Express��o g��nica diferencial por cDNA-AFLP em ra��zes de cana-de-a����car submetida ao d��ficit h��drico

P��s-gradua����o em Agronomia (Gen��tica e Melhoramento de Plantas) - FCAV

Reguladores de crescimento na dorm��ncia e germina����o de sementes de amendoim

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Reguladores vegetais na supera����o da dorm��ncia, balan��o hormonal e degrada����o de reservas em sementes de Annona diversifolia SAFF. e A. purpurea Moc. & Sess�� Ex Dunal (Annonaceae)

As sementes de anon��ceas s��o conhecidas por apresentarem mecanismos de dorm��ncia, o que dificulta a perpetua����o das esp��cies e a forma����o de ��reas produtivas para a explora����o comercial. Deste modo, os objetivos deste trabalho foram estudar curva de aquisi����o de ��gua; a germina����o de sementes tratadas com GA3 e GA4+7 + Benziladenina; o balan��o hormonal e a degrada����o de reservas em sementes de Annona diversifolia Saff e Annona purpurea Moc & Sess�� ex Dunal tratadas com reguladores vegetais para a supera����o da dorm��ncia. Para tanto foram realizados tr��s experimentos. Para a constru����o da curva de aquisi����o de ��gua foram utilizadas 4 repeti����es de 25 sementes que foram mantidas em embebi����o e pesadas durante 480 horas. O segundo experimento foi constitu��do pela germina����o das sementes tratadas com os reguladores vegetais; o delineamento experimental empregado foi o inteiramente casualizado com 4 repeti����es de 25 sementes por parcela em esquema fatorial 2 x 7 (reguladores x concentra����es). Os tratamentos foram constitu��dos pelas combina����es entre concentra����es de GA3 e de GA4+7 + Benziladenina (GA4+7 + BA) x 0, 200, 400, 500, 600, 800 e 1000 mg L-1 i.a.. No terceiro experimento foram quantificados ABA (��cido absc��sico) e GA (Giberelinas), prote��nas, a����cares...

Fisiologia e produ����o da soja tratada com cinetina e c��lcio sob deficit h��drico e sombreamento

The objective of this work was to evaluate the effects of kinetin and calcium applications on the physiologic and productive traits of soybean plants, subjected to drought and shade conditions, at flowering. A randomized complete block design was used, in a split-plot arrangement, with four replicates. Soybean plants cultivated in 38 dm�� pots were sprayed with calcium and kinetin, alone or mixed, and subjected to drought and shade during 12 days. After stress period, plants were cultivated under appropriate water and light availability. Calcium and kinetin application resulted in maintenance of the relative water content after four days of drought beginning. Membrane damage, measured at the end of stress period, was lower in plants sprayed with calcium and kinetin. CO2 assimilation diminished by stress condition, mainly under drought, and grain yield decreased at the same intensity in both environments.

Novel bioassay for the discovery of inhibitors of the 2-C-Methyl-D-erythritol 4-Phosphate (MEP) and terpenoid pathways leading to carotenoid biosynthesis

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Overexpression of the activated form of the AtAREB1 gene (AtAREB1 Delta QT) improves soybean responses to water deficit

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Fisiologia da germina����o das cipselas heterom��rficas em Bidens L

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Effects of hormonal priming on seed germination of pigeon pea under cadmium stress

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Expression studies in the embryo and in the micropylar endosperm of germinating coffee (Coffea arabica cv. Rubi) seeds

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Photomorphogenic modulation of water stress in tomato (Solanum lycopersicum L.): the role of phytochromes A, B1, and B2

Phytochromes are red/far-red light photoreceptors that mediate a variety of photomorphogenic processes in plants, from germination to flowering. In addition, there is evidence that phytochromes are also part of the stress signalling response, especially in response to water deficit stress, which is the major abiotic factor limiting plant growth and crop productivity worldwide. In this study, we used the phyA (far red-insensitive; fri), phyB1 (temporary red-insensitive; tri) and phyB2 mutants of tomato (Solanum lycopersicum L.) to study the roles of these three phytochromes in drought stress responses. Compared to wild type (WT) plants grown under water-deficit stress conditions, the fri, tri, and phyB2 mutants did not exhibit altered dry weights, leaf areas, stomatal densities, or stomatal opening. The stomatal conductance of all three mutants was severely reduced under both fully-hydrated and water-deficit conditions. Although relative water contents did change after drought stress in each mutant, the most significant reduction in water potential during water stress was observed in the fri mutant. However, this mutant returned its water status to WT levels during rehydration. Although the phyB2 mutant lost more water from detached leaves during abscisic acid (ABA) treatment, phyB2 behaved like WT plants, indicating that this mutant was not insensitive to ABA. Overall, these results indicate that the phytochromes phyA, phyB1, and phyB2 modulate drought stress responses in tomato.

A����o do ��cido absc��sico na cor das bagas, na qualidade e no armazenamento p��s-colheita da uva Rubi

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Caracteriza����o funcional da via miR159/SlyGAMYB-like ao longo do processo de frutifica����o em tomateiro (Solanum lycopersicum L.)

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Caracteriza����o funcional da via miR159/SlyGAMYB-like ao longo do processo de frutifica����o em tomateiro (Solanum lycopersicum L.)

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

A hormonal misunderstanding in Acca sellowiana embryogenesis: levels of zygotic embryogenesis do not match those of somatic embryogenesis

Endogenous levels of IAA, ABA and four types of CKs were analyzed in zygotic and indirect (ISE) and direct somatic embryogenesis of Acca sellowiana. Zygotic and somatic embryos at different developmental stages were sampled for morphological and hormonal analysis. Both embryo types showed substantial asymmetry in hormone levels. Zygotic embryos displayed a conspicuous peak of IAA in early developmental stages. The results outlined the hormonal variations occurring during zygotic and somatic embryogenesis regarding the timing, nature and hormonal status involved in both processes. The short transient pulse of IAA observed on the 3rd day in culture was suggested to be involved with the signaling for the induction of somatic embryogenesis. Fertilized ovule development was associated with increased IAA levels 21-24 days after pollination, followed by a sharp decrease in the cotyledonary stage, both in zygotic and somatic embryos. There was a prominent increase in ABA levels in cultures which generated ISE 24-30 days after pollination, a period that corresponds to the heart and torpedo stages. The levels of total CKs (Z, [9R]Z, iP and [9R]iP) were also always higher in zygotic than in somatic embryogenesis. While zygotic embryogenesis was dominated by the presence of zeatin, the somatic process, contrarily, was characterized by a large variation of the other cytokinin forms and amounts studied. The above results, when taken together, could be related to the previously observed high frequency formation of anomalous somatic embryos formed in A. sellowiana, as well as to their low germination ability.

Dissecting Phaseolus vulgaris Innate Immune System against Colletotrichum lindemuthianum Infection

Background: The genus Colletotrichum is one of the most economically important plant pathogens, causing anthracnose on a wide range of crops including common beans (Phaseolus vulgaris L.). Crop yield can be dramatically decreased depending on the plant cultivar used and the environmental conditions. This study aimed to identify potential genetic components of the bean immune system to provide environmentally friendly control measures against this fungus. Methodology and Principal Findings: As the common bean is not amenable to reverse genetics to explore functionality and its genome is not fully curated, we used putative Arabidopsis orthologs of bean expressed sequence tag (EST) to perform bioinformatic analysis and experimental validation of gene expression to identify common bean genes regulated during the incompatible interaction with C. lindemuthianum. Similar to model pathosystems, Gene Ontology (GO) analysis indicated that hormone biosynthesis and signaling in common beans seem to be modulated by fungus infection. For instance, cytokinin and ethylene responses were up-regulated and jasmonic acid, gibberellin, and abscisic acid responses were down-regulated, indicating that these hormones may play a central role in this pathosystem. Importantly, we have identified putative bean gene orthologs of Arabidopsis genes involved in the plant immune system. Based on experimental validation of gene expression, we propose that hypersensitive reaction as part of effector-triggered immunity may operate, at least in part, by down-regulating genes, such as FLS2-like and MKK5-like, putative orthologs of the Arabidopsis genes involved in pathogen perception and downstream signaling. Conclusions/Significance: We have identified specific bean genes and uncovered metabolic processes and pathways that may be involved in the immune response against pathogens. Our transcriptome database is a rich resource for mining novel defense-related genes, which enabled us to develop a model of the molecular components of the bean innate immune system regulated upon pathogen attack.