Detection of Plasmopara halstedii in sunflower seeds: A case study using molecular testing

Plasmopara halstedii (Farl.) Berl. & De Toni causing downy mildew of sunflower is responsible for considerable economic losses worldwide. Because P. halstedii can be seed-transmitted, monitoring of seeds for pathogen contamination is important for the sunflower seed trade. The relevance of asymptomatic or latent infections as factors of disease spread have not been studied by molecular techniques. A molecular marker based on a putative effector gene of P. halstedii was used to examine the pathogen´s presence in asymptomatic sunflowers growing near patches of mildewed plants in naturally infected fields. The method based on conventional PCR was highly sensitive for detection of P. halstedii in DNA from whole seeds. By the application of this protocol, we found that all seed samples obtained from symptomatic plants amplified the expected fragment, whereas the diagnostic marker identified the presence of pathogen in one out of 21 asymptomatic plants. Possible uses of this marker to detect downy mildew in seed from asymptomatic plants or for race identification are discussed.Fil: Martínez, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Quiroz, Facundo José. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Balcarce; ArgentinaFil: Carrera, Alicia Delia. Universidad Nacional del Sur. Departamento de Agronomía; Argentin

Control de la floración y tolerancia al frío: vernalización en cereales

La disminución de la tolerancia al frío en etapa reproductiva está relacionada con la expresión del gen de vernalización VRN-1, indicando una conexión entre los procesos de aclimatación al frío y floración.Fil: Basualdo, Jessica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Díaz, Marina. Universidad Nacional del Sur; ArgentinaFil: Echenique, Carmen Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Carrera, Alicia Delia. Universidad Nacional del Sur; Argentin

Effect of pollination mode on progeny of Panicum coloratum var. makarikariense: Implications for conservation and breeding = Efecto del modo de polinización sobre la progenie de Panicum coloratum var. makarikariense: Implicaciones para conservación y fitomejoramiento

Panicum coloratum var. makarikariense, a perennial grass native to Africa, is adapted to a wide range of soil and climatic conditions with potential to be used as forage in tropical and semi-arid regions around the world. Our objective was to understand how the pollination mode affects viable seed production and further survival of the progeny. We evaluated self- and open-pollinated progenies from different accessions by measuring the seed production of the parents and their germination performance, germination rate and seedling survival. Parents and progeny were also fingerprinted with Simple Sequence Repeats (SSR). Progeny produced through open-pollination resulted in significantly more filled seeds and superior seedling survival than self-pollination. These results indicate that accessions studied here rely heavily on cross-pollination, whereas the contribution of self-pollinated offspring to the population is likely to be low. SSR profiles showed that, on average, 85% of the progeny (arising from cross-pollination) possessed paternal specific markers and 100% of them were genetically different from the maternal genotype. All plants examined had 4x = 36 chromosomes. Overall, our findings indicate that var. makarikariense is able to generate highly polymorphic progeny through segregation and recombination. This study provides reference information for the formulation of appropriate strategies for pasture germplasm management, conservation and development of breeding programs.Panicum coloratum var. makarikariense es una gramínea perenne nativa de África. Se adapta a un amplio rango de ambientes y posee uso potencial como forraje en distintas regiones tropicales y semiáridas del mundo. El estudio tuvo como objetivo evaluar el efecto del modo de polinización sobre la producción de semilla viable y la supervivencia de la progenie. Se evaluaron progenies de autopolinización y de polinización cruzada en diferentes accesiones midiendo la producción de semillas, germinación, tasa de germinación y supervivencia de plántulas, y se obtuvieron perfiles moleculares con Secuencias Simples Repetidas (SSR). La progenie obtenida mediante polinización cruzada mostró significativamente mayor producción de semillas llenas y supervivencia de plántulas que la de autopolinización. Esto indica que las accesiones evaluadas dependen en gran medida de la alogamia y que la contribución de la descendencia por autofertilización a la población sería escasa. Los perfiles moleculares SSR mostraron que, en promedio, 85% de la progenie (obtenida a partir de polinización cruzada) presentó marcadores específicos paternos y 100% de ella difirió del genotipo materno. Todas las plantas examinadas presentaron 4x = 36 cromosomas. En conjunto, los resultados indican que la var. makarikariense puede generar progenie altamente polimórfica a través de la segregación y recombinación. Este estudio provee información útil para el diseño de estrategias de conservación, manejo del germoplasma y programas de mejoramiento.EEA RafaelaFil: Armando, Lorena Vanesa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Tomas, Maria Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Garayalde, Antonio Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Matemática; ArgentinaFil: Carrera, Alicia Delia. Universidad Nacional del Sur. Departamento de Agronomía; Argentin

Genetic characterization of Plasmopara halstedii populations in Argentina using simple sequence repeats (SSR) and effectorbased markers

Argentina is the fourth leading producing country of sunflower worldwide. Sunflower downy mildew, caused by the pathogenPlasmopara halstedii, is an economically important disease of sunflower. Since 2012, P. halstedii epiphytotics were identified inseveral production regions of Argentina. However, the genetic diversity of the pathogen in Argentina remains largely unknown. Fortytwofield isolates from Argentina were analyzed using eight loci SSR. The number of alleles per locus (APL), the expected (HE) andobserved heterozygosity (HO) were determined. SSR data were analyzed with regions (two), collection years (four) and races (six) asvariation sources (AMOVA), and the population structure was defined (Bayesian method). DNA sequences of two effector genes wereobtained from two isolates per race and the polymorphisms were analyzed (ClustalW). The mean APL was 2.6, varying from 1 to 4(total 21). The highest number of alleles and races were found in 2017. Average HO and HE were 0 and 0.369, respectively. Geneticvariation was observed among regions (7%) and years (32%), but not between races. Based on effectors, local races were similar to agroup of French races, without variation within the ARG races. Increased genetic variability observed in recent years seems to parallelwith the emergence of novel races reducing fungicides and/or R genes efficacy. The effector study suggests that the races evolutiondepends on country specific factors.Fil: Martínez, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. North Dakota State University; Estados UnidosFil: Garayalde, Antonio Francisco. Universidad Nacional del Sur. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Quiroz, Facundo José. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Carrera, Alicia Delia. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaAmerican Phytopathological Society North Central Division Meeting​IowaEstados UnidosAmerican Phytopathological Societ

QTL analysis of main and epistatic effects for flour color traits in durum wheat

The aim of this work was to map quantitative trait loci (QTLs) associated with flour yellow color (Fb*) and yellow pigment content (YPC) in durum wheat (Triticum turgidum L. var. durum). Additionally, QTLs affecting flour redness (Fa*) and brightness (FL*) color parameters were investigated. A population of 93 RILs (UC1113 × Kofa) was evaluated in three locations of Argentina over 2 years. High heritability values (>94%) were obtained for Fb* and YPC, whereas FL* and Fa* showed intermediate to high values. The main QTLs affecting Fb* and YPC overlapped on chromosome arms 4AL (4AL.2), 6AL (6AL.2), 7AS, 7AL, 7BS (7BS.2) and 7BL (7BL.2). The 7BL.1 QTL included the Psy-B1 locus, but one additional linked QTL was detected. A novel minor QTL located on 7AS affected Fb*, with an epistatic effect on YPC. An epistatic interaction occurred between the 7AL and 7BL.2 QTLs. The 4AL.2 QTL showed a strong effect on Fb* and was involved in two digenic epistatic interactions. The 6AL.2 QTL explained most of the variation for Fb* and YPC. The main QTLs affecting FL* and Fa* were located on 2BS and 7BL, respectively. These results confirm the complex inheritance of flour color traits and open the possibility of developing perfect markers to improve pasta quality in Argentinean breeding programsFil: Roncallo, Pablo F. CERZOS-Consejo Nacional de Investigaciones Científicas y Técnicas/UNS. CCT. Laboratorio de Biotecnología Vegetal; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Cervigni, Gerardo. CEFOBI-Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jensen, Carlos Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Barrow; ArgentinaFil: Miranda, Rubén. Asociación de Cooperativas Argentinas; ArgentinaFil: Carrera, Alicia Delia. CERZOS-Consejo Nacional de Investigaciones Científicas y Técnicas/UNS. CCT. Laboratorio de Biotecnología Vegetal; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Helguera, Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; ArgentinaFil: Echenique, Carmen Viviana. CERZOS-Consejo Nacional de Investigaciones Científicas y Técnicas/UNS. CCT. Laboratorio de Biotecnología Vegetal; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; Argentin

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Genetic diversity in wild apple (Malus sp.) populations in Argentina

In Argentina, wild apple trees are distributed in the western areas of Neuquén province, along the Andean low hillsides. A collection of 23 wild populations was investigated with RAPD primers to evaluate variability and genetic relationships. The data were analyzed by multivariate analysis. A low germplasm variability of 0.115 was estimated with Nei’s genetic diversity index. Cluster and principal coordinate analyses did not reveal distinct geographic patterns or strong grouping among individuals of the same origin, but there was a clear partition between wild and cultivated materials. AMOVA showed the largest level of diversity within populations (57%). A strong human influence seems to have shaped wild apple distribution.Fil: Calvo, Paula. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Carrera, Alicia Delia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Sanchez, Enrique. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Poverene, María Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; Argentin

Collection and morphological characterization of Panicum coloratum L. in Argentina

Panicum coloratum (Poaceae) is a perennial grass native to South Africa, distributed all over the world, but poorly adopted by ranchers in Argentina. Adapted to a wide range of soil and climatic conditions, it constitutes a good forage resource for zones with edaphic and climatic restrictions, where cattle rising activities are here displaced. The high polymorphism in the species has made it difficult to delineate sub specific taxonomic categories. It has been classified in botanical varieties, types and/or cultivars. In order to document the morphological variability in P. coloratum and to investigate the differences between var. makarikariense and var. coloratum, a collection was gathered in INTA Rafaela composed by fourteen accessions from different provinces of Argentina: six accessions of var. makarikariense and eight from var. coloratum. The evaluation of 152 individuals gives evidence of a wide morphological variation in the collection in traits related to forage and caryopses production; seven out of nine traits showed significant differences between var. makarikariense and var. coloratum. Based on the study of local type specimens, a morphological key to distinguish between P. coloratum varieties is provided. These results report new information about the diversity in P. coloratum in Argentina and provide valuable insights for future use of the collection as the base material of a breeding program.EEA RafaelaFil: Armando, Lorena Vanesa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carrera, Alicia Delia. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Tomas, Maria Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentin

Identification of genes induced by Fusarium graminearum inoculation in the resistant durum wheat line Langdon(Dic-3A)10 and the susceptible parental line Langdon

The wheat recombinant chromosome inbred line LDN(Dic-3A)10, obtained through introgression of a Triticum dicoccoides disomic chromosome 3A fragment into Triticum turgidum spp. durum var. Langdon, is resistant to fusarium head blight (FHB) caused by Fusarium graminearum. To identify genes involved in FHB resistance, we used a cDNA-AFLP approach to compare gene expression between LDN(Dic-3A)10 and the susceptible parental line LDN at different time points post-inoculation. In total, 85 out of the ∼500 transcript-derived fragments (TDFs) were found to be differentially expressed: 36 and 19% were upregulated in LDN(Dic-3A)10 and LDN, respectively, whereas 45% were induced in both genotypes. Several of the cloned TDFs showed similarity to proteins involved in specific recognition of plant pathogens or associated with early responses to infection. Some TDFs specific to the inoculation response did not show similarity to characterized proteins. The availability of T. aestivum genome sequences allowed the in silico mapping of 28 TDFs and the acquirement of the corresponding gene sequences and, in some cases, their regulatory regions. Analysis of promoter regions revealed the potential existence of shared transcription regulation mechanisms. For instance, three TDF-associated genes contained binding sites for WRKY transcription factors, which have been implicated in the regulation of genes associated with pathogen defense, and three for abscisic acid-responsive element (ABRE). Collectively, our results revealed specific pathogen recognition in the interactions of LDN and LDN(Dic-3A)10 with F. graminearum. Such recognition leads to changes in the expression of several transcripts, attributable to the presence of the wheat QTL Qfhs.ndsu-3AS.Fil: Soresi, Daniela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); ArgentinaFil: Carrera, Alicia Delia. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Echenique, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Garbus, Ingrid. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Universidad Nacional del Sur; Argentin

Assessing the genetic diversity of Panicum coloratum var. makarikariense using agro‐morphological traits and microsatellite‐based markers

Panicum coloratum var. makarikariense is a perennial C4 grass native to South Africa with relatively good forage production under limited‐resource conditions. Genetic characterisation and breeding efforts have been scant, thus limiting its use in cattle raising systems. The goal of the present study was to assess the genetic diversity of a collection of P. coloratum var. makarikariense using agro‐morphological traits and molecular markers, in comparison with one accession of var. coloratum and one population of Panicum bergii. Agro‐morphological variability between and within accessions of var. makarikariense in a common garden setting was observed, showing that there is still opportunity for selection. Some accessions performed better than the commercialised material in relation to potential forage production. A total of 117 ISSR bands and 48 SSR alleles allowed the detection of genetic variability between and within accessions. The presence of accession‐specific bands suggested distinctness and limited gene flow. The genetic variability encountered in the commercialised material suggested that it is a stabilised population which has not undergone a strong selection process. Low correlation between agro‐morphologic and molecular variability was observed indicating that both approaches provide complementary information. Both morphological and molecular markers reveal genetic differentiation between varieties and species. This study provides a set of new SSR markers available for diversity assessment and valuable information that can be applied directly in collection management for breeding and conservation programmes.EEA RafaelaFil: Armando, Lorena Vanesa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Tomas, Maria Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Garayalde, Antonio Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Matemática; ArgentinaFil: Carrera, Alicia Delia. Universidad Nacional del Sur. Departamento de Agronomía; Argentin