48 research outputs found
Transcriptome Analysis in Cotton Boll Weevil (Anthonomus grandis) and RNA Interference in Insect Pests
No full textCotton plants are subjected to the attack of several insect pests. In Brazil, the cotton boll weevil, Anthonomus grandis, is the most important cotton pest. The use of insecticidal proteins and gene silencing by interference RNA (RNAi) as techniques for insect control are promising strategies, which has been applied in the last few years. For this insect, there are not much available molecular information on databases. Using 454-pyrosequencing methodology, the transcriptome of all developmental stages of the insect pest, A. grandis, was analyzed. The A. grandis transcriptome analysis resulted in more than 500.000 reads and a data set of high quality 20,841 contigs. After sequence assembly and annotation, around 10,600 contigs had at least one BLAST hit against NCBI non-redundant protein database and 65.7% was similar to Tribolium castaneum sequences. A comparison of A. grandis, Drosophila melanogaster and Bombyx mori protein families' data showed higher similarity to dipteran than to lepidopteran sequences. Several contigs of genes encoding proteins involved in RNAi mechanism were found. PAZ Domains sequences extracted from the transcriptome showed high similarity and conservation for the most important functional and structural motifs when compared to PAZ Domains from 5 species. Two SID-like contigs were phylogenetically analyzed and grouped with T. castaneum SID-like proteins. No RdRP gene was found. A contig matching chitin synthase 1 was mined from the transcriptome. dsRNA microinjection of a chitin synthase gene to A. grandis female adults resulted in normal oviposition of unviable eggs and malformed alive larvae that were unable to develop in artificial diet. This is the first study that characterizes the transcriptome of the coleopteran, A. grandis. A new and representative transcriptome database for this insect pest is now available. All data support the state of the art of RNAi mechanism in insects
Form and Volume of the Stem of Tectona grandis L.f. in the Central-WESTERN Region of Brazil
No full textThe international market has recognized the high value of Tectona grandis L.f. plantations, requiring the development of reliable and accurate tools and techniques to quantify forest stocks accurately. In this study, we developed suitable equations to estimate the stem diameters and volume of Tectona grandis trees in the central-western region of Brazil, evaluating the stem form change points (FCPs) and testing the stratification of data as a measure to control their variation. The Schöepfer model was tested in the study of the FCPs of the stem, and single equation, segmented and variable-exponent taper functions were used to describe the stem profile. After the selection of the model for the taper, data stratification in the DBH classes, form parameter “r” and artificial form factor were proposed. The total volumes of each tree were calculated by integrating the Clark III et al. model. The FCPs of the Tectona grandis stems occurred at 28%, 57% and 73% of the total height, corresponding, on average, to the absolute positions of 6.4 m, 13.3 m and 16.5 m. The Clark III et al. equation, without stratification, was the most appropriate equation to estimate the diameters along the stem and the volume of Tectona grandis trees in the central-western region of Brazil
Transcriptome analysis in cotton boll weevil (Anthonomus grandis) and RNA interference in insect pests.
No full textCotton plants are subjected to the attack of several insect pests. In Brazil, the cotton boll weevil, Anthonomus grandis, is the most important cotton pest. The use of insecticidal proteins and gene silencing by interference RNA (RNAi) as techniques for insect control are promising strategies, which has been applied in the last few years. For this insect, there are not much available molecular information on databases. Using 454-pyrosequencing methodology, the transcriptome of all developmental stages of the insect pest, A. grandis, was analyzed. The A. grandis transcriptome analysis resulted in more than 500.000 reads and a data set of high quality 20,841 contigs. After sequence assembly and annotation, around 10,600 contigs had at least one BLAST hit against NCBI non-redundant protein database and 65.7% was similar to Tribolium castaneum sequences. A comparison of A. grandis, Drosophila melanogaster and Bombyx mori protein families' data showed higher similarity to dipteran than to lepidopteran sequences. Several contigs of genes encoding proteins involved in RNAi mechanism were found. PAZ Domains sequences extracted from the transcriptome showed high similarity and conservation for the most important functional and structural motifs when compared to PAZ Domains from 5 species. Two SID-like contigs were phylogenetically analyzed and grouped with T. castaneum SID-like proteins. No RdRP gene was found. A contig matching chitin synthase 1 was mined from the transcriptome. dsRNA microinjection of a chitin synthase gene to A. grandis female adults resulted in normal oviposition of unviable eggs and malformed alive larvae that were unable to develop in artificial diet. This is the first study that characterizes the transcriptome of the coleopteran, A. grandis. A new and representative transcriptome database for this insect pest is now available. All data support the state of the art of RNAi mechanism in insects
Localized mapping of RAPD markers in Eucalyptus grandis
No full textStudies on the QTL expression and the adequacy of methodologies involved in the analysis of molecular markers are important to make an effective use of molecular markers in genetic forest improvement programs possible. The technique of localized mapping was used aiming at the saturation of a specific genomic region in the linkage map of an E. grandis (G1) genotype with new RAPD markers. To saturate the region of interest containing one QTL for volumetric growth, five of the 265 oligonucleotides tested for polymorphisms among the DNA clusters have seven RAPD markers mapped in the same group of the marker R4_1300, proving the efficiency of the technique in localized mapping in specific regions of genetic linkage maps. Such results are necessary to make the application of molecular markers in genetic improvement programs for Eucalyptus feasible
MICOBIOTA ASSOCIADA À MADEIRA SERRADA DE Eucalyptus grandis HILL EX MAIDEN DURANTE A SECAGEM AO AR LIVRE
No full textO objetivo principal deste trabalho foi o de acompanhar a secagem ao ar livre da madeira serrada de Eucalyptus grandis conduzida na região de Lavras, MG e identificar a micobiota associada à madeira em diversas fases da secagem. As tábuas foram cortadas de oito toras de 3,0 m de comprimento, oriundas de três árvores, com 27 anos de idade, plantadas em área experimental da UFLA. Dos resultados, pôde-se concluir que a secagem da madeira de Eucalyptus grandis ao ar livre, iniciada em janeiro, consumiu 158 dias até atingir umidade próxima a 12,5%. A curva de secagem foi representada por uma equação logarítmica com coeficiente de determinação (R2) igual a 98,3%. Os fungos causadores de bolores superficiais e de manchas tiveram maior ocorrência no início da secagem. As mais altas freqüências de fungos, verificadas no início da secagem, foram observadas para Penicillium spp. e Pestalotiopsis sp. O fungo Lentinus lepideus ocorreu com maior freqüência no final da secagem
RNAi-mediated suppression of Laccase2 impairs cuticle tanning and molting in the cotton boll weevil (Anthonomus grandis).
No full textInternational audienceThe cotton boll weevil, Anthonomus grandis, is the most economically important pest of cotton in Brazil. Pest management programs focused on A. grandis are based mostly on the use of chemical insecticides, which may cause serious ecological impacts. Furthermore, A. grandis has developed resistance to some insecticides after their long-term use. Therefore, alternative control approaches that are more sustainable and have reduced environmental impacts are highly desirable to protect cotton crops from this destructive pest. RNA interference (RNAi) is a valuable reverse genetics tool for the investigation of gene function and has been explored for the development of strategies to control agricultural insect pests. This study aimed to evaluate the biological role of the Laccase2 (AgraLac2) gene in A. grandis and its potential as an RNAi target for the control of this insect pest. We found that AgraLac2 is expressed throughout the development of A. grandis with significantly higher expression in pupal and adult developmental stages. In addition, the immunolocalization of the AgraLac2 protein in third-instar larvae using specific antibodies revealed that AgraLac2 is distributed throughout the epithelial tissue, the cuticle and the tracheal system. We also verified that the knockdown of AgraLac2 in A. grandis resulted in an altered cuticle tanning process, molting defects and arrested development. Remarkably, insects injected with dsAgraLac2 exhibited defects in cuticle hardening and pigmentation. As a consequence, the development of dsAgraLac2-treated insects was compromised, and in cases of severe phenotypic defects, the insects subsequently died. On the contrary, insects subjected to control treatments did not show any visible phenotypic defects in cuticle formation and successfully molted to the pupal and adult stages. Taken together, our data indicate that AgraLac2 is involved in the cuticle tanning process in A. grandis and may be a promising target for the development of RNAi-based technologies
Quality, operational performance and cost of eucalyptus grandis hand and machine planting, implemented with minimal tillage.
No full textO método de plantio manual de mudas de árvores é predominante no Brasil. Para a redução dos custos com mão-de-obra, aumento de produtividade e qualidade operacional, o plantio manual deve ser substituído total ou parcialmente por operações mecanizadas. Com esse enfoque foram avaliadas as atividades de plantios manual e mecanizado de eucaliptos, bem como de preparo mecanizado do solo, em área pertencente a uma empresa florestal. O plantio manual foi feito por onze trabalhadores rurais, com o uso da transplantadora de acionamento manual. O plantio mecanizado foi realizado por uma máquina de transplantio de mudas, operada por um trabalhador rural e tracionada por um trator. Na área do estudo foram locadas duas parcelas amostrais, formando uma malha de setenta e cinco pontos amostrais para cada sistema de plantio. Os itens do preparo do solo avaliados foram a profundidade do sulco, o diâmetro dos torrões e o volume cilíndrico dos galhos de madeira sobre a faixa de sulcamento. O itens dos sistemas de plantio avaliados foram a presença de defeitos da operação, a distância entre plantas, a altura da parte aérea das mudas e a sobrevivência das plantas após um mês de idade. As ferramentas da qualidade total utilizadas foram os histogramas, o diagrama de causa e efeito, os gráficos de Pareto e de controle. As análises estatísticas dos resultados foram feitas pelo teste t e pelo teste de qui-quadrado Para avaliar o desempenho operacional do sistema manual estimou-se somente a capacidade de campo operacional. No sistema mecanizado foram estimadas as capacidades de campo efetiva e operacional. Nos dois sistemas de plantio foram estimados também os custos horários e operacionais das máquinas e da mão-de-obra. Entre os sistemas de plantio, a distância entre plantas foi diferente estatisticamente, com melhor distribuição das mudas no sistema manual. O número de defeitos por muda plantada foi semelhante estatisticamente entre os sistemas de plantio. Os principais defeitos do sistema manual foram as mudas plantadas com colo encoberto pelo solo e as mudas plantadas fora do centro do sulco, os quais representaram 72,8% do total. No sistema mecanizado, esses defeitos, somados às mudas não plantadas e mudas não firmes, representaram 76,7% do total. A altura da parte aérea foi diferente estatisticamente, tanto no plantio como um mês após. A sobrevivência das mudas efetivamente plantadas, após um mês de idade, foi semelhante estatisticamente. Concluiu-se, assim, que a qualidade em ambos os sistemas de plantio não variaram dentro de padrões aceitáveis pela empresa florestal. O tempo produtivo do sistema de plantio mecanizado foi igual a 48,2%, gerando uma capacidade de campo operacional 60,0% menor do que no sistema manual. Inferiu-se que o número médio de mudas plantadas por trabalhador por hora foi igual a 95 no sistema manual, enquanto que no sistema mecanizado foi igual a 205. O custo operacional estimado do sistema mecanizado foi 44,9% maior do que no sistema manual, fato devido a baixa capacidade de campo operacional observada no sistema mecanizado.Hand planting of tree seedlings is the predominant method in Brazil. In order to reduce labor costs, increase productivity, and improve operational quality, hand planting should be totally or partially replaced by machine operations. Having this in mind, eucalyptus hand and machine planting activities were assessed, as well as those of mechanical tillage, in an area belonging to a forestation company. Hand planting had been carried out by 11 rural workers by using a planting tube. Machine planting had been carried out by using a seedling transplant machine, which was operated by a rural worker and pulled by a tractor. In the study area, two sampling parts were allocated, forming a web with 75 sampling points for each planting system. Tillage items that were assessed included furrow depth, stone diameter, and the cylindrical volume of wood branches on the furrow belt. Planting system items that were assessed included the presence of operation defects, distance between plants, height of the top portion of the seedlings, and plant survival after one month of age. Total quality tools included histograms, cause and effect diagram, control graphs, and Pareto's graphs. Statistical analyses of the results were performed by using test and qui-square test. To evaluate hand planting systems operational performance, only the operational field capacity was estimated. As for the machine system, effective and operational field capacities were estimated. Labor and machine hourly costs, as well as the operational costs for both planting systems were assessed. When comparing planting systems, the distance between plants was statistically different, with hand planting system showing better seedling distribution. The number of defects per planted seedling was statistically similar for both planting systems. The major defects in the hand planting system were seedlings planted with soil-covered base and those planted out of the furrow center, which represented 72.8% of the total. With the machine system, these defects, in addition to non-planted and loose seedlings, represented 76.7% of the total. The height of the top portion was statistically different, both when planting and after one month. The survival of effectively planted seedlings after one month of age was statistically similar. Thus, we concluded that the quality of both planting systems did not vary within the standards that are acceptable for the forestation company. Machine planting system's productive time was 48.2%, and generated an estimated operational field capacity 60.0% less to that for the hand planting system. The average number of planted seedlings per worker by hour was inferred to be equal to 95 in the hand planting system, whereas it was equal to 205 in the machine system. The operational cost for the machine system was estimated to be 44.9% greater to that for the hand planting system, which is due to the low operational field capacity observed in the machine system
Genes involved in RNAi mechanism found in <i>A. grandis</i> transcriptome.
No full text<p>The comparison with genes of <i>C. elegans</i>, <i>T. castaneum</i>, and <i>D. melanogaster</i> suggested that RNAi mechanism is well conserved in insects (A, B, C, D), including lack of amplification (E). No gene involved in dsRNA degradation was found (F). The number of contigs found in <i>A. grandis</i> transcriptome for each gene class is shown. </p
A relationship between fungi (Basidiomycota, Agaricomycetes, Agaricales) and nutrient content in riparian area of reforestation with Eucalyptus grandis W. Hill ex Maiden (Myrtaceae) in southern Brazil
No full textABSTRACT Due the tolerance in soil degraded, Eucalyptus is widely used in reforestation area. This study aims to evaluate the fungi that use Eucalyptus grandis W. Hill ex Maiden as substrate in reforestation area in southern Brazil. Fungi were identified and macronutrient and micronutrient contents were evaluated in order to understand the relationship between the fungi and the substrate. There were 200 specimens found, categorized into 25 species belonging to 10 families of Agaricales (Basidiomycota, Fungi). Substrates used by fungi were branches, roots, stems, humus, and soil. Macronutrients mean level found in fungi followed the order Ca>K>P>Mg, and micronutrients S>Fe>Mn>Cu/B>Zn. C:N ratio mean was 13:1, associated with substrate degradation potential, since the enzymatic production of fungi is affected by disposition of these nutrients. The data obtained in this study allowed a better understanding of fungi associated with the exotic arboreal substrate, and their nutritional significance in reforestation area
Cinética de absorção e eficiência nutricional de K+, Ca2+ e Mg2+ em plantas jovens de quatro clones de eucalipto Uptake kinetics and nutritional efficiency for K+, Ca2+ and Mg2+ in four eucalypt clones seedlings
No full textModelos mecanísticos baseados em princípios de transporte de solutos pode ser de grande utilidade para prever os impactos do cultivo de florestas plantadas, por exemplo, com eucalipto sobre o capital e fluxo de nutrientes no solo. Dentre as variáveis de entrada demandadas por tais modelos, tem-se os valores das constantes Vmax, Km e Cmin da cinética de absorção iônica. Assim, os objetivos do presente trabalho foram determinar os valores de Vmax, Km e Cmin para K, Ca e Mg, bem como avaliar as respectivas eficiências nutricionais de clones de eucalipto. O estudo consistiu de três ensaios em solução nutritiva (um para cada cátion), sendo utilizadas mudas propagadas vegetativamente de um híbrido de E. grandis x E. urophylla (clone 1213) e de três híbridos de E. grandis (clones 7074, 57 e 129). Com base nos teores de cada um desses nutrientes nas soluções de depleção, em cada tempo de amostragem, no volume inicial e final de solução nos vasos e no peso de matéria fresca de raízes, foram obtidos os valores das constantes cinéticas. Para K, o clone 7074 apresentou o menor valor de Vmax em relação aos demais clones, os quais não diferiram entre si, e em relação ao Km e Cmin, os clones não diferiram estatisticamente. Para Ca, os clones estudados diferiram quanto ao valor de Vmax e Km, não diferindo, entretanto, para o Cmin. Os menores valores de Km para Mg foram verificados para os clones 57 e 7074, ou seja, as proteínas transportadoras de Mg na membrana plasmática das células radiculares apresentaram maior afinidade para esse nutriente. Contudo, os valores de Vmax e Cmin não diferiram entre os clones estudados. Diferenças na eficiência nutricional dos clones estudados quanto a K e a Ca foram devidas às diferenças na eficiência de absorção, e para Mg às diferenças na eficiência de absorção e de utilização.The use of mechanistic models based on principles of solute transport may be of great utility to estimate, for example, the impact of eucalypt forest cultivation on the pools and fluxes of nutrient in soils. Among the parameters required by such models are the values of the ion absorption kinetics constants Vmax, Km and Cmin. Thus, the objective of this study was to determine the values of Vmax, Km and Cmin for K, Ca and Mg, as well as to evaluate the nutritional efficiency of eucalypt clones to these nutrients. The present study consisted of three experiments in solution culture (one for each cation). It was employed four genetic materials (clones 7074, 57, 1213 and 129) originated from clonal propagation. Clone 1213 is an Eucalyptus grandis x Eucalyptus urophylla hybrid, whereas the others are natural hybrids of E. grandis. The concentration of each nutrient being studied in the depletion solution at specific sampling times, initial and final pot solution volume and fresh root weight were used in order to obtain the value of the kinetics constants. For K, clone 7074 showed the lowest Vmax value in relation to the other clones, which did not differ among themselves. All clones did not differ statistically in relation to Km and Cmin for K. For Ca, the studied clones differed in relation to the values of Vmax and Km but, they did not differ for Cmin. The lower values of Km for Mg were observed for the clones 57 and 7074, that is, the carrier proteins at the root cells plasma membrane have a high affinity for this nutrient. Nevertheless, the values of Vmax and Cmin did not differ among the studied clones. Differences in nutritional efficiency of the studied clones in relation to K and Ca were due to differences in the absorption efficiency and for Mg were related with differences in the nutrient use efficiency and absorption efficiency
