Macrophomina phaseolina: General Characteristics of Pathogenicity and Methods of Control

Macrophomina phaseolina is a generalist soil-borne fungus present all over the world. It cause diseases such as stem and root rot, charcoal rot and seedling blight. Under high temperatures and low soil moisture, this fungus can cause substantial yield losses in crops such as soybean, sorghum and groundnut. The wide host range and high persistence of M. phaseolina in soil as microsclerotia make disease control challenging. Therefore, understanding the basis of the pathogenicity mechanisms as well as its interactions with host plants is crucial for controlling the pathogen. In this work, we aim to describe the general characteristics and pathogenicity mechanisms of M. phaseolina, as well as the hosts defense response.We also review the current methods and most promising forecoming ones to reach a responsible control of the pathogen, with minimal impacts to the environment and natural resources.Instituto de Patología VegetalFil: Marquez, Nathalie. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentina.Fil: Marquez, Nathalie. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFYMA); ArgentinaFil: Giachero, María Lorena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Giachero, María Lorena.Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFYMA); ArgentinaFil: Declerck, Stéphane. Université Catholique de Louvain. Earth and Life Institute. Applied Microbiology. Mycology; BélgicaFil: Ducasse, Daniel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentin

Soybean responseto initial stage of Fusarium virguliforme infection

Fusarium virguliforme causes the Sudden Death Syndrome, an important disease in soybean crops. In this work, we investigated the defensive response mechanisms in soybean root, at cell wall level, during F. virguliforme infection using an in vitro culture system. We measured total root lignin content by the acetyl bromide method and estimated the in-situ lignin and suberin deposition by confocal microscopy on local and systemic root tissues, i.e. adjacent and distant to the pathogen entry site respectively. Moreover, the expression dynamics of phenylalanine ammonia lyase (PAL), shikimate/quinate hydroxycinnamoyltransferase (HCT) and cinnamyl alcohol dehydrogenase (CAD) was evaluated by real-time quantitative PCR. The results showed that, although the most significant increment of lignin deposition was observed in the epidermal cells of local tissues, F. virguliforme also induced lignin deposition changes in a sistemic fashion. In fact, inoculated plants presented a higher deposition of lignin in hypodermis and cortex than the control ones, independently of the distance from the inoculum source, while suberin deposition was higher in local zones. Moreover, the gene expression analysis showed an up-regulation of PAL, HCT and CAD genes after the inoculation with the pathogen, which correlates with the cell wall modifications observed in the local tissues. The results presented here suggest that the increase in lignin and suberin deposition during soybean root/F. virguliforme interaction is probably a strategy not only to stop the pathogen entrance, but to provide the plant more time to prepare its defences as well.Instituto de Patología VegetalFil: Giachero, María Lorena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Marquez, Nathalie. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Ortega, Leandro Ismael. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Ducasse, Daniel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentin

Argentinean National Plant Protection Network Website

The Argentinean National Plant Protection Network (RedNPV) was created in 2006 as a proposal of the National Plant Protection Program (PNPV), National Institute of Agricultural Technology (INTA). The National Plant Protection Network (RedNPV) main objective is to articulate national scientific-technological capabilities in Plant Protection.Inst. de Microbiología y Zoología Agrícola IMyZAFil: Gasoni, Amelia Laura. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Haelterman, Raquel Mercedes. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Truol, Graciela Ana Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Frana, Jorge. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Vigna, Mario Raul. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: Ducasse, Daniel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentin

Relevamiento y caracterización de fitopatógenos presentes en Digitaria eriantha Steudel. Sobre parcelas fertilizadas con Urea

En el diagnóstico de los problemas fitosanitarios, es muy importante la correcta identificación del agente causal, lo que resulta fundamental para el manejo del problema. Esto permite generar medidas de control efectivas, optimizar el uso de los recursos, reduce los efectos negativos en el medio ambiente y originan información respecto a la interacción patógeno – hospedante (Rivas Figueredo et al. 2008). Las gramíneas perennes del tipo C4 se destacan por su adaptación a las condiciones ambientales de la provincia de San Luis, y Digitaria eriantha ocupa un lugar preponderante como forraje diferido de uso otoño invernal (Veneciano et al. 2006). D. eriantha, es perenne, de origen sudafricana, posee resistencia a sequías y versatilidad en cuanto a suelos, tolerando arenosos, arcillosos y franco arenosos bien drenados.EEA San LuisFil: Bravo, Maria Belen. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; ArgentinaFil: Andrada, Nora Raquel. Universidad Nacional de San Luis. Facultad de Ingeniería y Ciencias Agropecuarias; Argentina.Fil: Terenti, Oscar Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Luis; ArgentinaFil: Ducasse, Daniel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentin

Efficiency of cytogenetic methods in detecting a chromosome rearrangement induced by ionizing radiation in a cultivated chili pepper line (Capsicum baccatum var. pendulum – Solanaceae)

Purpose: To locate transient chromosome aberrations on a selected pepper cultivar and determine the tracing efficiency of different cytogenetic methods. Materials and methods: Seeds from Capsicum baccatum var. pendulum cultivar ‘Cayenne’ were treated with an acute dose of X-rays (300 Gy) and chromosome aberrations were analysed by different cytogenetic methods [Feulgen, silver staining for nucleolus organizer regions (silver positive nucleolus organizing regions or AgNOR), fluorescent banding, fluorescence in situ hybridization (FISH) and meiotic analysis]. Results: A rearranged chromosome carrying two nucleolus organizing regions (NOR) induced by ionizing radiation was detected in the cultivar, with the occurrence of a small reciprocal exchange between a chromosome of pair no. 1 and another chromosome of pair no. 3, both carrying active NOR in short arms and associated chromomycin A positive/diamidino-phenylindole negative (CMA+/DAPI−) heterochromatin. Meiotic analysis showed a quadrivalent configuration, confirming a reciprocal translocation between two chromosomes. Conclusions: The use of X-rays in Capsicum allowed us to develop and identify a pepper line with structural rearrangements between two NOR-carrying chromosomes. We postulate that all the cytological techniques employed in this research were efficient in the search for chromosome aberrations. Particularly, Feulgen and AgNOR were the most suitable in those cases of transient rearrangements, whereas fluorescent banding and FISH were appropriate for intransitive ones.Instituto de Patología VegetalInstituto de GenéticaFil: Scaldaferro, Marisel Analía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Grabiele, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Seijo, Jose Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste; ArgentinaFil: Debat, Humberto Julio. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Romero, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Ducasse, Daniel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Prina, Alberto Raul. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Moscone, Eduardo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal; Argentin

Plant microRNAs: Recent Advances and Future Challenges

MicroRNAs (miRNAs) are small ∼20–24 nt species of non-coding RNAs that modulate plant gene expression by means of gene silencing through sequence-specific inhibition of target mRNAs. MiRNAs derive from pol-II transcription of non-coding genes that are precisely processed in nuclear Dicing bodies by a microprocessor complex (dicer-like1–serrate–hyponastic leaves 1: DCL1-SE-HYL1), which recognizes stem-loop secondary-structure features of primary precursor miRNA transcripts (pri-miRNA). The proper processing of the pri-miRNAs results in a double-stranded small RNA that will eventually exit the nucleus and be loaded predominantly onto the effector complex Argonaute1 (Ago1). The single-stranded mature miRNA will guide AGO1, leading to cleavage or translational arrest of complementary mRNAs. MiRNA steady-state levels and activity are regulated not only by transcription rate of precursor transcripts, but also by direct degradation mediated by small RNA degrading nuclease1 (SDN1). miRNAs are retailored by 3′ editing through 2-O-methylation, uridylation and adenlylation, involving Hua enhancer1 (HEN1), HEN1 suppressor1 (HESO1) and probably the exosome—a phenomenon that has been elucidated only scarcely to date in Arabidopsis. MiRNA activity is involved not only in plant development, but also in signaling, abiotic stresses such as drought, heat and metal toxicity, pathogen interaction and symbiotic relationship regulation, among others. The engineering of miRNAs is paving the way to next-generation plant biotechnology by means of over-expression of natural miRNAs, generation of artificial microRNAs and inhibition of miRNA activity by target mimicry. This review highlights the importance of miRNAs in plant sciences by describing the latest updates in this research field.Instituto de Patología VegetalFil: Debat, Humberto Julio. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Ducasse, Daniel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentin

Switching between monocot and dicot crops in rotation schemes of Argentinean productive fields results in an increment of arbuscular mycorrhizal fungi diversity

Despite the importance of mycorrhizal symbiosis, we understand little how different soil managements affect arbuscular mycorrhizal fungi (AMF) communities. Crop rotation is recommended in sustainable agriculture because of its benefits in soil fertility improvement and positive effect decreasing soil borne diseases incidence and pest abundance. Amplicon sequencing of LSU and SSU rRNA gene fragments was used to analyse AMF diversity in fields from one of the most productive regions in Argentina, which varied in the main class of the plant component included in the crop rotation scheme. The samples encompassed different agricultural settings; one involving only monocot plants in the crop rotation schemes, one including a dicot crop, and the other an alternation and/or a combination of monocot and dicot plant components. We found lower richness and diversity in soils under monocot succession than in a dicot/monocot rotation or consociation. We observed that agricultural management had an influence on beta diversity patterns. Principal coordinate analysis showed that communities from the dicot/monocot rotation or consociation samples clustered together and separated from the monocots samples. These findings suggested that the increment of soil AMF diversity is more dependent on the alternation between monocot and dicot crops than other factors related to the farming systems.Instituto de Patología VegetalFil: Albarracín Orio, Andrea G. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Laboratorio de Biología Molecular; ArgentinaFil: Brücher, Elsa. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Laboratorio de Biología Molecular; ArgentinaFil: Ducasse, Daniel Adrian. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Laboratorio de Biología Molecular; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentin

A strain of Bacillus subtilis subsp. subtilis shows a specific antagonistic activity against the soil-borne pathogen of onion Setophoma terrestris

Pink Root is among the major diseases of onion and its causal agent, Setophoma terrestris, is one of the most severe pathogens in soils of tropical and subtropical climates. The management of Pink Root is difficult and the strategies currently used are ineffective. Although, there are some varieties resistant to S. terrestris, they are not resistant to every isolate of the pathogen and it is not unusual to find isolates that break that resistance. Moreover, chemical control is not technically or economically feasible. So, we decided to address biocontrol as a mean to manage the main onion disease in Argentina.We tested the efficiency of a strain of Bacillus subtilis subsp. subtilis isolated from the rhizosphere of onion plants to inhibit the growth of S. terrestris in vitro. Our strain of Bacillus subtilis showed a strong capacity of growth inhibition of S. terrestris. No antagonistic activity against two other onion pathogens, Fusarium oxysporum f. sp. cepae and F. proliferatum, was observed. Interestingly, we found a high growth inhibition of S. terrestris on plates containing cell-free supernatant of B. subtilis previously grown in the presence of the fungus. No significant differences in the fungal growth were obtained between control plates and plates containing cell-free supernatant from B. subtilis grown without previous contact with S. terrestris. Electron microscopy of S. terrestris from co-cultures plates revealed thickened, tortuous or coiledfungal hyphae, with granules and globular like terminations. These results suggested that the strain of B. subtilis under study has a strong biocontrol activity against S. terrestris and that it would be acting diffusible bacterial inhibitory compounds specifically induced by this pathogen.Instituto de Patología VegetalFil: Albarracín Orio, Andrea Georgina. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Laboratorio de Biología Molecular; ArgentinaFil: Brücher, Elsa. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Laboratorio de Biología Molecular; ArgentinaFil: Ducasse, Daniel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentina. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Laboratorio de Biología Molecular; Argentin

Molecular characterization of the 5S rDNA non-transcribed spacer and reconstruction of phylogenetic relationships in Capsicum

Capsicum includes ca. 41 species of chili peppers. In this original report we PCR amplified, cloned, sequenced and characterized the 5S rDNA non-transcribed spacer -NTS- in 23 taxa of nine clades of Capsicum, divergent at geographical origin and fruit and chromosome traits, and compared the NTS features throughout Solanaceae. According to GC content, inner variability and regulatory elements, the NTS organizes into three distinct structural regions; genetic variability at the NTS in Capsicum and related genus clusters into defined taxa hierarchies. Based on the reconstruction of a maximum-likelihood phylogenetic tree and phylogenetic networks, NTS sequences of Capsicum and related taxa grouped into well recognized categories -genus, section, clade, species, variety-. An evolutionary scenario arose from combined genetic and phylogenetic NTS data, in which monophyly and lineage diversification over time of Capsicum are addressed. Our analysis is original to include all domesticated species of Capsicum prevailing in germplasm collections and breeding programs, together with a large group of wild taxa that demanded further genetic characterization. The NTS set up as a double purpose marker in Capsicum, to directly evaluate genetic variability and reconstruct phylogenetic relationships to a broad extent, and constitutes a valuable tool for germplasm characterization and evolutionary studies within Solanaceae.Capsicum incluye ca. 41 especies de ajíes. En este trabajo original, el espaciador no-transcrito (NTS) del ADNr 5S fue PCR-amplificado, clonado, secuenciado y caracterizado en 23 taxones de nueve clonados de Capsicum, divergentes en origen, fruto y cromosomas, y comparado a lo largo de Solanaceae. El NTS se organiza en tres regiones estructurales distintas de acuerdo a contenido GC, variabilidad y elementos reguladores; la variabilidad genética del NTS en Capsicum y géneros relacionados se agrupó en categorías taxonómicas definidas. Las secuencias NTS de Capsicum y taxa relacionados también se agruparon en categorías reconocidas -género, sección, clonado, especie, variedad- durante la reconstrucción de un árbol filogenético de máxima-verosimilitud y diversas redes filogenéticas. De la combinación de datos genéticos y filogenéticos del NTS surge un escenario evolutivo que considera monofilia y diversificación de Capsicum a lo largo del tiempo. Nuestro análisis es original al incluir todas las especies domesticadas de Capsicum, mayoritarias en colecciones y programas, además de un amplio número de ajíes silvestres que demandaban mayor caracterización genética. El NTS constituye un marcador de doble propósito en Capsicum, al evaluar directamente variabilidad genética y reconstruir relaciones filogenéticas extensas, además de ser útil a la caracterización de germoplasma y estudios evolutivos en Solanaceae.Instituto de Patología VegetalFil: Grabiele, Mauro. Universidad Nacional de Misiones, Instituto de Biología Subtropical. Instituto de Biotecnología Misiones; ArgentinaFil: Aguilera, Patricia Mabel. Universidad Nacional de Misiones, Instituto de Biología Subtropical. Instituto de Biotecnología Misiones; ArgentinaFil: Ducasse, Daniel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Debat, Humberto Julio. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentin