Melhoramento genetico em soja na COODETEC

Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Agronomia

Polyamine patterns in haploid and diploid tobacco tissues and in vitro cultures

The aim of this work was to determine PAs levels in pith tissues and callus cultures from haploid and diploid tobacco plants, explanted from the apical and basal regions of the stem. These explants were cultured in an RM-64 medium supplied with IAA and kinetin, under light or in the dark, during successive subcultures. PAs levels followed a basipetal decrease in diploid and an increase in haploid, pith tissues. A similar pattern of total PAs (free + conjugated) was observed for the callus of diploid and haploid plants maintained in the light, and for the haploid callus in the dark, whereas the diploid callus in the dark showed a constant increase in total PAs levels until the end of culture. The PA increase in the diploid callus in the dark was related to free Put levels increase. The ploidy status of the plants could express different PA gradients together with the plant pith and in vitro callus cultures.O objetivo deste trabalho foi determinar os níveis de PAs em tecidos de medula e cultura de calos de plantas haplóides e diplóides de tabaco, obtidas da região apical e basal do caule. Estes explantes foram cultivados em meio RM-64 suplementado com AIA e cinetina, na luz e no escuro, durante vários subcultivos. Nos tecidos medulares, os níveis de PAs apresentam um decréscimo basípeto em diplóides e um aumento em haplóides.Um padrão similar nos níveis de PAs totais (livres+ conjugadas) foi observado em calos haplóides e diplóides mantidos na luz, e haplóides no escuro, enquanto os diplóides cultivados no escuro mostraram um aumento constante até o final do cultivo. O aumento no conteúdo de PAs nos calos diplóides no escuro, foi devido ao aumento do conteúdo de Put livre. Foi observado que a ploidia da planta pode expressar diferentes gradientes de PA ao longo do tecido medular e nas culturas de calos in vitro.(FAPESP) São Paulo Research Foundation(CNPq) National Council for Scientific and Technological Developmen

Alterações no perfil proteômico e de poliaminas induzido pelo envelhecimento de sementes de Cariniana legalis (Martius) O. Kuntze

Studies on metabolic processes and seed germinability of native endangered species are essential for its conservation. The objective of this work was to evaluate the effect of accelerated aging on germination and on the proteomic and polyamine (PAs) profile in seeds of Cariniana legalis. The seeds were aged at 41, 43, 45 and 47ºC for 24, 48, 72 and 96 h, under 100 % relative humidity using a completely randomized factorial design. The data were submitted to analysis of variance followed by Tukey’s test. The temperature of 47ºC was efficient in simulating seed aging, with no germination after 72 h of incubation. At 41ºC, the germination did not change significantly until 96 h. The reduction in the concentration of total free PAs, mainly spermidine, and the down-accumulation of heat shock proteins in seeds aged at 47°C were associated with induction of seed aging. Furthermore, the down-accumulation of the aconitate hydratase protein and the up-accumulation of the alcohol dehydrogenase protein were associated with loss of seed germinability and rapid deterioration in seeds aged at 47°C. The aging of C. legalis seeds is related to alteration in the contents of PAs and accumulation of some proteins involved with the loss of germinability.Estudos sobre processos metabólicos e germinabilidade de sementes de espécies nativas ameaçadas de extinção são essenciais para sua conservação. O objetivo deste trabalho foi avaliar o efeito do envelhecimento acelerado na germinação e no perfil proteômico e de poliamina (PAs) em sementes de Cariniana legalis. As sementes foram envelhecidas a 41, 43, 45 e 47°C por 24, 48, 72 e 96 h, sob 100% de umidade relativa, usando um delineamento fatorial inteiramente casualizado. Os dados foram submetidos à análise de variância seguida de teste Tukey. A temperatura de 47°C foi eficiente em simular o envelhecimento das sementes, que não germinaram após 72 h de incubação. Em 41°C, a germinação não mudou significativamente até 96h. A redução na concentração de PAs livres totais, principalmente espermidina e a diminuição no acúmulo de proteínas de choque térmico em sementes envelhecidas à 47°C foram associados à indução do envelhecimento das sementes. Além disso, a diminuição no acúmulo da proteína aconitato hidratase e o aumento no acúmulo da proteína álcool desidrogenase foram associados à perda de germinabilidade das sementes e rápida deterioração em sementes envelhecidas à 47°C. O envelhecimento de sementes de C. legalis está relacionado à alteração no conteúdo de PAs e a alteração de acúmulo de algumas proteínas envolvidas na perda da germinabilidade

Two-dimensional gel electrophoretic protein profile analysis during seed development of Ocotea catharinensis: a recalcitrant seed species

The aim of the present work was to characterize changes in the protein profile throughout seed development in O. catharinensis, a recalcitrant species, by two-dimensional gel electrophoresis. Protein extraction was undertaken by using a thiourea/urea buffer, followed by a precipitation step with 10% TCA. Comparative analysis during seed development showed that a large number of proteins were exclusively detected in each developmental stage. The cotyledonary stage, which represents the transition phase between embryogenesis and the beginning of metabolism related to maturation, presents the highest number of stage-specific spots. Protein identification, through MS/MS analysis, resulted in the identification of proteins mainly related to oxidative metabolism and storage synthesis. These findings contribute to a better understanding of protein metabolism during seed development in recalcitrant seeds, besides providing information on established markers that could be useful in defining and improving somatic embryogenesis protocols, besides monitoring the development of somatic embryos in this species.O objetivo deste trabalho foi a caracterização dos perfis protéicos expressos durante o desenvolvimento da semente de O. catharinensis, uma espécie recalcitrante, via eletroforese bidimensional. A extração de proteínas foi realizada utilizando tampão uréia/tiouréia seguido de uma etapa de precipitação com TCA 10%. A análise comparativa durante o desenvolvimento da semente mostrou um grande número de proteínas exclusivas em cada estádio do desenvolvimento. O estádio cotiledonar, que representa a fase de transição entre a embriogênese e o começo do metabolismo relacionado a maturação, apresentou o maior número de proteínas estádio-específicas. Proteínas relacionadas ao metabolismo oxidativo e a síntese de reservas foram identificadas via MS/MS. Estes resultados contribuem para o melhor entendimento do metabolismo de proteínas durante o desenvolvimento de sementes recalcitrantes, além de prover informações no estabelecimento de parâmetros para protocolos de embriogênese somática.(FAPESP) São Paulo Research Foundation(CNPq) National Council for Scientific and Technological Developmen

Dynamics of physiological and biochemical changes\ud during somatic embryogenesis of Acca sellowiana

Feijoa (Acca sellowiana [O. Berg] Burret [Myrtaceae]) is a native fruit species of southern Brazil and northern Uruguay. This species is amenable to somatic embryogenesis and therefore suitable as a model system for comparative studies of zygotic and somatic embryo development. In seed plants, embryogenesis involves three main steps, which are regulated by many factors, such as hormones, proteins, polyamines, and transcription factors. In the present work, the dynamics of protein, sugar, starch, amino acid, and polyamine accumulation were assayed during somatic embryogenesis of A. sellowiana. Protein, starch, amino acid, and polyamine levels accumulated unevenly during the induction phase of somatic embryogenesis, while the sugar content remained stable. Throughout the different developmental stages of somatic embryogenesis, synthesis and accumulation of proteins and amino acids showed patterns similar to those reported previously during the development of zygotic embryos of this same species. Differential patterns of polyamine accumulation were observed. This is important because these compounds affect the synthesis of other endogenous growth regulators, such as auxinindole-3-acetic acid that is mainly involved in the establishment of embryo polarity. Taken together, the present work brings new insights to the physiological and biochemical dynamics that occur during somatic embryogenesis of A. sellowiana

Oryza sativa cv. Nipponbare and Oryza barthii as unexpected tolerance and susceptibility sources against Schizotetranychus oryzae (Acari: Tetranychidae) mite infestation

Cultivated rice (Oryza sativa L.) is frequently exposed to multiple stresses, including Schizotetranychus oryzae mite infestation. Rice domestication has narrowed the genetic diversity of the species, leading to a wide susceptibility. This work aimed to analyze the response of two African rice species (Oryza barthii and Oryza glaberrima), weedy rice (O. sativa f. spontanea), and O. sativa cv. Nipponbare to S. oryzae infestation. Surprisingly, leaf damage, histochemistry, and chlorophyll concentration/fluorescence indicated that the African species present a higher level of leaf damage, increased accumulation of H2O2, and lower photosynthetic capacity when compared to O. sativa plants under infested conditions. Infestation decreased tiller number, except in Nipponbare, and caused the death of O. barthii and O. glaberrima plants during the reproductive stage. While infestation did not affect the weight of 1,000 grains in both O. sativa, the number of panicles per plant was affected only in O. sativa f. spontanea, and the percentage of full seeds per panicle and seed length were increased only in Nipponbare. Using proteomic analysis, we identified 195 differentially abundant proteins when comparing susceptible (O. barthii) and tolerant (Nipponbare) plants under control and infested conditions. O. barthii presents a less abundant antioxidant arsenal and is unable to modulate proteins involved in general metabolism and energy production under infested condition. Nipponbare presents high abundance of detoxification-related proteins, general metabolic processes, and energy production, suggesting that the primary metabolism is maintained more active compared to O. barthii under infested condition. Also, under infested conditions, Nipponbare presents higher levels of proline and a greater abundance of defense-related proteins, such as osmotin, ricin B-like lectin, and protease inhibitors (PIs). These differentially abundant proteins can be used as biotechnological tools in breeding programs aiming at increased tolerance to mite infestation

Morphological and polyamine content changes in embryogenic and non-embryogenic callus of sugarcane

Differences in competence acquisition and subsequent embryo maturation in embryogenic and non-embryogenic callus of sugarcane var. SP79-1011 were evaluated using histomorphological analysis, growth curves, numbers of somatic embryos, and polyamine contents. Embryogenic callus was formed by cells with embryogenic characteristics such as a rounded shape, prominent nuclei, a high nucleus: cytoplasm ratio, small vacuoles and organized globular structures. However, non-embryogenic callus presented dispersed, elongated and vacuolated cells with a low nucleus: cytoplasm ratio; these characteristics did not allow for the development of somatic embryos even upon exposure to a maturation stimulus. These results suggest that non-embryogenic callus does not acquire embryogenic competence during induction and that maturation treatment is not sufficient to promote somatic embryo differentiation. The use of activated charcoal (AC; 1.5 g L−1) resulted in a higher somatic embryo maturation rate in embryogenic callus but did not yield success in non-embryogenic callus. Embryogenic callus incubated with control (10 μM 2,4-dichlorophenoxyacetic acid) and maturation (1.5 g L−1 AC) treatments for 28 days showed similar patterns of total free polyamines; these results differed from the results observed with non-embryogenic callus, suggesting that embryogenic callus already exhibits a characteristic pattern of endogenous polyamine levels. At 28 days of culture with maturation treatment, embryogenic callus exhibited significantly higher levels of free Spm than embryogenic callus incubated with control treatment and non-embryogenic callus incubated with both treatments. This result suggests that Spm could be important for the acquisition of embryogenic competence and somatic embryo maturation in sugarcane var. SP79-1011.Funding for this work was provided by the CNPq (403015/2008-1 and 480142/2010-6) and FAPERJ (E-26/101.513/2010) to VS. AMV thanks CAPES for her fellowship

Memorial de infantería: Época 2 Número 9 - marzo 1873

Rice is the staple food for over half of the world’s population. Infestation of Schizotetranychus oryzae (Acari: Tetranychidae) causes great losses in rice productivity. To search for rice genotypes that could better tolerate S. oryzae infestation, we evaluated morphological and production parameters in Brazilian cultivars, and identified two cultivars with contrasting responses. Leaf damage during infestation was similar for all cultivars. However, infestation in Puitá INTA-CL resulted in reduction in the number of seeds per plant, percentage of full seeds, weight of 1,000 seeds, and seed length, whereas infestation in IRGA 423 increased weight of 1,000 seeds and seed length. Reduction in seed weight per plant caused by infestation was clearly higher in Puitá INTA-CL (62%) compared to IRGA 423 (no reduction detected), thus Puitá INTA-CL was established as susceptible, and IRGA 423 as tolerant to S. oryzae infestation. Photosynthetic parameters were less affected by infestation in IRGA 423 than in Puitá INTA-CL, evidencing higher efficiency of energy absorption and use. S. oryzae infestation also caused accumulation of H2O2, decreased cell membrane integrity (indicative of cell death), and accelerated senescence in leaves of Puitá INTA-CL, while leaves of IRGA 423 presented higher levels of total phenolics compounds. We performed proteomics analysis of Puitá INTA-CL and IRGA 423 leaves after 7 days of infestation, and identified 60 differentially abundant proteins (28 more abundant in leaves of Puitá INTA-CL and 32 in IRGA 423). Proteins related to plant defense, such as jasmonate synthesis, and related to other mechanisms of tolerance such as oxidative stress, photosynthesis, and DNA structure maintenance, together with energy production and general metabolic processes, were more abundant in IRGA 423. We also detected higher levels of silicon (as amorphous silica cells) in leaves of infested IRGA 423 plants compared to Puitá INTA-CL, an element previously linked to plant defense, indicating that it could be involved in tolerance mechanisms. Taken together, our data show that IRGA 423 presents tolerance to S. oryzae infestation, and that multiple mechanisms might be employed by this cultivar. These findings could be used in biotechnological approaches aiming to increase rice tolerance to mite infestation