Alternative products to control late season diseases in soybeans / Produtos alternativos para o controle de doenças de final de ciclo na soja

In the last crop seasons, the complex of late season diseases (CLSD) of soybean (Glycine max L. (Merrill)), has been causing considerable reductions in the crop yield. Currently, there are no cultivars resistant to all pathogens that causes CLSD. The present study evaluated the effect of applying the acibenzolar-S-methyl resistance inducer, alternative products and fungicide on the severity of CLSD in the soybean cultivar BMX Potência RR during the 2013/2014 and 2014/2015 crops, in the field. The treatments for the experiments were: 1 - control (water); 2 - acibenzolar-S-methyl; 3 - calcium; 4 - micronutrients: copper, manganese and zinc; 5 - micronutrients: manganese, zinc and molybdenum; 6 - nitrogen-potassium fertilizer; 7 - Ascophyllum nodosum and 8 - azoxystrobin + cyproconazole with the addition of the adjuvant. Four applications of alternative products and two of fungicide were carried out in both harvests. A diagrammatic scale assessed the severity of CLSD at the phenological stage R7.1. The acibenzolar-S-methyl resistance inducer, alternative products (macro and micronutrients) and A. nodosum had no effect on the severity of CLSD in the two harvests. The fungicide (azoxystrobin + cyproconazole) reduced the severity of CLSD and prevented damage to productivity in both experiments.

Nas últimas safras, o complexo de doenças de final de ciclo (DFC) da soja (Glycine max L. (Merrill)), vem provocando reduções consideráveis no rendimento da cultura. Atualmente, não há variedades resistentes a todos os patógenos causadores das DFC. O objetivo do presente trabalho foi avaliar o efeito da aplicação do indutor de resistência acibenzolar-S-methyl, produtos alternativos e fungicida na severidade de DFC na cultivar de soja BMX Potência RR durante as safras 2013/2014 e 2014/2015, em campo. Os tratamentos para os experimentos foram: 1 - testemunha (água); 2 - acibenzolar-S-methyl; 3 - cálcio; 4 - micronutrientes: cobre, manganês e zinco; 5 - micronutrientes: manganês, zinco e molibdênio; 6 - adubo NK; 7 - Ascophyllum nodosum e 8 - azoxistrobina + ciproconazol com adição do adjuvante. Foram realizadas quatro aplicações dos produtos alternativos e duas do fungicida, nas duas safras. A severidade de DFC foi avaliada por escala diagramática no estádio fenológico R7.1. O indutor de resistência acibenzolar-S-methyl, os produtos alternativos (macro e micronutrientes) e A. nodosum não apresentaram efeito sobre a severidade das DFC nas duas safras. O fungicida (azoxistrobina + ciproconazol) reduziu a severidade das DFC e evitou danos a produtividade nos dois experimentos.

Identification and recombinant expression of an antimicrobial peptide (cecropin B-like) from soybean pest Anticarsia gemmatalis

Insects can be found in numerous diverse environments, being exposed to pathogenic organisms like fungi and bacteria. Once these pathogens cross insect physical barriers, the innate immune system operates through cellular and humoral responses. Antimicrobial peptides are small molecules produced by immune signaling cascades that develop an important and generalist role in insect defenses against a variety of microorganisms. In the present work, a cecropin B-like peptide (AgCecropB) sequence was identified in the velvetbean caterpillar Anticarsia gemmatalis and cloned in a bacterial plasmid vector for further heterologous expression and antimicrobial tests. Methods AgCecropB sequence (without the signal peptide) was cloned in the plasmid vector pET-M30-MBP and expressed in the Escherichia coli BL21(DE3) expression host. Expression was induced with IPTG and a recombinant peptide was purified using two affinity chromatography steps with Histrap column. The purified peptide was submitted to high-resolution mass spectrometry (HRMS) and structural analyses. Antimicrobial tests were performed using gram-positive (Bacillus thuringiensis) and gram-negative (Burkholderia kururiensis and E. coli) bacteria. Results AgCecropB was expressed in E. coli BL21 (DE3) at 28°C with IPTG 0.5 mM. The recombinant peptide was purified and enriched after purification steps. HRMS confirmed AgCrecropB molecular mass (4.6 kDa) and circular dichroism assay showed α-helix structure in the presence of SDS. AgCrecropB inhibited almost 50% of gram-positive B. thuringiensis bacteria growth. Conclusions The first cecropin B-like peptide was described in A. gemmatalis and a recombinant peptide was expressed using a bacterial platform. Data confirmed tertiary structure as predicted for the cecropin peptide family. AgCecropB was capable to inhibit B. thuringiensis growth in vitro.(AU)

Screening of Beneficial Microorganisms to Improve Soybean Growth and Yield

Abstract The objective of this research was to identify the best microorganisms, alone or in mixture for total biomass gain (root + shoot), positive change in gas exchange, nutrient uptake (root, shoot and grain) and yield and yield components in the soybean crop. Trial under greenhouse conditions had the experimental design in a completely randomized scheme with 26 treatments and four replicates. The treatments consisted of the rhizobacteria BRM 32109, BRM 32110 and 1301 (Bacillus sp.), BRM 32111 and BRM 32112 (Pseudomonas sp.), BRM 32113 (Burkholderia sp.), BRM 32114 (Serratia sp.), Ab-V5 (Azospirillum brasilense) and 1381 (Azospirillum sp.), and the fungus Trichoderma asperellum (a mix of the isolates UFRA.T06, UFRA.T09, UFRA.T12 and UFRA.T52). Besides, the same isolates were combined in pairs, completing 16 combinations. Control treatments received no microorganism. Microorganisms applied isolated or in combination, provided biomass gain, positive gas exchange, increases in nutrients uptake at the shoot and grain, and improved grain yield and its components than control plants. Stood out the combination Ab-V5 + T. asperellum pool, which provided a 25% improvement in grain yield.

Newly Isolated Penicillium sp. for Cellulolytic Enzyme Production in Soybean Hull Residue

Abstract (1) Background: The aim of this study was to evaluate the production and partial characterization of xylanase and avicelase by a newly isolated Penicillium sp. in solid-state fermentation, using soybean hulls as substrate. (2) Methods: Temperature, time, number of spores, and substrate moisture on xylanase and avicelase bioproduction were evaluated, maximizing activity with 30°C, 1x106 spores/g substrate, 14 and 7 days of fermentation with 70 and 76% substrate moisture contents, for xylanase and avicelase, respectively. (3) Results: Different solvents, temperatures, and agitation in the enzymatic extraction were evaluated, obtaining higher activities, 430.77 and 26.77 U/g for xylanase and avicelase using 30 min extraction and 0.05 M citrate buffer solution (pH 4.5 ), respectively at 60°C and 175 rpm and 50°C and 125 rpm. The optimum pH and temperature for enzymatic activity determination were 5.3 and 50°C. Enzyme extract stability was evaluated, obtaining higher stability with pH between 4.5 and 5.5, higher temperature of up to 40°C. The kinetic thermal denaturation (Kd), half-life time, D-value, and Z-value were similar for both enzymes. The xylanase Ed value (89.1 kJ/mol) was slightly lower than the avicelase one (96.7 kJ/mol), indicating higher thermostability for avicelase. (4) Conclusion: In this way, the production of cellulases using alternative substrates is a way to reduce production costs, since they represent about 10% of the world demand of enzymes, with application in animal feed processing, food production and breweries, textile processing, detergent and laundry production, pulp manufacturing and the production of biofuels.

Multivariate optimization of Staphylococcus xylosus AD1biomass production using sugarcane molasses plus yeast extract and soybean meal

Staphylococcus xylosusis a microorganism that has important physiological and technological characteristics that make it suitable for use as a starter culture in fermented meat products. For the development of these products in the food industry, it is necessary to produce biomass by the multiplication of starter cultures using low-cost media. This study developed a culture medium based on sugarcane molasses (SCM) supplemented with yeast extract (YE) and soybean meal (SM) to produce S. xylosusAD1 biomass employing a Box Behnken multivariateoptimization design,usingthe best concentrations of the constituents of the culture medium for S. xylosusAD1 growth. By combining the mathematical models by the desirability function, it was possible to establish the optimal condition for the maximum production of viable cells and biomass. The optimal experimental condition was found when the fermentative process medium was composed of 10% SCM, 2% YE and 4% SM. In addition, the results of all experiments, except for the medium formulated with only SCM,presented a better performance than the commercial medium Brain Heart Infusion for the growth of S. xylosusAD1. The culture medium with agro-industrial byproduct (SCM) supplemented with YE and SM is an excellent alternative for producing S. xylosusAD1 biomass.

Combining Ability for Resistance to White Mold in a Diallel Cross of Soybean

Abstract The white mold, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is one of the most important diseases of soybean. The objective of the present work was to evaluate the soybean reaction to the fungus S. sclerotiorum, which causes white mold, in a partial diallel with 50 crosses. The Group I of parents was composed of ten experimental lines with high grain yield and the group II consisted in five genotypes with possible resistance to white mold. Ten plants of each cross in the F4 generation and the parents were evaluated for reaction to fungus infection using the method of inoculation in detached leaves in order to assess the severity of the disease and to later estimate the combining abilities. Estimates of the specific combining ability (SCA) was a significant reaction to S. sclerotiorum, indicating that there is variability for fungus resistance due to non-additive genes action.

Antagonistic endophytic bacteria associated with nodules of soybean (Glycine max L. ) and plant growth-promoting properties

Abstract A total of 276 endophytic bacteria were isolated from the root nodules of soybean (Glycine max L.) grown in 14 sites in Henan Province, China. The inhibitory activity of these bacteria against pathogenic fungus Phytophthora sojae 01 was screened in vitro. Six strains with more than 63% inhibitory activities were further characterized through optical epifluorescence microscopic observation, sequencing, and phylogenetic analysis of 16S rRNA gene, potential plant growth-promoting properties analysis, and plant inoculation assay. On the basis of the phylogeny of 16S rRNA genes, the six endophytic antagonists were identified as belonging to five genera: Enterobacter, Acinetobacter, Pseudomonas, Ochrobactrum, and Bacillus. The strain Acinetobacter calcoaceticus DD161 had the strongest inhibitory activity (71.14%) against the P. sojae 01, which caused morphological abnormal changes of fungal mycelia; such changes include fracture, lysis, formation of a protoplast ball at the end of hyphae, and split ends. Except for Ochrobactrum haematophilum DD234, other antagonistic strains showed the capacity to produce siderophore, indole acetic acid, and nitrogen fixation activity. Regression analysis suggested a significant positive correlation between siderophore production and inhibition ratio against P. sojae 01. This study demonstrated that nodule endophytic bacteria are important resources for searching for inhibitors specific to the fungi and for promoting effects for soybean seedlings.

Validación de una técnica de Dot blot para la detección de Cercospora kikuchii en plantas de soja / Validation of the technique based on Dot blot for the detection of Cercospora kikuchii in soybean plants

Cercospora kikuchii, fitopatógeno usual en plantas de soja, ocasiona deterioro en la scosechas. Su identificación precoz y correcta evitaría el uso indebido de plaguicidas y permitiría iniciar un tratamiento adecuado. Una técnica rápida, económica y de fácil ejecución es el Dot blot, capaz de reconocer la presencia de una proteína específica del género conocida como CFP (Cercosporin Facilitator Protein). El objetivo de este trabajo fue validar dicha técnica para garantizar la fiabilidad del resultado. Para ello, se procesaron 29 plantas de soja infectadas y 31 plantas sanas teniendo en cuenta una confianza deseada del 95% y un error permitido del 5%. La técnica presentó una sensibilidad diagnóstica del 93,3% y una especificidad diagnóstica del 96,7%. La eficacia fue del 95% y los valores predictivos positivo y negativo del 96,6 y el 93,5%, respectivamente. Estos resultados la postulan como una herramienta útil para detectar precozmente c. kikuchii en plantas de soja.

Cercospora kikuchii is a common pathogen in soybean plants that causes crop spoilage. Its early and precise identification would prevent the misuse of pesticides and allow the initiation of an appropriate treatment. A quick, economical and easy-to-execute technique is the Dot blot, capable of recognizing the presence of a genus-specific protein called CFP (Cercosporin Facilitator Protein). The objective was to validate this technique to guarantee the reliability of the results. For that purpose, 29 infected soybean plants and 31 healthy plants were processed, taking into account a 95% desired confidence level and a permissible error of 5%. The technique provided a diagnostic sensitivity of 93.3% and a diagnostic specificity of 96.7%. The efficiency was 95% and positive and negative predictive values were 96.6% and 93.5%, respectively. These results postulate it as a useful resource for the early detection of C. kikuchii in soybean plants.

Fermentation profile and microbial population in soybean silages with inoculant and powdered molasses / Perfil fermentativo e população microbiana em silagens de soja com inoculante e melaço em pó

Fermentation profile and microbial population were assessed in soybean silages without any additive (control), with inoculant (I), with I + powdered molasses (I+M), and with powdered molasses only (M). Soybean plants were harvested at the R6 stage and ensiled in 2kg-capacity laboratory silos. The additives were added to the natural matter base of silages. The assessed fermentation periods were 1, 3, 7, 14, 28, and 56 days. A 4 × 6 factorial arrangement (4 additives × 6 fermentation periods) in a completely randomized design with 3 replicates was used. Lactic, acetic, and butyric acids concentrations were influenced by additives and periods (P< 0.05). It was observed higher lactic acid values to control silages, on the 56th day. Lower average values of acetic and butyric acids were observed to I+M and M silages. It was observed quadratic effect to pH values with a reduction estimated of 0.5504, 0.5358, 0.6312 and 0.6680 units to pH values to control, I, I+M, and M silages in the first 10 days. A maximum lactic acid bacteria population was observed at the 28th day of fermentation in silages with inoculant. The inoculant and powdered molasses improve the fermentation profile of soybean silages.(AU)

Avaliou-se o perfil fermentativo e a composição microbiana de silagens de soja sem aditivos (controle), com inoculante (I), com I + melaço em pó (I+M) e com melaço em pó (M). As plantas de soja foram colhidas no estádio R6 e ensiladas em silos laboratoriais com capacidade de 2kg. Os aditivos foram adicionados às silagens na matéria natural. Os períodos de fermentação avaliados foram: 1, 3, 7, 14, 28 e 56 dias. Utilizou-se um esquema fatorial 4 × 6 (quatro aditivos × seis períodos), em um delineamento completamente ao acaso, com três repetições. Observou-se efeito de aditivos e de período (P<0,05) sobre os ácidos láctico, acético e butírico. Foi constatado maior teor de ácido láctico na silagem controle aos 56 dias. Para os teores dos ácidos acético e butírico, registraram-se menores valores médios nas silagens I+M e M. Observou-se efeito quadrático para o pH das silagens, com estimativa de redução de pH nos primeiros 10 dias igual a 0,5504; 0,5358; 0,6312 e 0,6680 nas silagens controle, I, I+M e M, respectivamente. A máxima população de bactéria ácido-láctica foi observada aos 28 dias nas silagens inoculadas. O inoculante e o melaço em pó melhoram o perfil fermentativo de silagens de soja.(AU)

Inoculação de diferentes doses de Bradyrhizobium por cobertura e seu efeito na cultura da soja / Inoculation by different doses of Bradyrhizobium by side dressing and its effect on Soybean / Inoculación de diferentes dosis de Bradyrhizobium por cubierta y su efecto en la Cultura de la soja

A soja é a cultura que mais cresceu no Brasil, com grande destaque para o agronegócio. Sendo o nutriente mais requerido, o nitrogênio, torna se necessário muitas vezes a utilização de fertilizantes nitrogenados e como uma alternativa sustentável, recomenda-se a inoculação com Bradyrhizobium realizando desse modo a fixação biológica de nitrogênio. O objetivo deste estudo foi avaliar os benefícios da inoculação de Bradyrhizobium na cultura da soja, pela pulverização em cobertura, na nodulação, no desenvolvimento das plantas e na produtividade. Foram conduzidos quatro tratamentos com design inteiramente casualizado e com quatro repetições, sendo tratamento 1 (controle) isento de pulverização, o segundo com pulverização de 500 mL ha­1, o terceiro de 1000 mL ha­1 e o quarto de 1500 mL ha­1 do inoculante com Bradyrhizobium. O número de sacas ha­1 com a inoculação de Bradyrhizobium por pulverização de 1500 mL ha­1 foi de 59 sacas. Reificouse ainda, aumentos significativos (p ≤ 0,05), sendo de 180,65 para número de nódulos, 4,44 g planta­1 para massa seca dos nódulos, 17,30 g planta­1 para massa seca das raízes e de 64,33 g planta­1 para massa seca da parte aérea em comparação com o tratamento controle, evidenciando o maior rendimento de soja para este tratamento. Conclui-se, portanto que a inoculação da soja com 1500 mL ha­1 de Bradyrhizobium em pulverização por cobertura, é a mais eficiente diante dos parâmetros testados no desenvolvimento e produção da soja.(AU)

The cultivation of soybean has presented the greatest increase in Brazil, with strong emphasis on agribusiness. Since nitrogen is the most required nutrient, nitrogen fertilizers are sometimes necessary. As a sustainable alternative, the inoculation of Bradyrhizobium is recommended, which can perform the biological fixation of nitrogen. The objective of this study was to evaluate the benefits of Bradyrhizobium inoculation in soybean crop, by spraying on its side dressing, nodulation, plant development and on productivity. Four treatments were carried out with a completely randomized design with four replications. The first treatment was left spray-free, the second was sprayed with 500 mL ha­1, the third with 1000 mL ha­1, and the fourth with 1500 mL ha­1 of the Bradyrhizobium inoculant. A total of 59 bags ha­1 were harvested with the application of the inoculation of Bradyrhizobium by spraying 1500 mL ha­1, and significant increases (p ≤ 0.05) were observed, namely 180.65 nodules, 4.44 g plant­1 for nodule dry matter, 17.30 g plant­1 for root dry matter, and 64.33 g plant­1 for shoot dry matter when compared to the control treatment, evidencing the higher soybean yield for this treatment. It can be concluded that the inoculation of soybean with 1500 mL ha­1 Bradyrhizobium in spray by side dressing is the most efficient in the tested parameters for the development and production of soybean.(AU)

La soja es la cultura que más creció en Brasil, con gran destaque para el agronegocio. Con el nutriente más requerido el nitrógeno, se hace necesario a menudo la utilización de fertilizantes nitrogenados y como una alternativa sostenible, se recomienda la inoculación con Bradyrhizobium realizando de ese modo la fijación biológica de nitrógeno. El objetivo de este estudio fue evaluar los beneficios de la inoculación de Bradyrhizobium en el cultivo de la soja, la pulverización en cobertura, la nodulación, el desarrollo de las plantas y la productividad. Se realizaron cuatro tratamientos con diseño completamente casualizado y con cuatro repeticiones, siendo tratamiento 1 (control) exento de pulverización, el segundo con pulverización de 500 mL ha-1, el tercero de 1000 mL ha-1 y el cuarto de 1500 mL ha-1 del inoculante con Bradyrhizobium. El número de sacas ha-1 con la inoculación de Bradyrhizobium por pulverización de 1500 mL ha-1 fue de 59 sacas Se observaron también aumentos significativos (p ≤ 0,05), siendo de 180,65 para número de nódulos, 4,44 g planta-1 para masa seca de los nódulos, 17,30 g planta-1 para masa seca de las raíces y de 64,33 g planta-1 para masa seca de la parte aérea en comparación con el tratamiento control, evidenciando mayor rendimiento de soja para este tratamiento. Se concluye, por lo tanto, que la inoculación de la soja con 1500 mL ha-1 de Bradyrhizobium en pulverización por cubierta es la más eficiente, frente a los parámetros probados en el desarrollo y producción de la soja.(AU)

Endophytic fungi from selected varieties of soybean (Glycine max L. Merr.) and corn (Zea mays L.) grown in an agricultural area of Argentina / Hongos endófitos aislados de cultivares de soja (Glycine max L. Merr) y maíz (Zea mays L.) presentes en áreas agrícolas argentinas

Endophytic fungi are ubiquitous and live within host plants without causing any noticeable symptoms of disease. Little is known about the diversity and function of fungal endophytes in plants, particularly in economically important species. The aim of this study was to determine the identity and diversity of endophytic fungi in leaves, stems and roots of soybean and corn plants and to determine their infection frequencies. Plants were collected in six areas of the provinces of Buenos Aires and Entre Ríos (Argentina) two areas were selected for sampling corn and four for soybean. Leaf, stem and root samples were surface-sterilized, cut into 1 cm² pieces using a sterile scalpel and aseptically transferred to plates containing potato dextrose agar plus antibiotics. The species were identified using both morphological and molecular data. Fungal endophyte colonization in soybean plants was influenced by tissue type and varieties whereas in corn plants only by tissue type. A greater number of endophytes were isolated from stem tissues than from leaves and root tissues in both species of plants. The most frequently isolated species in all soybean cultivars was Fusarium graminearum and the least isolated one was Scopulariopsis brevicaulis. Furthermore, the most frequently isolated species in corn plants was Aspergillus terreus whereas the least isolated one was Aspergillus flavus. These results could be relevant in the search for endophytic fungi isolates that could be of interest in the control of agricultural pests.

Los hongos endófitos son ubicuos y se encuentran en el interior de los tejidos de las plantas de manera asintomática. Se sabe muy poco acerca de la diversidad y la función de estos hongos, particularmente en especies de importancia económica. El objetivo de este trabajo fue determinar la diversidad y la frecuencia de colonización de hongos endófitos en raíces, tallos y hojas de 2 variedades de maíz y de 4 variedades de soja; las muestras se tomaron de 6 áreas diferentes ubicadas en las provincias de Buenos Aires y Entre Ríos (Argentina). Con un bisturí estéril se obtuvieron porciones de 1 cm² de raíz, tallo y hoja, que fueron colocados en placas con agar papa dextrosa más antibiótico. Las especies de hongos fueron identificadas a partir de características morfológicas y moleculares. La colonización de hongos endófitos en soja estuvo influenciada por la variedad y por el tipo de tejido, en tanto que en el maíz solo hubo influencia del tipo de tejido. El mayor número de endófitos se encontró en los tallos de ambas especies. El aislamiento más frecuente en todas las variedades de soja fue Fusarium graminearum y el menos frecuente Scopulariopsis brevicaulis. En ambas variedades de maíz la especie con mayor frecuencia de aislamiento fue Aspergillus terreus y la de menor fue Aspergillus flavus. Estos resultados son relevantes para la búsqueda de especies de hongos endófitos que podrían ser de interés en el control de plagas agrícolas.

Manejo químico da ferrugem asiática da soja, baseado em diferentes métodos de monitoramento / Chemical management of the soybean asian rust based on different monitoring methods

O objetivo do trabalho foi determinar o momento ideal da aplicação dos fungicidas de ação preventiva, (Opera + Assist)* e (PrioriXtra + Nimbus)*, baseado na detecção inicial de primeiros esporos associado às condições ambientais, monitoramento climático e monitoramento convencional (após a detecção dos primeiros sintomas), verificando sua eficiência no controle da ferrugem asiática da soja. O trabalho foi desenvolvido na fazenda Escola da Universidade Estadual de Londrina, onde foram instalados coletores de esporos na área para detecção dos primeiros esporos e também se fez anotação das condições climáticas obtidas em estação metereológica. As aplicações foram feitas a 1, 7, 14 e 21 dias após detecção dos primeiros esporos, seguindo o monitoramento climático e monitoramento convencional. Foram avaliadas a porcentagem da área foliar infectada, desfolha e produtividade de grãos. Observou-se uma menor porcentagem de infecção foliar, quando os produtos foram aplicados logo no início da detecção dos primeiros esporos (1, 7 e 14 dias após detecção) e seguindo o monitoramento climático e, apesar do produto (PrioriXtra +Nimbus)* ter apresentado menores porcentagens de infecção foliar e desfolha quando aplicado nos diferentes momentos, observou-se que na produtividade de grãos não houve diferença entre os produtos testados.

The objective of this study was to determine the ideal time for the application of the fungicides of preventive action (Opera + Assist)* and (PrioriXtra + Nimbus)*, based on the initial detection of early spores associated with environmental conditions, climate monitoring and conventional monitoring (after the detection of the first symptoms), verifying their effectiveness in the control of Asian soybean rust. The study was conducted at the Londrina State University Experimental Station, where spore collectors were installed in the area for early detection of spores and the climate conditions were monitored in a climate station. The applications were made at 1, 7, 14 and 21 days after first detection of spores, according to the climate monitoring and conventional monitoring. Evaluations were made of the infected leaf area, defoliation and soybean yield. There was a lower percentage of leaf infection when the products were applied early in the detection of spores (1, 7 and 14 days after detection), and according to the climate monitoring. Moreover, despite that the product (Nimbus + PrioriXtra)* presented lower percentages of infected leaf and defoliation when applied at the different times, it was observed that in the final yield of the crop there was no difference between the products tested.

Genetic relatedness of Brazilian Colletotrichum truncatum isolates assessed by vegetative compatibility groups and RAPD analysis

The genetic variation among nine soybean-originating isolates of Colletotrichum truncatum from different Brazilian states was studied. Nitrate non-utilizing (nit) mutants were obtained with potassium chlorate and used to characterize vegetative compatibility reactions, heterokaryosis and RAPD profile. Based on pairings of nit mutants from the different isolates, five vegetative complementation groups (VCG) were identified, and barriers to the formation of heterokaryons were observed among isolates derived from the same geographic area. No complementation was observed among any of the nit mutants recovered from the isolate A, which was designed heterokaryon-self-incompatible. Based on RAPD analysis, a polymorphism was detected among the wild isolate C and their nit1 and NitM mutants. RAPD amplification, with five different primers, also showed polymorphic profiles among Brazilian C. truncatum isolates. Dendrogram analysis resulted in a similarity degree ranging between 0.331 and 0.882 among isolates and identified three RAPD groups. Despite the lack of a correlation between the RAPD analysis and the vegetative compatibility grouping, results demonstrated the potential of VCG analysis to differentiate C. truncatum isolates genotypically similar when compared by RAPD.

Evolutionary history of Phakopsora pachyrhizi (the Asian soybean rust) in Brazil based on nucleotide sequences of the internal transcribed spacer region of the nuclear ribosomal DNA

Phakopsora pachyrhizi has dispersed globally and brought severe economic losses to soybean growers. The fungus has been established in Brazil since 2002 and is found nationwide. To gather information on the temporal and spatial patterns of genetic variation in P. pachyrhizi, we sequenced the nuclear internal transcribed spacer regions (ITS1 and ITS2). Total genomic DNA was extracted using either lyophilized urediniospores or lesions removed from infected leaves sampled from 26 soybean fields in Brazil and one field in South Africa. Cloning prior to sequencing was necessary because direct sequencing of PCR amplicons gave partially unreadable electrophoretograms with peak displacements suggestive of multiple sequences with length polymorphism. Sequences were determined from four clones per field. ITS sequences from African or Asian isolates available from the GenBank were included in the analyses. Independent sequence alignments of the ITS1 and ITS2 datasets identified 27 and 19 ribotypes, respectively. Molecular phylogeographic analyses revealed that ribotypes of widespread distribution in Brazil displayed characteristics of ancestrality and were shared with Africa and Asia, while ribotypes of rare occurrence in Brazil were indigenous. The results suggest P. pachyrhizi found in Brazil as originating from multiple, independent long-distance dispersal events.

Aspectos físico-químicos e microbiológicos de grãos de soja tratados com ácidos orgânicos e seus sais / Physical-chemical and microbiological aspects of soybean grain treated with organic acid and their salts

Este trabalho teve por objetivo avaliar os parâmetros microbiológicos e físico-químicos do grão de soja (Glycine max L.) desativado, tratado com três diferentes dosagens (2, 4 e 6L t-1) de uma mistura de ácidos orgânicos e seus sais (AOS), com a função de aditivo antifúngico. O ensaio teve uma duração de 90 dias, em que foram feitas a contagem de bolores e leveduras (UFC g-1), e a identificação dos gêneros fúngicos, da umidade (U), da atividade de água (AA), do índice de peróxido (IP) e do índice de acidez (IA). As análises foram realizadas em triplicata, em intervalos de 15 dias entre cada análise, até o 60o dia de avaliação e depois no 90o dia do experimento. Verificou-se aumento na UFC g-1 nas doses de 2 e 4L t-1, bem como mudança nos gêneros fúngicos encontradas nestes tratamentos a cada avaliação, diferentemente da baixa UFC g-1 e da identificação de gêneros na dose de 6L t-1. Os valores de U e AA mantiveram-se acima dos padrões recomendados de 14 por cento e 0,70, respectivamente em todos os tratamentos e avaliações. O IP aumentou significativamente a partir do 45o dia de avaliação no controle e a partir do 60o dia nos demais tratamentos. O IA não variou significativamente durante o período de avaliação. Conclui-se que a dosagem de 6L t-1 foi eficiente na proteção antifúngica desta matéria-prima.

This research had the objective to evaluate microbiological and physical-chemical parameters of deactivated soybean grain (Glycine max L.) treated with three different dosages (2, 4 and 6L t-1) of organic acids and their salts mixture (AOS), as an antifungical additive. The assay had a duration of 90 days, where executed fungi count (UFC g-1), fungi specie identification, humidity (U), activity of water (AA), peroxide value (IP) and acidity value (IA). The analyses were carried out in triplicate, in intervals of 15 days among analysis, until 60th day of evaluation and, at the 90th day of evaluation. There were increases in the UFC g-1 in dosages of 2 and 4L t-1, as well a change in fungi species found in these treatment at each evaluation, distinguished of low UFC g-1 and fungi species in dosage of 6L t-1. The values of U and AA were above of recommended patterns of 14 percent and 0.70, respectively for all treatments and evaluations. The IP increased significative from 45th day of evaluation in control and from 60th day in other treatments. The IA had no significative variation during the period of evaluation. The dosage of 6L t-1 was efficient in the antifungical protection of this raw material.

Detección de variabilidad genética en aislamientos de Cercospora kikuchii contaminantes de un mismo sembradío de soja / Detection of genetic variability in Cercospora kikuchii isolates from a single soybean field

El conocimiento de la epidemiología y la estructura poblacional de Cercospora kikuchii está poco desarrollado y no se han comunicado estudios al respecto en la Argentina. El objetivo de este trabajo fue seleccionar oligonucleótidos que permitan detectar variabilidad genética en aislamientos de C. kikuchii obtenidos a partir de soja proveniente de un mismo sembradío, mediante la aplicación de RAPD. Se trabajó con 6 aislamientos de C. kikuchii, 5 de ellos se obtuvieron a partir de trozos de tejido enfermo y el restante provenía de una colección de cultivos. De los 7 oligonucleótidos empleados, 5 resultaron útiles para el estudio poblacional de los aislamientos de C. kikuchii.

Current knowledge about epidemiology and population structure of Cercospora kikuchii is little developed and no studies regarding this subject have been reported in Argentina. The aim of this work was to select primers to study genetic variability in C. kikuchii isolated from the same soybean field using RAPD (Random Amplified Polymorphism DNA). RAPD was applied to the DNA of 5 C. kikuchii, isolated from diseased tissue of the soybean in the same field, another isolate, from a strain collection. Out of seven primers, five of them proved to be useful to study the population of C. kikuchii isolates.

Inactivation of Staphylococcus aureus and Salmonella enteritidis in tryptic soy broth and caviar samples by high pressure processing

We studied the action of high pressure processing on the inactivation of two foodborne pathogens, Staphylococcus aureus ATCC 6538 and Salmonella enteritidis ATCC 13076, suspended in a culture medium and inoculated into caviar samples. The baroresistance of the two pathogens in a tryptic soy broth suspension at a concentration of 10(8)-10(9) colony-forming units/ml was tested for continuous and cycled pressurization in the 150- to 550-MPa range and for 15-min treatments at room temperature. The increase of cycle number permitted the reduction of the pressure level able to totally inactivate both microorganisms in the tryptic soy broth suspension, whereas the effect of different procedure times on complete inactivation of the microorganisms inoculated into caviar was similar.

RAPD and SCAR markers linked to resistance to frogeye leaf spot in soybean

The soybean (Glycine max (L.) Merrill) frogeye leaf spot is caused by the fungus Cercospora sojina Hara and is a widespread disease in Brazil and other countries, causing severe losses in grain yield and also affecting seed quality. The availability of DNA markers linked to genes for resistance to this disease would accelerate breeding programs, particularly when other traits are also being evaluated. Bulked segregant analysis was applied to 3 F2 populations derived from crosses between the resistant cultivars Parana, Cristalina and Uberaba, and the susceptible cultivar Bossier. In the cross 'Parana' x 'Bossier', 2 RAPD markers were identified, CSOPA1800C and CSOPA21,250C, located at 4.4 1.8 centiMorgans (cM) and 3.4 1.7 cM respectively from the resistance locus. DNA fragments of similar molecular weight were observed in the population derived from the cross 'Cristalina' x 'Bossier' at 2.3 1.2 and 4.7 1.5 cM from the resistance locus, respectively. In the offspring of the cross 'Uberaba' x 'Bossier', a DNA fragment corresponding to marker CSOPA1800C was detected at 5.6 2.1 cM from the resistance locus. Although marker CSOPA21,250C was not observed in this population, an additional marker was detected (CSOUB11,100C) at 6.7 2.2 cM from the resistance locus. The 1,250 bp fragment of CSOPA21,250C was cloned and converted into a SCAR marker, which amplified a single fragment whose size corresponded to the cloned segment of the crosses involving cultivars Cristalina and Parana. Markers CSOPA1800C, CSOPA21,250C and CSOUB11,100C were mapped to soybean linkage group J with the aid of known SSRs linked to the Rcs3 locus, indicating that the RAPD and SCAR markers identified in our research also tag this resistance gene

Avaliação microbiológica do extrato hidrossolúvel de soja com sabor de cupuaçu (Theobroma grandiflorum) e bacuri (Platonia insigns) e aproveitamento do resíduo na merenda escolar / Microbiological evaluation of soymilk with capuaçu (Theobroma grandiflorum) and bacuri (Platonia insignis) flavors and utilization of the residue in school snack

Foram elaborados leite de soja com sabores de bacuri (Platonia insignis) e cupuaçu (Theobroma grandiflorum). Realizaram-se análises microbiológicas (coliformes totais e fecais e salmonelas), e determinado o valor calórico do derivado, indicando-o como sendo de ótima qualidade e destacada aceitação. A análise econômica constatou reduzido custo de produção, cerca de R$0,71 (setenta e um centavos de real) para cada 1.000 ml. Para antender às necessidades nutricionais indicadas para merenda escolar (250 a 300 calorias/aluno) são necessários 426 ml desse derivado, o que corresponde a R$0,28 (vinte e oito centavos de real). Visando utilizar os resíduos da preparação do "leite de soja" (cerca de 80 por cento) indica-se o fornecimento associado de 250 ml do derivado líquido e seis biscoitos elaborados com esses resíduos por aluno, o que atende às demandas nutricionais "per capita" e tem custo de R$0,22 (vinte e dois centavos de real). Os derivados de soja, "leite de soja", salgados e doces constituem produtos alternativos em Programas Especiais financiados pelo governo, visando minimizar a fome de estudantes das redes públicas federal, estadual, municipal e filantrópica, além de comunidades de baixa renda, pois são alimentos nutritivos de elevados valores calórico-protéicos e de baixo custo, além de usar matérias-primas passíveis de serem produzidas em nível local, gerando renda, trabalho e incentivo à produção agrícola regional.