Emotionsreglering är ett närmast transdiagnostiskt fenomen med relevans för såväl individ- som parrelaterade problembilder. Kopplingar till relationsnöjdhet har tidigare gjorts via observationsstudier på parnivå eller självskattningsstudier på individnivå. Studiens huvudsyfte var att undersöka om mellanmänskliga skattningsskalor för emotionsreglering kan förklara varians i pars relationsnöjdhet utöver den varians som förklaras av en intrapersonell skattningsskala för emotionell dysreglering. Som ett andra syfte översattes och undersöktes två skattningsskalor med potentiell relevans för mellanmänsklig emotionsreglering. I studien fyllde ett urval av vuxna par (n = 110) i självskattningsformulär över internet. För att kunna undersöka både egen (aktörens) och partnerns emotionsreglerings inverkan på aktörens relationsnöjdhet användes en actor-partner interdependence model (APIM). En första modell bestående av intrapersonell emotionsreglering visades förklara 19.7% av variansen i relationsnöjdhet, en andra modell som också inkluderade mellanmänskliga mått visade signifikant bättre model-fit och större variansförklaring (64.6%). Effekter på relationsnöjdhet i den andra modellen kom ifrån tre aktörskattade mått och ett partnerskattat mått. Adekvat intern konsistens fanns för delskalorna för inre affektförbättrande, yttre affektförbättrande, inre affektförsämrande, yttre affektförsämrande, stoppbeteenden och negativ eskalering, men inte för undfallenhet. Affektförbättrande delskalor och stoppbeteenden visade inga samband med intrapersonell dysreglering. Fortsatta undersökningar krävs för att uttala sig om eventuell kausal inverkan på relationsnöjdhet och för att kunna etablera de översatta skalornas validitet och reliabilitet.

Fusarium verticillioides (Teleomorph Giberella moniliformis) is an ascomycete fungus responsible for ear and stalk rots of maize. Most importantly, it produces a group of mycotoxins called fumonisins upon colonization of maize kernels. Fumonisin B1 (FB1), the most prevalent fumonisin in nature, was first identified in 1988 and has been found to be toxic to human and animals. The gene cluster for FB1 biosynthesis and some environmental conditions responsible for the toxin production are known, but gaps in our understanding of the signaling pathways leading to FB1 biosynthesis still remain. MADS-box transcription factors (TF) are known to regulate diverse cellular functions in all eukaryotes, and in silico analyses revealed two genes, MADS1 and MAD2, in F. verticillioides. Reverse genetics studies indicated that MADS1 and MADS2 positively regulate sexual mating and FB1 biosynthesis but not pathogenicity in F. verticillioides. Furthermore, MADS1 was found to act as a broad regulator of polyketide-derived secondary metabolism. Additionally, population diversity studies were conducted in 164 F. verticillioides cultures isolated from 65 maize-producing counties in Texas. The result showed a fluid population with no particular niches formed. F. verticillioides strains were also isolated from counties that have previously tested negative for FB1 contamination in maize. The presence of the pathogen represents a risk for future FB1 contamination events if suitable conditions were to arise. My research revealed new genetic components involved in F. verticillioides secondary metabolite biosynthesis and provided a better understanding of the pathogen population fluidity in Texas.

A ausência de semente em videira, também chamada de apirenia, é amplamente apreciada pelo mercado consumidor de uvas de mesa. No entanto, os mecanismos moleculares que controlam a morfogênese da semente não são totalmente compreendidos. Por este trabalho, buscou-se caracterizar funcionalmente o gene candidato VviAGL11, avaliando seu papel na morfogênese de sementes de Vitis vinifera. Dados prévios permitiram determinar o padrão de expressão de VviAGL11 na camada da endotesta da casca da semente, que precisa alongar e aumentar o número de células para que haja a lignificação e a determinação do tamanho final da semente. No presente estudo, a função de VviAGL11 foi avaliada por meio de sua expressão ectópica no mutante de seedstick (AGL11) de Arabidopsis thaliana, o que restaurou o fenótipo e confirmou o papel direto deste gene no desenvolvimento da semente, sugerindo que a depleção de sua expressão é responsável pelo desenvolvimento errôneo da camada de endotesta da semente, culminando no fenótipo de apirenia típico. Além disso, a função de VviAGL11 foi avaliada em videira com o uso de plasmídeos vegetais. Os resultados permitiram demonstrar que a alta expressão de VviAGL11 na cultivar apirênica Linda, após tratamento, está relacionada com a presença de pequenas sementes que não foram encontradas nas amostras-controle não tratadas Além disso, cachos de ‘Italia’ e ‘Ruby’ tratados com o plasmídeo de silenciamento VviAGL11 mostraram diminuição da expressão desse gene, número reduzido de sementes e aumento do número de traços de sementes. Em conjunto, os resultados confirmam que VviAGL11 é um importante regulador da morfogênese de sementes em videira. Em adição, populações segregantes para ausência de sementes foram testadas com cinco marcadores SSR, dos quais três marcadores microssatélites mostraram-se relacionados à ausência de sementes e poderiam ser usados com 100% de eficiência em um haplótipo para seleção assistida. Ao mesmo tempo, nove marcadores do tipo SNPs e INDELs foram desenvolvidos com base na sequência do alelo de VviAGL11 associado à ausência de sementes em V. vinifera. Para os marcadores VvAGL11_KASP_2, VvAGL11_KASP_3, VvAGL11_KASP_8 e VvAGL11_KASP_9, polimorfismos foram observados segregando em indivíduos apirênicos genotipados, confirmando sua associação com a ausência de sementes e sugerindo seu uso na estratégia de seleção assistida rápida e eficaz de videiras apirênicas. / Grapevine seedlessness, also known as apyreny, is widely appreciated by the table grape’s market. Nevertheless, the molecular mechanisms that control seed morphogenesis are not fully understood. This study aimed to characterize the function of the candidate gene VviAGL11, evaluating its role in Vitis vinifera seed morphogenesis. Previous data allowed us to determine the VviAGL11 expression pattern in the endotesta layer of the seed coat, which needs to elongate and increase in cell number to accomplish seed lignification and final seed size. In the present study VviAGL11 function was evaluated by its ectopic expression in Arabidopsis thaliana seedstick (AGL11) mutant background, which restored the phenotype and confirmed the direct role of this gene in seed development, suggesting that depletion of its expression is responsible for the erroneous development of the endotesta layer of the seed, therefore culminating in the typical seedless phenotype. Furthermore, we evaluated VviAGL11 function in grapevine with the use of plant plasmids. The results showed that a high expression of VviAGL11 in the seedless cultivar Linda, after treatment, was related with the presence of small seeds that were not found in untreated control samples Additionally, seeded ‘Italia’ and ‘Ruby’ bunches treated with a VviAGL11-silencing plasmid showed decreased gene expression, reduced number of seeds and increased number of seed traces. Taken together, the results confirm that VviAGL11 is a key master regulator of seed morphogenesis in grapevine. Moreover, segregating populations for seedlessness were tested with five SSR markers of which three microsatellite markers were proven to be related with seedlessness and could be used with 100% efficiency in a haplotype for assisted selection. Additionally, nine unique SNPs and INDELs markers were developed based on VviAGL11 allele associated with the absence of seeds in V. vinifera. For the markers VvAGL11_KASP_2, VvAGL11_KASP_3, VvAGL11_KASP_8 and VvAGL11_KASP_9, polymorphisms were observed segregating in genotyped seedless individuals, confirming their seedlessness association and suggesting their use in fast and effective assisted selection strategy for seedlessness grapevines.

A ausência de semente em videira, também chamada de apirenia, é amplamente apreciada pelo mercado consumidor de uvas de mesa. No entanto, os mecanismos moleculares que controlam a morfogênese da semente não são totalmente compreendidos. Por este trabalho, buscou-se caracterizar funcionalmente o gene candidato VviAGL11, avaliando seu papel na morfogênese de sementes de Vitis vinifera. Dados prévios permitiram determinar o padrão de expressão de VviAGL11 na camada da endotesta da casca da semente, que precisa alongar e aumentar o número de células para que haja a lignificação e a determinação do tamanho final da semente. No presente estudo, a função de VviAGL11 foi avaliada por meio de sua expressão ectópica no mutante de seedstick (AGL11) de Arabidopsis thaliana, o que restaurou o fenótipo e confirmou o papel direto deste gene no desenvolvimento da semente, sugerindo que a depleção de sua expressão é responsável pelo desenvolvimento errôneo da camada de endotesta da semente, culminando no fenótipo de apirenia típico. Além disso, a função de VviAGL11 foi avaliada em videira com o uso de plasmídeos vegetais. Os resultados permitiram demonstrar que a alta expressão de VviAGL11 na cultivar apirênica Linda, após tratamento, está relacionada com a presença de pequenas sementes que não foram encontradas nas amostras-controle não tratadas Além disso, cachos de ‘Italia’ e ‘Ruby’ tratados com o plasmídeo de silenciamento VviAGL11 mostraram diminuição da expressão desse gene, número reduzido de sementes e aumento do número de traços de sementes. Em conjunto, os resultados confirmam que VviAGL11 é um importante regulador da morfogênese de sementes em videira. Em adição, populações segregantes para ausência de sementes foram testadas com cinco marcadores SSR, dos quais três marcadores microssatélites mostraram-se relacionados à ausência de sementes e poderiam ser usados com 100% de eficiência em um haplótipo para seleção assistida. Ao mesmo tempo, nove marcadores do tipo SNPs e INDELs foram desenvolvidos com base na sequência do alelo de VviAGL11 associado à ausência de sementes em V. vinifera. Para os marcadores VvAGL11_KASP_2, VvAGL11_KASP_3, VvAGL11_KASP_8 e VvAGL11_KASP_9, polimorfismos foram observados segregando em indivíduos apirênicos genotipados, confirmando sua associação com a ausência de sementes e sugerindo seu uso na estratégia de seleção assistida rápida e eficaz de videiras apirênicas. / Grapevine seedlessness, also known as apyreny, is widely appreciated by the table grape’s market. Nevertheless, the molecular mechanisms that control seed morphogenesis are not fully understood. This study aimed to characterize the function of the candidate gene VviAGL11, evaluating its role in Vitis vinifera seed morphogenesis. Previous data allowed us to determine the VviAGL11 expression pattern in the endotesta layer of the seed coat, which needs to elongate and increase in cell number to accomplish seed lignification and final seed size. In the present study VviAGL11 function was evaluated by its ectopic expression in Arabidopsis thaliana seedstick (AGL11) mutant background, which restored the phenotype and confirmed the direct role of this gene in seed development, suggesting that depletion of its expression is responsible for the erroneous development of the endotesta layer of the seed, therefore culminating in the typical seedless phenotype. Furthermore, we evaluated VviAGL11 function in grapevine with the use of plant plasmids. The results showed that a high expression of VviAGL11 in the seedless cultivar Linda, after treatment, was related with the presence of small seeds that were not found in untreated control samples Additionally, seeded ‘Italia’ and ‘Ruby’ bunches treated with a VviAGL11-silencing plasmid showed decreased gene expression, reduced number of seeds and increased number of seed traces. Taken together, the results confirm that VviAGL11 is a key master regulator of seed morphogenesis in grapevine. Moreover, segregating populations for seedlessness were tested with five SSR markers of which three microsatellite markers were proven to be related with seedlessness and could be used with 100% efficiency in a haplotype for assisted selection. Additionally, nine unique SNPs and INDELs markers were developed based on VviAGL11 allele associated with the absence of seeds in V. vinifera. For the markers VvAGL11_KASP_2, VvAGL11_KASP_3, VvAGL11_KASP_8 and VvAGL11_KASP_9, polymorphisms were observed segregating in genotyped seedless individuals, confirming their seedlessness association and suggesting their use in fast and effective assisted selection strategy for seedlessness grapevines.

A ausência de semente em videira, também chamada de apirenia, é amplamente apreciada pelo mercado consumidor de uvas de mesa. No entanto, os mecanismos moleculares que controlam a morfogênese da semente não são totalmente compreendidos. Por este trabalho, buscou-se caracterizar funcionalmente o gene candidato VviAGL11, avaliando seu papel na morfogênese de sementes de Vitis vinifera. Dados prévios permitiram determinar o padrão de expressão de VviAGL11 na camada da endotesta da casca da semente, que precisa alongar e aumentar o número de células para que haja a lignificação e a determinação do tamanho final da semente. No presente estudo, a função de VviAGL11 foi avaliada por meio de sua expressão ectópica no mutante de seedstick (AGL11) de Arabidopsis thaliana, o que restaurou o fenótipo e confirmou o papel direto deste gene no desenvolvimento da semente, sugerindo que a depleção de sua expressão é responsável pelo desenvolvimento errôneo da camada de endotesta da semente, culminando no fenótipo de apirenia típico. Além disso, a função de VviAGL11 foi avaliada em videira com o uso de plasmídeos vegetais. Os resultados permitiram demonstrar que a alta expressão de VviAGL11 na cultivar apirênica Linda, após tratamento, está relacionada com a presença de pequenas sementes que não foram encontradas nas amostras-controle não tratadas Além disso, cachos de ‘Italia’ e ‘Ruby’ tratados com o plasmídeo de silenciamento VviAGL11 mostraram diminuição da expressão desse gene, número reduzido de sementes e aumento do número de traços de sementes. Em conjunto, os resultados confirmam que VviAGL11 é um importante regulador da morfogênese de sementes em videira. Em adição, populações segregantes para ausência de sementes foram testadas com cinco marcadores SSR, dos quais três marcadores microssatélites mostraram-se relacionados à ausência de sementes e poderiam ser usados com 100% de eficiência em um haplótipo para seleção assistida. Ao mesmo tempo, nove marcadores do tipo SNPs e INDELs foram desenvolvidos com base na sequência do alelo de VviAGL11 associado à ausência de sementes em V. vinifera. Para os marcadores VvAGL11_KASP_2, VvAGL11_KASP_3, VvAGL11_KASP_8 e VvAGL11_KASP_9, polimorfismos foram observados segregando em indivíduos apirênicos genotipados, confirmando sua associação com a ausência de sementes e sugerindo seu uso na estratégia de seleção assistida rápida e eficaz de videiras apirênicas. / Grapevine seedlessness, also known as apyreny, is widely appreciated by the table grape’s market. Nevertheless, the molecular mechanisms that control seed morphogenesis are not fully understood. This study aimed to characterize the function of the candidate gene VviAGL11, evaluating its role in Vitis vinifera seed morphogenesis. Previous data allowed us to determine the VviAGL11 expression pattern in the endotesta layer of the seed coat, which needs to elongate and increase in cell number to accomplish seed lignification and final seed size. In the present study VviAGL11 function was evaluated by its ectopic expression in Arabidopsis thaliana seedstick (AGL11) mutant background, which restored the phenotype and confirmed the direct role of this gene in seed development, suggesting that depletion of its expression is responsible for the erroneous development of the endotesta layer of the seed, therefore culminating in the typical seedless phenotype. Furthermore, we evaluated VviAGL11 function in grapevine with the use of plant plasmids. The results showed that a high expression of VviAGL11 in the seedless cultivar Linda, after treatment, was related with the presence of small seeds that were not found in untreated control samples Additionally, seeded ‘Italia’ and ‘Ruby’ bunches treated with a VviAGL11-silencing plasmid showed decreased gene expression, reduced number of seeds and increased number of seed traces. Taken together, the results confirm that VviAGL11 is a key master regulator of seed morphogenesis in grapevine. Moreover, segregating populations for seedlessness were tested with five SSR markers of which three microsatellite markers were proven to be related with seedlessness and could be used with 100% efficiency in a haplotype for assisted selection. Additionally, nine unique SNPs and INDELs markers were developed based on VviAGL11 allele associated with the absence of seeds in V. vinifera. For the markers VvAGL11_KASP_2, VvAGL11_KASP_3, VvAGL11_KASP_8 and VvAGL11_KASP_9, polymorphisms were observed segregating in genotyped seedless individuals, confirming their seedlessness association and suggesting their use in fast and effective assisted selection strategy for seedlessness grapevines.

A new method for measuring the hardness-intensity correlation (HIC) present in gamma-ray bursts (GRB) is developed. This method is used to measure the HIC for 100 single-peak gamma-ray bursts, 17 with known redshifts. The HIC is thus shown to be a consequence of energy-dependent lag times between hard and soft photons. Parameters derived from time profile fits using a modified double sigmoidal function are used to calculate a new set of lag time parameters for bursts, and these parameters are analyzed statistically to look for correlations with intrinsic GRB properties. This analysis shows that GRB red shift is related to lag times between hard and soft photons and that, to within 65% accuracy, GRB redshift can be predicted by the equation: z = 2.49 - 0.131(dpeak) - 0.473(MADS_dpeak)+ 0.143(decay_lag)

Orientador: Marcelo Carnier Dornelas / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T06:53:10Z (GMT). No. of bitstreams: 1 Araujo_Pedro_M.pdf: 2104641 bytes, checksum: 7acaf538c544b73058eb3bbaf4bf0ee5 (MD5) Previous issue date: 2010 / Resumo: Na planta modelo Arabidopsis thaliana o desenvolvimento do fruto foi amplamente estudado e uma série de genes foram relacionados com a ontogênese e o amadurecimento. A identidade dos tecidos dos frutos secos de Arabidopsis é determinada principalmente pelos genes FRUITIFULL (FUL) e SHATTERPROOF (SHP), pertencentes à família multigênica MADS-box. Homólogos a estes genes foram encontrados em frutos carnosos, no entanto a expressão destes homólogos e o papel biológico dos mesmos durante o desenvolvimento dos frutos carnosos são desconhecidos. No banco de dados de genes expressos em Citrus (CitEST), sequências homólogas a FUL e SHP foram encontradas. Uma vez que os frutos de Citrus são carnosos e não apresentam as mesmas estruturas dos frutos de Arabidopsis, decidiu-se caracterizar detalhadamente o desenvolvimento dos frutos em Citrus sinensis e Citrus reticulata e estudar as possíveis funções dos homólogos de FUL e SHP durante o desenvolvimento dos frutos em C. sinensis. Técnicas de microscopia óptica e eletrônica de varredura foram utilizadas para caracterização do desenvolvimento dos frutos. Resultados de RT-PCR mostraram a expressão diferencial dos homólogos de Citrus de FUL e SHP em frutos maduros. Os resultados de hibridização in situ mostraram que o homólogo de FUL expressou-se diferencialmente durante o desenvolvimento do fruto, principalmente nas células secretoras das cavidades oleíferas e das vesículas de suco, nos tecidos do epicarpo, mesocarpo e endocarpo. O homólogo de SHP também se expressou no epicarpo, mesocarpo, endocarpo e nas vesículas de suco. Os resultados obtidos poderão auxiliar num melhor entendimento do desenvolvimento do fruto em Citrus. / Abstract: Fruit development is extensively studied in the model plant Arabidopsis thaliana and a number of genes is being related to the control of fruit ontogenesis and ripening. The FRUITFULL (FUL) and SHATTERPROOF (SHP) genes, which belong to the MADS-box multigenic family are, in large part, responsible for determining the identity of the Arabidopsis dry fruit tissues. Homologs to these genes have been described for species harbouring fleshy fruits, but the expression patterns and biological functions for these genes during fruit development are unknown. Sequences showing similarity to FUL and SHP were found at the database of the CitEST Project (expressed sequence tags in Citrus). Since Citrus fruits are fleshy and do not have the same structures of the Arabidopsis fruits, we decided to characterize in detail the development of fruits in Citrus sinensis and Citrus reticulata and to study the possible functions of FUL and SHP homologues during the development of C. sinensis fruits. These sequences were characterized by bioinformatic's tools and phylogenetic analysis. The use of light and scanning electron microscopy (SEM) techniques allowed the morpho-anatomical characterization of Citrus fruit development. The RT-PCR results showed a preferential expression of FUL and SHP in developing fruits. The in situ hybridization results showed that the C. sinensis homolog of the FUL gene is differentially expressed in the secretory cells of the oil cavity as well as in the juice vesicles, epicarp, mesocarp and endocarp tissues. The homolog of the SHP gene also expressed in epicarp, mesocarp, endocarp and juice vesicles. All the results taken together might contribute to a better understanding of the processes involved in Citrus fruit development. / Mestrado / Mestre em Biologia Vegetal

Dans ce travail, nous expliquons l'application de la méthodologie MADS/MOSAR sur le secteur de extraction minier colombien et nous analysons le lien existant entre la législation colombienne et trois scénarios d'accident (explosion, effondrement post-opération et les maladies pulmonaires). L'ensemble réglementaire d’un pays peut être appréhendé comme des barrières de sécurité et joue un rôle important dans la gestion de la sécurité. La définition, la classification et l'exécution des barrières réglementaires, permet à l’administrateur des risques technologiques d'effectuer une réduction du risque afin d'augmenter l'acceptabilité dans le contexte régional. Il permet d'identifier les flux de dangers pour un groupe d'événements, de définir l'existence ou l’absence de barrières réglementaires et de produire un panorama global positionnant les différents instruments existants et autorisant de futures opportunités de gestion. Les résultats de notre analyse montrent un point de vue qui peut être très utile pour qu'un gouvernement local ou un système national développe et/ou évalue son propre ensemble réglementaire pour la gestion des risques / N this work, we explain the application of the MADS/MOSAR methodology in the Colombian mining sector and analyze the current legislation linked with three scenarios (explosion, post-operation collapsing and pulmonary diseases). The entire normative body of a country can be conceived as safety barriers and it plays an important role in industrial safety management. The definition, classification and performance of the normative barriers, allows the management of technological risks to perform a risk reduction in order to enhance the acceptability in the regional context. It permits to identify the flux of danger for a group of events, to define the existence of normative barriers and to generate a global panorama over the position of the different instruments that already exist allowing future management opportunities. The results of our analysis show a point of view that can be very useful for a local government or a whole national system to develop and/or evaluate his legislative instruments of risk management

L'objectif de mon travail de thèse a consisté à étudier la fonction chez le riz d'une famille de facteurs de transcription de type MADS box (OsMADS23, OsMADS25, OsMADS27, OsMADS57 et OsMADS61) homologues au clade AGL17-like d'Arabidopsis thaliana dans le développement du riz. Dans un premier temps, nous avons recherché les profils d'expression des différents gènes étudiés. Nous avons pu mettre en évidence que les gènes OsMADS23, OsMADS25 et OsMADS27 sont des gènes principalement exprimés dans la racine au niveau du cylindre central, OsMADS57 dans les parties aériennes et OsMADS61 au niveau des bases de tige. Nous avons pu également montrer que l'expression de ces gènes est différente en réponse aux stress salin et osmotique, aux hormones et au nitrate. Ceci suggère que ces gènes possèdent des fonctions distinctes et non redondantes.Mon travail s'est ensuite focalisé sur l'étude fonctionnelle du gène OsMADS25 dont l'expression est spécifiquement détectée dans le cylindre central des racines. Le mutant d'insertion Osmads25 présente un phénotype aérien caractérisé par une réduction drastique du nombre de talles, et un phénotype racinaire caractérisé par une diminution importante du nombre de racines adventives. Ce phénotype a pu être mimé par la création de lignées transgéniques sur-exprimant l'ADNc de OsMADS25 en fusion avec le motif dominant-répresseur de la transcription « EAR ». Ces résultats ainsi que la complémentation du mutant Osmads25 par surexpression de l'ADNc correspondant montre que OsMADS25 agit en tant qu'activateur est un régulateur positif du développement des méristèmes axillaires et de racines adventives chez le riz, agissant probablement des racines aux bases de tiges via une voie de signalisation systémique. Des études complémentaires de phénotypage du mutant au niveau histologique sont en cours afin de préciser le rôle joué par OsMADS25 sur l'initiation ou le développement des méristèmes axillaires. Des analyses de qRT-PCR dans les fonds mutant et sauvage ont montré que ce gène est impliqué dans le développement du riz via une voie de signalisation indépendante des strigolactones. En revanche, l'expression de facteurs de transcription comme OsNAC2 et MOC1, connus pour être impliqués dans le développement des talles ou de CRL1, un régulateur de l'initiation des primordia de racines adventives est atténuée chez les mutant Osmads25 suggérant qu'OsMADS25 pourrait, au moins en partie, directement ou indirectement réguler l'expression de ces gènes. Enfin, des analyses de transcriptome différentiel entre Osmads25 et le fond sauvage ont révélé l'inhibition de l'expression chez le mutant de 60 gènes dont neuf ont une fonction relative à des mécanismes de sécrétion, de transport d'auxine, ou de développement. De manière intéressante, l'un d'entre eux RCN4/Oscen4, appartient à une famille de protéines mobiles connues pour réguler l'activité des méristèmes et qui pourrait constituer un relais moléculaire systémique entre les racines et les bases de tiges permettant d'expliquer le phénotype contrôlé par OsMADS25. / The aim of this work was to study AGL17-like clade MADS box transcription factors (OsMADS23, OsMADS25, OsMADS27 and OsMADS61) in rice development. First, we analyzed expression patterns of the different genes. We showed that OsMADS23, OsMADS25 and OsMADS27 are mainly expressed in the central cylinder of roots; OsMADS57 in aerial parts and OsMADS61 in stem base. Then, we showed that all these have a different response to osmotic and salt stresses, nitrate and hormone. This suggests that these genes have distinct and no redundant functions. My work focused on functional characterization of OsMADS25 which is specifically expressed in root stele. T-DNA mutant Osmads25 presents aerial phenotype characterized by drastic reduction of culm number; and also a root phenotype characterized by a strong decrease of adventitious root number. This phenotype was mimicked by the creation of transgenic lines overexpressing cDNA OsMADS25 in fusion with the “EAR” motif, which acts as a dominant repressor of transcription. These results added to mutant complementation by overexpression of corresponding cDNA show that OsMADS25 acts as an positive regulator of axillary meristem and nodal root development in rice; acting probably from root to stem base via a systemic pathway. Complementary studies as regards mutant microscopic phenotyping are in progress to precise the role acting by OsMADS25 on initiation or development of axillary buds. RT-qPCR analyses showed that this gene is involved in rice development by an strigolactones-independent pathway. On the other hand, expression if transcription factors as OsNAC2 and OsMOC1, known to be involved in tiller development, or as CRL1, regulator of adventitious root primordia initiation, are decreased in Osmads25; suggesting that OsMADS25 could directly or indirectly regulate expression of these genes. Eventually transcriptomic analyses between Osmads25 and WT revealed inhibition of expression of 60 genes which 9 have relative function to secretion mechanism, auxin transport or development. Interestingly, one of its, RCN4/Oscen4 belonging to mobile protein family known to regulate meristem activity and which could constitute a systemic molecular intermediary between root and stem base allowing to explain the controlled phenotype by OsMADS25.

Plant embryogenesis is an intriguing developmental process that is controlled by many genes. AGAMOUS Like 15 (AGL15) is a MADS-domain transcriptional regulator that accumulates preferentially during this stage. However, at the onset of this work it was unknown which genes are regulated by AGL15 or how AGL15 is regulated. This dissertation is part of the ongoing effort to understand the biological roles of AGL15. To decipher how AGL15 functions during plant development, a chromatin immunoprecipitation (ChIP) approach was adapted to obtain DNA fragments that are directly bound by AGL15 in vivo. Putative AGL15 targets were isolated, and binding and regulation was confirmed for one such target gene, ABF3. In addition, microarray experiments were performed to globally assess genes that are differentially expressed between wild type and agl15 young seeds. Among them, a gene, At5g23405, encoding an HMGB domain protein was identified and its response to AGL15 was confirmed. Preliminary results suggest that the loss-of-function of At5g23405 might have an effect on somatic embryogenesis, consistent with AGL15 repression of the expression of this gene. Lastly, to address the question about how the regulator is regulated, the cis elements controlling the expression of AGL15 must be identified. Deletion analysis of the AGL15 promoter indicated the presence of putative positive and negative cis elements contributing to the expression of AGL15. Further analysis suggested that AGL15 regulates the expression of its own gene and this regulation may partially be explained by the direct binding of the protein to the AGL15 promoter. The data presented in this dissertation demonstrate that ChIP can be used to identify previously unsuspected targets of AGL15. Based on ChIP, a ChIP-chip technique is being developed in the lab to allow a more global analysis of in vivo binding sites. The identification of target genes and cis elements in AGL15 promoter is a step towards characterization of the biological roles of AGL15.