Feromônios de agregação em curculionidae (insecta: coleoptera) e sua implicação taxonômica

The pheromones of the weevils has been the most studied and used so far for Coleoptera species. The majority of reported weevil pheromones is produced by males and usually attract both sexes. The identified pheromone compounds are classified in two categories: ten-carbon compounds with terpenoid branching and compounds of various sizes, apparently of fatty-acid origin. These pheromone structural categories are consistent within subfamilies. This review aims to give an overview of the aggregation pheromones identified for Curculionidae pests, describing the relationship of the molecules structural pattern among subfamilies, and propose an identification key based on the structure of the pheromone components.

Produção de concentrados de ácidos graxos por hidrólise de óleos vegetais mediada por lipase vegetal

The aim of this work was to verify the ability of enzymatic crude extract from dormant castor bean seeds to yield concentrated fatty acids by hydrolysis of polyunsaturated vegetable oils such as corn and sunflower. The enzymatic extract exhibited higher activity towards corn oil, which was selected for further studies to determine optimum hydrolysis conditions by factorial design. Maximum hydrolysis percentage (≈84%) was reached at 60% wt. oil:buffer acetate 100 mM pH 4.5, 33 ºC and 5.0% wt. of crude extract after 70 min of reaction. These results suggest that the use of low-cost lipase from castor bean seeds has potential for oil hydrolysis.

NANOPARTÍCULAS DE PROTEÍNA ISOLADA DE SOJA EM ÁGUA: EFEITO DA FORÇA IÔNICA E DAS CONCENTRAÇÕES DE PROTEÍNA E SURFACTANTE

Soft nanoparticles of size 200-400 nm were obtained from soybean protein isolate (SPI). The particles were formed and suspended in water by the coacervation of aqueous suspensions of SPI in hostile buffered aqueous solutions in the presence of surfactants. We investigate the effect of storage, ionic strength, and concentrations of SPI and surfactant on nanoparticle size and zeta potential. Transmission electron microscopy images and scattering techniques (SLS/ DLS) revealed that the particles are spherical, with hydrophilic chains at the surface.

Distribuição de geminivírus nas culturas do tomate e pimentão em doze municípios do Submédio do Vale São Francisco

Em 1996 e 1997, observaram-se sintomas de viroses causadas por geminivírus transmitidos por mosca branca em plantas de tomateiro (Lycopersicon esculentum) e pimentão (Capsicum annuum) no Submédio do Vale São Francisco, situado nos Estados de Pernambuco e Bahia. De outubro de 1996 a dezembro de 1998, foram coletadas 1.368 amostras foliares de tomateiro e 194 de pimentão, exibindo sintomas similares àqueles causados por geminivírus, em 104 e 16 plantios, respectivamente, de 12 municípios dessa região e em dois municípios vizinhos. A incidência de geminiviroses nas áreas amostradas foi estimada entre 5 e100% para tomate e entre 10 e 20% para pimentão. A detecção de geminivírus nas amostras foi feita por "dot blot" ou "squash blot" utilizando-se sondas heterólogas. Para as amostras de tomate, a sonda foi constituída pelos componentes A completos de dois isolados, um de Bean golden mosaic virus (BGMV) do Brasil e outro de Bean golden yellow mosaic virus (BGYMV) da Guatemala, enquanto que para pimentão, esta foi constituída apenas por um fragmento do componente A de um isolado de geminivírus de tomate do Distrito Federal. Do total de 1562 amostras analisadas, em 908 (58,1%) confirmou-se a presença de geminivírus, sendo 823 (60,2%) de tomate e 85 (43,8%) de pimentão. A presença de plantas infetadas foi detectada em todos os 120 plantios, com incidência entre 20 e 100%, indicando ampla disseminação de geminivírus nestas culturas no Submédio do Vale São Francisco.

Identification of Phaeoisariopsis griseola pathotypes from five States in Brazil

Due to the increased importance of angular leaf spot of common bean (Phaseolus vulgaris) in Brazil, monitoring the pathogenic variability of its causal agent (Phaeoisariopsis griseola) is the best strategy for a breeding program aimed at developing resistant genotypes. Fifty one isolates of P. griseola collected in five Brazilian States were tested on a set of 12 international differential cultivars in the greenhouse. When inoculated plants showed symptoms but no sporulation was observed, they were transferred to a moist chamber for approximately 20-24 h. After this period of time, if no sporulation was observed, the plants were considered resistant; otherwise, they were considered susceptible. From the fifty-one tested isolates, seven different pathotypes were identified. No Andean pathotypes were identified; consequently, all isolates were classified as Middle American pathotypes. Pathotype 63-31 was the most widespread. Pathotype 63-63 overcame resistance genes present in all differential cultivars and also the resistance gene(s) present in the cultivar AND 277. This fact has important implications for breeding angular leaf spot resistance in beans, and suggests that searching for new resistance genes to angular leaf spot must be pursued.

Telomere and microsatellite primers reveal diversity among Sclerotinia sclerotiorum isolates from Brazil

Sclerotinia sclerotiorum, the causal agent of white mold, is a problem of winter bean (Phaseolus vulgaris) production in Brazil under center-pivot irrigation. Isolates of S. sclerotiorum were obtained from a center-pivot-irrigated field near Guaíra-SP, Brazil. Mycelial compatibility group (MCG) studies revealed the presence of only two MCG. PCR/RFLP analysis of the ITS1-5.8S-ITS2 ribosomal subunit regions of these field isolates of S. sclerotiorum failed to show any genetic differences between these two MCGs. DNA amplification with a chromosomal telomere sequence-based primer and one microsatellite primer revealed genetic polymorphisms among isolates within the same MCG. Isolates taken from beans and two other crops from another region of Brazil showed the same two MCG and had identical banding patterns for the telomere and microsatellite primers. These findings support the use of telomere sequence-based primers for revealing genotypic differences among S. sclerotiorum isolates.

Análise molecular de segmento do RNA2 de comovirus isolados de soja no estado do Paraná

Nas áreas produtoras de feijão (Phaseolus vulgaris) do Estado do Paraná observa-se anualmente a ocorrência do vírus do mosaico em desenho do feijoeiro (Bean rugose mosaic virus, BRMV), principalmente em infecções mistas com o vírus do mosaico dourado do feijoeiro (Bean golden mosaic virus, BGMV), acarretando maior severidade de sintomas e causando perdas na produção. Recentemente constatou-se a presença do vírus do mosaico severo do caupi (Cowpea severe mosaic virus, CPSMV) associado a sintomas de queima do broto em plantações de soja (Glycine max) na região de Londrina, sendo este um fato novo no Estado. Neste trabalho, parte do RNA2 de dois comovirus isolados de soja no Paraná foram clonados e sequenciados, sendo 600 pares de bases (pb) do BRMV-PR e 594 pb do CPSMV-PR. Posteriormente, as seqüências correspondentes de aminoácidos foram comparadas com seis seqüências de vírus do gênero Comovirus depositadas no GenBank. Com base nestes dados observou-se que o segmento do RNA2 do isolado CPSMV-PR apresentou homologia de 85% com parte de uma seqüência já conhecida do RNA2 do CPSMV, enquanto que o segmento do RNA2 do isolado BRMV-PR apresentou homologia de 39% com o CPSMV, e de 44% com o Bean pod mottle virus (BPMV). Este trabalho apresenta pela primeira vez dados de sequenciamento parcial do BRMV, o que poderá contribuir para sua completa caracterização molecular e para o estabelecimento de estratégias para obtenção de plantas resistentes ao vírus.

Genetic linkage map of Phaseolus vulgaris and identification of QTLs responsible for resistance to Xanthomonas axonopodis pv. phaseoli

Common bean (Phaseolus vulgaris) cultivars with a high degree of resistance to Xanthomonas axonopodis pv. phaseoli (Xap) are not available in Brazil. Despite many studies, a low degree of resistance to Xap continues to exist due to its complex genetic inheritance, which is not well known. The objectives of this research were to complement a common bean genetic map based on the cross between a susceptible genotype 'HAB-52' and a resistant genotype 'BAC-6', and to map and analyze genomic regions (quantitative trait loci – QTLs) related to Xap resistance. Eleven linkage groups were determined using 143 RAPD markers, covering 1,234.5 cM of the genome. This map was used to detect QTLs associated with Xap resistance on leaves and pods. The averages of disease severity on leaves (represented by the transformed disease index – TDI) and pods (represented by the diameter of lesion on pods – DLP) were added to the data of the linkage map. Five TDI QTLs and only one LDP QTL were detected. The TDI QTLs were placed in the A, B, G and J linkage groups, with phenotypic variations ranging from 12.7 to 71.6%. The DLP QTL explained 12.9% of the phenotypic variation and was mapped in a distinct linkage group. These results indicate that there are different genes involved in the control of resistance on leaves and pods.

Cytogenetics of Colletotrichum lindemuthianum (Glomerella cingulata f. sp. phaseoli)

Cytogenetic and morphological studies were conducted with Colletotrichum lindemuthianum (Glomerella cingulata f. sp. phaseoli), the pathogen responsible for anthracnose of common bean (Phaseolus vulgaris). In this species, there is some evidence of genomic variation but it is unknown whether the process occurs in a manner similar to other fungal genetic models. Six isolates from bean plants were used and sexual reproduction was observed in vitro. Meiosis and ascospore formation were investigated by cytogenetical approaches and light microscopy. To study the nucleus and chromosome numbers, a mixture of carmine and orcein propionic dyes was used. Nucleus divisions as well as ascospore maturation were asynchronous. Meiosis was observed in three isolates. In the asexual form, chromosomal polymorphism in conidia was also observed microscopically and the mitosis process was described.

Análise comparativa da variabilidade patogênica de Uromyces appendiculatus em algumas regiões brasileiras

A ferrugem do feijoeiro comum (Phaseolus vulgaris), incitada pelo fungo Uromyces appendiculatus, é uma das mais importantes doenças que afetam essa cultura. Trabalhos anteriores demonstraram a ampla variabilidade patogênica de U. appendiculatus no Brasil. No entanto, o uso de distintos grupos de cultivares diferenciadoras em tais trabalhos dificulta a análise comparativa e a identificação de fontes de resistência de amplo espectro. Assim, os objetivos deste trabalho foram: 1) caracterizar sete isolados de U. appendiculatus, coletados em diferentes regiões do estado de Minas Gerais, frente às 19 cultivares diferenciadoras para ferrugem, adotadas no "The Bean Rust Workshop", realizado em 1983, em Porto Rico, e 2) comparar os padrões de resistência/suscetibilidade obtidos, com aqueles apresentados frente a patótipos isolados nos estados de Santa Catarina, Rio Grande do Sul e Goiás, visando identificar fontes de resistência de amplo espectro. Os sete isolados coletados em Minas Gerais foram classificados com sete patótipos distintos. As cultivares diferenciadoras com os maiores espectros de resistência foram 'Redlands Pioneer', 'California Small White 643', 'Brown Beauty', 'AxS 37' e 'Compuesto Negro Chimaltenango'. Portanto, apesar da exclusão das cultivares California Small White 643, AxS 37 e Brown Beauty da nova série diferenciadora internacional proposta em 2002, na África do Sul, recomenda-se adicionar estas cultivares nas futuras caracterizações de patótipos a serem realizadas no Brasil, como um modo de monitorar a variabilidade patogênica de populações de U. appendiculatus nas regiões produtoras.

Genetic divergence among and within Colletotrichum lindemuthianum races assessed by RAPD

Genetic divergence within and among races of Colletotrichum lindemuthianum was determined using RAPD markers. In addition to the different races of the fungus three isolates of the sexual stage of Colletotrichum lindemuthianum (Glomerella cingulata f.sp. phaseoli) were included in this study. The band patterns generated using 11 primers produced 133 polymorphic bands. The polymorphic bands were used to determine genetic divergence among and within the pathogen races. The isolates analyzed were divided into six groups with 0.75 relative similarity. Group VI, formed by three isolates of the sexual phase of Colletotrichum lindemuthianum, was the most divergent. Races previously determined using differential cultivars did not correlate with the results obtained using RAPD markers.

Identification of Races of Selected Isolates of Uromyces appendiculatus from Minas Gerais (Brazil) Based on the new international classification system

Twelve single-pustule isolates of Uromyces appendiculatus, the etiological agent of common bean rust, were collected in the state of Minas Gerais, Brazil, and classified according to the new international differential series and the binary nomenclature system proposed during the 3rd Bean Rust Workshop. These isolates have been used to select rust-resistant genotypes in a bean breeding program conducted by our group. The twelve isolates were classified into seven different physiological races: 21-3, 29-3, 53-3, 53-19, 61-3, 63-3 and 63-19. Races 61-3 and 63-3 were the most frequent in the area. They were represented by five and two isolates, respectively. The other races were represented by just one isolate. This is the first time the new international classification procedure has been used for U. appendiculatus physiological races in Brazil. The general adoption of this system will facilitate information exchange, allowing the cooperative use of the results obtained by different research groups throughout the world. The differential cultivars Mexico 309, Mexico 235 and PI 181996 showed resistance to all of the isolates that were characterized. It is suggested that these cultivars should be preferentially used as sources for resistance to rust in breeding programs targeting development lines adapted to the state of Minas Gerais.

Is it necessary to soak rice grains to prepare Rhizoctonia solani AG-4 inoculum?

A study was conducted to evaluate the effects on the development of root rot on common bean, cv. 'Dufrix' after treatment with four volumes of water (0, 30%, 60%, and 90%, v/w) added to rice grains previously immersed in water for 24 hours before autoclaving and colonization of grains by Rhizoctoniasolani AG-4. Colonized rice grains and non-infested rice grains were mixed in pots with sterilized soil and sand (2:1), where beans were sown. Based on results of area under plant emergence curve, plant height, plant dry weight, and disease severity, we conclude that inoculum is more effective in causing disease when no water is added to the rice grains before autoclaving.

Pseudomonas syringae pv. tabaci in papaya seedlings

The natural occurrence of Pseudomonas syringae pv. tabaci causing leaf spot symptoms in papaya seedlings is reported. The pathogen was identified through biochemical, physiological, serological, and molecular assays and artificial inoculations in papaya plants. It was also shown that the strains were pathogenic to bean and tobacco plants. The restriction patterns obtained with Afa I, Alu I, Dde I, Hae III, Hpa II, Hinf I, Sau 3A I and Taq I of the PCR-RFLP of 16S-23S DNAr were identical to the P. s. pv. tabaci patterns. Primers corresponding to hrpL gene of P. syringae were also tested and the results grouped the papaya strains with P s. pv. tabaci. Bacterial strains were deposited at Coleção de Culturas IBSBF, Instituto Biológico, Campinas, Brazil, under access numbers 1687 and 1822.

Characterization of Citrus tristeza virus isolates from grapefruit (Citrus paradisi Macf.) accessions of Citrus Active Germplasm Bank

Citrus tristeza virus (CTV) isolates from 35 grapefruit accessions belonging to Citrus Active Germplasm Bank of the "Instituto Agronômico de Campinas" located at the "Centro APTA Citros Sylvio Moreira", Cordeirópolis, São Paulo state, Brazil, were characterized and evaluated through symptoms in the trees, biological indexing, immunological diagnosis with different monoclonal antibodies and SSCP analysis (single-strand conformation polymorphism) of the coat protein gene. Symptomatology indicated that, in general, the group of plants with smaller canopy volume and severe stem pitting differed significantly from the group that presented greater vegetative development and mild to moderate stem pitting. However, the isolates from most of the accessions induced mild reaction on Mexican lime. The serological evaluation through the DAS-ELISA using monoclonal antibodies did not reveal any association between virus titer in the plant tissue and symptoms. The reaction with different monoclonal antibodies and the distinct electrophoresis patterns obtained through SSCP showed that there is a high degree of diversity among the isolates that infect these grapefruit accessions. High complexity within the same isolate was also observed in the SSCP profiles. This finding indicates that the CTV isolates from these plants are a complex mixture of CTV haplotypes. Similar SSCP banding patterns were observed among some plants with strong stem pitting symptoms, and among some plants with weak or moderate stem pitting symptoms.