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Caracterização Química e Disponibilidade de enxofre em solos de várzea do Rio Grande do Sul. / Chemical characterization and sulphur availability in lowland soils of Rio Grande do Sul stateReis, Cecília Estima Sacramento dos 24 March 2008 (has links)
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Previous issue date: 2008-03-24 / Soil chemical, physical and biological changes that occurr after soil flooding
are very important for the irrigated rice crop, since they affect essential soil properties
and nutrient availability. However, there is little information about the lowland soils in
the State of Rio Grande do Sul, Brazil. The present study had as objective to
evaluate the condition of 57 lowland soils regarding clay, organic matter and nitrogen
content, ion exchange, acidity and phosphorus and sulphur availability, as well as to
establish relationships among these soil attributes. Therefore, 57 samples of lowland
soils were collected at a depth ranging from 0 to 20 cm (arable layer) in different
locations, comprising the Santa Maria, Bagé, Hulha Negra, Jaguarão, Santa Vitória
do Palmar, Camaquã, Uruguaiana, Barra do Quarai, Itaqui, São Borja, Eldorado do
Sul, Rio Grande, São Lourenço do Sul and Pelotas Counties. Clay, total organic
carbon and nitrogen, available phosphorus, potassium and sulphur, exchangeable
calcium and magnesium, acidity, cation exchange ability and base saturation, were
determined. In general, the studied lowland soils presented low organic matter, clay
and nitrogen contents, a pH inferior to the recommended for the irrigated rice crop
(5.5), low potential acidity, potassium levels bellow the limiting values, high calcium
availability, magnesium, sulphur and phosphorus, besides the medium base
saturation. Also, a high variability in the ion exchange ability and sulphur
concentration available was found. The contents of total organic carbon, clay and
nitrogen are highly correlated. The carbon content determined by elemental analysis
and by the Walkley & Black method showed a high correlation. The relationships
between the pH and the base saturation and between ion exchange ability and
carbon content and clay are significant. Despite the low correlation between sulphur
concentration available and organic carbon and clay contents, soils that show
sulphur content below the critical level also possess low clay and organic carbon
contents. / As transformações químicas, físicas e biológicas decorrentes do alagamento
do solo são de grande importância para o arroz irrigado, visto que afetam os
atributos do solo e a disponibilidade de nutrientes essenciais a essa cultura. No
entanto, há carência de informações sobre os solos de várzea do Rio Grande do Sul.
O presente estudo teve por objetivo avaliar a condição de 57 solos de várzea quanto
ao teor de argila, matéria orgânica e nitrogênio, complexo de troca, acidez e
disponibilidade de fósforo e enxofre, bem como estabelecer relações entre estes
atributos do solo. Para isto, foram coletadas 57 amostras de solos de várzea, na
profundidade de 0 a 20cm (camada arável) em diferentes localidades, abrangendo
os municípios de Santa Maria, Bagé, Hulha Negra, Jaguarão, Santa Vitória do
Palmar, Camaquã, Uruguaiana, Barra do Quaraí, Itaqui, São Borja, Eldorado do Sul,
Rio Grande, São Lourenço do Sul e Pelotas, e determinados os teores de argila,
carbono orgânico total, nitrogênio total, fósforo, potássio e enxofre disponíveis, cálcio
e magnésio trocáveis, acidez, capacidade de troca de cátions e saturação por bases.
Em geral, os solos de várzea estudados apresentaram baixos teores de matéria
orgânica, argila e nitrogênio, pH inferior ao recomendado para o cultivo de arroz
irrigado (5,5), baixa acidez potencial, teor de potássio abaixo do nível de suficiência,
alta disponibilidade de cálcio, magnésio, enxofre e fósforo, além de média saturação
por bases. Além disto, foi verificada grande variabilidade na capacidade de troca de
cátions e na concentração de enxofre disponível nas amostras. Os parâmetros
carbono orgânico total, argila e nitrogênio estiveram diretamente correlacionados e
os métodos de determinação de carbono orgânico, análise elementar e Walkley &
Black, apresentaram alta associação entre si. As relações entre o pH e a saturação
por bases e entre a capacidade de troca de cátions e teores de carbono e argila
são significativas. Apesar da baixa correlação entre a concentração de enxofre
disponível e os teores de carbono orgânico e argila, os solos que apresentam teores
de enxofre abaixo do nível crítico também possuem baixos teores de argila e de
carbono orgânico.
Palavras-chave: Oryza sativa L. Alagamento. Sulfato. Fertilidade.
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Comportamento de plantas de arroz híbrido em função da qualidade fisiológica das sementes / Hybrid rice plants behavior regarding the seeds physiological qualityMielezrski, Fabio 12 February 2008 (has links)
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Previous issue date: 2008-02-12 / The work had the objective of evaluating the behavior of
populations of hybrid rice plants which were cultivated isolated, and the
individual behavior and plants originated from seeds of high and low vigor of
hybrid rice, inside of populations that were constituted of different combinations
of seed line distributions. The experiment was conducted in the didactic
experimental area of the agronomy school. It was used seeds of hybrid rice of
the cultivar Avaxi, which belongs to the Ricetec®, including two types
characterized as low and high vigor. Two studies were conducted. On the first,
the effect of seed vigor on isolated plants, cultivated in hollows of 50 cm of
depth, was evaluated. Two treatments were tested; plants originated from low
and high vigor seeds, being each parcel composed by only one plant. On the
second study, the evaluation was on the individual behavior of plants inside a
population, as long as the entire population behavior established with different
systems of distribution of plants originated from high and low vigor seeds, on
the seed line. The experiment had 5 different combinations of seed line
distribution of the plants originated from high and low vigor seeds, in seed lines
of 4 meters of length. The plants were obtained by sowing each lot in distinct
treys with soil as subtract, in a depth of 2,5cm with later transplant of the
emerged plants to the field. It was concluded that plants of hybrid rice originated
from seeds of high vigor shows better performance than the plants originated
from low vigor seeds inside of a population. Increases at the ratio of plants
originated from high vigor seeds, at the establishment of a population of hybrid
rice plants, provide increases on the population yield and yield components.
Hybrid rice populations established with high vigor seeds presents grain yield
over 30%. Although presenting a superior performance, the plants originated
from high vigor seeds don´t exert dominance effects on the plants originated
from low vigor seeds. / O trabalho teve como objetivo avaliar o efeito do vigor de sementes
sobre o comportamento de plantas de arroz híbrido cultivadas isoladamente e o
comportamento individual e de populações de plantas de arroz híbrido
originadas de sementes de alto e baixo vigor em comunidades constituídas de
diferentes combinações de distribuição dessas plantas ao longo da linha de
semeadura. Os experimentos foram realizados na Área Experimental e Didática
do Departamento de Fitotecnia da Faculdade de Agronomia Eliseu Maciel
(FAEM/UFPel). Utilizou-se sementes de arroz do híbrido Avaxi da empresa
RiceTec®, de dois lotes devidamente caracterizados como alto e baixo vigor.
Realizaram-se dois trabalhos. No primeiro avaliou o efeito do vigor de
sementes em plantas cultivadas isoladamente, em covas espaçadas de 50
cm.Testaram-se dois tratamentos; plantas originadas de sementes de alto e de
baixo vigor, sendo cada parcela constituída por uma única planta. No segundo
trabalho avaliou-se o comportamento individual de plantas dentro de
comunidades, bem como o comportamento geral das comunidades
estabelecidas com diferentes sistemas de distribuição de plantas originadas de
sementes de alto e de baixo vigor, ao longo das linhas de semeadura. Foram
realizadas cinco diferentes combinações de distribuição de plantas originadas
de sementes de alto e baixo vigor, em linhas de 4 metros de comprimento. As
plantas foram obtidas pela semeadura de cada lote em bandejas distintas com
solo como substrato, a uma profundidade de 2,5 cm com posterior transplante
para o campo. Conclui-se que plantas de arroz híbrido originadas de sementes
de alto vigor apresentam desempenho superior em relação às originadas de
sementes de baixo vigor dentro das comunidades. Aumentos na proporção de
plantas originadas de sementes de alto vigor, no estabelecimento das
comunidades de plantas de arroz híbrido, proporcionam acréscimos nos
componentes do rendimento e na produtividade das comunidades.
Comunidades de arroz híbrido estabelecidas com sementes de alto vigor
apresentaram produtividade de grãos superiores a 30%. Embora apresentem
um desempenho superior, as plantas originadas de sementes de alto vigor não
exercem efeito de dominância sobre as plantas originadas de sementes de
baixo vigor, dentro das comunidades.
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Análise proteômica diferencial em raízes de plântulas de arroz( Oryza sativa L.) submetidas ao estresse por ferro / Differential proteomic analysis for the roots of rice (Oryza sativa L.) seedlings submitted to iron stress.Ahlert, Renata Juliana 20 April 2010 (has links)
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Previous issue date: 2010-04-20 / Rice crop has great food and economic importance. Iron is an essential
element for the development of crop and necessary for essential plants functions,
such as photosynthesis, respiration and DNA synthesis. However, under irrigated
cultivation conditions, the low redox potential leads to reduction of iron in the soil
solution which is readily available and can become toxic to plants if absorbed in
excess. In rice production areas of Rio Grande do Sul, the iron has caused problems
toxicity and the use of tolerant cultivars becomes an important strategy to solve the
problem being necessary the study of mechanisms that give this tolerance to plants
application in breeding programs. Proteomics is an important tool, which through
combination of techniques such as two-dimensional gel electrophoresis and mass
spectrometry allows the analysis of proteins complex involved in response to adverse
environmental conditions. The objective of this study was to analyze and identify
proteins with differential expression in roots of rice cultivars exposed to iron stress, to
identify mechanisms involved in stress tolerance. It was used two rice cultivars,
Epagri 107 and BR-IRGA 410, tolerant and sensitive to the iron toxicity, respectively,
which were subjected to treatment with 7mM FeSO4EDTA. Through two-dimensional
electrophoresis, it was identified 284 spots with differential expression between
combinations of treatment (between cultivars and plants treated and control). Of this
total, 93 proteins were identified by mass spectrometry. The identified proteins were
involved in carbohydrate metabolism, signal transduction, related to plant defense,
transcription factors, transposons, nucleic acids, redox reactions, among other
functions. Many of the proteins have no known function. The glutathione Stransferase
protein and GATA type transcription factor that have direct relation to iron
metabolism were differentially expressed in the tolerant cultivar when submitted to
stress. Its association with the tolerance mechanism requires, however, be
confirmed. / O arroz é uma cultura que possui grande importância alimentar e econômica.
O ferro é um elemento essencial para o desenvolvimento da cultura e necessário
para funções essenciais da planta, como fotossíntese, respiração e síntese de DNA.
Porém, em condições de cultivo irrigado, o baixo potencial redox do meio leva a
redução do ferro presente na solução do solo o qual torna-se prontamente
disponível, podendo se tornar tóxico à planta quando absorvido em excesso. Em
áreas de cultivo de arroz do Rio Grande do Sul, o ferro tem causado problemas de
toxidez e o uso de cultivares tolerantes torna-se uma importante estratégia para
solucionar o problema, sendo necessário o estudo dos mecanismos que conferem
essa tolerância às plantas para aplicação em programas de melhoramento. A
proteômica é uma importante ferramenta, que através da combinação de técnicas
como a eletroforese em gel bidimensional e espectrometria de massa permite a
análise do complexo de proteínas envolvido nas respostas às condições ambientais
adversas. Assim, o objetivo desse trabalho foi analisar e identificar proteínas com
expressão diferencial em raízes de cultivares de arroz quando submetidas ao
estresse por ferro, para identificar mecanismos envolvidos na tolerância a esse
estresse. Foram utilizadas duas cultivares de arroz, Epagri 107 e BR-IRGA 410,
tolerante e sensível à toxidez por ferro, respectivamente, que foram submetidas ao
tratamento com FeSO4EDTA 7mM. Através de eletroforese em gel bidimensional,
foram identificados 284 spots com diferença de expressão entre as combinações de
tratamentos (entre cultivares e plantas tratadas e controle). Desse total, 93 proteínas
foram identificadas por espectrometria de massa. As proteínas identificadas estão
envolvidas no metabolismo de carboidratos, transdução de sinais, relacionadas à
defesa da plantas, a fatores de transcrição, transposons, ácidos nucléicos, reações
redox, entre outras funções. Grande parte das proteínas não possui função
conhecida. A proteína glutationa S-transferase e o fator de transcrição tipo GATA
que possuem relação direta com o metabolismo do ferro, foram diferencialmente
expressos na cultivar tolerante quando submetida ao estresse. Sua associação com
o mecanismo de tolerância necessita, no entanto ser confirmada.
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DORMÊNCIA E PRÉ-GERMINAÇÃO DE SEMENTES DE ARROZ / RADIATIONS OF ULTRASOUND TO OVERCOME THE DORMENCE IN SEEDS OF RICEFranzin, Simone Medianeira 20 March 2006 (has links)
Several causes are pointed as responsible for the numbness in
seeds of rice. The fenolic compounds have influence in the swinging between
promoters and inhibitors of the germination of seeds, could represent an
obstacle to the diffusion of gases. Several treatments are used with the purpose
of overcoming the dormence in seeds and alternative methods appear to try to
solve this problem, as the ultrasound radiations. That technique, for being little
used in seeds, however, it presents optimization difficulty, as well as the lack of
specific knowledge about the action of the radiation promoted by the ultrasonic
waves in living tissues. The objective of the work was to evaluate the chemical
effects produced by the ultrasound about the overcoming of the dormence and
physiologic quality of seeds of rice. Seeds of irrigated rice cv. IRGA 417 and of
drier cv. Spring, submitted to the exhibition of the ultrasonic waves by periods of
5, 10, 15 and 20 minutes and temperatures of 20, 30 and 40 oC. The variables
analyzed after each treatment were: germination, first counting and index of
germination speed. The results indicated that there was variation in the answers
of the culture to the treatments, and the best results were found in the highest
temperatures. It was concluded that the ultrasound radiations affect the quality
of the seeds of rice, being a promising method for the overcoming of the
dormence, still needing her standardization. / Inúmeras causas são apontadas como responsáveis pela
dormência em sementes de arroz. Os compostos fenólicos destacam-se por
interferirem no balanço entre promotores e inibidores da germinação de
sementes, podendo representar um obstáculo à difusão de gases. Vários
tratamentos são utilizados com a finalidade de superar a dormência em
sementes e, portanto, surgem métodos alternativos para sua superação, como
as radiações de ultra-som. Essa técnica, por ser pouco utilizada em sementes,
no entanto, apresenta dificuldade de otimização, bem como a falta de
conhecimento específico sobre o efeito da radiação promovida pelas ondas
ultra-sônicas em tecidos vivos. O objetivo do trabalho foi avaliar os efeitos
sonoquímicos produzidos pelo ultra-som sobre a superação da dormência e
qualidade fisiológica de sementes de arroz. Utilizaram-se sementes de arroz
irrigado cv. IRGA 417 e de sequeiro cv. Primavera, submetidas à exposição
das ondas ultra-sônicas por períodos de 5, 10, 15 e 20 minutos e temperaturas
de 20, 30 e 40 oC. As variáveis analisadas após cada tratamento foram:
germinação, primeira contagem e índice de velocidade de germinação. Os
resultados indicaram que houve variação nas respostas das cultivares aos
tratamentos, sendo que os melhores resultados foram encontrados nas
temperaturas mais elevadas. Concluiu-se que as radiações de ultra-som
afetam a qualidade das sementes de arroz, sendo um método promissor para a
superação da dormência, necessitando ainda sua padronização.
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Adubação boratada na cultura do arroz em solos de cerrado de baixa fertilidade / Adubation of boro in culture of rice in soils of savanna of low fertilitySilva, Iassanã Francisco da 25 January 2011 (has links)
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Previous issue date: 2011-01-25 / The production cost of new areas in the cerrado presents high values due to larger amount of farming operations when compared to conventional crops. The cerrado soils have low natural fertility and require large quantities of limestone for its correction significantly increasing the cost of production. The objective this study was to evaluate whether the Boro when applied in the cultivation of upland rice with low technological level, increases the productivity rice. The field work was conducted in the municipality of Nova Xavantina - MT in 2009/10 in two areas (first and second year of production). We used six treatments of boron in the source of boric acid (17 % of B), with doses of 0, 0.5, 1.0, 1.5, 2.0, and 2.5 kg B per ha. The plots were 10 m long and 3.4 m wide with 20-sowing rows, with spaced at 0.17 m. The fertilization of 160 kg of 08-28-16 fertilizer was formulated according to the results of soil analysis and used the cultivar BRS Sertaneja in amount of 115 kg of seeds per ha. Among the variables analyzed the productivity in the area of the first year was influenced by boron fertilization, whre the treatment that used a dose of 2.5 kg B hit productivity of 2.677 kg/ha-1. The cost analysis positive for both areas, where in the area of the first year, the cost benefit of boron fertilization was R$169,44 (with a dose of 1 kg B/ha). As for the second year the area of greatest cost benefit was obtained with a dose of 2.5 kg B, which resulted in na increase in productivity of 11.80 bags (60 kg) and therefore a cost benefit of R$333.83 per hectare. The use of boron into new areas of cerrado compensated the low technological level that was used in the formation of the crops, providing positive results in the cost benefit of the crop without significant increases inproduction costs. / O custo de produção de áreas novas no cerrado apresenta valores elevados devido á maior quantidade de operações agrícolas, quando comparado a lavouras convencionais. Os solos do cerrado apresentam baixa fertilidade natural e exigem grandes quantidades de calcário para sua correção, aumentando significamente o custo de produção. O objetivo deste trabalho foi avaliar se o Boro quando aplicado na cultura do arroz de terras altas com baixo nível tecnológico, proporcionaria um ganho de produtividade na cultura do arroz. O trabalho foi conduzido a campo no município de Nova Xavantina MT na safra 2009/10 em duas áreas (primeiro e segundo ano de produção). Foram utilizados 6 tratamentos de boro na fonte de ácido bórico (17% de B), sendo as doses de: 0; 0,5; 1,0; 1,5; 2,0; e 2,5 kg de B por ha. As parcelas tiveram 10 m de comprimento por 3,4 m de largura com 20 linhas de plantio no espaçamento de 0,17 m. A adubação de 160 kg do adubo formulado 08-28-16 foi em função dos resultados da análise do solo e utilizou-se a cultivar BRS Sertaneja na quantidade de 115 kg de sementes por ha. Dentre as variáveis avaliadas a produtividade da área de primeiro ano foi influenciada pela adubação boratada, onde o tratamento que utilizou a dose de 2,5 kg de B atingiu a produtividade de 2.677 kg/ha-1. A análise de custo foi positiva para as duas áreas, onde na área de primeiro ano, o custo beneficio da adubação boratada foi de R$169,44 (com a dose de 1 kg B/ha). Já para a área de segundo ano o maior custo beneficio foi obtido com a dose de 2,5 kg de B, que proporcionou um aumento na produtividade de 11,80 sacas (60 kg) e conseqüentemente um custo beneficio de R$333,83 por hectare. O uso do boro em áreas novas do cerrado compensou o baixo nível tecnológico que foi empregado na formação das lavouras, proporcionando resultados positivos no custo beneficio da lavoura sem acréscimos significativos no custo de produção.
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Adubação boratada na cultura do arroz em solos de cerrado de baixa fertilidade / Adubation of boro in culture of rice in soils of savanna of low fertilitySilva, Iassanã Francisco da 25 January 2011 (has links)
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Previous issue date: 2011-01-25 / The production cost of new areas in the cerrado presents high values due to larger amount of farming operations when compared to conventional crops. The cerrado soils have low natural fertility and require large quantities of limestone for its correction significantly increasing the cost of production. The objective this study was to evaluate whether the Boro when applied in the cultivation of upland rice with low technological level, increases the productivity rice. The field work was conducted in the municipality of Nova Xavantina - MT in 2009/10 in two areas (first and second year of production). We used six treatments of boron in the source of boric acid (17 % of B), with doses of 0, 0.5, 1.0, 1.5, 2.0, and 2.5 kg B per ha. The plots were 10 m long and 3.4 m wide with 20-sowing rows, with spaced at 0.17 m. The fertilization of 160 kg of 08-28-16 fertilizer was formulated according to the results of soil analysis and used the cultivar BRS Sertaneja in amount of 115 kg of seeds per ha. Among the variables analyzed the productivity in the area of the first year was influenced by boron fertilization, whre the treatment that used a dose of 2.5 kg B hit productivity of 2.677 kg/ha-1. The cost analysis positive for both areas, where in the area of the first year, the cost benefit of boron fertilization was R$169,44 (with a dose of 1 kg B/ha). As for the second year the area of greatest cost benefit was obtained with a dose of 2.5 kg B, which resulted in na increase in productivity of 11.80 bags (60 kg) and therefore a cost benefit of R$333.83 per hectare. The use of boron into new areas of cerrado compensated the low technological level that was used in the formation of the crops, providing positive results in the cost benefit of the crop without significant increases inproduction costs. / O custo de produção de áreas novas no cerrado apresenta valores elevados devido á maior quantidade de operações agrícolas, quando comparado a lavouras convencionais. Os solos do cerrado apresentam baixa fertilidade natural e exigem grandes quantidades de calcário para sua correção, aumentando significamente o custo de produção. O objetivo deste trabalho foi avaliar se o Boro quando aplicado na cultura do arroz de terras altas com baixo nível tecnológico, proporcionaria um ganho de produtividade na cultura do arroz. O trabalho foi conduzido a campo no município de Nova Xavantina MT na safra 2009/10 em duas áreas (primeiro e segundo ano de produção). Foram utilizados 6 tratamentos de boro na fonte de ácido bórico (17% de B), sendo as doses de: 0; 0,5; 1,0; 1,5; 2,0; e 2,5 kg de B por ha. As parcelas tiveram 10 m de comprimento por 3,4 m de largura com 20 linhas de plantio no espaçamento de 0,17 m. A adubação de 160 kg do adubo formulado 08-28-16 foi em função dos resultados da análise do solo e utilizou-se a cultivar BRS Sertaneja na quantidade de 115 kg de sementes por ha. Dentre as variáveis avaliadas a produtividade da área de primeiro ano foi influenciada pela adubação boratada, onde o tratamento que utilizou a dose de 2,5 kg de B atingiu a produtividade de 2.677 kg/ha-1. A análise de custo foi positiva para as duas áreas, onde na área de primeiro ano, o custo beneficio da adubação boratada foi de R$169,44 (com a dose de 1 kg B/ha). Já para a área de segundo ano o maior custo beneficio foi obtido com a dose de 2,5 kg de B, que proporcionou um aumento na produtividade de 11,80 sacas (60 kg) e conseqüentemente um custo beneficio de R$333,83 por hectare. O uso do boro em áreas novas do cerrado compensou o baixo nível tecnológico que foi empregado na formação das lavouras, proporcionando resultados positivos no custo beneficio da lavoura sem acréscimos significativos no custo de produção.
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Détection de l'activité des éléments transposables chez les plantes cultivées : étude du mobilome par la caractérisation du compartiment extrachromosomique / Detection of transposable elements activity in crops : caracterisation of mobilome by the study of the extrachromosomal compartmentLanciano, Sophie 10 November 2017 (has links)
Les éléments transposables (ET) sont des éléments génétiques ubiquitaires et potentiellement mobiles dans les génomes eucaryotes. Les génomes hôtes ont développé des mécanismes épigénétiques pour contrôler et prévenir la prolifération des ET. Néanmoins, certains ET semblent capables de s’activer en réponses à des stress ou à des facteurs développementaux. Les méthodes disponibles pour détecter l’activité transpositionnelle d’un ET sont souvent limitées au stade transcriptionnel ou sont adaptées à des génomes de petite taille. Relativement peu d’ET sont actuellement connus pour être actifs et les mécanismes spécifiques qui les contrôlent ne sont pas clairement identifiés.Durant mes travaux de thèse, nous avons développé une stratégie de séquençage à haut débit qui permet la détection d’ADN extrachromosomique circulaire (ADNecc) témoignant notamment de l’activité des ET et de la stabilité d’un génome. Ainsi nous avons pu caractériser chez plusieurs espèces le mobilome, défini comme l’ensemble des ADNecc présents dans un tissu.La technique du mobilome-seq s’est avérée être un outil puissant pour la détection des ET actifs notamment chez le riz asiatique Oryza sativa. Notre analyse du mobilome a permis l’identification d’un rétrotransposon PopRice actif dans l’albumen (tissu nourricier du grain) chez différentes variétés de riz. Pour la première fois chez les plantes, nous avons également détecté des insertions somatiques d’ET par re-séquençage de génome entier. À partir de nos résultats, nous avons combiné nos données mobilomiques avec une analyse GWAS pour proposer des pistes afin d’identifier de nouveaux mécanismes de régulation de cet élément.En parallèle, nous avons appliqué la technique du mobilome-seq à différents organismes animaux et végétaux révélant ainsi des spécificités de mobilome propre à chaque espèce. Nos travaux en collaboration avec d’autres équipes ont notamment contribué à préciser le rôle de l’ARN polymérase II dans le contrôle des ET chez O. sativa et à mettre en évidence le lien entre la présence d’ADNecc viral et la réponse immunitaire chez Drosophila melanogaster.Mes travaux de thèse ouvrent des perspectives pour l’étude du mobilome, ce répertoire génomique encore largement inexploré et qui se révèle être à la fois une source d’information au niveau des mouvements des ET mais aussi de la stabilité des génomes. L’étude future des mobilomes promet d’apporter des réponses sur notre compréhension de la dynamique des génomes. / Transposable elements (TEs) are mobile genetic elements that constitute a major part of eukaryotic genomes. Host genomes have developed epigenetic mechanisms to control and prevent their proliferation. While efficiently silenced by the epigenetic machinery, they can be reactivated upon stress or at precise developmental stages. However, available methods to detect TE activity are often limited to transcriptional level or more adapted to small genomes. Today, only few TEs are known to be active and specific mechanisms controlling TEs are not well defined.
To address this question during my phD, we developed a strategy of high throughput sequencing that detects extrachromosomal circular DNA (eccDNA) forms which reflect TE activity and genome stability. We characterised mobilomes from different organisms defined as all eccDNA in a cell.
Our mobilome-seq technique successfully identified active TEs especially in asian rice Oryza sativa. We identified an active retrotransposon PopRice in endosperm tissue from different rice varieties. Interestingly and for the first time in plants, we detected somatic insertions from genome- wide resequencing. We combined our mobilome-seq results with a GWAS analysis to propose new PopRice regulation mechanisms.
In a second step, we applied our mobilome seq technique to different animal and plant organisms showing mobilome specificities from each species. Our work in collaboration with different labs help contributed to define role of RNA polymerase II in the control of TEs in O. sativa and have revealed a link between presence of eccDNA from virus and immune response in Drosophila melanogaster.
Altogether, our mobilome-sequencing method opens the possibility to explore unexplored genomic compartment. Future mobilome analysis represents new possibilities to improve our understanding of dynamics of genomes.
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RiTE database: a resource database for genus-wide rice genomics and evolutionary biologyCopetti, Dario, Zhang, Jianwei, El Baidouri, Moaine, Gao, Dongying, Wang, Jun, Barghini, Elena, Cossu, Rosa M., Angelova, Angelina, Maldonado L., Carlos E., Roffler, Stefan, Ohyanagi, Hajime, Wicker, Thomas, Fan, Chuanzhu, Zuccolo, Andrea, Chen, Mingsheng, Costa de Oliveira, Antonio, Han, Bin, Henry, Robert, Hsing, Yue-ie, Kurata, Nori, Wang, Wen, Jackson, Scott A., Panaud, Olivier, Wing, Rod A. January 2015 (has links)
BACKGROUND: Comparative evolutionary analysis of whole genomes requires not only accurate annotation of gene space, but also proper annotation of the repetitive fraction which is often the largest component of most if not all genomes larger than 50 kb in size. RESULTS: Here we present the Rice TE database (RiTE-db) - a genus-wide collection of transposable elements and repeated sequences across 11 diploid species of the genus Oryza and the closely-related out-group Leersia perrieri. The database consists of more than 170,000 entries divided into three main types: (i) a classified and curated set of publicly-available repeated sequences, (ii) a set of consensus assemblies of highly-repetitive sequences obtained from genome sequencing surveys of 12 species; and (iii) a set of full-length TEs, identified and extracted from 12 whole genome assemblies. CONCLUSIONS: This is the first report of a repeat dataset that spans the majority of repeat variability within an entire genus, and one that includes complete elements as well as unassembled repeats. The database allows sequence browsing, downloading, and similarity searches. Because of the strategy adopted, the RiTE-db opens a new path to unprecedented direct comparative studies that span the entire nuclear repeat content of 15 million years of Oryza diversity.
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Structural Comparative Genomics of Four African Species of OryzaGoicoechea, Jose Luis January 2009 (has links)
Rice is one of the most important crops in the world and is the first whose genome was completely sequenced. This landmark accomplishment placed O. sativa as a leading model in plant biology, especially for cereals. The genus Oryza includes 23 species, two of them independently domesticated in Asia and Africa. Wild species of Oryza contain a reservoir of useful agronomical traits which could be exploited for the benefit of rice agriculture, which is facing global problems as other crops, mainly due to a rampant increase in the human population and progressive deterioration of soils and water supplies. The Oryza Mapping Alignment Project has opened great opportunities to tap the genetic potential encapsulated in these species. Four BAC libraries generated from the African species of Oryza: O. barthii, O. glaberrima (AA genome), O. punctata (BB genome) and O. brachyantha (FF genome) were fully characterized and shown to provide enough coverage to represent their respective genomes. BAC clones from these libraries were fingerprinted and end-sequenced to assemble physical maps that were heavily manually edited using the sequence of O. sativa as a reference genome. The physical maps showed high coverage for all the species across all chromosomes. Both, BAC libraries and physical maps were used to investigate synteny and structural variation. The four species show high colinearity to the reference genome, although synteny perturbations were detected, including contractions, expansions, and putative inversions and translocations, which potential have an important impact in the evolution of these species.
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Sequencing of Australian wild rice genomes reveals ancestral relationships with domesticated riceBrozynska, Marta, Copetti, Dario, Furtado, Agnelo, Wing, Rod A., Crayn, Darren, Fox, Glen, Ishikawa, Ryuji, Henry, Robert J. 06 1900 (has links)
The related A genome species of the Oryza genus are the effective gene pool for rice. Here, we report draft genomes for two Australian wild A genome taxa: O. rufipogon-like population, referred to as Taxon A, and O. meridionalis-like population, referred to as Taxon B. These two taxa were sequenced and assembled by integration of short- and long-read next-generation sequencing (NGS) data to create a genomic platform for a wider rice gene pool. Here, we report that, despite the distinct chloroplast genome, the nuclear genome of the Australian Taxon A has a sequence that is much closer to that of domesticated rice (O. sativa) than to the other Australian wild populations. Analysis of 4643 genes in the A genome clade showed that the Australian annual, O. meridionalis, and related perennial taxa have the most divergent (around 3 million years) genome sequences relative to domesticated rice. A test for admixture showed possible introgression into the Australian Taxon A ( diverged around 1.6 million years ago) especially from the wild indica/O. nivara clade in Asia. These results demonstrate that northern Australia may be the centre of diversity of the A genome Oryza and suggest the possibility that this might also be the centre of origin of this group and represent an important resource for rice improvement.
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