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Diseases caused by fungi associated with adverse weather conditions are one of the main causes of decreases in sugarcane production. This study aimed to develop a protocol for a fast identification of Phaeocytostroma sacchari, which is the causal agent of bark rot in sugarcane. The reference sequences of three DNA regions of P. sacchari, namely internal transcribed spacer, ribosomal large subunit and translation elongation factor 1-alpha (TEF1-α), were analyzed with specific primers design. The specific primers generated that aligned in their entirety with P. sacchari were selected and synthesized. Polymerase chain reaction (PCR) assays were performed to confirm the primer specificity, using P. sacchari isolates and 10 species of other genera. Two sets of primers that amplify the TEF-1α region (PsF1/Psf1 and PsF2/PsR2) showed a high specificity and sensitivity in detecting P. sacchari using conventional PCR, what will allow large-scale surveys of this pathogen in sugarcane crops.

Sweet corn is susceptible to the attack of various pathogens that affect its metabolism and compromise its quality and production. This study aimed to identify the causal agent of stem rot in sweet corn plants under greenhouse conditions. The identity of the pathogenic isolate was confirmed by sequencing of internal transcribed spacer (ITS1/ITS4), beta-tubulin (BT2A/BT2B), calmodulin (CL1/CL2) and translation elongation factor 1α (TEF1). The morphological and sequencing characteristics showed that Fusarium sacchari, which belongs to the Fusarium fujikuroi complex, is directly associated with the symptoms observed in the field. This fungal isolate has never been associated with diseases in Zea mays (saccharata group) in Brazil; therefore, this is the first report of the fungus infecting sweet corn in a cultivated area.

Biological formulations used as inoculants are increasingly present in grasses, especially in corn. Positive results in promoting plant growth, with different associations with diazotrophic bacteria, show these capacities of interaction to act as plant growth regulators, making it a promising alternative with a low environmental impact. Thus, this study aimed to evaluate the efficiency of inoculation and co-inoculation of nodulating and non-nodulating diazotrophic bacteria as promoters of initial growth in corn plants. Therefore, the bacteria Azospirillum brasilense (UFG21 strain), Bradyrhizobium japonicum (commercial product), and their co-inoculation were used in seed treatment. The evaluations consisted of growth measuring of the root system and shoot and evaluating leaf chlorophyll concentration. The results showed a beneficial interaction between the bacteria and the corn plant, with an increase in the root system and chlorophyll content, compared to the control treatment.

Abstract Considering the lack of information on RNA extraction from arboreal species, specially from the Brazilian Cerrado, the aim of this study was to test RNA extraction methods for a wide variety of native plant species from this biome. The methods tested consisted of: (i) TRIzol® reagent, (ii) TRIzol® reagent with modifications, (iii) CTAB buffer, and (iv) Modified CTAB buffer, initially for leaf samples of Xylopia aromatica and Piper arboreum. Later the procedure with the best results was used to obtain purified RNA from 17 other native species. Based on A260/A280 absorbance ratio the Modified CTAB method was the best for total RNA extraction for those woody species. Ten out of eleven species tested through RT-PCR generated fragments of the expected size from the total RNA extracted by the selected method, confirming it as the best option to obtain high-quality RNA for molecular analyses and for use in the detection of viruses infecting these tree species.

White mold (Sclerotinia sclerotiorum) is one of the most important fungal diseases that affect soybean, primarily due to the production of resistant structures called sclerotia. The disease is difficult to control, and sources of genetic resistance are poorly understood. As such, the present study aimed to assess the resistance of soybean genotypes to white mold in two agroecosystems in the Brazil (Barreiras-BA, and Jataí-GO) and analyze the relationship between the disease incidence and the phenotypic characteristics of the genotypes, as well as determine the lodging index, crop cycle and yield. A total of 165 and 33 genotypes were assessed in the regions of Barreiras and Jataí, respectively. To verify the effect of the area, 37 genotypes were planted in both regions. The area effect was assessed for the study variables, and the correlation was significant between the disease and lodging, cycle and production. Considering resistance, area and yield, genotypes ANTA82, 2011L003, 2011L005 exhibited the highest yield and resistance to white mold.

The thermotherapy of sugarcane setts is currently the primary management method for Leifsonia xyli subsp. xyli (Lxx), in Brazil. When they are immersed, the enzymes and proteins of the bacterial cell are denatured without harming the setts buds. Due to possible escapes from detection and consequent bacterium survival to thermotherapy, what may result in asymptomatic seedlings, this study aimed to detect the Leifsonia xyli subsp. xyli bacterium in sugarcane setts using molecular techniques and different time and temperature combinations, with or without the addition of antibiotics. The conventional PCR method detected the Lxx bacterial DNA only in the positive control, consisting of a highly susceptible plant with a high bacterial concentration. Using the nested-PCR, the Lxx DNA was detected in all the treatments used. Thus, none of the treatments adopted in the thermotherapy was able to eliminate the Lxx from the setts, and the use of kasugamicin also did not eliminate the bacterium, but reduced the bacterial population in the tested treatments. These results confirm that the nested-PCR is a useful tool to detect the presence of this phytobacterium in setts that will be used as seedlings.

Vascular wilting in tomato plants is an important disease caused by soil-inhabiting pathogens, especially Verticillium dahliae, which results in significant production losses. Control measures against this disease are difficult to implement due to intrinsic pathogen characteristics, such as high adaptability to the subterranean environment, in association with the host, and development of resistance structures that remain viable in the soil for long periods. The introgression of genes that express resistance is the main control measure and requires a continuous characterization program of resistant accessions. This study aimed at identifying tomato (Solanum lycopersicum) accessions resistant to V. dahlia, by using the phenotypic and genotypic methods. The reaction of 33 tomato accessions to different V. dahliae isolates was reinforced by molecular analysis, through markers linked to Ve resistance genes. The combination of bioassays and specific molecular markers showed a high correlation (94.3 %), with the selection of 25 accessions resistant to V. dahliae.

Resumo: O objetivo deste trabalho foi elaborar e validar um protocolo de detecção simultânea, via reação em cadeia da polimerase multiplex (PCR multiplex), de regiões genômicas do tomateiro (Solanum lycopersicum) associadas a fatores de resistência às três raças fisiológicas de Fusarium oxysporum f. sp. lycopersici (FOL). Os pares de iniciadores empregados foram SSR-67 (específico para o gene I-1), TFusrr (específico para o gene I-2) e SSRD (específico para o gene I-3). Os resultados de genotipagem com marcadores moleculares foram comparados aos resultados de fenotipagem de uma coleção de germoplasma de tomateiro, em bioensaios de inoculação de isolados das três raças de FOL em plântulas, pelo método de imersão das raízes. A resistência ou a suscetibilidade foi confirmada por PCR, por meio de visualização dos âmplicons específicos para as regiões-alvo ligadas aos fatores de resistência às distintas raças de FOL. O protocolo elaborado para o uso conjunto dos marcadores moleculares, em PCR multiplex, permite a seleção de acessos de tomateiro resistentes às raças 1, 2, e 3 de F. oxysporum f. sp. lycopersici de maneira similar à realizada com a utilização de cada um separadamente. O PCR multiplex representa uma ferramenta viável para monitorar a incorporação desses fatores de resistência em linhagens de tomateiro.

Resumo: O objetivo deste trabalho foi avaliar a reação de 48 acessos de tomateiro (Solanum lycopersicum), inclusive de espécies selvagens, a diferentes isolados das três raças de Fusarium oxysporum f. sp. lycopersici (FOL). Utilizaram-se marcadores moleculares ligados aos genes de resistência I-1, I-2 e I-3. A combinação de bioensaios e marcadores moleculares específicos mostrou elevada correlação para a maioria dos acessos. Acessos de S. peruvianum e S. corneliomuelleri apresentaram resistência contra todas as raças de FOL; a introgressão de fatores de resistência destes genótipos em germoplasma-elite de tomateiro é de elevado interesse para o melhoramento genético desta cultura.

Vascular wilting in tomato plants constitutes an important group of diseases incited by soil inhabiting pathogens, especially Fusarium oxysporum f. sp. lycopersici, that causes significant production losses. The introgression of genes that express specific resistance is considered the main control method, however, due to the rapid emergence of races that suppress resistance, biocontrol has been presented as an option to be integrated with genetic control methods. This study aimed at evaluating the ability of rhizobacteria isolates, especially from the Bacillus genus, as biological control agents of Fusarium wilt in tomato plants. The laboratory assay was carried out to verify the ability of the isolates in acting as inhibitors of mycelial growth, besides detecting the genes involved in the expression of polypeptides with antimicrobial action. In the greenhouse, the assay comprised of microbiolized seeds and addition of a suspension of propagules of each rhizobacteria to the soil at the moment of transplanting the tomato seedlings. All the rhizobateria isolates showed variable control levels of the pathogen in vitro. The UFG-07 and UFG-10 isolates, with high similarity with Bacillus subtilis and Bacillus circulans, excelled in the disease suppression. PCR results detected target genes for expression of polypeptides, what reinforces the hypothesis of action of antimicrobial substances in biocontrol.

The intensive and uninterrupted tomato cultivation has favored the establishment of several diseases that affect fruit yield and quality. Genetic resistance is the best method to control the disease called 'vira-cabeça' (caused by distinct species of the genus Tospovirus), being Sw-5 the first resistance gene effectively identified to control it in tomato plants. This study aimed at identifying new potential sources of tospovirus resistance in wild Solanum(Lycopersicon) species, as well as performing phylogenetic analysis related to the evolutionary characteristics of the Sw -5b gene, in accessions of wild tomato species. These analyses showed that the different tomato species belong to distinct evolutionary groups. Most of the accessions with wide-spectrum resistance to Tospovirus species correspond to allelic variants closely related to the original Sw-5b gene copy. However, resistant accessions of S. chilense and S. habrochaites are located in distinct phylogenetic groups, meaning that they may represent promising sources of new genes/alleles, providing wide resistance to tospovirus.

Resumo:O objetivo deste trabalho foi avaliar a eficiência e a praticidade de métodos de inoculação de Sclerotinia sclerotiorum, para uso na seleção de cultivares de soja resistentes ao mofo-branco. Avaliaram-se quatro métodos de inoculação, em plantas no estádio fenológico V3/V4. Aos três e sete dias após a inoculação, mediu-se o comprimento da lesão na haste das plantas. As cultivares de soja BRS 8460RR, BRSGO Ipameri e P98Y11 apresentaram as menores lesões. O método de inoculação por meio de ponteira no pecíolo é o mais eficiente e mais prático para avaliar a resistência ao mofo-branco em soja.

ABSTRACT Citrus black spot, a fungal disease caused by the quarantine fungus Guignardia citricarpa, restricts the exportation of fresh fruit to countries in the European Union. The occurrence of latent infections and the time required for diagnosis using conventional methods have brought about the need to validate fast, efficient and reproducible molecular techniques to detect the pathogen in asymptomatic tissue. As such, this study aims to detect G. citricarpa in the symptomatic fruit and asymptomatic leaf tissue of sweet oranges by conventional and real-time polymerase chain reaction (PCR). Specificity and limit of detection (LOD) were assessed in tissue samples of fruit lesions and asymptomatic leaves. Low concentrations of the fungus were found in asymptomatic leaves. Under these conditions, real-time PCR proved to be viable, reproducible and highly sensitive to detection of the pathogen.

Soybean is an important crop in the economical agriculture of Brazil and it has productive potential compromised by a variety of diseases affecting the crop such as soybean rust (Phakopsora pachyrhizi). The aim of this study was to evaluate the efficiency of incorporating fluquinconazole into the soybean seed treatment in the management of the disease, associated with spray of different fungicides on leaves. The work consisted of two trials side by side on the field. The first trial consisted of several fungicides used to control soybean rust (azoxistrobin, cyproconazole, trifloxystrobin, tebuconazole and prothioconazole) and seed treatment with carbendazim + thiram, and fluquinconazole. The second trail was identical to the first, but without the use of fluquinconazole. The experiment was carried out into two localities – Goiânia (GO) and Senador Canedo (GO). In both experiments, fungicides applied on leaves were effective controlling soybean rust, however the incorporation of fluquinconazole on the soybean seed treatment did not increase the control of the disease since neither it delayed the onset of the disease nor significantly increased the productivity of the crop. A soja é uma das principais culturas de exploração econômica no Brasil, mas tem seu potencial produtivo comprometido por uma série de doenças que afetam a cultura. O objetivo do presente trabalho foi avaliar a eficiência da incorporação de fluquinconazol ao tratamento de semente de soja, no manejo da ferrugem asiática (Phakopsora pachyrhizi), associado a diferentes fungicidas na parte aérea. O trabalho constou de dois ensaios dispostos lado a lado no campo. O primeiro ensaio constou de vários fungicidas empregados no controle de ferrugem asiática da soja (azoxistrobina, ciproconazol, trifloxistrobina, tebuconazol e protioconazol) e de tratamento das sementes com carbendazim + thiram e fluquinconazol. O segundo ensaio foi idêntico ao primeiro, mas sem a utilização de fluquinconazol. Esse experimento foi realizado em dois locais – Goiânia (GO) e Senador Canedo (GO). Em ambos os locais, os fungicidas aplicados via foliar foram eficientes no manejo da ferrugem da soja, mas a incorporação de fluquinconazol não aumentou significativamente o controle do fungo P. pachyrhizi, uma vez que não retardou o aparecimento da doença nem acarretou ganhos significativos de produtividade.

A flutuação populacional de Euphoria lurida foi estudada em pomar cítrico misto, abandonado e formado pelas variedades de laranjas baianinha e natal, tangerinas-cravo e rio, tangor-sabará e limão-cravo. Os adultos foram coletados através de armadilhas plásticas iscadas com melaço de cana a 20 %. As coletas foram realizadas quinzenalmente, quando também se procedia à troca da isca. As amostragens ocorreram no período de janeiro/84 a dezembro/86. Foram coletados 716 adultos no período e verificada a ocorrência da espécie durante todos os meses do ano. As maiores médias de coletas foram obtidas nos meses de janeiro, fevereiro e dezembro. O maior pico populacional foi observado no mês de janeiro do terceiro ano. Foram coletados 21,4%, 28,8% e 49,8% dos adultos no primeiro, segundo e terceiro anos de amostragens, respectivamente. A grande disponibilidade de alimento representada pelo alto número de frutos abandonados no solo foi a principal causa do aumento populacional da espécie no último ano de coletas. Estes resultados evidenciam que pomares abandonados, principalmente aqueles com grande quantidade de frutos deixados no solo, propiciam condições favoráveis ao rápido aumento populacional da espécie, que poderá migrar para pomares cítricos produtivos e causar sérios prejuízos atacando as flores e provocando a queda dos frutos em formação. The population fluctuation of Euphoria lurida was studied in a mixed citric yard, abandoned and composed by the varieties of baianinha and natal oranges, cravo and rio tangerine, tangor-sabará, and cravo lemon. Adult insects were collected using a plastic bait trap with 20% sugar-cane molasses. The collections were carried out every two weeks, when the baits were also replaced. Samples were undertaken in the period between January/94 to December/86. 716 adult insects were collected in such period and specie occurrence was verified during all months of the year. The highest population averages were observed during January, February and December, while the lowest occurrences happened in June and July. The highest population peak was observed in January, in the third year of collection. 21.4%, 28.8% and 49.8% of the adult insects were collected respectively, in the first, second and third years. An elevated food availability, caused by the high number of dropped fruits on the ground, was the main cause for the population raise observed during the last year of collection. Abandoned yards, specially those presenting a high amount of dropped fruits on the ground, propitiate the necessary conditions for the rapid population raise of the specie. Such increased population can migrate to productive citric yards causing serious damage, since they attack the flowers and lead to the fall of petals and growing fruits.

O objetivo deste trabalho foi avaliar o efeito do extrato de favas de sucupira (Pterodon emarginatus) sobre o desenvolvimento de fungos e bactérias fitopatogênicos. Na avaliação sobre o desenvolvimento micelial de fungos, o extrato de sucupira e o fungicida tebuconazole reduziram significativamente o crescimento micelial de Alternaria brassicae, Fusarium oxysporum, Rhizoctonia solani e Ceratocystis fimbriata. Entretanto, tebuconazole foi significativamente superior ao extrato de sucupira, exceto para o fungo A. brassicae. O índice de eficácia do extrato de sucupira foi de 70%, 74%, 62% e 82% para os fungos A. brassicae, F. oxysporum, R. solani, C. fimbriata, respectivamente. A eficácia do tebuconazole foi de 93,6% para A. brassicae e 100% para os outros fungos. Na avaliação sobre o crescimento de colônias bacterianas, à medida que se aumentou à concentração do extrato de sucupira, a eficiência foi gradativamente aumentada. Contudo, houve inversão do efeito sobre o halo de inibição das colônias no tratamento com 100% do extrato. A alta viscosidade do extrato pode ter afetado negativamente a sua dispersão no meio de cultura (BDA) e, conseqüentemente, produzido menor halo de inibição. O extrato de sucupira a 10% foi significativamente o melhor tratamento; entretanto, o mesmo extrato, nas concentrações de 1% e 100%, apresentou redução significativa do desenvolvimento das colônias de Clavibacter michiganensis subsp. michiganensis, Xhantomonas campestris pv. campestris e Pseudomonas syringae, em relação à testemunha. PALAVRAS-CHAVE: Sucupira; crescimento micelial; fungicida. The objective of this work is to evaluate the effect ";in vitro"; of the sucupira extract (Pterodon emarginatus) on plant pathogenic fungi and bacteria. The sucupira extract was obtained from sucupira pods. In the evaluation of fungal development, the sucupira extract and tebuconazole fungicide significantly decreased the mycelium growth of Alternaria brassicae, Fusarium oxysporum, Rhizoctonia solani and Ceratocystis fimbriata. However, tebuconazole resulted in greater decrease than sucupira extract, except to A. brassicae fungus. The efficacy of the sucupira extract was 70%, 74%, 62% and 82% of A. brassicae, F. oxysporum, R. solani and C. fimbriata, respectively. Tebuconazole efficacy was 93.6% for A. brassicae and 100% for the other fungi. In the bacterial growth evaluation, results showed that efficiency gradually increased as sucupira extract concentration increased. However, there was an inverse effect on the treatment of sucupira extract 100%. The high viscosity of sucupira extract might have negatively affected its ability to disperse through the PDA, which, in turn, caused the output of smaller inhibition halos. The sucupira extract 10% was significantly the best treatment, however, the sucupira extracts at 1% and 10% significantly inhibited the development of Clavibacter michiganensis subsp. michiganensis, Xhantomonas campestris pv. campestris and Pseudomonas syringae. KEY-WORDS: Fungal growth; bacterial development; natural fungicide; bactericide.