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The multiplication of cells in all living organisms requires a tight regulation of DNA replication. Several mechanisms take place to ensure that the DNA is replicated faithfully and just once per cell cycle in order to originate through mitoses two new daughter cells that contain exactly the same information from the previous one. A key control mechanism that occurs before cells enter S phase is the formation of a pre-replication complex (pre-RC) that is assembled at replication origins by the sequential association of the origin recognition complex, followed by Cdt1, Cdc6 and finally MCMs, licensing DNA to start replication. The identification of pre-RC members in all animal and plant species shows that this complex is conserved in eukaryotes and, more importantly, the differences between kingdoms might reflect their divergence in strategies on cell cycle regulation, as it must be integrated and adapted to the niche, ecosystem, and the organism peculiarities. Here, we provide an overview of the knowledge generated so far on the formation and the developmental controls of the pre-RC mechanism in plants, analyzing some particular aspects in comparison to other eukaryotes.

AIP1 is a novel Agenet/Tudor domain protein from Arabidopsis that interacts with regulators of DNA replication, transcription and chromatin remodeling. AIP1 is a novel Agenet/Tudor domain protein from Arabidopsis that interacts with regulators of DNA replication, transcription and chromatin remodeling

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2021-07-19T22:26:51Z No. of bitstreams: 1 2018 - Leilson Novaes Arruda.pdf: 1524544 bytes, checksum: cb96f62021175bf3fe41ea093ce361a5 (MD5) Made available in DSpace on 2021-07-19T22:26:51Z (GMT). No. of bitstreams: 1 2018 - Leilson Novaes Arruda.pdf: 1524544 bytes, checksum: cb96f62021175bf3fe41ea093ce361a5 (MD5) Previous issue date: 2018-02-28 Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES, Brasil) Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do Rio de Janeiro (FAPERJ, Brasil) Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq, Brasil) Nitrogen (N) is one the most required elements by plants, being constituent of the main molecules of biological systems. Therefore, large quantities are applied to the soil in order to maximize productivity. However up to 70% of the applied N can be lost by different processes. Reducing Nitrogen fertilizer input and finding varieties with a high nitrogen use efficiency (NUE) are the main goals of plant nutrition. Among the strategies to increase NUE, was proposed in this work the knockdown and over expression of OsNPF4.11 nitrate transporter in Nipponbare rice variety. For this purpose, after obtaining the transgenic lines were carried out three experiments in growth chamber and one in a greenhouse. In the root of knockdown plants, the high affinity nitrate transporters were down regulated, but in the leaves the opposite was observed, in the transgenic plants high affinity nitrate transporters were up regulated. Over expression of OsNPF4.11 also affected the expression of high affinity nitrate transporters. In the root (both low and high nitrate availability) and in the leaves (under low nitrate availability) high affinity nitrate transporters were down regulated. Both the reduction and the increase in the expression levels of OsNPF4.11 negatively affected the nitrate uptake, as well as the root to shoots transport, resulting in short plants with a lower total biomass. In addition to the absorption, changes in the OsNPF4.11 expression also affected the N remobilization to the grains, resulting in a greater number of sterile spikelets and a lower yield, and thus a lower EUN. O nitrog?nio (N) ? um dos elementos mais requeridos pelas plantas, sendo constituinte das principais mol?culas dos sistemas biol?gicos. Portanto, grandes quantidades s?o aplicadas no solo com o intuito de maximizar a produtividade. Entretanto at? 70% do N aplicado pode ser perdido por diferentes processos. Assim, Reduzir as quantidades de fertilizantes nitrogenados e encontrar variedades com maior efici?ncia no uso de nitrog?nio (EUN) s?o os principais objetivos atualmente da nutri??o de plantas. Dentre as estrat?gias para aumentar a efici?ncia de uso de N foi proposto no presente trabalho silenciar e superexpressar o transportador de nitrato OsNPF4.11 em arroz da variedade Nipponbare. Para tal fim ap?s a obten??o das linhagens transformadas foram realizados tr?s experimentos em fitotr?n e um em casa de vegeta??o. As linhagens silenciando o OsNPF4.11 apresentam uma menor express?o dos transportadores de alta afinidade na raiz, por?m nas folhas o oposto foi observado, onde as linhagens transformadas apresentaram maiores valores de express?o em rela??o as plantas WT. A superexpress?o do OsNPF4.11 tamb?m afetou a express?o dos transportadores de alta afinidade, onde na raiz (tato em alta como baixa disponibilidade de NO3-) e nas folhas (sob baixa disponibilidade) as plantas transformadas apresentaram uma redu??o na express?o dos mesmos. Tanto a redu??o quanto o aumento nos n?veis de express?o do OsNPF4.11 afetou negativamente a absor??o de NO3-, assim como o transporte do mesmo da raiz para a parte a?rea acarretando em plantas menores e com uma menor biomassa total. Al?m da absor??o, as altera??es na express?o do OsNPF4.11 tamb?m afetaram a remobiliza??o do N para os gr?os, acarretando um maior n?mero de espiguetas est?reis e uma menor produ??o, e assim uma menor EUN.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2021-04-05T13:41:01Z No. of bitstreams: 1 2018 - Andressa Fabiane Faria de Souza1.pdf: 1296398 bytes, checksum: 0ab238e1fcd22badc26ae28df2145db0 (MD5) Made available in DSpace on 2021-04-05T13:41:01Z (GMT). No. of bitstreams: 1 2018 - Andressa Fabiane Faria de Souza1.pdf: 1296398 bytes, checksum: 0ab238e1fcd22badc26ae28df2145db0 (MD5) Previous issue date: 2018-02-28 Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES, Brasil. The availability of nutrients in the soil influences growth modulation and root architecture. Nitrogen (N) is one of the factors that most limits plant growth and productivity, as plants with a nitrogen deficiency invest more in root depth and do not limit lateral elongation of the root system. For efficient nutrient uptake to occur, specific transporters located on the plasma membrane are required to assist in the entry of the nutrient into the cellular interior, with emphasis on high-affinity nitrate transporters (NRT2). Thus, plants silencing the OsNRT2.4 gene, obtained through the gene silencing technique by artificial microRNA (amiRNA), and control plants (WT - wild type) were submitted to a low nitrate dose condition, with the aim of investigating the role of the OsNRT2.4 transporter in the promotion of root growth stimulus. After the process transformation, the seedlings obtained were transferred to greenhouse at the Department of Soils of UFRRJ, to obtain first generation seeds (T1). Seeds of the obtained lines presented problems regarding the germination, so a protocol to break seed dormancy was established to overcome the problem. Subsequently, three experiments were conducted in a growth chamber (fitotron). The first and second experiments were conducted in order to select those lines silencing the OsNRT2.4 gene. The lines and WT plants were grown in nutrient solution under a low nitrate dose (0.2 mM N-NO3 -) and selected based on the analysis of gene expression by the comparative CT method (2-??C T) and by the morphology and root parameters analysis, experiments I and II, respectively. Experiment III was carried out with the previously selected lines, L#5 and L#39. The aim was to analyze the effect of the silencing of the OsNRT2.4 gene on the soluble metabolites and on the expression pattern of enzymes of the metabolism of N and the high-affinity nitrate transporters, cultured in nutrient solution under low dose and resupply (0.1 mM N-NO3 -). It was observed that the silencing of the OsNRT2.4 gene induced a WT-like lateral root density, but lower lateral root elongation, smaller surface area, lower volume and fewer tips, confirming that the OsNRT2.4 transporter has a role in the regulation of root growth, being specifically involved in the growth of lateral roots. The silencing also affected the expression of other high-affinity nitrate transporters (OsNRT2.1 e OsNAR2.1). In addition, the OsNRT2.4 transporter has a role in the internal N flux regulation, acting in the nitrate transport from roots to shoot (efflux). A disponibilidade de nutrientes no solo influencia na modula??o do crescimento e arquitetura radicular. O nitrog?nio (N) ? um dos fatores que mais limita o crescimento e a produtividade, no entanto, plantas sob defici?ncia de nitrog?nio investem mais no aprofundamento radicular e n?o limitam o alongamento lateral do sistema radicular. Para que ocorra uma absor??o eficiente de nutrientes s?o necess?rios transportadores espec?ficos de membrana que ir?o auxiliar na entrada do nutriente para o interior celular, com ?nfase nos transportadores de nitrato de alta afinidade (NRT2). Deste modo, plantas silenciando o gene OsNRT2.4, obtidas por meio da t?cnica de silenciamento g?nico por micro RNA artificial, e plantas controle (WT - tipo selvagem) foram submetidas a uma condi??o de baixo fornecimento de nitrato com o objetivo de investigar o papel do transportador OsNRT2.4 na promo??o do est?mulo do crescimento radicular. Ap?s o processo de transforma??o, as pl?ntulas obtidas foram transferidas para casa de vegeta??o no Departamento de Solos da UFRRJ, para obten??o das sementes de primeira gera??o (T1). Sementes das linhagens obtidas apresentaram problemas quanto ? germina??o, por isso, para a supera??o da dorm?ncia das sementes, foi estabelecido um protocolo de quebra de dorm?ncia. Posteriormente, foram conduzidos tr?s experimentos em c?mara de crescimento (fitotron). O primeiro e o segundo experimento foram realizados com o intuito de selecionar aquelas linhagens silenciando o gene OsNRT2.4. As linhagens e as plantas WT foram cultivadas em solu??o nutritiva sob baixo fornecimento de nitrato (0,2 mM N-NO3 -) e selecionadas com base na an?lise de express?o g?nica por meio do m?todo do CT comparativo (2-??CT) e, pela an?lise morfol?gica e par?metros radiculares, experimentos I e II, respectivamente. O experimento III foi realizado com as linhagens selecionadas previamente, L#5 e L#39, e teve como objetivo analisar o efeito do silenciamento do gene OsNRT2.4 sobre os metab?litos sol?veis e sobre o padr?o de express?o das enzimas do metabolismo de N e os transportadores de nitrato de alta afinidade, cultivadas em solu??o nutritiva sob baixo fornecimento de nitrato e ressuprimento (0,1 mM N-NO3 -). Foi observado que o silenciamento do gene OsNRT2.4 induziu uma densidade de ra?zes laterais semelhantes a WT, por?m menor alongamento das ra?zes laterais, menor ?rea de superf?cie, menor volume e menor n?mero de pontas, confirmando que o transportador OsNRT2.4 possui um papel na regula??o do crescimento radicular, estando especificamente envolvido no crescimento de ra?zes laterais. O silenciamento tamb?m afetou a express?o de outros transportadores de nitrato de alta afinidade (OsNRT2.1 e OsNAR2.1). Al?m disso, o transportador OsNRT2.4 possui um papel na regula??o do fluxo interno de N, atuando no transporte de nitrato da raiz para a parte a?rea (efluxo).

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-01-24T17:49:23Z No. of bitstreams: 1 2017 - Leandro Martins Ferreira.pdf: 2738374 bytes, checksum: a6ccde64b30f6cd52122b9030ab6c92e (MD5) Made available in DSpace on 2018-01-24T17:49:25Z (GMT). No. of bitstreams: 1 2017 - Leandro Martins Ferreira.pdf: 2738374 bytes, checksum: a6ccde64b30f6cd52122b9030ab6c92e (MD5) Previous issue date: 2017-02-22 CAPES Faperj CNPq Among the abiotic stress, drought is a major environmental stress seriously limiting plant growth and crop productivity. Rice is one of the most important staple food crops in the world and requires a larger quantity of water to produce, once it is a crop extremely sensitive to drought stress. For this reason, to obtain rice plants that cope with drought stress without major reduction in productivity is the challenge for breeding programs nowadays. This work aimed: (i) identify upland rice varieties with contrasting drought tolerance through the evaluation of morphological and physiological traits, (ii) analyse root parameters which could explain the differences between tolerant and sensitive varieties to the drought stress and, (iii) identify new biotechnological targets related with the tolerance through transcript profile analysis in the contrasting varieties. Six experiments were performed, two in greenhouse and four in growth chamber conditions. The experimental design adopted was completely randomized. The first experiment started with ten rice varieties submitted to control and stress conditions during the reproductive stage. The contrasting varieties were selected based on morphological and physiological traits. Experiments from II to IV aimed to correlate the tolerance to the drought stress with the root development and morphology. Experiment V aimed to evaluate the regulation of genes related to the drought tolerance and the experiment VI aimed to analyse the differential expression of genes through the RNAseq analysis in rice roots. Data obtained from the productivity components, tolerance index and multivariate analysis through the evaluation of morphological and physiological traits allowed to identify Catet?o and Piau? variety as the most tolerant and Quebra Cacho and Mira as the most sensitive. Drought tolerance was correlated with a lower root angle and increase in the root density and emission of lateral roots by Catet?o variety during drought stress. Moreover, Catet?o variety has showed higher expression levels and early induction of genes and transcription factors related with drought tolerance. The RNAseq analysis allowed to identify several potential genes which can be used in future breeding programs aimimg the improvement of drought tolerance in rice. Dentre os estresses abi?ticos que podem limitar o crescimento das culturas agr?colas, a seca ? considerada um dos principais, sendo capaz de reduzir consideravelmente a produ??o global de alimentos. O arroz ? uma das mais importantes culturas agr?colas do mundo e sua produ??o demanda grande quantidade de ?gua, pois ? uma esp?cie extremamente sens?vel ao d?ficit h?drico. Portanto, a obten??o de plantas de arroz que lidam com o estresse h?drico, sem redu??o significativa de produtividade ? um desafio para os programas de melhoramento atuais. Este trabalho teve como objetivos: (i) identificar variedades de arroz de sequeiro contrastantes quanto ? toler?ncia ao estresse h?drico por meio da avalia??o de caracter?sticas morfol?gicas e fisiol?gicas, (ii) analisar par?metros radiculares que possam explicar a diferen?a entre variedades tolerantes e sens?veis ao estresse h?drico e, (iii) identificar novos alvos biotecnol?gicos envolvidos com essa toler?ncia por meio da an?lise do perfil de transcritos nas variedades de arroz contrastantes. Foram realizados seis experimentos, sendo dois em casa de vegeta??o e quatro em c?mara de crescimento. O delineamento experimental utilizado foi o inteiramente casualizado. O primeiro experimento iniciou com dez variedades de arroz submetidas a condi??o controle e estresse h?drico durante o per?odo reprodutivo. As variedades contrastantes foram selecionadas com base em caracter?sticas morfol?gicas e fisiol?gicas analisadas. Os experimentos II a IV foram realizados a fim de correlacionar a toler?ncia ao estresse com o desenvolvimento e morfologia do sistema radicular. O experimento V foi realizado para avaliar a regula??o de genes relacionados a toler?ncia ao estresse h?drico e o experimento VI teve como objetivo analisar a express?o diferencial de genes por meio da t?cnica de RNA-seq em ra?zes de arroz. Os dados obtidos dos componentes de produtividade, ?ndices de toler?ncia ao estresse e an?lise multivariada das caracter?sticas morfol?gicas e fisiol?gicas permitiram identificar as variedades Catet?o e Piau? como as mais tolerantes ao estresse h?drico, e Quebra Cacho e Mira como as mais sens?veis. Foi observado que a toler?ncia ao estresse h?drico est? correlacionada com o menor ?ngulo radicular, aumento da densidade e emiss?o de ra?zes laterais em condi??es de d?ficit h?drico na variedade Catet?o. Al?m disso, essa variedade mostra indu??o r?pida e elevados n?veis de express?o de genes e fatores de transcri??o relacionados ? toler?ncia ao estresse h?drico em arroz. Por meio do sequenciamento do RNA foi poss?vel identificar diversos genes com potencial para serem utilizados em programas de melhoramento visando o aumento da toler?ncia ao estresse h?drico em arroz.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2020-05-14T19:13:54Z No. of bitstreams: 1 2012 - Diego de Mello Conde de Brito.pdf: 3907319 bytes, checksum: 6bbecc358685fc4b9af8bcbb30c37255 (MD5) Made available in DSpace on 2020-05-14T19:13:54Z (GMT). No. of bitstreams: 1 2012 - Diego de Mello Conde de Brito.pdf: 3907319 bytes, checksum: 6bbecc358685fc4b9af8bcbb30c37255 (MD5) Previous issue date: 2012-07-23 Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES Crambe (Crambe abyssinica Hochst. ex. R.E. Fries) is an oleaginous culture that belongs to the cruciferae family, and is toxic for human feed, which presents a great potential for use in biofuel industry as well as a source of erucic acid. Nowadays, there is only one variety of crambe developed in Brazil and adapted to its conditions, designated FMS Brilhante. The main characteristics that highlight this variety as a promising option of market are precocity, high grain yield, low production cost and high oil percentage in seeds. However, few information about the metabolic aspects of this culture are available. In the context of vegetal nutrition, nitrogen must be mentioned because is generally the element required in major concentrations and is strongly related to the production costs and can cause serious environmental problems. Thus, the major objective of this work was evaluate the influence of variation in N levels, in nitrate form, under different aspects of crambe metabolism (FMS Brilhante variety), including gene expression, aiming primarily its relation with yield parameters. Also was evaluated the pH influence of cultivation medium under some metabolic aspects of this culture. Three experiments were done, with three replicates arranged in a completely randomized experimental design. In the experiments I and II plants were submitted in hydroponic system to different nitrate-N doses (0,2; 2 and 4 mM) and pH variation (5,0; 5,5; 6,0 and 6,5), respectively, and harvested at the end of vegetative period. In the experiment III plants were cultivated in a argisol soil under crescent nitrate-N supply (0,8; 1,6; 2,4 and 3,2 mM) and three harvests were done: One at initiation and the other one at end of flowering and the last at final of seed maturation. The results obtained with experiment I highlight the role of stem in nitrate storage in this specie. On the other hand, in experiment II was observed that variation in pH of nutrient solution do not influence significantly the mass production and that plants cultivated under pH 6,0 showed an increase in the processes related to nitrogen reduction and assimilation. Among the main results obtained with the experiment III is possible to highlight that with 1,6 mM of nitrate-N was obtained a high seed and oil yield and also a satisfactory fatty acid composition of oil, aiming the use of crambe in biodiesel industry. Furthermore, was observed an increase in erucic acid concentration of crambe oil with the reduction of nitrate-N supply. Important information is that the 3-cetoacil-CoA sintase (KCS) gene cannot be one of the main factors involved in erucic acid synthesis. However, the expression of lysophosphatidyl aciltransferase (LPAT) gene seems to be strongly related with the synthesis of erucic acid in this specie. Thereby, crambe cultivation is possible with low nitrate-N supply, for use of culture in biodiesel industry or for erucic acid extraction (Used in plastic, lubricants and other industries), and that contribute for a reduction in production costs and environmental impacts and for an increase in yield parameters. O crambe (Crambe abyssinica Hochst. ex. R.E. Fries) ? uma oleaginosa, pertencente ? fam?lia das cruc?feras, que ? t?xica para a alimenta??o humana e apresenta um grande potencial para emprego na agroenergia ou como fonte de ?cido er?cico. Atualmente, existe apenas uma variedade de crambe desenvolvida no Brasil e adaptada ?s suas condi??es, denominada FMS Brilhante. As principais caracter?sticas que colocam essa variedade como uma op??o de mercado promissora s?o a precocidade, a alta produtividade de gr?os, o baixo custo de produ??o e o elevado teor de ?leo nas sementes. Entretanto, ainda existem poucas informa??es sobre o metabolismo dessa cultura. No contexto da nutri??o vegetal, o nitrog?nio se destaca, pois, al?m de ser geralmente o elemento requerido em maiores concentra??es, est? intimamente relacionado aos custos da produ??o e pode acarretar s?rios impactos ambientais. Assim, o objetivo principal desse trabalho foi avaliar a influ?ncia da varia??o nas doses de N, na forma de nitrato, sobre diversos aspectos do metabolismo de plantas de crambe (FMS Brilhante), incluindo a express?o de genes, visando principalmente sua rela??o com os par?metros de produtividade. Foi avaliada tamb?m a influ?ncia do pH do meio de cultivo sobre alguns aspectos metab?licos da cultura. Foram realizados tr?s experimentos, com tr?s repeti??es em delineamento inteiramente casualizado. Nos experimentos I e II as plantas foram cultivadas em hidroponia a diferentes doses de N-nitrato (0,2; 2 e 4 mM) e a varia??o do pH (5,0; 5,5; 6,0 e 6,5), respectivamente, e coletadas ao fim da fase vegetativa. No experimento III as plantas foram cultivadas, em terra proveniente de um solo do tipo argissolo, com doses crescentes de N-nitrato (0,8; 1,6; 2,4 e 3,2 mM) e foram realizadas tr?s coletas: uma no in?cio e outra no fim do florescimento e a ?ltima ao t?rmino da matura??o de sementes. Os resultados obtidos no experimento I reiteram o papel do caule no armazenamento do nitrato nessa esp?cie. Entretanto, no experimento II observou-se que a varia??o do pH do meio de cultivo n?o exerceu influ?ncia significativa sobre a produ??o de massa e que, al?m disso, as plantas cultivadas sob pH 6,0 desenvolveram os processos relacionados a redu??o e assimila??o do nitrog?nio, com maior intensidade. Dentre os principais resultados obtidos com o experimento III, ? poss?vel destacar que na dose de 1,6 mM de N-nitrato houve uma elevada produ??o de sementes, ?leo e, tamb?m, um perfil de ?cidos graxos adequado, tendo-se em vista o emprego do crambe na ind?stria do biodiesel. Al?m disso, observou-se aumento na concentra??o de ?cido er?cico no ?leo de crambe, com a redu??o do suprimento de N-nitrato. Outro ponto importante ? que o gene da 3-cetoacil-CoA sintase (KCS) pode n?o ser um dos principais fatores envolvidos na s?ntese de ?cido er?cico. Entretanto, a express?o do gene da lisofosfatidil aciltransferase (LPAT) parece ter uma forte rela??o com a s?ntese de ?cido er?cico nessa esp?cie. Assim, seja visando seu uso na agroenergia ou para extra??o de ?cido er?cico (Utilizado na ind?stria de pl?sticos, lubrificantes etc.) ? poss?vel o cultivo de crambe com baixos suprimentos de N-nitrato, o que al?m de reduzir os custos envolvidos na produ??o e impactos ao ambiente favorece os par?metros de produtividade.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-05-26T20:35:35Z No. of bitstreams: 1 2012 - Renata Aparecida Costa Silva.pdf: 1687897 bytes, checksum: 4d1af8e117daa1842ae1766319ddf8d6 (MD5) Made available in DSpace on 2017-05-26T20:35:35Z (GMT). No. of bitstreams: 1 2012 - Renata Aparecida Costa Silva.pdf: 1687897 bytes, checksum: 4d1af8e117daa1842ae1766319ddf8d6 (MD5) Previous issue date: 2012-02-15 CAPES Nitrogen is one of the nutrient elements most limiting for plant growth. Thus, increasing plant nitrogen usage efficiency (NUE) is an essential factor for sustainable agriculture, leading to an increased food production with less fertilizer input and less environment impact. The aim of this study was to evaluate the effect of OsDof25 overexpression on N-NO3- and N-NH4+ uptake. In transgenic rice plants, OsDof25 was expressed under control of maize ubiquitin promoter (UBIL:OsDof25:3xHA). Two experiments were conducted: one to evaluate the kinetic parameters Vm?x and KM, and another to analyze the expression level of nitrate (NRT2.1~2.2 and NAR) and ammonium transporters (AMT1.1~1.3), both under high and low NO3- and NH4+ supply. The untransformed plants showed higher growth that transformed lineages. The L1 and L2 showed a lower value of the KM in the resupply treatment of 0.2 mM N-NO3-. In the resupply with 0.2 mM N-NH4 + the L4 showed higher Vmax and L1 lower KM. There were no large variations in uptake kinetics between the transformed and untransformed plants. At the root the NRT2 showed low expression in lineages L1 and L4, when under constant supply of N-NO3-, in contrast, in the treatment under resupply with 0.2 mM N-NO3-was increased expression of OsNTR2.1 ~ 2.2, and NAR in both transformed lineages, but in the root the concentration of NO3- was opposed to the expression of NRT2 and NAR, in both conditions. In the leaves, the line L4 showed high expression of the transporter OsNRT2.1 with the resupply of 0.2 and 2.0 mM N-NO3-. In plants grown under constant supply of N-NH4+, L1 showed lower expression of AMT1 in the root compared to L4 and untransformed plants. When subjected to nitrogen deficiency, there was an increased expression of the OsAMT1.2. However, there was no correlation between N transporter expression levels and NO3- and NH4+ content in the transformed plants, indicating a possible change in enzyme activity and reduction or assimilation of N in these plants. The transformed plants when subjected to resupply with low levels of nitrate and ammonium showed better response parameters Vmax and KM compared to the untransformed. In the plants transformed the resupply with nitrate at low concentration resulted in increasing the gene expression of the transporters (OsNTR2.1 ~ 2.2 and protein OsNAR2.1), and the treatment with constant supply provided greatest nitrate accumulation in these plants. The results of both kinetic parameters and accumulation of fresh matter suggest that plants transformed for the expression of the OsDof25 presented highest tolerance to nutritional stress. O nitrog?nio ? um dos elementos minerais que mais limita o desenvolvimento das plantas. Assim, aumentar a efici?ncia de uso de nitrog?nio (EUN) ? um fator ? essencial para uma agricultura sustent?vel, levando a um aumento da produ??o de alimentos com menor uso de insumos e menos impactos ao ambiente. Este trabalho teve por objetivo avaliar o efeito da superexpress?o do fator de transcri??o OsDof25 sobre a absor??o de nitrog?nio em duas linhagens transformadas de arroz (L1 e L4) da variedade Nipponbare comparando-as com plantas n?o transformadas (WT). Nas plantas transformadas, o OsDof25 foi expresso sob o controle do promotor da ubiquitina 1 de milho (UBIL:OsDof25:3xHA). For feitos dois experimentos: um para avaliar os par?metros cin?ticos Vm?x e KM, sob condi??es de alto e baixo suprimento de N-NO3- e N-NH4+, e outro para analisar a express?o dos transportadores de NO3- (NRT2.1~2.2 e NAR) e NH4+ (AMT1.1~1.3) tamb?m sob alto e baixo suprimento desses ?ons. As plantas n?o transformadas apresentaram maior crescimento do que as linhagens transformadas. As L1 e a L2 mostraram menor valor de KM no tratamento com ressuprimento de 0,2 mM de N-NO3-. No ressuprimento com 0,2 mM de N-NH4+ a L4 apresentou maior Vm?x e L1 menor KM, mas, n?o houve grandes varia??es nos par?metros cin?ticos de absor??o entre as plantas transformadas e n?o transformadas. Na raiz os NRT2 mostraram baixa express?o nas linhagens L1 e L4 quando submetidas ao suprimento constante de N-NO3-, em contrapartida, no tratamento sob ressuprimento com 0,2 mM de N-NO3- ocorreu aumento de express?o dos OsNTR2.1~2.2 e NAR nas duas linhagens transformadas, por?m na raiz a concentra??o de N-NO3- foi oposta a express?o dos NRT2 e NAR, em ambas as situa??es. Nas folhas, a linhagem L4 apresentou alta express?o do transportador OsNRT2.1 com o ressuprimento de 0,2 e 2,0 mM de N-NO3-. Nas plantas submetidas ao suprimento constante de N-NH4+, a L1 apresentou menor express?o dos AMT1 na raiz quando comparada a L4 e a planta n?o transformada. Quando submetida a defici?ncia de N-NH4+, a express?o do OsAMT1.2 aumentou nas ra?zes de todas as plantas. Entretanto, n?o houve correla??o positiva entre a express?o dos transportadores de N e os teores de NO3- e NH4+ nas linhagens transformadas, indicando uma poss?vel altera??o na atividade das enzimas de redu??o e ou assimila??o de N. As plantas transformadas quando submetidas ao ressuprimento com baixos teores de nitrato e am?nio apresentaram melhor resposta dos par?metros Vm?x e KM em rela??o a n?o transformadas. Nas plantas transformadas o ressuprimento com nitrato em baixa concentra??o resultou em maior express?o dos genes dos transportadores OsNTR2.1~2.2 e da prote?na OsNAR2.1 e o tratamento com suprimento constante proporcionou maior ac?mulo de nitrato nestas plantas. Os resultados tanto dos par?metros cin?ticos quanto do ac?mulo de mat?ria fresca sugerem que as plantas transformadas para express?o do OsDof25 apresentaram maior toler?ncia ao estresse nutricional.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2020-09-23T22:37:45Z No. of bitstreams: 1 2011 - Cassia Pereira Coelho.pdf: 691090 bytes, checksum: cc4c94ea9b51209fef42303cadfad701 (MD5) Made available in DSpace on 2020-09-23T22:37:47Z (GMT). No. of bitstreams: 1 2011 - Cassia Pereira Coelho.pdf: 691090 bytes, checksum: cc4c94ea9b51209fef42303cadfad701 (MD5) Previous issue date: 2011-02-22 Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do RJ, FAPERJ, Brasil. This study aimed to evaluate the contribution of nitrogen remobilization for Nitrogen Use Efficiency (NUE) in four rice varieties. IAC-47 represent an improved variety, and Piaui, Bico Ganga and Revenda are three local varieties from State of Maranh?o (Brazil), cultivated in systems with low N input. Local rice varieties in Maranh?o State are adapted to conditions of low N levels and therefore may be more efficient in the usage of this nutrient compared to improved varieties. This efficiency may be partly due to the strategy of accumulation and remobilization of N from vegetative parts to grains. The experiment was conducted in a greenhouse at Soils Department of the Federal Rural University of Rio de Janeiro (UFRRJ). The plants were cultured in pots containing 9 kg of soil from upper 20 cm of a Molisol, from Pinheiral ? RJ. The experimental design was completely randomized in a factorial 4 x 2 x 4 (varieties x N levels x harvest) with four replications. The soil in the pots was fertilized at planting with a dose equivalent to 60 kg N ha-1 of urea. In the flowering stage, the plants received or not supplemental fertilization with urea, at a dose equivalent to 40 kg N ha-1. Four harvests were taken: 15 days before anthesis, anthesis, 15 days after anthesis, and at the end of plant development. There were evaluated contents of free amino-N, N-NH4 +, N-NO3 - and soluble sugars in the roots and sheaths of the plants of the first harvest. In addition it was determined the activity of nitrate reductase and glutamine synthetase in samples of the first, second and third harvests, and plant dry matter production. Expression of OsGS1.1, OsGS2 and OsGS1.3 was analyzed in the flag leaves, second leaves and panicles of two varieties (IAC-47 and Piau?) in the first three harvests. The results indicate a strategy of the Piau? variety in accumulating N at vegetative stage and remobilize at anthesis and p?s-anthesis, demonstrating major efficiency of N remobilization. Variedades locais de arroz do Maranh?o s?o adaptadas a condi??es de baixa disponibilidade de N e, portanto, podem ser mais eficientes no uso desse nutriente quando comparadas a variedades melhoradas. Essa efici?ncia pode em parte ser devido ? estrat?gia de ac?mulo e remobiliza??o do N das partes vegetativas para os gr?os.Este trabalho teve como objetivo avaliar a contribui??o da remobiliza??o na Efici?ncia de Uso de Nitrog?nio (EUN) em quatro variedades de arroz. Dentre elas uma ? melhorada, a IAC 47, e tr?s s?o variedades locais: Piau?, Bico Ganga e Revenda, origin?rias de cultivos com baixa disponibilidade de nutrientes no estado do Maranh?o. O experimento foi conduzindo em casa de vegeta??o, no Departamento de Solos da Universidade Federal Rural do Rio de Janeiro (UFRRJ). Foram usados potes contendo 9 kg de terra, proveniente dos primeiros 20 cm de solo coletado em ?rea no munic?pio de Pinheiral ? RJ, classificado como Chernossolo. O delineamento experimental utilizado foi inteiramente casualizado, em esquema fatorial 4 x 2 x 4 (variedades x doses de N x coletas) com quatro repeti??es. Os vasos receberam aduba??o basal, no plantio, em dose equivalente a 60 kg de N/ha na forma de Ur?ia. Na antese as plantas receberam ou n?o aduba??o suplementar com ur?ia em dose equivalente a 40 kg de N/ha. Foram realizadas quatro coletas: no per?odo do emborrachamento (15 dias antes da antese - DAA), na antese, 15 dias ap?s antese (DAA) e ao final do ciclo de desenvolvimento das plantas. Foram avaliados os teores de N-amino livre, N-NH4 +, N-NO3 - e a??cares sol?veis nas folhas, ra?zes e bainhas das plantas da primeira coleta realizada. Foram determinadas as atividades das enzimas nitrato redutase e glutamina sintetase nas amostras provenientes da primeira, segunda e terceira coletas e a produ??o de massa seca das plantas. As express?es dos genes das isoformas de glutamina sintetase: OsGS1.1, OsGS2 e OsGS1.3 foram analisadas nas folhas bandeira, folhas 2 e pan?cula das variedades IAC-47 e Piau? nas tr?s primeiras coletas. Os resultados obtidos indicam uma estrat?gia da variedade Piau? em acumular o N nos per?odos iniciais do ciclo de desenvolvimento com maior efici?ncia que a variedade melhorada IAC-47, demonstrando uma maior efici?ncia de remobiliza??o de N.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2019-06-12T13:45:29Z No. of bitstreams: 1 2011 - Marcus Vinicius Loss Sperandio.pdf: 1632142 bytes, checksum: 048312c96197527c0c8373673d0611bb (MD5) Made available in DSpace on 2019-06-12T13:45:29Z (GMT). No. of bitstreams: 1 2011 - Marcus Vinicius Loss Sperandio.pdf: 1632142 bytes, checksum: 048312c96197527c0c8373673d0611bb (MD5) Previous issue date: 2011-02-22 CNPq - Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico The main goal of this study was to evaluate the nitrogen usage efficiency (NUE) of plants for a low input agriculture, as a fundamental step for tropical agriculture development. The objective was to evaluate the effect of N deficiency and resupply on expression of ten PM H+- ATPase isoforms, and NO3 - and NH4 + transporters in rice. Two experiments were set, one with the Nipponbare variety, to evaluate expression of PM H+-ATPase; and the other with IAC47 (improved) and Piaui (traditional) varieties, to study how PM H+-ATPase and NO3 - transporters behaved in varieties with contrasting N-use efficiency. The NO3 - and NH4 + uptake were highest under N-resupply. The NO3 --N resupply after 3 days of N-deficiency resulted in induction of OsA1, OsA2, OsA5 and OsA7 PM-H+-ATPases in the shoot, and of OsA2, OsA5, OsA7 and OsA8 in the roots. NH4 +-N resupply resulted in induction of the OsA1, OsA3, and OsA7 isoforms in roots and OsA1 in the shoots. A correlation was observed between nitrate and ammonium uptake, and an increase in the PM H+-ATPases. In the roots, the NO3 - transporters OsNRT2.1 and OsNRT2.2 had higher induction under NO3 - resupply, while the NH4 + transporter OsAMT1.1 and OsAMT1.2 were induced by NH4 +-N starvation. These results showed that the expression of PM H+-ATPases isoforms is related to both NO3 - and NH4 + transporters and in which plant part it takes place. The knowledge of the interaction between N-transporters and PM H+-ATPases specific isoforms is important for understanding NUE in plants. Two H+-ATPases isofoms OsA2 e OsA7 that were most induced under Nressuply can be thought as the most probable genes to affect N-uptake efficiency in rice. The second experiment showed that the varieties IAC-47 and Piaui differ widely about the N usage. The Piaui variety showed the highest level of nitrate and free Amino-N, and the lowest levels of NH4 +. Also, this variety had the highest PM H+-ATPase activity 24 hs after resupply with 0.2 mM NO3 --N, as well as the highest expression of the PM H+-ATPase OsA2 and OsA7. The Piaui variety showed the highest nitrate influx under N-resupply (0.2 and 5.0 mM NO3 --N) as well as higher expression of OsNRT2.1, OsNRT2.2 and OsNAR2.1 under those treatments. These results suggest that the highest NO3 - uptake of Piaui variety under Nresupply may be related to the highest expression of genes that code for nitrate transporters and PM H+-ATPases. Neste trabalho a principal meta foi avaliar a efici?ncia de uso de nitrog?nio (EUN) de plantas para uma agricultura de baixos insumos, um passo fundamental no desenvolvimento da agricultura tropical. O objetivo foi avaliar os efeitos de defici?ncia e ressuprimento de nitrog?nio na express?o de dez isoformas PM H+-ATPases em arroz e dos transportadores de NO3 - e NH4 +. Dois experimentos foram feitos: um com a variedade Nipponbare para avaliar a express?o das PM H+-ATPases e outro com as variedades IAC-47 (melhorada) e Piau? (tradicional) para estudar os efeitos das PM H+-ATPases em variedades contrastantes no uso de N, assim como transportadores de nitrato. A absor??o aparente de ambas as formas de NNO3 - e N-NH4 + foi maior com seu ressuprimento. O ressuprimento de NO3 - ap?s tr?s dias de defici?ncia de N resultou na indu??o das isoformas de PM H+-ATPases OsA1, OsA2, OsA5 e OsA7 na parte a?rea e OsA2, OsA5, OsA7 e OsA8 nas ra?zes. O ressuprimento de NH4 + resultou na indu??o das isoformas OsA1, OsA3 e OsA7 nas ra?zes, enquanto OsA1 foi induzida na parte a?rea. O aumento observado na absor??o de NO3 - e NH4 + resultou em maior atividade das PM H+-ATPases. Nas ra?zes, os transportadores de NO3 - OsNRT2.1 e OsNRT2.2 foram induzidos pelo ressuprimento com NO3 -, enquanto os transportadores de NH4 + OsAMT1.1 e OsAMT1.2 foram induzidos pela defici?ncia de NH4 +. Os resultados mostram que a express?o das isoformas de PM H+-ATPases est? relacionada aos transportadores de NO3 - e NH4 + e em qual parte da planta ? considerada. O conhecimento da intera??o entre transportadores de N e express?o de isoformas espec?ficas de PM H+-ATPases ? relevante para o entendimento da efici?ncia de absor??o de N em plantas. As isoformas de PM H+- ATPases OsA2 e OsA7 por terem sido as mais induzidas com o ressuprimento de N podem ser consideradas como genes candidatos a afetar a efici?ncia de absor??o de N em arroz. No segundo experimento conduzido com as variedades de arroz IAC-47 (melhorada) e Piau? (local) mostrou que essas duas variedades diferem quanto ao uso de N. A variedade Piau? apresentou maiores teores de NO3 - e N-amino livre e menores de NH4 +. Ainda, essa variedade apresentou maior atividade da PM H+-ATPase no tempo de 24 horas ap?s o ressuprimento com 0,2 mM de N-NO3 -, assim como maior express?o das isoformas de PM H+-ATPase OsA2 e OsA7. A variedade Piau? apresentou maior influxo de NO3 - no ressuprimento (0,2 e 5,0 mM de N-NO3 -), assim como maior express?o dos genes OsNRT2.1, OsNRT2.2 e OsNAR2.1 nesses tratamentos. Esses resultados sugerem que a maior absor??o de NO3 - com o ressuprimento na variedade Piau? pode estar relacionada ? maior express?o de genes que codificam para transportadores de NO3 - e PM H+-ATPases.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2020-09-11T09:52:53Z No. of bitstreams: 1 2010 - Osm?rio Jos? Lima de Ara?jo.pdf: 1678228 bytes, checksum: c8b81f8e51deb4db3524c8af60900c9b (MD5) Made available in DSpace on 2020-09-11T09:52:53Z (GMT). No. of bitstreams: 1 2010 - Osm?rio Jos? Lima de Ara?jo.pdf: 1678228 bytes, checksum: c8b81f8e51deb4db3524c8af60900c9b (MD5) Previous issue date: 2010-02-24 Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES, Brasil. The largest efficiency of N uptake from low concentrations in the solution, and the capacity of accumulation of this nutrient could propitiate a larger stock of N in the vegetative period, which during the grains development would be the responsible for the largest protein in the grains of the traditional rice (Oryza sativa) varieties. Thus, in this study, to identify the metabolic mechanisms responsible for this efficiency 56 traditional rice varieties and 10 improved varieties were compared for their genetic similarities, using the RADP technique. Among the two main groups obtained, the contrasting varieties IAC-47, Bico Ganga and Revenda were selected to represent the Group I, and Manteiga for Group II. It was also considered the crude proteins content of the grains. The varieties were evaluated for the kinetic parameters of absorption of nitrate and kinetics of expression of the genes that codify high affinity nitrate transporters. The genetic similarity resulted in two great groups: Group I and Group II. The group I was shown to be quite heterogeneous as for the origin of the analyzed varieties. All of the improved varieties were contained in the Group I. Most of the varieties named Lageado, originated from the germoplasm bank were in the Group I. The group II contained exclusively varieties form farms in the State of Maranh?o, what suggests a narrow genetic base of the varieties. The rice varieties with thinnest and longest grains (with larger relationship length width ? L/W) were in the Group I, while in the Group II they were more rounded, in other words, with the smallest relationships L/W. The varieties Revenda and Manteiga presented larger expression of high affinity transporters OsNRT2.1 and 2.2, in all times. When compared the kinetics of absorption of nitrate with the expression of the transporters it was observed that the variety IAC-47 presented the smallest Vm?x, and that there was not great increase of the expression of NRT2.1. the variety IAC-47, despite of belonging to the same grouping of genetic similarity of the variety Revenda and both with similar size of grain and length/width ratios, presented only 65% of genetic similarity. Therefore the results showed that the rice variety Revenda has mechanisms that propitiate larger capacity of nitrate absorption when it is available to the plant. A maior efici?ncia de absor??o de N a partir de baixas concentra??es na solu??o externa, e a capacidade de ac?mulo desse nutriente poderia propiciar um maior estoque de N no per?odo vegetativo, que durante o enchimento dos gr?os seria o respons?vel pelo maior teor de prote?na nos gr?os das variedades locais de arroz (Oryza sativa). Desta forma, neste projeto para se identificar os mecanismos metab?licos respons?veis por esta efici?ncia inicialmente foram comparadas 56 variedades locais de arroz e 10 variedades melhoradas quanto a suas similaridades gen?ticas utilizando-se a t?cnica de RAPD. Entre os dois principais agrupamentos obtidos foram selecionadas as variedades contrastantes IAC-47, Bico Ganga e Revenda do Grupo I e Manteiga do Grupo II, levando-se em considera??o tamb?m os teores de prote?na bruta dos gr?os. As variedades foram avaliadas quanto aos par?metros cin?ticos de absor??o de nitrato e quanto ? cin?tica de express?o dos genes que codificam os transportadores nitrato de alta afinidade. O dendrograma de similaridade gen?tica apresentou dois grandes grupos: Grupo I e Grupo II. O grupo I se mostrou bastante heterog?neo quanto ? origem das variedades analisadas. Todas as variedades melhoradas agruparam no Grupo I. A maior parte das variedades de nome Lajeado provenientes de banco germoplasma esta no grupo I. O grupo II agrupou exclusivamente variedades provenientes das lavouras do estado do Maranh?o, o que sugere uma estreita base gen?tica das variedades l? cultivadas. Os gr?os mais finos e longos (com maior rela??o comprimento largura ? C/L) estavam nas variedades de arroz no Grupo I, enquanto no Grupo II os gr?os de arroz foram mais redondos, ou seja, com as menores rela??es C/L. As variedades Revenda e Manteiga apresentaram maior express?o dos transportadores de alta afinidade OsNRT2.1 e 2.2, em todos os tempos. Ao se comparar a cin?tica de absor??o de nitrato com a express?o dos transportadores foi observado que a variedade IAC-47 apresenta a menor Vm?x, e que n?o houve grande aumento da express?o do NRT2.1. A variedade IAC-47, apesar de pertencer ao mesmo agrupamento de similaridade gen?tica da variedade Revenda e terem ambas, tamanhos de gr?os e rela??es comprimento largura semelhantes, apresentaram apenas 65% de similaridade gen?tica. Portanto os resultados obtidos mostram que a variedade de arroz Revenda possui mecanismos que propiciam maior capacidade de absor??o de nitrato, quando ele est? dispon?vel para a planta.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-03-30T12:28:08Z No. of bitstreams: 1 2010 - Marco Andre Alves de Souza.pdf: 5657340 bytes, checksum: becf46e090a1ebcc4a731b733c77fb6a (MD5) Made available in DSpace on 2017-03-30T12:28:08Z (GMT). No. of bitstreams: 1 2010 - Marco Andre Alves de Souza.pdf: 5657340 bytes, checksum: becf46e090a1ebcc4a731b733c77fb6a (MD5) Previous issue date: 2010-01-18 Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq The cultivation of aromatic specimens for obtaining essential oils have great economic importance, mainly by increasing demand in the food, cosmetic and pharmaceutical industry. Brazil is the largest producer of essential oil, however, is what earns less in money value, because, its production is mainly of orange essential oil, with low added value. The essential oil of M. arvensis is rich in menthol (70-80%), a natural products with higher demand in daily life of modern man. Currently, Brazil has become a major importer of menthol which has contributed negatively to the brazilian trade balance. Thus, for the development of this work was chosen to be a specimens of economic interest and social demand, the Mentha arvensis. The purpose of study was to evaluate whether changes in light intensities and different levels of phosphorus promote changes in biomass production and nutrition, with consequences for the biosynthesis of essential oils. We also analyzed the influence of leaf age on the quality of essential oil. To this end, the plant of M. arvensis was grown under the effect of different conditions, which allowed the analysis of the levels of soluble fractions, of photosynthetic pigments, the activities of enzymes related to nitrogen assimilation and the anatomical and histochemical study of trichomes, morphological structure where it is produce the essential oil. The study also included analysis of the expression of genes related to the route of menthol synthesis. The essential oil was obtained by extraction with hydrodestillation in modified Clevenger and the chemical analysis of substances obtained by GC-MS. The Kovats index was used to collaborate in identification of the main substances in essential oil. The results showed that the essential oil quality is determined by physiological conditions and leaf age and that the production is dependent on the synthesis efficiency and density of trichomes on the leaves. In addition, it was found that different concentrations of phosphorus affected some aspects of plant metabolism, which reflected the production of biomass in the soluble fraction, with consequences on production and quality of essential oils. Also showed that variations in light levels affected the expression of six of the eight genes involved in the route of synthesis of menthol, in plants of M. arvensis and that changes in gene expression are probably associated with a transcription factor, which could be acting on the whole pathway. All of this information showed that environmental conditions and / or nutritional affected some aspects of plant metabolism, which reflected the production of biomass, of trichomes and on the expression of genes related to the route of menthol, which reflect on the quality and the production of essential oils O cultivo de esp?cies arom?ticas para a obten??o de ?leos essenciais tem grande import?ncia econ?mica, principalmente, pela crescente demanda nas ind?strias de alimentos, de cosm?ticos e a farmac?utica. O Brasil ? o maior produtor de ?leo essencial, entretanto, ? o que menos arrecada em valores monet?rios, pois, sua produ??o ? basicamente de ?leo essencial de laranja, com baixo valor agregado. O ?leo essencial de Mentha arvensis L. ? rico em mentol (70-80%), uma dos produtos naturais com maior demanda no dia-a-dia do homem moderno. Atualmente, o Brasil tornou-se um grande importador de mentol o que tem contribu?do negativamente para a balan?a comercial brasileira. Deste modo, para o desenvolvimento deste trabalho escolheu-se a planta M. arvensis. O objetivo do estudo foi avaliar se varia??es nas intensidades luminosas e diferentes concentra??es de f?sforo promovem altera??es na produ??o de biomassa e em aspectos nutricionais, com reflexos na bioss?ntese de ?leos essenciais. Tamb?m foi avaliada a influ?ncia da idade da folha sobre a qualidade do ?leo essencial. Com esta finalidade, a planta de M. arvensis foi cultivada sob o efeito de diferentes condi??es, o que permitiu a an?lise dos teores das fra??es sol?veis, dos pigmentos fotossint?ticos, das atividades das enzimas relacionadas com a assimila??o do nitrog?nio e o estudo histoqu?mico e anat?mico dos tricomas secretores, estrutura morfol?gica onde ? produzido o ?leo essencial. Tamb?m foram realizadas analises da express?o dos genes relacionados com a rota de s?ntese do mentol. O ?leo essencial foi obtido por hidrodestila??o em Clevenger modificado e as analises qu?micas das subst?ncias realizadas por CG/EM. A utiliza??o do ?ndice de Kovats auxiliou na identific??o das principais subst?ncias no ?leo essencial. Os resultados permitiram concluir que a qualidade do ?leo essencial ? determinada pelas condi??es fisiol?gicas e a idade das folhas e que a produ??o ? dependente da efici?ncia de s?ntese e a densidade de tricomas secretores nas folhas. Al?m disso, foi constatado que as diferentes concentra??es de f?sforo afetaram alguns aspectos do metabolismo vegetal, os quais refletiram na produ??o de biomassa, nas fra??es sol?veis, com conseq??ncias na produ??o e qualidade dos ?leos essenciais. Tamb?m, mostraram que varia??es nos n?veis de luminosidade afetaram a express?o de seis entre os oito genes envolvidos com a rota de s?ntese do mentol, em plantas de M. arvensis e que as altera??es na express?o dos genes provavelmente est?o associados a um fator de transcri??o, o qual deve estar atuando sobre toda a rota metab?lica