CENTRE OF MOLECULAR AND ENVIRONMENTAL BIOLOGY

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Phylogenetic analysis and genetic diversity of the xylariaceous ascomycete Biscogniauxia mediterranea from cork oak forests in different bioclimates

Publication . Costa, Daniela; Ramos, Vitor; Tavares, Rui Manuel; Baptista, Paula; Lino-Neto, Teresa

Cork 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.

2022Journal article

Open access

Protective properties of the edible halophyte Carpobrotus edulis (L.) N.E.Br. towards neoformed food contaminants-related oxidative stress and genotoxicity

Publication . Oliveira, Daniela; Hayrapetyan, Ruzanna; Dias, Maria Inês; Barros, Lillian; Séverin, Isabelle; Custódio, Luísa; Chagnon, Marie-Christine; Oliveira, Rui P.

Carpobrotus edulis (L.) N.E.Br. is an edible halophyte native to South Africa, where it has been traditionally consumed as food, revealing its nutritional value, and used in the treatment of human diseases probably due to the accumulation of bioactive compounds such as polyphenols. These compounds have potential to display valuable biological activities that could bring several benefits to the human being, including the mitigation of toxicity induced by food contaminants. Therefore, this study investigated biological activities with health-promoting potential of a C. edulis ethanol extract (CEE), such as antioxidant, antigenotoxic, and antimutagenic. CEE was shown by LC-DAD-ESI/MSn to be composed of 16 polyphenols. The extract exhibited antioxidant properties by protecting Saccharomyces cerevisiae viability and improving the redox state of HepG2 cells under oxidative stress. Antigenotoxicity of CEE against H2O2-induced oxidative damage was detected in HepG2 and Caco-2 cells by comet assay and subsequently observed in the dominant deletion assay in S. cerevisiae. Antigenotoxicity and antimutagenicity of CEE towards the neoformed contaminant benzo[a]pyrene was found in HepG2 and Caco-2 cells by comet assay and in Salmonella typhimurium using the Ames test, respectively. The disclosed antigenotoxic and antimutagenic properties of C. edulis further advance its potential for application in food and nutraceutical industries for health benefits.

2024Journal article

Restricted access

The influence of bioclimate on soil microbial communities of cork oak

Publication . Costa, Daniela; Tavares, Rui Manuel; Baptista, Paula; Lino-Neto, Teresa

Background: Soil microbiomes are important to maintain soil processes in forests and confer protection to plants against abiotic and biotic stresses. These microbiomes can be affected by environmental changes. In this work, soil microbial communities from different cork oak Portuguese forests under different edaphoclimatic conditions were described by using a metabarcoding strategy targeting ITS2 and 16S barcodes. Results: A total of 11,974 fungal and 12,010 bacterial amplicon sequence variants (ASVs) were obtained, revealing rich and diverse microbial communities associated with different cork oak forests. Bioclimate was described as the major factor influencing variability in these communities (or bioclimates/cork oak forest for fungal community), followed by boron and granulometry. Also, pH explained variation of fungal communities, while C:N ratio contributed to bacterial variation. Fungal and bacterial biomarker genera for specific bioclimates were described. Their co-occurrence network revealed the existence of a complex and delicate balance among microbial communities. Conclusions: The findings revealed that bacterial communities are more likely to be affected by different edaphoclimatic conditions than fungal communities, also predicting a higher impact of climate change on bacterial communities. The integration of cork oak fungal and bacterial microbiota under different bioclimates could be further explored to provide information about useful interactions for increasing cork oak forest sustainability in a world subject to climate changes.

2022Journal article

Open access

Olive fungal epiphytic communities are affected by their maturation stage

Publication . Castro, Joana; Costa, Daniela; Tavares, Rui Manuel; Baptista, Paula; Lino-Neto, Teresa

The 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.

2022Journal article

Open access

Diversity, Composition, and Specificity of the Philaenus spumarius Bacteriome

Publication . Cameirão, Cristina; Costa, Daniela; Rufino, José; Pereira, J.A.; Lino-Neto, Teresa; Baptista, Paula

Philaenus 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.

2024Journal article

Open access