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- A genotype dependent-response to cadmium contamination in soil is displayed by Pinus pinaster in symbiosis with different mycorrhizal fungiPublication . Sousa, Nadine R.; Ramos, Miguel A.; Marques, Ana P. G. C.; Castro, Paula M. L.Soil contamination with Cd is of primary concern and beneficial soil restoration strategies urge. The aim of this work is to evaluate the response of two different genotypes of Pinus pinaster (wild and selected) to Cd contamination and to assess how inoculation with ectomycorrhizal fungi, Suillus bovinus and Rhizopogon roseolus, influenced each genotype. Seedlings were exposed to soil contaminated at 15 and 30 mg Cd kg−1. Plant growth, mycorrhizal traits and Cd accumulation in different tissues of the plant were determined at harvest. The fungal community was assessed by denaturing gradient gel electrophoresis. At 15 mg Cd kg−1 S. bovinus increased aboveground development in both genotypes. At 30 mg Cd kg−1 non-inoculated wild genotype accumulated more Cd in the shoots (1.7-fold) than the selected genotype; inoculation with R. roseolus decreased Cd concentration in the roots of the selected genotype whereas the opposite occurred in the wild genotype. Cd concentration in the root system was the parameter most influenced by the interaction between the three studied variables. The fungal community established was affected by the Cd concentration in the soil. Results show that different genotypes of P. pinaster react differently to Cd exposure depending on the mycorrhizal association. The importance of considering the combination between plant genotype and its symbiotic partners when aiming at the forestation of degraded land is highlighted.
- Non-invasive monitoring of stress response of urban trees inoculated with EcMPublication . Serafim, Cindy; Ramos, Miguel; Yilmaz, Tugce; Sousa, Nadine; Castro, Paula M. L.
- Selection and acclimatization of strains of edible mycorrhizal fungi for improved field persistencePublication . Ramos, Miguel; Sousa, Nadine; Castro, Paula M. L.
- The response of Betula pubescens to inoculation with an ectomycorrhizal fungus and a plant growth promoting bacterium is substrate-dependentPublication . Sousa, Nadine R.; Franco, Albina R.; Ramos, Miguel A.; Oliveira, Rui S.; Castro, Paula M. L.The combination of ectomycorrhizal (ECM) fungi and plant growth promoting bacteria (PGPB) has considerable potential in forestry. Here we report on the combined effects of PGPB Mesorhizobium sp. and the ECM fungus Paxillus involutus on the growth of Betula pubescens in two different substrates, a forest soil and an alkaline anthropogenic sediment. Growth, nutrient concentration and mycorrhizal formation of B. pubescens were determined at the end of the experiment and the fungal and bacterial communities were assessed by denaturing gradient gel electrophoresis. The combined effects of ECM and PGPB enhanced root and shoot growth most in the forest soil with Mesorhizobium appearing to stimulate mycorrhizal formation. However, in the alkaline sediment, an antagonistic interaction was detected between P. involutus and Mesorhizobium sp., with Mesorhizobium sp. alone stimulating growth. The significant interaction between the ECM and the PGBP across the two substrates is discussed.
- Variability in the composition of extracellular polymeric substances from a full-scale aerobic granular sludge reactor treating urban wastewaterPublication . Oliveira, Ana S.; Amorim, Catarina L.; Ramos, Miguel A.; Mesquita, Daniela P.; Inocêncio, Paulo; Ferreira, Eugénio C.; Loosdrecht, Mark van; Castro, Paula M. L.Within the framework of the circular economy, there is a need for waste management alternatives that promote the reuse of materials produced in wastewater treatment plants (WWTP). An interesting option is the recovery of extracellular substances from sludge. The variability of characteristics of potential recovered bioproducts has to be assessed in full scale operational settings. In this study, aerobic granular sludge (AGS) from a full-scale WWTP treating urban wastewater was regularly collected for 4 months to assess variability in extracellular polymeric substances (EPS) composition and in granular morphology. Variations in the EPS composition occurred with time. Proteins and humic substances were the main EPS components (329–494 and 259−316 mg/g VSS of AGS, respectively), with polysaccharides and DNA representing minor components. The application of an extra purification step after extraction to obtain a purer EPS led to a decrease in the yield of each EPS component, particularly pronounced for the polysaccharides. The final product had a rather constant composition for the monthly samples. The granules showed morphological stability throughout the sampling period and the yield of EPS was correlated to the size of the granules, higher when there was a higher content of small granules (Deq<150 μm) comparing to intermediate (150 ≤ Deq<1500 μm) or large granules (Deq≥1500 μm). This is the first time that a potential valorization strategy for surplus AGS biomass is studied in a full-scale environment. Knowledge on yield and product homogeneity is important as these features are essential for downstream application of the recovered EPS.
- Teste de susceptibilidade ao nemátode da madeira do pinheiro (bursaphelenchus xylophilus) - optimização para utilização em larga escalaPublication . Lima, Marta R. M.; Ramos, Miguel; Sampedro, Luis; Moreira, Xoaquín; Zas, Rafael; Marta W. VasconcelosA doença da murchidão do pinheiro é uma doença grave que afecta florestas de coníferas com uma elevada taxa de mortalidade, sendo causada pelo nemátode Bursaphelenchus xylophilus. Dado que este organismo foi recentemente introduzido na Europa, é importante determinar o grau de susceptibilidade de espécies florestais autóctones ao nemátode. Neste trabalho optimizou-se um teste de susceptibilidade para utilização num grande número de amostras. O teste baseia-se na capacidade de nemátodes virulentos atravessarem secções de 5 cm de ramos jovens, com cerca de 2 cm de diâmetro. O processo de optimização passou pela forja de recipientes de dimensões adequadas, criação de um modo de sustentar os ramos em posição vertical, optimização do volume de água onde a base do ramo fica mergulhada e criação de um modo de evitar a desidratação do topo do ramo após inoculação. O crescimento dos nemátodes em laboratório também passou por um scale-up para obtenção de nemátodes em grande quantidade, passando do crescimento em tubos de ensaio para sacos. O teste foi optimizado usando ramos de Pinus pinaster, mas pode ser adaptado a outras espécies.
- Teste de susceptibilidade ao nemátode da madeira do pinheiro (Bursaphelenchus xylophilus) – Optimização para utilização em larga escalaPublication . Lima, Marta R. M.; Ramos, Miguel; Sampedro, Luís; Moreira, Xoaquín; Zas, Rafael; Vasconcelos, Marta W.
- Soil organic matter rather than ectomycorrhizal diversity is related to urban tree healthPublication . Geel, Maarten Van; Yu, Kang; Peeters, Gerrit; van Acker, Kasper; Ramos, Miguel; Serafim, Cindy; Kastendeuch, Pierre; Najjar, Georges; Ameglio, Thierry; Ngao, Jérôme; Saudreau, Marc; Castro, Paula; Somers, Ben; Honnay, OlivierUrban trees provide many ecosystem services, including carbon sequestration, air quality improvement, storm water attenuation and energy conservation, to people living in cities. Provisioning of ecosystem services by urban trees, however, may be jeopardized by the typically poor quality of the soils in urban areas. Given their well-known multifunctional role in forest ecosystems, ectomycorrhizal fungi (EcM) may also contribute to urban tree health and thus ecosystem service provisioning. Yet, no studies so far have directly related in situ EcM community composition to urban tree health indicators. Here, two previously collected datasets were combined: i) tree health data of 175 Tilia tomentosa trees from three European cities (Leuven, Strasbourg and Porto) estimated using a range of reflectance, chlorophyll fluorescence and physical leaf indicators, and ii) ectomycorrhizal diversity of these trees as characterized by next-generation sequencing. Tree health indicators were related to soil characteristics and EcM diversity using canonical redundancy analysis. Soil organic matter significantly explained variation in tree health indicators whereas no significant relation between mycorrhizal diversity variables and the tree health indicators was found. We conclude that mainly soil organic matter, through promoting soil aggregate formation and porosity, and thus indirectly tree water availability, positively affects the health of trees in urban areas. Our results suggest that urban planners should not overlook the importance of soil quality and its water holding capacity for the health of urban trees and potentially also for the ecosystem services they deliver. Further research should also study other soil microbiota which may independently, or in interaction with ectomycorrhiza, mediate tree performance in urban settings.
- Performance of Quercus suber L. at nursery stage - application of two bio-inoculants under two distinct environmentsPublication . Araújo, Giovânia C.; Sousa, Nadine; Ramos, Miguel; Vega, Alberto L.; Castro, Paula M. L.Key message - Despite the fact that the technique of application of bioinoculants improved the quality of Quercus suber L. seedlings produced in nurseries, these benefits are dependent on the ecological conditions of the site and the composition of the applied inoculum, which interferes with the profile of the local fungal community. Context - Quercus suber L. plays a key ecological and socio-economical role in the Iberian Peninsula. Symbiotic ectomycorrhizal fungi-ECM are crucial partners of several tree species, and assessing the efficacy of bioinoculants at nursery stage helps devising tools to increase plant resilience. Aims - The aim of this study was to compare the effects of two inocula formulations of mixed ECM fungi and bacteria on the quality of seedlings produced in two forest nurseries, differing in environmental conditions and forest embedment. Methods - Quercus suber L. seedlings were inoculated with a commercial product containing Pisolithus tinctorius (Pers) Coker Couch - Scleroderma sp., and six bacterial species and with a non-commercial fungal and bacterial dual inoculum (Suillus granulatus (L.) Roussel + Mesorhizobium sp.). Biometric and nutritional parameters and morphological quality indexes were determined on seedlings. The ECMcommunity was assessed by denaturing gradient gel electrophoresis and cloning-sequencing. Results - In both nurseries, the seedling quality index in inoculated was up to 2-fold higher than in non-inoculated seedlings. Plant biomass differed significantly among nurseries. The inoculum influenced the profile of the fungal community. S. granulatus and P. tinctorius persisted for 6 months in the inoculated seedlings. Conclusion- The nursery ecosystem influenced plant growth. Inoculation treatments increased plant performance; however, the dual inoculum resulted in more consistent improvements of Q. suber at nursery stage, highlighting the importance of inocula selection.
- Degradation of 3-fluorophenol and Sodium Trifluoroacetate by Ectomycorrhizal fungiPublication . Franco, Albina R.; Ramos, Miguel; Sousa, Nadine R.; Silva, Débora S.; Oliveira, Rui S.; Castro, Paula M. L.