated to fulfill Koch’s Postulates and was identified as F. sudanense (strain LBEA 3100), a new species recorded in Argentina. The fungal identity was corroborated using molecular techniques by sequencing the ITS region, D1/D2 domains of the LSU gene and TEF-1 alpha region and by comparison with international databases. Ecophysiological studies of F. sudanense (LBEA 3100) performed at different water activities and temperatures showed faster growth rate at the highest water activity and 25 C. This is the first report of F. sudanense, isolated from healthy wheat seeds, causing typical symptoms of seedling blight and seed rot on wheat.Centro de Investigaciones en Fitopatologí

Endophytic Trichoderma strains increase soya bean growth and promote charcoal rot control

Charcoal rot, caused by Macrophomina phaseolina (Tassi) Goid., is one of the world’s most serious diseases because it reduces yield and seed quality. Nowadays, biological control is an environment-friendly option for controlling plant diseases. The goals of this study were to (i) test eight endophytic Trichoderma spp. strains as biocontrol agents against M. phaseolina and (ii) further investigate two selected strains showing good behaviour against the pathogen. Pathogen-antagonist interactions were studied in dual culture, and the morphological alterations of M. phaseolina mycelia in the interaction zone were examined by light microscopy. Trichoderma strains were applied to soya bean seeds by a seed coating technique. Their bioprotective effects were assessed by in vitro and in vivo assays to evaluate radicle length, the germination percentage and the presence of typical charcoal rot symptoms in seedlings. Two Trichoderma strains were selected and they were molecularly identified as T. harzianum species complex. Their antagonistic ability against M. phaseolina was evaluated under different water availability conditions. The mechanisms used by these two endophytic strains against the pathogen were evaluated by cryo-scanning electron microscopy. The results showed that all eight Trichoderma strains successfully performed biocontrol activity against M. phaseolina by reducing colony growth and causing morphological alterations in the mycelia of M. phaseolina. All endophytes improved seed germination and radicle length, and reduced typical symptoms and disease progression on seedlings. Water availability in the medium impacted on fungal growth. At 0.995 ɑw, all the fungi grew more and faster. At 0.95 ɑw M. phaseolina grew more than the Trichoderma strains, while the pathogen grew slightly more at 0.98 ɑw than the Trichoderma strains. However, both selected Trichoderma strains grew larger and faster than the pathogen at 0.995 ɑw. The mechanisms involved in pathogen control revealed by the light and cryo-scanning microscopy studies included competition for nutrients or space and direct mycoparasitism. All the endophytic Trichoderma strains were antagonistic against M. phaseolina, however our study allowed us to select two Trichoderma strains with good potential to be included for charcoal rot management.Centro de Investigaciones en Fitopatologí