Percorrer por autor "Costa, Daniela"
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- Avaliação de citotoxicidade de nanotransportadores sem substância ativa em função da sua densidade populacionalPublication . Costa, Daniela; Sousa, Marcelo; Amaral, Joana S.; Lima, Eliana; Valadares, Marize CamposA par da evolução da nanotecnologia, assiste-se a uma crescente preocupação sobre eventuais riscos/toxicidade que os nanotransportadores possam representar [1]. A maioria dos trabalhos publicados relativos à avaliação da citotoxicidade in vitro de nanotransportadores (NT) incide na comparação quando a substância ativa (SA) é administrada em solução ou nanoencapsulada, sendo escassos os estudos que visam avaliar a possível toxicidade do NT por si só (sem SA). O objetivo deste trabalho consistiu na avaliação da citotoxicidade de NT sem SA em função da sua densidade populacional, tendo sido testados quatro NT distintos: nanocápsulas (NC), nanoesferas (NE), transportadores lipídicos nanoestruturados (NLC) e lipossomas, com oito densidades populacionais (diluições décimais de 2,10×1012 part/mL a 2,10×105 part/mL). A avaliação da citotoxicidade realizou-se numa cultura primária (linfócitos) pelo teste do MTT e numa linha celular (fibroblastos 3T3) pelo teste do vermelho neutro (NR).
- Climatic impacts on the bacterial community profiles of cork oak soilsPublication . Reis, Francisca; Soares-Castro, Pedro; Costa, Daniela; Tavares, Rui Manuel; Baptista, Paula; Santos, Pedro M.; Lino-Neto, TeresaClimate changes comprise increasing global temperature and water cycle deregulation (precipitation storms and long dry seasons). Many affected ecosystems are located within the Mediterranean basin, where cork oak (Quercus suber L.) is one of the most important forest ecosystems. Despite cork oak tolerance to drought, the decrease of water availability and increase of temperature is causing a serious decline of cork oak populations. In the present work, the bacterial community of cork oak soils was assessed by metabarcoding using Illumina Miseq. Soils from seven independent cork oak forests were collected along a climate gradient. In all forest soils, Proteobacteria and Actinobacteria were the richest and more abundant bacteria. Acidobacteria also presented a high relative abundance, and Chloroflexi was a rich phylum. The soil bacterial community diversity and composition was strongly affected by the climatic region where cork oak resides and specific bacterial taxa were differently affected by precipitation and temperature. Accordingly, cork oak bacterial communities clustered into three distinct groups, related with humid, sub-humid and arid/semi-arid climates. Driest and warmer forests presented more diverse bacterial communities than humid and coolest forests. However, driest climates presented more homogenous bacterial communities among forests than humid climates. Climate (mainly precipitation) revealed to be the strongest driver leading to significant variations of bacterial community profiles. The most impacted bacterial taxa by climatic variables were Proteobacteria, in particular Gammaproteobacteria and Deltaproteobacteria, Chloroflexi, and Firmicutes. Humid forests presented mainly Acidobacteria as good indicators of climate, whereas Actinobacteria members were better indicators for arid forests (mainly Gaiellales and Frankiales). Some indicator species for different climate conditions were members of the bacterial core of cork oak stands (7% of the total bacterial community). Taken together, different microbiomes were selected by the climate conditions in cork oak stands along a climate gradient and might provide the key to forest sustainability in times of global warming.
- Cork oak endophytic fungi as potential biocontrol agents against biscogniauxia mediterranea and diplodia corticolaPublication . Costa, Daniela; Tavares, Rui Manuel; Baptista, Paula; Lino-Neto, TeresaAn increase in cork oak diseases caused by Biscogniauxia mediterranea and Diplodia corticola has been reported in the last decade. Due to the high socio-economic and ecologic importance of this plant species in the Mediterranean Basin, the search for preventive or treatment measures to control these diseases is an urgent need. Fungal endophytes were recovered from cork oak trees with different disease severity levels, using culture-dependent methods. The results showed a higher number of potential pathogens than beneficial fungi such as cork oak endophytes, even in healthy plants. The antagonist potential of a selection of eight cork oak fungal endophytes was tested against B. mediterranea and D. corticola by dual-plate assays. The tested endophytes were more efficient in inhibiting D. corticola than B. mediterranea growth, but Simplicillium aogashimaense, Fimetariella rabenhorstii, Chaetomium sp. and Alternaria alternata revealed a high potential to inhibit the growth of both. Simplicillium aogashimaense caused macroscopic and microscopic mycelial/hyphal deformations and presented promising results in controlling both phytopathogens’ growth in vitro. The evaluation of the antagonistic potential of non-volatile and volatile compounds also revealed that A. alternata compounds could be further explored for inhibiting both pathogens. These findings provide valuable knowledge that can be further explored in in vivo assays to find a suitable biocontrol agent for these cork oak diseases.
- Differences in the endophytic microbiome of olive cultivars infected by xylella fastidiosa across seasonsPublication . Giampetruzzi, Annalisa; Baptista, Paula; Morelli, Massimiliano; Cameirão, Cristina; Neto, Teresa Lino; Costa, Daniela; D’Attoma, Giusy; Kubaa, Raied Abou; Altamura, Giuseppe; Saponari, Maria; Pereira, J.A.; Saldarelli, PasqualeThe dynamics of Xylella fastidiosa infections in the context of the endophytic microbiome was studied in field-grown plants of the susceptible and resistant olive cultivars Kalamata and FS17. Whole metagenome shotgun sequencing (WMSS) coupled with 16S/ITS rRNA gene sequencing was carried out on the same trees at two different stages of the infections: In Spring 2017 when plants were almost symptomless and in Autumn 2018 when the trees of the susceptible cultivar clearly showed desiccations. The progression of the infections detected in both cultivars clearly unraveled that Xylella tends to occupy the whole ecological niche and suppresses the diversity of the endophytic microbiome. However, this trend was mitigated in the resistant cultivar FS17, harboring lower population sizes and therefore lower Xylella average abundance ratio over total bacteria, and a higher α-diversity. Host cultivar had a negligible effect on the community composition and no clear associations of a single taxon or microbial consortia with the resistance cultivar were found with both sequencing approaches, suggesting that the mechanisms of resistance likely reside on factors that are independent of the microbiome structure. Overall, Proteobacteria, Actinobacteria, Firmicutes, and Bacteriodetes dominated the bacterial microbiome while Ascomycota and Basidiomycota those of Fungi.
- Diversity of fungal endophytic community in Quercus suber L. and detection of opportunistic phytopathogenic fungiPublication . Costa, Daniela; Cunha, Joana; Tavares, Rui Manuel; Baptista, Paula; Lino-Neto, TeresaCork oak (Quercus suber L.) is a species of high ecological importance in Mediterranean Basin and has high relevance for Portuguese economy due to cork production and processing. The sustainability of cork oak is currently being threatened by reduction of water availability that would increase the occurrence of diseases. Charcoal disease, caused by the fungus Biscogniauxia mediterrânea, leads to death of the tree. Diplodia corticola is involved in various diseases considered responsible for the decline of cork oak in Mediterranean Basin. To identify endophytic fungi in cork oak, including these opportunistic pathogens, four sites of continental Portugal (Bragança, Geres, Alcobaça and Grândola) with differences in water availability were selected to carry out the collection of biological material. The community of fungal endophytes of leaves, st^ms and roots was evaluated. The roots displayed a more diverse fungal community than the aboveground organs. Although no disease symptoms were detected in studied cork oaks, the referred pathogenic fungi were essentially affecting stems and leaves. In general, Grândola presented the highest colonization frequency and diversity of endophytes, while Alcobaça had the lowest. From ali studied sites, cork oaks from Geres showed the most distinct community and did not presentthose pathogens. D. corticola only infected southern regions, while S. mediterrânea also infected trees in Bragança. The exclusive presence of both pathogens in aboveground organs and the absence of visible disease symptoms in ali studied cork oaks encourage the searching of adequate biocontrol agents from the endophytic community for restricting these diseases in cork oak.
- Diversity, Composition, and Specificity of the Philaenus spumarius BacteriomePublication . Cameirão, Cristina; Costa, Daniela; Rufino, José; Pereira, J.A.; Lino-Neto, Teresa; Baptista, PaulaPhilaenus spumarius (Linnaeus, 1758) (Hemiptera, Aphrophoridae) was recently classified as a pest due to its ability to act as a vector of the phytopathogen Xylella fastidiosa. This insect has been reported to harbour several symbiotic bacteria that play essential roles in P. spumarius health and fitness. However, the factors driving bacterial assemblages remain largely unexplored. Here, the bacteriome associated with different organs (head, abdomen, and genitalia) of males and females of P. spumarius was characterized using culturally dependent and independent methods and compared in terms of diversity and composition. The bacteriome of P. spumarius is enriched in Proteobacteria, Bacteroidota, and Actinobacteria phyla, as well as in Candidatus Sulcia and Cutibacterium genera. The most frequent isolates were Curtobacterium, Pseudomonas, and Rhizobiaceae sp.1. Males display a more diverse bacterial community than females, but no differences in diversity were found in distinct organs. However, the organ shapes the bacteriome structure more than sex, with the Microbacteriaceae family revealing a high level of organ specificity and the Blattabacteriaceae family showing a high level of sex specificity. Several symbiotic bacterial genera were identified in P. spumarius for the first time, including Rhodococcus, Citrobacter, Halomonas, Streptomyces, and Providencia. Differences in the bacterial composition within P. spumarius organs and sexes suggest an adaptation of bacteria to particular insect tissues, potentially shaped by their significance in the life and overall fitness of P. spumarius. Although more research on the bacteria of P. spumarius interactions is needed, such knowledge could help to develop specific bacterial-based insect management strategies.
- Fungal endophytic community of cork oaks (Quercus suber L.) depends on the forest locationPublication . Lino-Neto, Teresa; Costa, Daniela; Tavares, Rui Manuel; Baptista, PaulaQuercus suber is an evergreen tree species with high socio-economic and ecologic importance in the Mediterranean Basin. Cork oak forests occupy an área of more than 2 Mha worldwide, being the largest áreas located in Portugal, Spain, Morocco and Algeria. Despite cork oak is well adapted to the Mediterranean climate, which is characterized by warm, dry summers and rainy winters, plant growth and cork productivity is sensitive to climatic changes. Plant microbiomes are determining factors for preserving plant health and productivity within challenging climates, due to their dual ecological function as detrimental or beneficiai symbionts. Endophytes can play a beneficiai role for plant sustainability, but some ofthem are opportunistíc pathogens that take advantage of the weakened plants, stressed by different environmental conditions. Several Portuguese cork oak stands, with differences in water availability, were used for accessing the fungal endophytic of stems and branches. The diversity of funga! endophytic community in each cork stand and relations with edaphoclimatic conditíons are described. Many cork oak stands presented high incidence of pathogens, such as Biscogniauxia mediterrânea, which is deposited by Platypus cylindrus Fab. into the tunnels walls for feeding adults and their offspring.
- Illuminating Olea europaea L. endophyte fungal communityPublication . Costa, Daniela; Fernandes, Telma; Martins, Fátima; Pereira, J.A.; Tavares, Rui Manuel; Santos, Pedro M.; Baptista, Paula; Lino-Neto, TeresaA wide array of fungal endophytes is known to inhabit plant tissues and were recently recognized as essential for plant health. A better description of the scarcely known endophyte microbiota in olive tree phyllosphere is the first step for elucidating the microbial interactions that lead to olive disease establishment. In this work, the fungal endophytic community of the phyllosphere of different olive tree cultivars (Cobrançosa, Galega vulgar, Madural, Picual, Verdeal Transmontana) is revealed by using a metabarcoding strategy targeting ITS1 barcode. A total of 460 OTUs were obtained, increasing the broad view of fungal endophytes inhabiting the olive tree phyllosphere, in particular yeast endophytes. New endophytes were persistently found in all cultivar tissues. Different olive tree cultivars depicted distinct endophyte communities. Olive cultivars exhibited dissimilar amounts of fungi with distinct ecological functions, which could explain at least in part their differential susceptibility/tolerance to olive diseases.
- Olive fungal epiphytic communities are affected by their maturation stagePublication . Castro, Joana; Costa, Daniela; Tavares, Rui Manuel; Baptista, Paula; Lino-Neto, TeresaThe phyllosphere comprises the aerial parts of plants and is colonized by a great diversity of microorganisms, either growing inside (as endophytes) or on the surface (as epiphytes) of plant tissues. The factors that structure the diversity of epiphytes and the importance of these microorganisms for host plant protection have been less studied when compared to the case of endophytes. In this work, the epiphytic fungal communities from fruits of the olive tree (olives) in different maturation stages (green and semi-ripened), obtained from different olive orchard managements (integrated and organic production) and from distinct cultivars displaying different susceptibilities to olive anthracnose (Cobrançosa and Madural), are compared by using a metabarcoding approach. We discuss whether such differences in host resistance against anthracnose depend on both the fungal taxa or fungal community composition. A total of 1565 amplicon sequence variants (ASVs) were obtained, mainly belonging to the Ascomycota phylum and Saccharomycetes class. Although significant differences on epiphytic fungal richness were observed among olives obtained in different production systems and maturation stages, these factors in addition to host cultivar did not influence the composition of the epiphytes. Despite these results, a co-inertia analysis showed that Aureobasidium spp. and Sporocadaceae spp. were positively associated with the green olives of the cv. Madural produced under integrated production, while Saccharomycetales spp. (Kluyveromyces, Candida, Kazachstania and Saccharomyces) were positively associated with the semi-ripened olives of the cv. Cobrançosa obtained from organic production. The discriminant power of these fungi, some of them recognized as biocontrol agents, suggest that they might be important in conferring differences on host plant susceptibility to anthracnose.
- Phylogenetic analysis and genetic diversity of the xylariaceous ascomycete Biscogniauxia mediterranea from cork oak forests in different bioclimatesPublication . Costa, Daniela; Ramos, Vitor; Tavares, Rui Manuel; Baptista, Paula; Lino-Neto, TeresaCork oak is a tree species with ecological importance that contributes to economic and social development in the Mediterranean region. Cork oak decline is a major concern for forest sustainability and has negative impacts on cork oak growth and production. This event has been increasingly reported in the last decades and seems to be related with climate changes. Biscogniauxia mediterranea is an endophytic fungus of healthy cork oak trees that turns into a pathogen in trees weaken by environmental stress. Understanding the drivers of B. mediterranea populations diversity and differentiation is expected to allow a better control of cork oak decline and preserve forest sustainability. Endophyte isolates from different cork oak forests were identified as B. mediterranea and their genetic diversity was evaluated using phylogenetic and microsatellite-primed PCR analyses. Genetic diversity and variability of this fungus was correlated with environmental/phytosanitary conditions present in forests/trees from which isolates were collected. High genetic diversity and variability was found in B. mediterranea populations obtained from different forests, suggesting some degree of isolation by distance. Bioclimate was the most significant effect that explained the genetic variability of B. mediterranea, rather than precipitation or temperature intensities alone or disease symptoms. These findings bring new implications for the changing climate to cork oak forests sustainability, cork production and quality.