Browsing by Author "Ramalho, J. C."
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- A comprehensive assessment of the transcriptome of cork oak (Quercus suber) through EST sequencingPublication . Pereira-Leal, José B.; Abreu, Isabel A.; Alabaça, Cláudia S.; Almeida, Maria H.; Almeida, Paulo; Almeida, Tânia; Amorim, Maria I.; Araújo, Susana; Azevedo, Herlânder; Badia, Aleix; Batista, Dora; Bohn, Andreas; Capote, Tiago; Carrasquinho, Isabel; Chaves, Inês; Coelho, A. C.; Costa, Maria M. R.; Costa, Rita; Cravador, A.; Egas, Conceição; Faro, Carlos; Fortes, Ana M.; Fortunato, Ana S.; Gaspar, Maria J.; Gonçalves, Sónia; Graça, José; Horta, Marília; Inácio, Vera; Leitão, J. M.; Lino-Neto, Teresa; Marum, Liliana; Matos, José; Mendonça, Diogo; Miguel, Andreia; Miguel, Célia M.; Morais-Cecílio, Leonor; Neves, Isabel; Nóbrega, Filomena; Oliveira, Maria M.; Oliveira, Rute; Pais, Maria S.; Paiva, Jorge A.; Paulo, O. S.; Pinheiro, Miguel; Raimundo, João A. P.; Ramalho, J. C.; Ribeiro, Ana I.; Ribeiro, Teresa; Rocheta, Margarida; Rodrigues, Ana I.; Rodrigues, José C.; Saibo, Nelson J. M.; Santo, Tatiana; Santos, Ana M.; Sá-Pereira, Paula; Sebastiana, Mónica; Simões, Fernanda; Sobral, Rómulo S.; Tavares, Rui; Teixeira, Rita; Varela, Carolina; Veloso, Maria M.; Ricardo, Cândido P. P.Background: Cork oak (Quercus suber) is one of the rare trees with the ability to produce cork, a material widely used to make wine bottle stoppers, flooring and insulation materials, among many other uses. The molecular mechanisms of cork formation are still poorly understood, in great part due to the difficulty in studying a species with a long life-cycle and for which there is scarce molecular/genomic information. Cork oak forests are of great ecological importance and represent a major economic and social resource in Southern Europe and Northern Africa. However, global warming is threatening the cork oak forests by imposing thermal, hydric and many types of novel biotic stresses. Despite the economic and social value of the Q. suber species, few genomic resources have been developed, useful for biotechnological applications and improved forest management. Results: We generated in excess of 7 million sequence reads, by pyrosequencing 21 normalized cDNA libraries derived from multiple Q. suber tissues and organs, developmental stages and physiological conditions. We deployed a stringent sequence processing and assembly pipeline that resulted in the identification of ~159,000 unigenes. These were annotated according to their similarity to known plant genes, to known Interpro domains, GO classes and E.C. numbers. The phylogenetic extent of this ESTs set was investigated, and we found that cork oak revealed a significant new gene space that is not covered by other model species or EST sequencing projects. The raw data, as well as the full annotated assembly, are now available to the community in a dedicated web portal at http://www.corkoakdb.org. Conclusions: This genomic resource represents the first trancriptome study in a cork producing species. It can be explored to develop new tools and approaches to understand stress responses and developmental processes in forest trees, as well as the molecular cascades underlying cork differentiation and disease response.
- Cryptogein and capsicein promote defence responses in Quercus suber against Phytophthora cinnamomi infectionPublication . Medeira, C.; Quartin, V.; Maia, I.; Diniz, I.; Matos, M.; Semedo, J.; Scotti Campos, P.; Ramalho, J. C.; Pais, Isabel P.; Ramos, P.; Melo, Eduardo P.; Leitao, A.; Cravador, A.The decline of cork oak (Quercus suber) stands in Iberian Peninsula is associated with infection by Phytophthora cinnamomi. Most Phytophthora species secrete elicitins, which can enhance defence reactions against some pathogens. Here cytological and physiological effects of the elicitins cryptogein and capsicein on cork oak root infection by P. cinnamomi were evaluated. The progression of the pathogen in root tissue and its effects on total fatty acid (TFA) composition of roots and leaves were analysed in seedlings. Net photosynthesis (P (n) ), stomatal conductance (g (s) ), chlorophyll a fluorescence measurements (quantum yield of linear electron transport I center dot (e) , photochemical quenching q (P,) non-photochemical quenching NPQ) and carotenoid determinations were carried out in well established (4 months) plants. In elicitin-treated roots, 2 days after inoculation, the pathogen which presented loss of viability and membrane degradation was mainly restricted to the intercellular spaces of the cortical parenchyma, and did not reach the vascular cylinder. Electron dense materials accumulated in the intercellular spaces of the cortex next to disorganized hyphae, suggested to be related with defence reactions. Cryptogein (or its interaction with P. cinnamomi) induced enhanced lipid synthesis in leaves, which may contribute to preserve membrane stability. P. cinnamomi decreased P (n) , g (s) , I center dot (e) , and q (P), whereas elicitin-treated plants displayed values similar to controls. Overall, the results indicated a resistance response of cork oak against this oomycete, induced by the elicitins.
- Sugar variation in healthy, blue mold infected and aureobasidium pullulans treated ‘rocha’ pearPublication . Ramalho, J. C.; Pais, Isabel P.; Silva, M. J.; Nunes, CarlaSoluble sugars variation in ‘Rocha’ pear was studied in healthy, infected with Penicillium expansum (blue mold) and treated with the antagonist Aureobasidium pullulans fruits. Pears from four pickings were analyzed after 1, 3 and 5 months of cold storage (-0.5 ºC, 95% RH). For each storage period fruits were inoculated and kept at room temperature (ca. 20 ºC) for 5 d and analyzed. After 1 month of cold storage sucrose increased from the first to the last picking, while fructose, glucose and sorbitol were stable in healthy fruits. After 5 d at room temperature non-inoculated fruits presented fructose and glucose rises and sorbitol decreases for the 4 harvest dates, while sucrose increased in earlier yielded fruits but decreased in the last two pickings. After infection with P. expansum, in general, was observed a tendency to decrease in all sugars. The application of the antagonist A. pullulans partly reverses such tendency. The antagonist alone causes lower disturbances in sugar contents, except in glucose that may present slight decreases. Considering only the fruits of the commercial harvest date (DC3), sugars tend to increase along cold storage (except sucrose), particularly in healthy fruits and for most cases of both blue mold and antagonist inoculated fruits. On the other hand, the tendency for sugar decrease in P. expansum infected fruits, reported for 1 month of cold storage, is still detectable for glucose and sucrose after 3 months, and glucose, fructose and sorbitol after 5 months. After 3 and 5 months of storage, the maintenance of sugar content in fruits of the DC3 inoculated with both blue mold and the antagonist was not as clear as for 1 month. Data suggested that cold storage was beneficial for sugar increase of healthy fruits, except for sucrose. In the DC3 fruits, sugar loss caused by P. expansum was higher after 1 month of storage, but the use of the antagonist A. pullulans partly reverses that tendency.