Relationship between microbial functions and community structure following agricultural intensification in South American Chaco

Intensification of agricultural systems through the use of intensive agriculture and the advance of deforestation have led to a decrease of soil biological quality. Soil functional and structural microbiota are sensitive parameters to monitor changes caused by agricultural use. Different sites under soybean monoculture (continuous soybean) and soybean/maize rotation practices were selected. Samples were collected from agricultural soils under different periods of implantation: 4-year rotation; 15-year rotation; 5-year monoculture; and 24-year monoculture (M24). A site of native vegetation recently under agricultural production (RUA) was also sampled. Native vegetation soils (NV) adjacent to agricultural sites were sampled as a control. In general, the results showed that RUA and M24 had lower enzyme activities, less microbial abundance and low physical and chemical soil quality than those subjected to crop rotation. In contrast, both the bacterial and total microbial biomasses were significantly higher in NV and crop rotation than in soils under monoculture systems. Although it was expected that differences in microbial activities would be due to changes in microbial community abundance, the results indicated that changes in soil management produced faster alterations to soil enzyme activities than any modifications induced in the microbial community structure. Consequently, both aspects of microbial diversity, namely function and structure, were affected independently by agricultural intensification.EEA SaltaFil: Perez Brandan, Carolina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Huidobro, Dina Jorgelina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Galvan, Marta Zulema. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Vargas Gil, Silvina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Patología Vegetal; ArgentinaFil: Meriles, Jose Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Survey for major grapevine viruses in commercial vineyards of Northwestern Argentina

This study aimed to survey the occurrence of eight grapevine viruses in commercial vine yards located in the Calchaquíes Valleys in the northwest region of Argentina. A total of 103 samples of mature canes of vines showing either none or some viral-like symptoms were randomly collected. The samples were tested by RT-PCR/PCR-based assays for the screening of the following viruses: Grapevine fanleaf virus (GFLV), Grapevine leafroll-associated viruses (GLRaV-1, -2, -3, -4), Grapevine virus A (GVA), Grapevine rupestris stem pitting-associated viruses (GRSPaV), and Grapevine red blotch virus (GRBV). Sixty percent of the analyzed samples showed infection with some of the analyzed viruses, except GRBV. GLRaV-3 and GFLV were the most frequent viruses, present in 34% and 21% of the pos itive samples, respectively. This study represents the first survey report of the presence of grapevine viruses in the region of the Calchaquíes Valleys and contributes to the knowledge to maintain the sanitary status of commercial vineyards in Argentina.EEA SaltaFil: Rivadeneria, Monica. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Galvan, Marta Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aban, Marina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Aban, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Semke, Rosa Elena. Centro de Desarrollo Vitícola del Valle Calchaquí; ArgentinaFil: Rivadeneria, Josefina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Rivadeneira, Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lanza Volpe, Melisa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Gomez Talquenca, Gonzalo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentin

Genetics and mapping of a new anthracnose resistance locus in Andean common bean Paloma

Background: The Andean cultivar Paloma is resistant to Mesoamerican and Andean races of Colletotrichum lindemuthianum, the fungal pathogen that causes the destructive anthracnose disease in common bean. Remarkably, Paloma is resistant to Mesoamerican races 2047 and 3481, which are among the most virulent races of the anthracnose pathogen. Most genes conferring anthracnose resistance in common bean are overcome by these races. The genetic mapping and the relationship between the resistant Co-Pa gene of Paloma and previously characterized anthracnose resistance genes can be a great contribution for breeding programs. Results: The inheritance of resistance studies for Paloma was performed in F2 population from the cross Paloma (resistant) × Cornell 49–242 (susceptible) inoculated with race 2047, and in F2 and F2:3 generations from the cross Paloma (resistant) × PI 207262 (susceptible) inoculated with race 3481. The results of these studies demonstrated that a single dominant gene confers the resistance in Paloma. Allelism tests performed with multiple races of C. lindemuthianum showed that the resistance gene in Paloma, provisionally named Co-Pa, is independent from the anthracnose resistance genes Co-1, Co-2, Co-3, Co-4, Co-5, Co-6, Co-12, Co-13, Co-14, Co-15 and Co-16. Bulk segregant analysis using the SNP chip BARCBean6K_3 positioned the approximate location of Co-Pa in the lower arm of chromosome Pv01. Further mapping analysis located the Co-Pa gene at a 390 kb region of Pv01 flanked by SNP markers SS82 and SS83 at a distance of 1.3 and 2.1 cM, respectively. Conclusions: The results presented here showed that Paloma cultivar has a new dominant gene conferring resistance to anthracnose, which is independent from those genes previously described. The linkage between the Co-Pa gene and the SS82 and SS83 SNP markers will be extremely important for marker-assisted introgression of the gene into elite cultivars in order to enhance resistance.EEA SaltaFil: Castro, Sandra Aparecida de Lima. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Gonçalves-Vidigal, Maria Celeste. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Gilio, Thiago Alexandre Santana. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Lacanallo, Giselly Figueiredo. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Valentini, Giseli. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Martins, Vanusa da Silva Ramos. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Qijian, Song. United States Department of Agriculture. Agricultural Research Service. Soybean Genomics and Improvement Laboratory; Estados UnidosFil: Galvan, Marta Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Hurtado-Gonzales, Oscar P. United States Department of Agriculture. Agricultural Research Service. Soybean Genomics and Improvement Laboratory; Estados UnidosFil: Pastor-Corrales, Marcial Antonio. United States Department of Agriculture. Agricultural Research Service. Soybean Genomics and Improvement Laboratory; Estados Unido

Population structure of the fungus Sclerotinia sclerotiorum in common bean fields of Argentina

S. sclerotiorum is the causal agent of the white mould disease on common bean crops, one of the most threatening fungal diseases occurring across major bean production regions. Currently, there are no commercial cultivars with high levels of genetic resistance to white mould. The aim of this study was to analyse the population structure of 109 isolates of S. sclerotiorum from six dry bean fields in the main production area of Argentina using nine microsatellite loci. A total of 30 multilocus haplotypes (MLHs) were identified, of which 18 MLHs were unique. The remaining 12 MLHs were constituted by 83% of the isolates, six MLHs of which (composed of 75 isolates) were shared at least between two locations. Population genetic structure analysis and discriminant analysis of principal components (DAPC) identified two genetic clusters (subpopulations). The genetic cluster 1 (GC 1) was composed of 21 isolates and 15 MLHs. Similarly, the genetic cluster 2 (GC 2) was composed of 23 isolates and 15 MLHs. These two genetic clusters were observed in most locations sampled. Low levels of genetic differentiation (ΦST = 0.198; P  1) between genetic clusters were observed. Linkage disequilibrium analysis showed that one of the two genetic subpopulations was under linkage equilibrium (P > 0.001), which is consistent with recombinant populations. These results suggest the occurrence of both modes of reproductive behaviour, clonal and recombining, compromising the durability of management strategies for white mould disease in common bean cultivars.EEA SaltaFil: Aban, Carla Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Aban, Carla Luciana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Taboada, Gisel María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Taboada, Gisel María. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Spedaletti, Yamila Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Spedaleti, Yamila Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Maita, Efraín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Maita, Efraín Universidad Nacional de Salta. Facultad de Ciencias Naturales. Laboratorio de Investigaciones Botánicas; ArgentinaFil: Galvan, Marta Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Galvan, Marta Zulema. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; Argentin

Population Structure and Genetic Diversity in Sweet Cassava Cultivars from Paraná, Brazil

The objectives of the present study were to assess the population structure and genetic diversity in traditional sweet cassava cultivars collected in “backyard” cultivations in the municipalities of Maringá, Cianorte, and Toledo, State of Paraná, Southern Brazil, using 13 SSR molecular markers. All the loci analyzed were considered polymorphic with a mean of 3.15 alleles per locus; the mean polymorphism information content (PIC) value found was 0.4598, indicating that the primers were reasonably informative and the heterozygosity amplitude observed ranged from 0.0270 (GA134) to 0.8718 (SSRY45), with a mean of 0.4762, while the mean genetic diversity obtained was 0.5407, ranging from 0.3138 (GA21) to 0.6502 (GA140). The most divergent combinations were BGM434T-BGM20M, BGM35C-BGM20M, BGM430T-BGM232M, BGM430T-BGM164M, BGM430T-BGM322M, and BGM35C-BGM164M. The analysis of population structure distributed the traditional cultivars assessed in four different groups. The analysis of molecular variance (AMOVA) estimated that 11, 15, and 74 % of the variance were between groups, between individuals within groups, and between individuals within the population as a whole, respectively. The F is (0.170) and F it (0.259) values indicated a number of heterozygotes present in the population under study lower than that necessary to reach the Hardy-Weinberg equilibrium. The genetic variability found among the traditional sweet cassava cultivars assessed was considered wide, and the groups that were most distant were mostly cultivars from Toledo and Maringá.EEA SaltaFil: Ortiz, Alex Henrique Tiene. Universidade Estadual de Maringá. Pós-Graduação em Genética e Melhoramento; BrasilFil: Rocha, Vanesca Priscila Camargo. Universidade Estadual de Maringá. Pós-Graduação em Genética e Melhoramento; BrasilFil: Moiana, Leonel Domingos. Universidade Estadual de Maringá. Pós-Graduação em Genética e Melhoramento; Brasil. Instituto de Investigação Agrária; MozambiqueFil: Vidigal, Maria Celeste Gonçalves. Universidade Estadual de Maringá. Pós-Graduação em Genética e Melhoramento; BrasilFil: Galvan, Marta Zulema. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina.Fil: Vidigal Filho, Pedro Soares. Universidade Estadual de Maringá. Pós-Graduação em Genética e Melhoramento; Brasi

Characterization of Fusarium species associated with tobacco diseases in Northwestern Argentina

Tobacco (Nicotiana tabacum L.) production is centred in the northwestern region of Argentina (NWA), where the incidence of root rot and stem diseases has increased considerably in recent years. This study aimed to analyse the genetic, morphological and pathogenic diversity of the Fusarium oxysporum and F. solani complexes (hereafter FOSC-FSSC), causing Fusarium wilt and root rot. One hundred tobacco fields were surveyed at six locations during two consecutive seasons, and 130 isolates were recovered from symptomatic tobacco plants. The isolates were characterized by morphological traits, molecular characteristics (EF1-α sequence) and pathogenicity tests. All of the isolates were identified as members of the FOSC or FSSC, exhibiting considerable intra-group variation. Three morphotypes were differentiated based on morphological characters in both complexes. The phylogenetic tree generated from the EF1-α sequences confirmed the isolates’ identification. The pathogenicity of the isolates towards tobacco seedlings was assessed in a greenhouse. Considerable variability in pathogenicity was observed among the isolates. Differences in the levels of pathogenicity were recorded. In the FOSC and FSSC, 81% and 60% of the isolates were pathogenic, respectively. In this study, members of FOSC and FSSC exhibited considerable variability in morphological characteristics and virulence, and a portion of them were non-pathogenic for tobacco. To the best of our knowledge, this study is the first to provide information on the variability of the pathogens associated with tobacco wilt and root rot in NWA. This work contributes to the development of sustainable management strategies in tobacco production.EEA SaltaFil: Berruezo, Lorena Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Mercado Cardenas, Guadalupe Eugenia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Harries, Eleonora Del Milagro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Stenglein, Sebastian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biologia Funcional y Biotecnología; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomia; ArgentinaFil: Curti, Ramiro Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Rodriguero, Marcela Silvina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Galvan, Marta Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; Argentin

Molecular, morphological and pathogenic diversity of Sclerotinia sclerotiorum isolates from common bean (Phaseolus vulgaris) fields in Argentina

White mould, caused by Sclerotinia sclerotiorum, is one of the most threatening fungal diseases occurring across major bean production regions worldwide. In Argentina, under favourable weather conditions, up to 100% seed yield losses occur on susceptible common bean cultivars. The aim of this study was to characterize the diversity of S. sclerotiorum isolates from six dry bean fields in the main production area of Argentina by means of molecular, morphological (mycelium colour, number and pattern of sclerotia distribution) and pathogenic approaches. Among 116 isolates analysed, high genotypic and morphological variability was observed. A total of 52 mycelial compatibility groups (MCGs) and 59 URPs (universal rice primers) molecular haplotypes were found. All the MCGs were location specific, while only 12% of the URP haplotypes were shared among locations. The molecular analysis of variance revealed a significant differentiation among populations, with higher genetic variability within the populations analysed than among them. The aggressiveness of the isolates towards bean seedlings was assessed in the greenhouse. Most of the isolates were highly aggressive, while no variation among locations was observed. The information generated in the present study provides, for the first time, information on the variability of S. sclerotiorum associated with white mould in the main common bean production area in Argentina. In addition, the findings suggest the occurrence of both clonal and sexual reproduction in the populations analysed. This work contributes to the development of sustainable managemeEEA SaltaFil: Aban, Carla Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Taboada, Gisel María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Spedaletti, Yamila Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Aparicio, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Curti, Ramiro Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Casalderrey, Norma Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Maggio, Maria Elisa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Chocobar, Mario Osvaldo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Salgado, M. Actividad Privada; ArgentinaFil: Galvan, Marta Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; Argentin

Genetic characterization and pathogenicity of Rhizoctonia solani associated with common bean web blight in the main bean growing area of Argentina

Common bean web blight (WB), caused by the fungus Rhizoctonia solani (teleomorph Thanatephorus cucumeris), is among the endemic fungal diseases of major impact in north‐western Argentina (NWA). This study aimed to analyse the genetic and pathogenic diversity of R. solani in Salta, NWA, where 97 isolates were recovered from commercial bean cultivars and wild beans showing WB symptoms in a major bean production area. The isolates were characterized on the basis of specific primers, rDNA‐ITS sequences and morphological characteristics. All the isolates were identified as R. solani AG 2‐2WB, and they exhibited considerable intragroup variation. The phylogenetic tree generated with the ITS sequences confirmed the isolates identification. Aggressiveness of the isolates towards bean seedlings was assessed in the greenhouse. A great variability in virulence was observed among the isolates analysed. On the basis of the disease reaction on foliar tissues, the isolates were grouped into three virulence categories as follows: weakly virulent (30%), moderately virulent (38%) and highly virulent (32%). However, no correlation between virulence and geographical origin was detected. The information generated in this study provides initial data on the population variability of the WB pathogen in north‐western Argentina and represents a valuable contribution to regional breeding programmes aimed to obtain cultivars with durable resistance.EEA SaltaFil: Spedaletti, Yamila Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Aparicio Gonzalez, Monica Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Mercado Cardenas, Guadalupe Eugenia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Rodriguero, Marcela Silvina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina.Fil: Taboada, Gisel María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Aban, Carla Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Sühring, Silvia Susana. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Vizgarra, Oscar N. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Galvan, Marta Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; Argentin