Orientador: Edson Luiz Furtado / Resumo: A seringueira (Hevea brasiliensis) é a terceira cultura florestal mais plantada no Brasil, e o estado de São Paulo é responsável por mais de 60% da produção de látex do país. É uma espécie nativa da região amazônica que possui hábito caducifólio, e durante o período de reenfolha é suscetível ao ataque de fitopatógenos foliares, que prejudicam e até limitam seu estabelecimento em determinadas regiões. Dentre os principais patógenos foliares da seringueira, destacam-se os fungos causadores de oídios, microrganismos biotróficos que infectam tecidos jovens, e podem causar desfolha, principalmente em condições de viveiro e jardim clonal. O agente causal do oídio da seringueira é descrito como Erysiphe quercicola, porém, devido a insuficientes descrições taxonômicas, morfológicas e moleculares desta doença, seu agente causal permanece em discussão, além da fase sexual deste patógeno carecer de qualquer registro neste hospedeiro. Portanto, o objetivo deste trabalho é caracterizar o oídio da seringueira, utilizando caracterizações morfológicas, análises moleculares e testes de patogenicidade. No período de julho a dezembro de 2019, foram coletadas amostras foliares de seringueira em diferentes estágios fenológicos infectadas com oídio na região de Botucatu, São Paulo. Para a caracterização morfológica, foram registradas e mensuradas características das hifas, conídios e conidióforos, que correspondem à fase assexuada do fungo. A caracterização molecular foi realizada através de análi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Rubber tree (Hevea brasiliensis) is the third most planted forest crop in Brazil, and the state of São Paulo is responsible for more than 60% of the country's latex production. It is a species native to the Amazon region that has a deciduous habit, and during the re-leafing period it is susceptible to the attack of leaf phytopathogens, which harm and even limit its establishment in certain regions. Among the main leaf pathogens of the rubber tree, there are the fungi that cause powdery mildew, biotrophic microorganisms that infect young tissues, and can cause defoliation, especially in nursery and clonal garden conditions. The causal agent of rubber mildew is described as Erysiphe quercicola, however, due to insufficient taxonomic, morphological and molecular descriptions of this disease, its causal agent remains under discussion, in addition to the sexual phase of this pathogen lacking any record in this host. Therefore, the objective of this work is to characterize powdery mildew mildew, using morphological characterizations, molecular analyzes and pathogenicity tests. From July to December 2019, leaf samples of rubber trees were collected at different phenological stages infected with powdery mildew in the Botucatu region, São Paulo. For morphological characterization, characteristics of hyphae, conidia and conidiophores, which correspond to the asexual phase of the fungus, were recorded and measured. Molecular characterization was performed through phylogenetic analyzes o... (Complete abstract click electronic access below) / Mestre

Orientador: Sergio Augusto Mello da Silva / Resumo: Estudos sobre florestas plantadas para aproveitamento de madeiras em vários setores industriais tem se intensificado no mundo. A utilização dessas madeiras no Brasil, além de garantir a sustentabilidade de espécies nativas, possibilita a produção de derivados de madeiras e o amplo emprego na construção civil. A Seringueira (Hevea brasilienses) e Teca (Tectona grandis) representam duas espécies de reflorestamento cultivadas no Brasil e que serão utilizadas neste trabalho para produção de painéis de partículas homogêneas. A Seringueira é utilizada para produção de borracha natural, entretanto, precisam ser substituídas ao final do ciclo de produção (25 a 30 anos) e, as árvores improdutivas são utilizadas para geração de energia. Com relação à Teca, espécie de origem asiática, sua madeira apresenta excelentes características de resistência e durabilidade e vem sendo empregada na construção civil de modo geral e para a produção de móveis. Vale ressaltar, que tanto a Seringueira quanto a Teca, adaptadas às condições edafológicas das regiões em que são reflorestadas, apresentam rápido crescimento e poderiam ser utilizadas para produção de painéis de partículas. Entretanto, para este trabalho, será considerada a utilização dessas espécies com mais de 20 anos, buscando-se avaliar a possibilidade de aproveitamento dessas para a produção de painéis de partículas aglutinadas com adesivo poliuretano derivado de mamona (PU-Mamona). Os painéis produzidos foram avaliados de acordo com NBR 1... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Studies on planted forests to use wood in various industrial sectors has intensified in the world. The use of these woods in Brazil, in addition to ensuring the sustainability of native species, enables the production of wood derivatives and wide employment in civil construction. The rubber tree (Hevea brasilienses) and Teca (Tectona grandis) represent two species of reforestation cultivated in Brazil and which are used in this work for the production of particleboards. The rubber tree is used for the production of natural rubber, however, it needs to be replaced at the end of the production cycle (25 to 30 years) and, the unproductive trees are used for power generation. Regarding Teca, a species of Asian origin, its wood has excellent resources of resistance and durability and has been used in civil construction in general and for furniture production. It is worth mentioning that both Seringueira and Teca, adapted to the edaphological conditions of the regions where they are reforested, show quick growth and are used for the production of particleboards. However, for this work, the use of these species with more than 20 years will be considered, looking for the possibility of using them for the production of agglutination panels with castor oil-based polyurethane adhesive (PU-Castor). The panels produced were evaluated according to NBR 14810 - 1 and 2: 2013 and international documents to verify their physical and mechanical properties, as well as, using scanning electron mi... (Complete abstract click electronic access below) / Mestre

A busca por condições climáticas que minimizem efeitos negativos de extremos de temperatura e irradiância, a arborização pode viabilizar a cafeicultura brasileira, em particular, com o advento das mudanças climáticas. A pesquisa avaliou a dinâmica do crescimento e da maturação do fruto e a produtividade do café sob diferentes níveis de luminosidade. O experimento foi composto por seringueiras e cafeeiros, plantados dentro e na interface do seringal, e em monocultivo. O gradiente de radiação disponível aos cafeeiros nas diferentes distâncias das seringueiras foi de 40, 45, 80 e 100 % e caracterizou os tratamentos. Avaliou-se o acúmulo de matéria seca de frutos nas fases da frutificação e a produtividade. Nas fases chumbinho, expansão e granação, o incremento varia com a quantidade de frutos na planta. A expansão depende da irradiância e a granação, do tempo de deposição de reservas. A matéria seca de frutos verde, verde-cana e cereja é superior nas plantas protegidas da face soalheira, favorecida pela exposição até 80 % de luminosidade. A produtividade aumenta, proporcionalmente, com a disponibilidade de luz, enquanto a expansão, o processo e a uniformidade da maturação são, também, beneficiados à exposição até 80 % da radiação solar. / In the searching for climatic conditions to minimize negative effects of high temperature and radiation excess, the shading system can make possible the Brazilian coffee crop. This research aimed to evaluate the growth and maturation of coffee fruits and its productivity under different levels of natural irradiance. Coffee plants were planted inside and aside of a rubber trees plantation and in monocrop. The irradiance gradient level available to coffee plants at different distances from rubber trees were of 40, 45, 80 and 100% and characterized the treatments. The accumulation of the fruits dry matter was evaluated in the phases of the fruiting / fructification and the productivity. In the fruit set (pellet-like berries), expansion and seed-filling stage phases, that increment varies according to the fruits amount in the plant. The expansion depends on the radiation and the seed-filling stage depends on the reserve deposition time. The dry matter increment of "green fruits", "green-cane" and "cherry" coffee fruits is superior in the shaded plants up to 80% of brightness with shade at afternoon. The productivity (grains.planta-1) increases proportionally to the available irradiância, while the expansion, the maturation and its uniformity are also benefited up to 80% available irradiance.

Orientador: Reinaldo José Fazzio Feres / Banca: Marineide Rosa Vieira / Banca: Marcel Ricardo Tanzini / Resumo: Esse trabalho teve como objetivo estudar o ciclo biológico de T. heveae em folíolos de seringueira dos clones RRIM 600, PB 235 e GT 1. Inicialmente foi estabelecida uma colônia de manutenção de T. heveae. As arenas de criação e para estudos da biologia foram confeccionadas a partir de folíolos de seringueira dos clones acima citados sendo mantidas sob condições controladas em câmara climatizada do tipo BOD com umidade relativa de 70+10%, fotoperíodo de 12 h, 28+0,1oC na fotofase e 25+0,1oC na escotofase. Três observações diárias foram realizadas, acompanhando-se o desenvolvimento de 60 ovos em folíolos de cada clone para verificação do estágio de desenvolvimento em que o ácaro se encontrava, assim como a oviposição das fêmeas. A fase mais longa registrada nos três clones foi a de ovo e o período mais curto foi o protoninfal. Em todos os clones estudados a fase de maior viabilidade foi a deutoninfal, e a menor, a larval. Quatorze fêmeas e quatro machos atingiram a fase adulta no clone PB 235, sendo observada uma taxa média de oviposição de 1,2 ovo/dia/fêmea. No clone RRIM 600, nove fêmeas e dois machos foram observados, sendo registrada a taxa de oviposição de 0,7 ovo/dia/fêmea. No clone GT 1, sete fêmeas chegaram à fase adulta com taxa média de 0,51 ovo/dia/fêmea. O ciclo completo da incubação do ovo até a morte do adulto durou 25 dias, em média, nos clones RRIM 600 e PB 235. A taxa intrínseca de crescimento populacional (rm) foi de 0,09; 0,08 e 0,02 nos clones PB 235, RRIM 600 e GT 1, respectivamente. O clone PB 235 possibilitou um melhor desenvolvimento de T. heveae, seguido pelo clone RRIM 600. O clone GT 1 foi o menos favorável ao desenvolvimento. / Abstract: This work aims to study the biological cycle of T. heveae in rubber tree leaflets of clones RRIM 600, PB235 and GT 1. Initially, a maintenance colony was established. The breeding arenas and those for the study of the biology were created using leaflets of the aforementioned rubber tree clones, which had been kept under controlled conditions in a climatic chamber. Three daily observations were done, following the development of 60 eggs in each clone to check the developmental stage and female oviposition. The egg was the longest-lasting phase registered and the protonymph was the shortest period. The deutonymph was the most viable phase in all clones, whereas the least viable was the larval stage. Fourteen females and four males reached the adult stage in the clone PB 235, an average oviposition rate of 1.2 egg per day per female. In the RRIM 600 clone, nine females and two males were viable, and an oviposition rate of 0.70 egg per day per female was observed. In the GT 1 clone, seven females reached the adult stage, the average ovoposition rate was 0.51 egg per day per female. The complete cycle of incubation of the egg until the death of the adult lasted, on average, 25 days in RRIM 600 and PB 235 clones. The intrinsic rate of population increase (rm) was 0.09; 0.08 and 0.02 in clones PB 235, RRIM 600 and GT1, respectively. The clone PB 235 allowed a better development of T. heveae, followed by RRIM 600. The clone GT 1 was the least favourable for the development of that mite species. / Mestre

Made available in DSpace on 2015-03-26T13:37:49Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2148996 bytes, checksum: 0f782ede5a559058721ff442c36a8c2f (MD5) Previous issue date: 2012-07-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Ceratocystis fimbriata sensu lato (s.l.) is a complex of many species that are important pathogens of a large number of woody and herbaceous plants. One of this hosts is rubber tree (Hevea sp.), that is native to the Amazon and belong to the family Euphorbiacea. Rubber tree is grown in order to produce latex, the main raw material for obtaining natural rubber that is used in many different industries. Ceratocystis fimbriata infects the rubber tree panel, causing gray mold that affects latex production. C. fimbriata is considered now as a "species complex" containing cryptic species, and many of them remain undescribed. Thus, the aim of this work was to determine the morphology and phylogenetic relationships of the fungus that causes gray mold in rubber tree in order to confirm whether it is a new species of fimbriata complex. For this, it was used 20 isolates obtained from rubber tree for analysis of genetic variability. Of these, four isolates were selected for morphological and phylogenetic analysis and of those, two isolates were used for pathogenicity tests. According to the sequences of ITS r-DNA, the isolates of C. fimbriata of rubber tree belong to the Latin American clade, with two ITS genotypes, that is related to their geographical origin. One genotype was originated from the state of Acre and the other one from the state of Bahia, which was also confirmed by microsatellite markers. The inoculations showed no specialization to the host, since they were pathogenic to different host species (mango, crotalaria, acacia, eucalyptus and kiwi). Therefore, according to the results of this work, the isolates of rubber tree belong to the Latin American clade and confirmed as C. fimbriata and not a distinct species. / Espécies do complexo Ceratocystis fimbriata sensu lato (s.l.) são importantes patógenos de um grande número de plantas arbóreas e herbáceas, dentre elas a seringueira (Hevea sp.), nativa da região amazônica e pertencente a família Euphorbiaceae. A seringueira é cultivada visando a produção do látex, a principal matéria prima para obtenção da borracha natural que é utilizada em diversos setores. Ceratocystis fimbriata infecta o painel da seringueira, causando uma doença conhecida como mofo cinzento que afeta negativamente a produção de látex. Ceratocystis fimbriata s.l. considerado, atualmente, como um complexo de espécies contendo várias espécies crípticas, muitas das quais ainda não descritas. Deste modo, objetivou-se com este trabalho, determinar a morfologia, o relacionamento filogenético e especificidade de hospedeiro do fungo causador do mofo cinzento em seringueira, de modo a confirmar se é uma nova espécie do complexo fimbriata. Para isso, foram utilizados 20 isolados de seringueira para análise de variabilidade genética. Dentre estes, quatro isolados foram selecionados para análises morfológicas e filogenéticas e destes, dois foram utilizados para testes de patogenicidade. De acordo com as sequências de ITS r-DNA analisadas, os isolados de C. fimbriata de seringueira pertencem ao clado da América Latina, com dois genótipos de ITS, de acordo com a origem geográfica, sendo eles originados do Estado do Acre e o outro do Estado da Bahia, também confirmados por análises de microssatélites. As inoculações mostraram que não há especialização, quanto ao hospedeiro, uma vez que foram patogênicos a diferentes espécies hospedeiras (manga, crotalária, acácia, eucalipto e kiwi). Portanto, de acordo com os resultados deste trabalho, os isolados de seringueira pertencem ao clado da América Latina e são confirmados como C. fimbriata e não uma espécie distinta.

Resumo: Clones com alta produtividade, adaptabilidade e estabilidade a vários ambientes são imprescindíveis para o desenvolvimento da heveicultura no Brasil. O objetivo do trabalho foi selecionar progênies com maior adaptabilidade e estabilidade a partir do diâmetro da planta a 50 cm do solo (DA50) e a produção de borracha seca (PBS, a partir do teste Hamaker Morris Mann modificado), de uma população de seringueira, aos três anos de idade, plantada em três ambientes distintos (Selvíria-MS, Votuporanga-SP e Colina-SP), utilizando-se do método MHPRVG (média harmônica da performance relativa dos valores genéticos) preditos por BLUP e estimar a variabilidade genética a partir de caracteres quantitativos, tais como: altura da planta (ATP), DA50, forma da planta (FOP), sobrevivência das progênies (SOP) e PBS dos três locais, aos dois e três anos de idade, pelo procedimento REML/BLUP visando a conservação dos recursos genéticos da espécie. As sementes utilizadas na produção das mudas dos testes de progênies foram, na sua maioria, coletadas de clones de origem Asiática provenientes da coleção de clones instalada na área experimental da Agência Paulista de Tecnologia dos Agronegócios - APTA - Polo Regional de Votuporanga, Estado de São Paulo. As progênies foram instaladas nos três locais sob o delineamento de blocos ao acaso, compostos por 30 tratamentos (progênies), três repetições e parcelas lineares de 10 plantas, no espaçamento de 3,00 x 3,00 metros, totalizando 900 plantas úteis em cada local. O método da MHPRVG propiciou um ganho genético de 12,03 a 45,65% entre 10 progênies selecionadas a partir da PBS e permitiu a seleção de progênies com alto potencial produtivo predito. As 10 melhores progênies foram oriundas dos clones GT1, PB 28/59, PR 261, RRIM 606, PB 217, IAC 41, IAC 35, PR 255, RRIM 701 e IAC 301. Os caracteres ATP, DA50, FOP, SOP e a PBS ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Clones with high yield, adaptability and stability for many environments are indispensables to the development of the rubber tree crop in Brasil. The paper objective was to select progenies with high adaptability and stability from the diameter gauges from 50 cm of height of soil (DA50) and dry rubber yield (PBS, from the Hamaker Morris Mann modified test), of genotypes from a rubber tree population, two and three years old, installed in three different locations (Selvíria-MS, Votuporanga-SP e Colina-SP), by the MHPRVG (Harmonic Average Performance Relative breeding values) method predicted by BLUP and to estimate the genetic variability from quantitative characters: total height of the plant (ATP), DA50, plant form (FOP), survival of progeny (SOP) and PBS of three locations, two and three years old, by REML/BLUP procedure, intending the genetic resources conservation of the specie. The seeds used on seedlings production of progenies tests were in majority collected on Asiatic clones origin from the clones installed in the experimental area of Agência Paulista de Tecnologia dos Agronegócios - APTA - Votuporanga regional pole, State of São Paulo. The progenies were installed in a randomized block design of 30 treatments (progenies), three replications and 10 plants per plot, with spacing of 3,00 x 3,00 m, a total of 900 useful plants in each location. The method of MHPRVG provided a genetic gain ranging from 12,03 to 45,65% in 10 progenies to the PBS and allowed the selection of progenies with high yield potential predicted. The 10 best progenies were derived from clones GT1, CR 28/59, PR 261, RRIM 606, PB 217, IAC 41, IAC 35, PR 255, RRIM 701 and IAC 301. The characters ATP, DA50, FOP, SOP and PBS presented considerable coefficients of genetic variation, ranging from 1,25% for the ATP to 21,33% for PBS and medium heritability for DA50 and PBS being 0,23 and 0,80, respectively... (Complete abstract click electronic access below) / Orientador: Mario Luiz Teixeira de Moraes / Coorientador: Enes Furlani Júnior / Banca: João Antonio da Costa Andrade / Banca: Paulo de Souza Gonçalves / Mestre

A busca por condições climáticas que minimizem efeitos negativos de extremos de temperatura e irradiância, a arborização pode viabilizar a cafeicultura brasileira, em particular, com o advento das mudanças climáticas. A pesquisa avaliou a dinâmica do crescimento e da maturação do fruto e a produtividade do café sob diferentes níveis de luminosidade. O experimento foi composto por seringueiras e cafeeiros, plantados dentro e na interface do seringal, e em monocultivo. O gradiente de radiação disponível aos cafeeiros nas diferentes distâncias das seringueiras foi de 40, 45, 80 e 100 % e caracterizou os tratamentos. Avaliou-se o acúmulo de matéria seca de frutos nas fases da frutificação e a produtividade. Nas fases chumbinho, expansão e granação, o incremento varia com a quantidade de frutos na planta. A expansão depende da irradiância e a granação, do tempo de deposição de reservas. A matéria seca de frutos verde, verde-cana e cereja é superior nas plantas protegidas da face soalheira, favorecida pela exposição até 80 % de luminosidade. A produtividade aumenta, proporcionalmente, com a disponibilidade de luz, enquanto a expansão, o processo e a uniformidade da maturação são, também, beneficiados à exposição até 80 % da radiação solar. / In the searching for climatic conditions to minimize negative effects of high temperature and radiation excess, the shading system can make possible the Brazilian coffee crop. This research aimed to evaluate the growth and maturation of coffee fruits and its productivity under different levels of natural irradiance. Coffee plants were planted inside and aside of a rubber trees plantation and in monocrop. The irradiance gradient level available to coffee plants at different distances from rubber trees were of 40, 45, 80 and 100% and characterized the treatments. The accumulation of the fruits dry matter was evaluated in the phases of the fruiting / fructification and the productivity. In the fruit set (pellet-like berries), expansion and seed-filling stage phases, that increment varies according to the fruits amount in the plant. The expansion depends on the radiation and the seed-filling stage depends on the reserve deposition time. The dry matter increment of "green fruits", "green-cane" and "cherry" coffee fruits is superior in the shaded plants up to 80% of brightness with shade at afternoon. The productivity (grains.planta-1) increases proportionally to the available irradiância, while the expansion, the maturation and its uniformity are also benefited up to 80% available irradiance.

Les plantations d’hévéa (Hevea brasiliensis) s’étendent vers des zones non traditionnelles de production en Thaïlande où des conditions plus sèches ont pu conduire à une diminution de la croissance des arbres et de la production de latex. Des paramètres physiologiques utiles pour sélectionner des génotypes adaptés sont nécessaires, comme l’efficience d’utilisation de l’eau (WUE). La discrimination isotopique du carbone est largement utilisée comme proxy pour WUE et peut être aisément utilisée dans des programmes de sélection pour la tolérance à la sécheresse. δ13C des feuilles et les échanges gazeux foliaires ont été mesurés sur de jeunes plants de dix clones d’hévéa cultivés en pot dans une pépinière. La gamme de δ13C des feuilles entre ces dix clones était restreinte et la corrélation entre δ13C et WUEi était significative que sous fort déficit de pression de vapeur saturante, ce qui signifie que la prédiction de WUE par δ13C serait peu précise. Il y avait une large gamme de δ13C entre les génotypes dans une collection de 49 génotypes sauvages d’hévéa cultivés dans le nord-est de la Thaïlande en saison sèche et en saison des pluies. δ13C était relativement stable avec une bonne corrélation entre les saisons. Cette étude montre que la variabilité génétique de δ13C est prometteuse pour des futurs programmes de sélections si une bonne corrélation entre δ13C et WUE peut être établie. L’absence de corrélation entre de δ13C du latex (δ13C-L) et des composés solubles extraits des feuilles (δ13C-S) prélevées sur des arbres saignés et non saignés âgés de 20 ans suggère que photosynthétats récemment produits se mélangent à un stock important d’hydrate de carbone impliqués dans la régénération du latex après la saignée. Donc, δ13C du latex n’est pas un indicateur pertinent de WUE / The rubber (Hevea brasiliensis) plantations extend to non-traditional area in Thailand where dryer conditions has been reported to impair the growth of rubber trees and latex production. Physiological parameters helpful for breeding adapted genotypes are required, such as water use efficiency (WUE). Carbon isotope discrimination is widely used as a proxy for WUE that can easily be used for selection and breeding programs for drought tolerance. Leaf δ13C and leaf gas exchange were measured on young saplings of 10 rubber clones growing in pot in a common garden. The range of leaf δ13C among 10 clones was narrow and the correlation between δ13C and WUEi was significant under high vapour pressure deficit only, which means the prediction of WUE by δ13C would have low precision. There were large δ13C variations among the genotypes at all seasons in a collection of 49 wild genotypes of rubber in Northeastern Thailand. δ13C was rather stable with a good correlation between rainy and dry season. The genetic variability of δ13C is promising for breeding if a good correlation between δ13C of leaf and WUE can be established. The lack of correlation between δ13C of latex (δ13C-L) and of leaf soluble compounds (δ13C-S) collected from tapped and untapped 20 year-old rubber trees suggests that recent photosynthates are mixed in the large pool of stored carbohydrates that are involved in latex regeneration after tapping. Thus δ13C of latex is not a relevant indicator of WUE of rubber trees

Les jasmonates et l'éthylène sont d'importants signaux de régulation du développement des plantes et de réponse aux stress biotiques et abiotiques. La production de jasmonates est induite à la suite d'une blessure mécanique ou des agents pathogènes. L'acide jasmonique et l'éthylène agissent en synergie sur l'activation de l'expression des gènes de défense tels que PDF1.2. Le Facteur de Réponse à l'Ethylène 1 (ERF1) est un intégrateur clé de ces signaux hormonaux chez Arabidopsis. ERF1 appartient à la superfamille des facteurs de transcription AP2/ERF, lesquels jouent un rôle crucial dans le développement et la réponse aux stress. Hevea brasiliensis est la seule source commerciale de caoutchouc naturel, lequel est synthétisé dans les cellules laticifères. Le latex s'écoule du tronc des hévéas après la saignée. L'éthéphon, un générateur d'éthylène, est un stimulant exogène adopté largement dans les plantations d'hévéa pour améliorer la production de latex en prolongeant l'écoulement de latex et en stimulant le métabolisme des cellules requis pour la régénération du latex. Les jasmonates sont aussi impliqués dans la formation des laticifères. Etant donné l'implication de l'éthylène et de l'acide jasmonique dans la réponse coordonnée à la saignée et à la stimulation par l'éthéphon chez Hevea brasiliensis, leur interaction est supposée jouer un rôle important dans la production de latex.L'objectif de cette thèse est de découvrir les régulateurs clés de l'interaction entre la blessure, le jasmonate et l'éthylène chez Hevea brasiliensis. A travers l'analyse de l'expression de 25 gènes impliqués dans les voies de transduction du jasmonate, de l'éthylène et dans le métabolisme cellulaire, nous avons montré que des voies de réponse dépendantes et indépendantes à l'éthylène et au jasmonate coexistent chez Hevea brasiliensis. La régulation temporelle influence aussi l'expression des gènes. L'étude s'est alors focalisée sur les facteurs de transcription de la superfamille des AP2/ERF. A partir de bases de données de séquences transcriptomiques de différents tissus obtenu par pyroséquençage, 173 membres AP2/ERF ont été identifiés chez Hevea brasiliensis. Cette superfamille est divisée en 3 familles majeures : AP2, ERF et RAV. Soixante six membres sont exprimés dans le latex ce qui suggère qu'ils ont une fonction importante dans le métabolisme des laticifères. En plus du microARN 172 connu pour cibler les transcrits AP2/ERF, six autres microARNs ont été prédits pour inhiber les transcrits de cette superfamille. L'identification de l'orthologue à AtERF1 a été aussi menée chez Hevea brasiliensis. L'expression de 14 gènes HbERF du groupe IX a été étudiée en réponse à la blessure, au méthyl jasmonate et à l'éthylène. L'accumulation relative des transcrits est remarquable pour trois gènes : HbERF-IXc4, HbERF-IXc5 et HbERF-IXc6. Ces gènes candidats ont été caractérisés pour la localisation subcellulaire et la trans-activation du promoteur du gène PDF1.2. La fusion traductionnelle HbERF-IXc4::GFP a révélé que HbERF-IXc4 code pour une protéine nucléaire comme les facteurs de transcription. Le HbERF-IXc5 induit la plus forte activation du promoteur du gene PDF1.2 qui est un gène de défense induit fortement par AtERF1 et ORA59. Ces résultats suggèrent que HbERF-IXc5 est l'orthologue à AtERF1 chez Hevea brasiliensis, lequel est impliqué dans la communication des voies de signalisation de l'éthylène et du jasmonate. L'identification des transcrits AP2/ERF chez Hevea brasiliensis, et la caractérisation des ERFs du groupe IX apportent les bases générales pour étudier la régulation moléculaire de la production de latex en réponse aux stress et de la différentiation des cellules laticifères. Nos résultats suggèrent que HbERF-IXc5 est un intégrateur essentiel des voies de signalisation éthylène et jasmonate chez Hevea brasiliensis. / Jasmonates and ethylene are important signals in regulating the plant development and metabolism, and in response to biotic and abiotic stresses. Production of jasmonates is induced by mechanical wounding and pathogens. Jasmonic acid and ethylene are synergistically required to activate the expression of some defence related genes such as PDF1.2. Ethylene Response Factor 1 (ERF1) was demonstrated as a key integrator in the signal interaction in Arabidopsis. ERF1 belongs to AP2/ERF transcription factors superfamily, which plays a crucial role in plant development and response to biotic and abiotic stresses. Hevea brasiliensis is the sole source of natural rubber, which is synthesized in latex cells. Latex is expelled out after tapping the soft bark. Ethephon, an ethylene releaser, is an exogenous stimulant adopted widely in the rubber plantation for improving latex yield by prolonging latex flow and by stimulating the metabolism required for the latex regeneration. Jasmonates are also involved in the laticifer formation. Given the involvement of ethylene and jasmonic acid in the coordinated response to tapping and ethephon stimulation in Hevea brasiliensis, their interaction is considered to play an important role in latex production. The objective of this thesis is aiming to discover the key regulators in the interaction of wounding, jasmonate and ethylene in Hevea brasiliensis. Through the expression analysis on one group of 25 genes involved in the jasmonate and ethylene and cellular metabolism, we discovered that jasmonate and ethylene dependent and independent response coexist in Hevea brasiliensis. Temporal regulation can also have an influence on the gene expression. We then focused the study on the AP2/ERF transcription factor superfamily. Based on new generation of sequencing data, we identified 173 AP2/ERF members from several Hevea brasiliensis transcripts libraries. This superfamily is divided into 3 major families: AP2, ERF and RAV. Sixty six members are expressed in latex which may indicate that they have an important function in the latex metabolism. In addition to the microRNA 172, which is known to target AP2/ERF transcripts, six other microRNAs were predicted to inhibit transcripts of this superfamily. The identification of the AtERF1 orthologous gene was further conducted in Hevea brasiliensis. Expression analysis of 14 HbERF genes from the group IX was studied in response to wounding, methyl jasmonate and ethylene. A remarkable relative transcript accumulation was observed for genes HbERF-IXc4, HbERF-IXc5 and HbERF-IXc6. These candidate genes were further analysed for subcellular localization and trans-activation of the promoter of the PDF1.2 gene. The translational fusion HbERF-IXc4::GFP revealed that HbERF-IXc4 encoded a nuclear targeted protein like transcription factor. The HbERF-IXc5 was shown to mediate the activation of the PDF1.2 promoter, which is a defence gene dramatically induced by AtERF1 and ORA59. For that reason, HbERF-IXc5 is suggested to be AtERF1 ortholog gene in Hevea brasiliensis, which is at the crosstalk of jasmonic acid and ethylene signalling pathways. This identification of the Hevea brasiliensis AP2/ERF transcripts and the characterization of the ERF group IX provide general basis for studying the molecular regulation of both latex production in response to abiotic stresses and differentiation of latex cells. Our results suggested that the HbERF-IXc5 is an essential integrator of the jasmonic acid and ethylene signalling pathways in Hevea.

Hevea brasiliensis est cultivé pour le caoutchouc naturel contenu dans le latex. Une exploitation intensive combinée aux stress environnementaux affectent la production de latex. L'encoche sèche ou Tapping Panel Dryness (TPD) est déclenché par un désordre physiologique complexe au sein des laticifères. Il est responsable d'une perte annuelle de production de 10 à 40% en fonction de l'âge de la plantation et des clones d'hévéa utilisés Le stress oxydatif, point de départ de la maladie, affecte l'écoulement, par la coagulation in situ des particules du caoutchouc. Chez les plantes, la réponse adaptative aux stress abiotiques dépend de la finesse de la régulation de l'expression des gènes. Ce contrôle se fait au niveau transcriptionnel mais également au niveau post-transcriptionnel. Les micro-ARNs jouent un rôle crucial en menant les ARN messagers cibles à la dégradation ou au blocage de leur traduction L'objectif de cette thèse est de comprendre et d'identifier la régulation du stress oxydatif en étudiant l'implication des micro-ARNs en réponse aux stress abiotiques et suite à l'apparition du TPD chez l'hévéa. L'isolement et le séquençage à haut débit de petits-ARNs ont permis l'identification de micro-ARNs d'hévéa. Dans un premier temps, une banque de petits ARNs a été effectuée à partir de vitroplants soumis ou non à des stress abiotiques, à laquelle s'est ajoutée dans un second temps deux banques fabriquées à partir de latex d'arbres en exploitation atteints ou non par le TPD. L'analyse de la population de petits ARNs montre une diminution de la taille des séquences en réponse à la maladie, la majorité des séquences de petits ARNs de latex étant de 21 nucléotides chez les arbres malades et 24 nucléotides chez les arbres sains. En combinant le pipeline LeARN et les données transcriptomiques, soixante huit familles de micro-ARNs conservés entre les espèces et quinze nouvelles familles de micro-ARNs ont été identifiées chez l'hévéa. Les gènes codant pour la voie de biogenèse des micro-ARNs sont présents dans le latex, suggérant leur production dans ce compartiment cellulaire particulier. L'identification des séquences de trente précurseurs de micro-ARNs ont permis d'étudier l'expression des gènes MIR en réponse aux stress abiotiques et en réponse au TPD. Les gènes MIR étudiés sont différentiellement exprimés chez des hévéas immatures en réponse au stress abiotiques et aux traitements par l'éthylène et le méthyl-jasmonate. L'abondance relative de transcrits des gènes MIR est fortement réduite par le TPD dès 5% de longueur d'encoche sèche à l'exception d'un gène.Les cibles potentielles des 83 familles de micro-ARNs ont été prédites. Ces micro-ARNs sont impliqués dans les voies de détoxication des espèces activées de l'oxygène, dans les voies de biosynthèse du caoutchouc naturel, dans les voies de biosynthèse et de signalisation de l'éthylène et du jasmonate. Trois cibles ont été validées expérimentalement dont la CuZnSOD chloroplastique, enzyme importante du système antioxydant. / Hevea brasiliensis is cultivated for natural rubber produced in latex cells. Intensive harvesting systems combined with environmental cues affect latex production. The Tapping Panel Dryness (TPD), a complex physiological disorder, causes a loss of production of 10-40%. Oxidative stress, starting point of the disease, affect latex flow because of in situ coagulation of rubber particles. In plants, the adaptation to abiotic stress relies on the fine tuning of the gene expression at the transcriptional and post-transcriptional levels. MicroRNAs play a crucial roles leading to mRNAs degradation or repression of their translation.The aim of this thesis is to understand and identify the regulation of the oxidative stress by studying the involvement of microRNAs in the regulation of abiotic stress and TPD occurrence in Hevea. Isolation and high-throughput sequencing of small RNAs allowed identifying Hevea microRNAs. Firstly, a small RNA library was constructed from in vitro plantlets subjected or not to abiotic stress, and secondly, two others small RNA libraries were constructed with latex from healthy and TPD-affected trees. Analyses of the small RNA population showed a decrease in the size of the reads in response to TPD, the majority of the small RNAs from latex being 21 nucleotides in TPD-affected trees and 24 nucleotides in healthy trees. Combining the LeARN pipeline and transcriptomic data, sixty eight microRNAs families conserved between plant species and fifteen new families were identified in Hevea. Genes involved in microRNA biogenesis are present in latex suggesting their production in this particular cellular compartment. Identification of thirty precursors of microRNAs allowed the expression analyses of the corresponding MIR genes in response to abiotic stress and upon TPD occurrence. MIR genes are differentially expressed in young plants in response to abiotic stress and in response to ethylene and methyl jasmonate treatments. Moreover, relative transcript abundance of MIR genes is strongly repressed upon TPD occurrence a soon as 5% of dry cut length except for one MIR gene.Putative targets were predicted for the 83 families. MicroRNAs are involved in ROS detoxification, natural rubber biosynthesis, ethylene and jasmonate biosynthesis and signalling pathways. Three targets were experimentally validated including the chloroplastic isoform of CuZnSOD, which is an important enzyme of the ROS-scavenging system.