Browsing by Author "Santos, Pedro M."
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- 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.
- 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.
- Soil DNA pyrosequencing and fruitbody surveys reveal contrasting diversity for various fungal ecological guilds in chestnut orchardsPublication . Baptista, Paula; Reis, Francisca; Pereira, Eric Carvalho; Tavares, Rui Manuel; Santos, Pedro M.; Richard, Franck; Selosse, Marc André; Lino-Neto, TeresaFungal diversity in Mediterranean forest soils is poorly documented, particularly when considering saprobic and pathogenic organisms. Next-generation sequencing (NGS) methods applied to soil fungi provide the opportunity to unveil the most inconspicuous functional guilds (e.g. saprobes) and life forms (e.g. Corticiaceae) of this tremendous diversity. We used fruitbody surveys over 2 years and soil 454 metabarcoding in Castanea sativa orchards to evaluate res pectively the reproductive (fruitbodies) and vegetative (mycelia) parts of fungal communities in three 100-year-old stands. Analysis of 839 fruitbodies and 210291 ITS1 reads revealed high fungal diversity, mainly shown by belowground analysis, with high (dominant) abundance of mycorrhizal fruitbodies and reads. Both methods displayed contrasted composition and structure of fungal communities, with Basidio- and Ascomycetes dominating above- and belowground, respectively. For the two dominant fungal guilds (i.e. ectomycorrhizal and saprobic), diversity above- and belowground overlapped weakly. This study is the first assessment of the complementarity of fruitbody surveys and NGS for analysing fungal diversity in Mediterranean ecosystems and shows that belowground methods still need to be completed by fruiting diversity to provide a comprehensive overview of the different fungal guilds. The results shed light on chestnut soil biodiversity and question the spatial distribution and synergies among fungal guilds.