Orientador: Rinaldo Cesar de Paula / Banca: Paulo Henrique Muller da Silva / Banca: Felipe Batistella Filho / Banca: Gustavo Vitti Môro / Banca: Sérgio Valiengo Valeri / Resumo: Os programas de melhoramento florestal no Brasil têm o desafio de atender à demanda crescente por produtos madeireiros. Por outro lado, a ocorrência de secas sucessivas no Brasil vem criando uma instabilidade produtiva nas florestas plantadas. Com isto, este trabalho teve como objetivos: i) estimar parâmetros genéticos e avaliar a adaptabilidade, estabilidade e produtividade de famílias de polinização aberta de Eucalyptus grandis em diferentes locais no Brasil e propor estratégia de seleção para o conjunto desses locais; ii) avaliar o comportamento de uma amostra destas famílias, cultivadas em vasos em casa de vegetação, submetidas a dois regimes hídricos na presença e ausência de adubação potássica e iii) relacionar os resultados obtidos em casa de vegetação com aqueles obtidos em campo. A primeira parte do trabalho foi realizada com os dados de altura, diâmetro à altura do peito e volume de madeira, cedidos pelo Instituto de Pesquisas e Estudos Florestais (IPEF), provenientes de testes de 165 famílias de polinização aberta de Eucalyptus grandis avaliados em oito locais no Brasil. Estes dados foram submetidas à análise de adaptabilidade, estabilidade e produtividade pelo método da Média Harmônica da Performance Relativa dos Valores Genéticos (MHPRVG). Com base neste estudo, uma amostra de 15 das 165 famílias foi usada para o experimento conduzido em casa de vegetação, onde estas foram submetidas a dois regimes de irrigação, na presença e ausência de adubação potássica, avali... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The programs of forest improvement in Brazil have the challenge of meeting this rising demand. On the other hand, the occurrence of repeated droughts in Brazil has been creating a productive instability in commercial forests. Likewise, this work had the objective: i) estimated genetic parameters and evaluating the adaptability, stability and productivity of open-pollinated families of Eucalyptus grandis in different sites in Brazil, and proposing selection strategy for the set of these sites; ii) evaluating the behavior of a sample of these families, cultivated in pots at greenhouse, subject to two hydric regimes in the presence and absence of potassium fertilizations and iii) relating the results obtained in greenhouse with those obtained in the field. The first part of this work was done with height, diameter at breast height and wood volume data, provided by the Instituto de Pesquisas e Estudos Florestais (IPEF), from tests of 165 open-pollinated families of Eucalyptus grandis evaluated in eight places. These data were submitted to analysis of adaptability, stability and productivity through the method of Harmonic Mean of the Relative Performance of the Genetic Values (HMRPGV). Based on this study, a sample of 15 out of 165 families was used for the experiments realized in greenhouse, where these were submitted to two irrigation regimes, in the presence and absence of potassium, evaluating the growth, nutritional and physiological traits. There was genotype by environment interaction with change in the order of genotypes in different environments as detected by the method HMRPFV compared with the order of genotypes in each site, which shows the simultaneous selection for all sites is not the best strategy of improvement. The sites Pratânia and Monte Dourado B can be used for obtaining representative and superior genotypes for most regions studied. Ev... (Complete abstract click electronic access below) / Doutor

Polyploidy is widely acknowledged as a widespread mechanism in the evolution and speciation of the majority of flowering plants. Allopolyploid forms through interspecific hybridization and whole genome duplication. While allopolyploids may display increased vigor relative to their progenitors, they can also face challenges to fertility following hybridization. Genetic changes in allopolyploids result from recombination between the hybridized subgenomes, which can influence phenotype and ultimately determine fitness of future generations. To study dynamic changes that follow allopolyploid formation, Brassica napus lineages were derived by hybridizing Brassica oleracea and Brassica rapa. Two lineages of B. napus were analyzed for genetic and phenotypic changes in the S2, S7, and S12 generations. Although these lineages were genetically identical at the time of hybridization, divergence was apparent by the S2 generation. There was a significant increase in sequence loss across generations within both lineages. Four of six generations from both lineages displayed no significant differences to each other in sequence loss relative to the parental generation. In both lineages, there was a bias towards losing sequences from the B. olereacea subgenome. Some individual plants showed novel phenotypes; however, there was no correlation between the examined genetic changes and selected phenotypes.

Alfalfa is the most important forage crop in Utah. It is of particular importance to the Uintah Basin, Utah area where alfalfa hay and seed production are major sources of agricultural income. This crop owes much of its popularity to the fact that it will normally produce large yields of good forage on land which is unsuited to more intensive cultivation. In many cases it is impractical to advocate disease control practices which involve extra labor or expense and as a result most diseases of alfalfa, if controlled at all, are controlled by the use of resistant varieties. During the past few years alfalfa witches' broom has become detrimental in the Uintah Basin area. This disease shortens the length of life of alfalfa stands and reduces the yield. Some diseased stands are killed out in a period of three years. It is difficult and expensive to reestablish alfalfa in this area where water supplies are usually low. Therefore, it is imperative that alfalfa stands remain in production for several years. These problems justify a study to find resistance to alfalfa witches' broom. The objectives of this study are to select varieties of alfalfa which are resistant to alfalfa witches' broom in the Uintah Basin area, to select varieties of alfalfa which are best adapted to the area for high yield per acre, to determine which of a few insects tested are responsible for transmission of alfalfa witches' broom virus, and to determine if certain dodder species (Cuscuta spp.) act as transmission bridges for alfalfa witches' broom.

New and better adapted varieties of crop plants have resulted from the application of the principles of genetics. Fundamental research in the field of barley genetics has helped the plant breeder in developing better varieties for specific uses and adaptability. Barley is one of the best cultivated crop plants for making genetic studies. It has a wide range of adaptability, exhibits a host of contrasting genetic characters, is a simple diploid with only seven pairs of chromosomes, and all the cultivated species are interfertile.

The use of F1 hybrids for commercial production of such cross-pollinated crops as corn, sorghum, sugar beets, onions, and pearl millet suggests the feasibility of using this technique for alfalfa. Production of F1 hybrids of commercial value is dependent on the use of breeding material expressing good combining ability. In order to obtain precise estimates of combining ability for quantitative characters in alfalfa, it is necessary to produce all possible single crosses among a number of parents. The single cross seed required is difficult to obtain due to the vegetative reproduction and isolation required; and, subsequently, limited testing of this type has been conducted in alfalfa. Testing breeding material for combining ability based on seed production has been more limited than testing based on forage yield or various other measurements. In this experiment a diallel crossing system was used to test the general and specific combining ability of five alfalfa clones previously selected for good general combining ability. The report is based on first-year data of a three-year study, and the results are subject to errors which may occur due to variability inherent in the year of establishment. This is especially true for conclusions based on seed production. However, first-year data should be valid for such characteristics as flower color and seedling height. The analysis of seed production and seedling height is designed to measure the relative amount of general and specific combining ability of the cones involved. Reciprocals of the single crosses were evaluated for flower color, seedling height, and seed yield to check if reciprocal cross progeny give equal performance.

Abiotic stresses such as drought, salt and exposure to toxic metals adversely affect the growth and productivity of crop plants and are serious threats to agriculture. We are currently working with an Arabidopsis family of proteins known as Stress Associated Proteins (SAPs). There are a total of 14 proteins in the Arabidopsis SAP family whose members have been suggested to provide tolerance to abiotic stresses in plants. For this project, we aim to characterize AtSAP13, which codes for a protein of 249 amino acid residues. Through overexpression, we investigated the sensitivity or tolerances provided by the overexpressed protein in comparison to wild-type plants. Our preliminary results showed that Arabidopsis plants overexpressing SAP13 showed strong tolerance to arsenite, cadmium, and zinc. A semi-quantitative RT-PCR was performed to analyze SAP13’s mRNA levels in wild type plants exposed to the same set of stresses. Tissue specific expression was analyzed using a GUS histochemical assay. Sub-cellular localization of AtSAP13 was analyzed by creating an in-frame fusion of SAP13 and enhanced GFP (eGFP). We set out to optimize growth conditions for Crambe abyssinica in order to determine if Crambe could be grown as a biofuel crop in New England. We have determined that Crambe can be grown successfully in the New England climate. We tested three fertilizer application rates, two different cultivars, and two different soil types for changes in yield. In the end, we observed the greatest increase in yield when planted on well drained soil.

Flavonoids are plant secondary metabolites well known for many key roles in the life cycle of plants. They also can affect human health. Citrus paradisi is known to produce several glucosylated flavonoids and these compounds are glucosylated by enzymes known as glucosyltransferases (GTs). The focus of this research was to optimize the heterologous expression, enrichment, and biochemical characterization of grapefruit putative GT protein, PGT2, and to test the hypothesis that PGT2 is a flavonoid GT. Results showed detectable amounts of activity with quercetin, a flavonol; however, activity was lower than what would be expected if this enzyme were a flavonol-specific GT. In an additional aspect of this study, bioinformatics were used to test the hypothesis that additional putative GT clones could be identified using the harvEST database.

The domesticated tomato Solanum lycopersicum (L.), formerly known as Lycopersicon esculentum is a genetically well-studied crop species with high-density linkage and molecular maps based on crosses done between cultivated tomato and its distant related wild species. Wild tomato species harbor a wealth of resistance to many pathogens that have been introgressed into domesticated tomato for genetic control of diseases and pests and for improvement of many agronomic traits. The wild tomato S. peruvianum (L.) is the source of the Sw-5 gene, characterized and mapped to chromosome 9 of the tomato genome and introgressed into elite tomato germplasm, providing resistance to the tospovirus Tomato spotted wilt virus (TSWV). TSWV has been reported to be a major problem for tomato growers in many parts of the world, which in some cases, has resulted in tomato fields having been abandoned for some time. Additionally, there are reports that new races of TSWV have evolved that overcome Sw-5. TSWV replicates in both, plant cells and in the alimentary canal cells of thrips and then transmitted to plants by this insect acting as a vector. Both, TSWV and thrips have co-evolved to infest and infect more than 1090 plants species in over 100 families, thrips becoming resistant to pesticides and easily escaping by hiding deep in plant parts. World trade has disseminated thrips all over the world and environmental pressures have forced TSWV to recombine its RNA to overcome new resistance.

Genetic modification of plastids in the model plant tobacco (Nicotiana tabacum) has demonstrated that numerous foreign gene products can accumulate to high levels in this setting. Plastid biotechnology is maturing to encompass the improvement of food and feed species and the production of biopharmaceutical proteins for oral delivery necessitating development of stable transplastomic edible plants. In the interest of establishing an edible platform we have investigated the use of native and foreign regulatory elements in relation to foreign gene expression in plastids. Multiple sequence alignments of intergenic regions for 20 species of angiosperm showed that despite 95% identity in the coding region, identity in the psbA upstream region is 59% across all taxa examined, other gene coding regions displayed sequence identity of 80-97%, whereas the non-coding regions were 45-79% suggesting that our physical data can be extrapolated beyond the model presented. We found that by exchanging psbA untranslated regions (UTRs) between N. tabacum and lettuce (Lactuca sativa), the expression of the CTB-proinsulin (CTB-Pins) monocistronic transcript declined by 84% and foreign protein accumulation was reduced by as much as 97% in mature leaves. Polyribosome association assays suggest that ribosome-free transgenic transcripts are stabilized where the native UTR is employed. RNA EMSA revealed that binding proteins interacted with psbA 5' UTRs in a species specific manner and the half life of the L. sativa 5'UTR-CTB-Pins mRNA was reduced by 3.7 fold in N. tabacum stromal extracts. Our data indicate that the use of species-specific regulatory elements could lead to establishment of reproducible plastid transformation in desirable target species such as L. sativa. Using transplastomic L. sativa for oral delivery of bioencapsulated CTB-Pins we delayed the onset of diabetes in NOD mice when retinyl acetate supplement was provided compared to untouched mice. In this 30 week study we monitored blood glucose levels and evaluated the in vitro suppressive capacity of regulatory T cells isolated from diabetic mice. Whether delay or prevention was achieved appeared to be a function of antigen dose as high dose resulted in a nine week delay of onset while low dose reduced the incidence of diabetes by 36%. In addition we have evaluated metabolic engineering in the N. tabacum model where we generated cis-genic lines expressing nucleus-encoded methionine pathway enzymes in plastids. Transplastomic expression of Cystathionine gamma-Synthase led to a three-fold increase in enzyme activity and a doubling of methionine content in leaves without a deleterious phenotype. In exploring molecular mechanisms supporting gene expression in plastids and applying transplastomic technology to real human problems this work seeks address the potential of plastid biotechnology for improvement of commodity crops and production of biopharmaceuticals.

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