A cultura do feijoeiro, no Brasil, apresenta constantes danos associados à ocorrência do crestamento bacteriano comum, incitado pela bactéria Xanthomonas axonopodis pv. phaseoli. O objetivo deste trabalho foi avaliar alterações nas isoenzimas peroxidases em plantas de feijoeiro em resposta ao tratamento com biocontrolador do crestamento bacteriano comum. Realizaram-se três experimentos: dois experimentos microbiolizando as sementes com o biocontrolador, avaliando-se as isoenzimas na fase de plântula e na fase de planta adulta e outro experimento aplicando o biocontrolador por aspersão da parte aérea da planta. Para a realização dos experimentos utilizaram-se sementes naturalmente infestadas/infectadas e/ou que sofreram inoculação artificial com o patógeno. Nas análises isoenzimáticas foram detectados 15 padrões de bandas em plântulas e 12 padrões de bandas em planta adulta, tanto nos tratamentos de sementes pela microbiolização com biocontrolador como também nos tratamentos em que a aplicação foi por aspersão da parte aérea com o biocontrolador. Foram observadas diferenças quantitativas (presença e ausência de bandas) quando os tratamentos e os dias após a semeadura foram comparados. Constatou-se o aparecimento de isoperoxidases na região catódica apenas para aqueles tratamentos que receberam o biocontrolador. O microrganismo utilizado como um agente de biocontrole foi efetivo no controle do crestamento bacteriano comum do feijoeiro mostrando ser efetivo na indução de enzimas relacionadas às defesas da planta tanto na aplicação via semente como em aplicação por aspersão na planta.

Bean crops in Brazil frequently show damages associated with the occurrence of common bacterial blight, incited by Xanthomonas axonopodis pv. phaseoli bacteria. The objective of this study was to evaluate the changes in peroxidase isoenzyme in bean leaves in response to treatment with a biocontroller of common bacterial blight. Three experiments were carried out: two of microbiolization of seed with biocontroller and evaluations at seedling and adult plant stages, and another experiment spraying above-ground parts of plant with the biocontroller. Fifteen band patterns at seedling and twelve patterns at different cycle dates of the crop were detected, both in seeds and above-ground treatments. Quantitative differences were observed (presence and absence of bands) when the treatments and the days after sowing were compared. The presence of isoperoxidases in the cathodic region was seen in the treatments using biocontroller. This organism, used as a method of plant protection against plant pathogens, was shown to be effective after application on plants or seeds, under conditions of common bacterial blight disease.

No Brasil, prejuízos ocasionados pela ferrugem da folha do trigo (Puccinia triticina) ocorrem anualmente. A incidência generalizada nas diferentes regiões produtoras varia em intensidade, dependendo das condições climáticas, da resistência genética das cultivares e do controle químico, sendo que a utilização de cultivares resistentes é o método mais eficiente de controle. Os genes que conferem resistência à ferrugem da folha em trigo são denominados Lr (leaf rust). Vários desses genes já foram identificados e mapeados. Alguns deles foram mapeados diretamente em genótipos hexaplóides, enquanto outros foram primeiramente encontrados em espécies afins, com menor nível de ploidia e, posteriormente, transferidos para o trigo cultivado. Das espécies afins, destaca-se a espécie diplóide Aegilops tauschii, doadora do genoma D do trigo cultivado, como uma importante fonte de genes de resistência. O objetivo desse trabalho foi avaliar a resistência à ferrugem da folha em acessos de Ae. tauschii, oriundos do Banco Ativo de Germoplasma da Embrapa Trigo (BAG - Passo Fundo, RS), para utilização das seleções nos programas de melhoramento. Quarenta acessos foram avaliados quanto à reação à raça SPJ-RS de Puccinia triticina e, destes, 25% (10 acessos) apresentaram resistência. Os dados obtidos neste estudo servem como subsídio na escolha de acessos resistentes que poderão ser utilizados como genitores em programas de melhoramento genético a fim de incremento de resistência a esse patógeno.

In Brazil, losses caused by wheat leaf rust (Puccinia triticina) occur annually. The widespread incidence in the different producing areas varies in intensity, depending on climatic conditions, level of genetic resistance of the cultivars and efficacy of chemical control. The use of resistant cultivars is the most efficient control method, and the genes conferring resistance to leaf rust fungus are denominated Lr. Several of these genes have already been identified and mapped. Some of them were mapped directly in hexaploid wheats, while others were initially found in related species, with lower ploidy level and later transferred to cultivated wheat. Among related species, Aegilops tauschii, the diploid species donor of the D genome of cultivated wheat, is indicated as an important source of resistance genes to leaf rust. The objective of this work was to evaluate the resistance of A. tauschii accessions from the Active Germplasm Bank of Embrapa Trigo (BAG - Passo Fundo, RS) to leaf rust, in order to incorporate this resistance in commercial varieties. The reaction to race SPJ-RS of Puccinia triticina was evaluated in forty accessions of A. tauschii and 25% (10 accessions) were resistant. The data obtained in this study can help in choosing resistant accessions to be used as parents in breeding programs in order to increase resistance to the pathogen.

Com o objetivo de conhecer as alterações metabólicas promovidas pelo Soil-borne wheat mosaic virus (SBWMV), um dos vírus economicamente mais importantes da cultura do trigo (Triticum aestivum), foram analisados os níveis de proteínas solúveis e determinadas as atividades da peroxidase e da protease em quatro cultivares (BRS Guabiju, BRS 194, BRS 179, BR 23) e uma linhagem (PF 980524) de trigo com diferentes níveis de resistência ao vírus. Os dados obtidos foram submetidos à análise de variância, comparando-se as médias, pelo Teste de Duncan a 5%. Os níveis de proteínas solúveis foram mais elevados nas plantas sem sintomas, enquanto que as atividades da peroxidase e da protease foram maiores em plantas com sintoma de mosaico do que em plantas assintomáticas. Além disso, pode-se constatar que quanto maior a suscetibilidade do genótipo, maior o nível de atividade da protease. Estes resultados são promissores para estudos de inibição da protease para controle de viroses.

The objective of this study was to verify the metabolic alterations induced by Soil-borne wheat mosaic virus (SBWMV), one of the most economically harmful viruses infecting wheat (Triticum aestivum) farming. The study analyzed the levels of soluble proteins and determined the activities of peroxidase and protease in four wheat cultivars (BRS Guabiju, BR 23, BRS 179, BRS 194) and one line (PF 980524) with different levels of resistance to the virus. The data obtained were submitted to analysis of variance, and averages were compared by Duncan's Test at 5%. Soluble protein levels were higher in plants without symptoms, while peroxidase and protease activities were higher in plants with mosaic symptoms than in assymptomatic plants. Moreover, it appeared that genotypes with high susceptibility to SBWMV have high protease activity. These results could help in the design of future studies aimed at controlling the virus through inhibition of protease.

A triticultura brasileira apresenta constantes perdas no rendimento, associadas à ocorrência da ferrugem da folha, causada pelo fungo Puccinia triticina. A incorporação da resistência genética e o conhecimento do número de genes envolvidos são importantes para os programas de melhoramento genético vegetal, que a cada ano têm introduzido resistência qualitativa nas cultivares, visando superar o aparecimento de novas raças do patógeno. As técnicas bioquímicas, baseadas na análise de polimorfismo de enzimas, possibilitam a rápida e precisa detecção de marcadores moleculares, para o estudo de aspectos básicos de genética vegetal, bem como representam valiosa ferramenta de apoio aos programas de melhoramento, pois permitem a identificação antecipada de genótipos resistentes e suscetíveis. Este trabalho visa avaliar, fitopatológica e molecularmente, a população haplodiplóide Trigo BR 35 (resistente)/IAC 13-Lorena (suscetível) de trigo (Triticum aestivum), quanto à resistência de planta adulta à ferrugem da folha, bem como à similaridade genética presente na progênie haplodiploidizada na geração F1. Nas avaliações fitopatológicas em planta adulta, das 96 linhas duplo-haplóide, 29 foram resistentes, 15 suscetíveis e 52 intermediárias apresentaram reação que variou entre nível de resistência inferior ao determinado para Trigo BR 35 a menos suscetível do que IAC 13-Lorena. A análise genética revelou dois genes parcialmente dominantes. Na análise bioquímica, através do sistema isoenzimático das esterases, foram detectadas, seis bandas, todas anódicas e com especificidade alfa-esterásica, cujas MRs (migração relativa) variaram de 0,09 a 0,69. Quanto à variabilidade genética, foi detectada, para as 96 linhas, elevada similaridade genética, a qual confirmou as análises isoesterásicas.

Yield redutions associated with leaf rust, caused by the fungus Puccinia triticina, are recorded for Brazilian wheat (Triticum aestivum) crops. Incorporation of genetic resistance and knowing the number of genes involved are important tools for plant genetic breeding programs, which are consistently introducing qualitative resistance in cultivars aiming to cope with new races of the pathogen. Biochemical techniques, based upon the analysis of the polymorphism of enzymes, provide a rapid and accurate detection of molecular markers and, also, play a valuable support role in breeding programs for predicting the identification of resistant and susceptible genotypes. The objective of this investigation was to carry out a phytopathological and molecular assessment of the haplodiploid population Trigo BR 35 (resistant)/IAC13-Lorena (susceptible) as to its adult plant resistance to leaf rust, as well as to the genetic similarity available in the progeny haplodiploidized in F1 generation. From a total of 96 double haploid lines evaluated for leaf rust, at adult-plant stage, 29 were resistant, 15 were susceptible and 52 showed less resistance than Trigo BR 35 than that presented by IAC 13-Lorena. The genetic analysis showed that the resistance was due to two partially dominant genes. In the biochemical analysis, made through isoenzymatic esterase system, six bands were detected, all of them anodic and with alpha-esterasic specificity the relative migration varied from 0,09 to 0,69. A high genetic similarity was detected, which confirmed isoesterasic analyses, for the 96 double haploid lines.

The wheat line PF 839197 and six hybrid derivatives from a cross between PF 839197 and Thinopyrum ponticum were cytologically characterized by fluorescent in situ hybridization (FISH). Probes for the 5S and 45S rDNA genes (pTa794 and pTa71, respectively), a highly repetitive rye sequence (pSc119.2), the synthetic oligonucleotide (AAG)5, and total genomic DNA from Th. ponticum and rye were used. In the wheat line, a 1RS.1BL translocation was revealed by the labeling patterns produced with pSc119.2 and (AAG)5, and confirmed by genomic in situ hybridization (GISH) using rye genomic DNA as a probe. Analyses of partial amphiploids confirmed previous results indicating mitotic instability, with a tendency to stabilize at 2n = 42 or 56. GISH with Th. ponticum genomic DNA showed that in one hybrid derivative, with lower chromosome numbers (2n = 42-45), chromosomes were not labeled, whereas in the hybrids with 2n = 48-56 up to 14 chromosomes were labeled. These data suggest that the original chromosome set of these hybrids was 2n = 56, and that chromosomes from both genomes were lost by mitotic instability. FISH using the rDNA probes and GISH with Thinopyrum genomic DNA suggested that cells with 2n = 56 contained an entire wheat genome plus two monoploid chromosome sets of Th. ponticum.

Thinopyrum ponticum (2n = 10x = 70, JJJJsJs) belongs to the Triticeae tribe, and is currently used as a source of pathogen resistance genes in wheat breeding. In order to characterize its chromosomes, the number and position of 45S and 5S rDNA sites, as well as the distribution of the repetitive DNA sequences pAs1 and pSc119.2, were identified by fluorescent in situ hybridization. The number of nucleoli and NORs was also recorded after silver nitrate staining. Seventeen 45S and twenty 5S rDNA sites were observed on the short arms of 17 chromosomes, the 45S rDNA was always located terminally. On three other chromosomes, only the 5S rDNA site was observed. Silver staining revealed a high number of Ag-NORs (14 to 17) on metaphase chromosomes, whereas on interphase nuclei there was a large variation in number of nucleoli (one to 15), most of them (82.8%) ranging between four and nine. The pAs1 probe hybridized to the terminal region of both arms of all 70 chromosomes. In addition, a disperse labeling was observed throughout the chromosomes, except in centromeric and most pericentromeric regions. When the pSc119.2 sequence was used as a probe, terminal labeling was observed on the short arms of 17 chromosomes and on the long arms of five others. The relative position of 45S and 5S rDNA sites, together with the hybridization pattern of pAs1 and pSc119.2 probes, should allow whole chromosomes or chromosome segments of Th. ponticum to be identified in inbred lines of wheat x Th. ponticum.