Fungal Perspective of Pine and Oak Colonization in Mediterranean Degraded Ecosystems

Forest restoration has become one of the most important challenges for restoration ecology in the recent years. In this regard, soil fungi are fundamental drivers of forest ecosystem processes, with significant implications for plant growth and survival. However, the post-disturbance recovery of belowground communities has been rarely assessed, especially in highly degraded systems such as mines. Our aim was to compare forests and mined systems for biomass and structure of fungal communities in soil during early stages of tree establishment after disturbance. We performed ergosterol analysis and PacBio and Illumina sequencing of internal transcribed spacer 2 amplicons across soil layers in P. sylvestris, Q. robur and Q. ilex (holm oak) forests and naturally revegetated mined sites. In pine forests, total fungal biomass was significantly higher in litter and humus compared to mineral layers, with dominance of the mycorrhizal genera Tomentella, Inocybe and Tricholoma. Conversely, in oak forests the most abundant mycorrhizal genera were Tomentella, Cortinarius and Sebacina, but the biomass of saprotrophic fungi was greater in the litter layer compared to mycorrhizal fungi, with the genus Preussia being the most abundant. In the revegetated mined sites, ectomycorrhizal fungi dominated in the humus and mineral layers, with the mycorrhizal genus Oidiodendron being dominant. In contrast, in holm oak forests saprotrophic fungi dominated both soil humus and mineral layers, with the genera of Alternaria, Bovista and Mycena dominating the soil humus forest layer, while the genus Cadophora dominated the mineral layer. The habitat-specific differences in soil fungal community composition and putative functions suggest that an understanding of soil–plant–microbial interactions for different tree species and use of specific soil/litter inoculum upon planting/seeding might help to increase the effectiveness of tree restoration strategies in Mediterranean degraded sites.This project has received funding from the European Union’s H2020 research and innovation programme under Marie Sklodowska-Curie grant agreement No 801586. This work was supported by the Spanish Ministry of Science, Innovation and Universities, grants RTI2018-099315-AI00. I.A. was supported by a H2020-Marie Slodowska Curie Action Cofund fellowship (801596) and J.G.A. was supported by Ramon y Cajal fellowship (RYC-2016-20528)

Silvicultural management and altitude prevail on soil properties and fungal community in shaping understorey plant communities in a Mediterranean pine forest

Understorey vegetation plays a key role in Mediterranean forest ecosystem functioning. However, we still lack a thorough understanding of the patterns and drivers of understorey composition and diversity. As a result, understoreys are often ignored during assessments of forest functioning under climate change. Here we studied the effect of silvicultural management, topography, soil fungal community composition and soil physical and chemical properties on understorey community composition and diversity. The plant cover and number of individuals of understorey perennial plants, shrubs and non-dominant trees was recorded on 24 plots (paired: control-thinned) in a Mediterranean pine-dominated mountainous area in Northeast Spain. The study area represented a broad thinning intensity gradient (from 0 to 70 % in removed stand basal area) along a 400-m altitudinal range (from 609 m to 1013 m). Our results showed that thinning intensity and topography explained the greatest proportion of the total variance in the understorey species composition, i.e., 18 % and 16 %, respectively. Interestingly, the effects of the silvicultural treatments were significant only when considering the altitudinal effect, so that, the main impacts of thinning on the understorey community composition occurred at low altitudes (between 609 m and 870 m). Moreover, we found a significant decrease in both richness and abundance of understorey species in both the control and thinned plots with increasing altitude, with thinned plots being significantly richer in species compared to the control plots. The difference in the understorey community sensitivity to forest thinning along the altitudinal gradient suggests changes in factors that limit plant growth. Low elevation plots were restrained by light availability while high altitudes plots limited by winter freezing temperatureThis work was supported by the Spanish Ministry of Science and Innovation and Universities (RTI2018-099315-A-I00). Josu G. Alday was supported by Ramon y Cajal fellowship (RYC-2016-20528). José Antonio Bonet and Sergio de Miguel benefitted from a Serra-Húnter Fellowship provided by the Generalitat of Catalonia

Spatial dynamics of soil fungal communities after forest clearcutting in a Pinus sylvestris forest

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Molecular and physiological approaches to enhance the performance and productivity of rice

Estressos abiòtics com la sequera i la salinitat són els factors ambientals més importants que limiten la productivitat dels cultius. Estratègies per millorar el creixement dels cultius sota condicions d'estrès abiòtic inclouen la millora convencional, la selecció assistida per marcadors, l'enginyeria genètica i l'aplicació de bioreguladors naturals o sintètics. Els bioreguladors naturals són hormones vegetals com l'àcid abscísic (ABA), citoquinines, giberelines i l’àcid jasmònic, mentre que els bioreguladors sintètics són productes químics que milloren el creixement de les plantes en condicions de camp. Els fitoprotectors són bioreguladors sintètics que selectivament protegeixen les plantes del cultiu, però no les males herbes dels herbicides induint de forma coordinada les vies de detoxificació d'herbicides. A més del seu paper directe en la detoxificació, alguns fitoprotectors també poden millorar el creixement de plantes en particular sota condicions d'estrès abiòtic. He avaluat un nombre de potencials bioreguladors sintètics sols o en combinació amb ABA per seleccionar les combinacions que milloren el creixement i la productivitat de l'arròs en condicions de sequera (o estrès hídric) moderada, però a llarg termini i d’estrès per salinitat, optimitzat en una cambra de creixement. L’agent fitoprotector ciprosulfamida sol o en combinació amb ABA s'ha trobat que promou el creixement de l'arròs sota condicions d’estrès salí, donant lloc a una floració avançada i a l'aparició de tiges noves. Aquestes respostes van estar absents o van ser molt més limitades en les plantes no tractades sotmeses a estrès. Experiments per desentranyar les bases moleculars de l'efecte de la ciprosulfamida han resultat en la identificació de gens que són potencialment responsables de la millora del rendiment de les plantes d'arròs sota estrès per salinitat. L'anàlisi proteòmic de les plantes d'arròs sense tractar i de les tractades amb ciprosulfamida i / o ABA en presència o absència d'estrès per salinitat ens ha permès identificar gens de resposta a l'estrès amb funcions relacionades amb la defensa, la destoxificació, l'energia, el metabolisme, la fotosíntesi, el plegament i el transport de proteïnes, entre d'altres. Curiosament, moltes proteïnes que eren modulades per l'exposició a estrès per salinitat també van ser modulades per ciprosulfamida o ciprosulfamida més ABA. Proposem que l’agent fitoprotector ciprosulfamida indueix gens de resposta a l'estrès abiòtic i preadapta les plantes per suportar les condicions d’estrès abiòtic. Tres gens que codifiquen per late embryogenesis abundant group 3 protein (OsLEA3), putative fumarylacetoacetate hydrolase (FAH) i mitochondrial import inner membrane translocase (TIM) estan induïdes fortament per l'estrès salí, així com per ciprosulfamida o ciprosulfamida més ABA en l'absència d'estrès. Es va trobar una correlació positiva entre els perfils d'expressió génica determinada per la reacció en cadena de la polimerasa quantitativa o en temps real amb la transcriptasa inversa (qRT-PCR) i les dades de proteòmica.Estreses abióticos como la sequía y la salinidad son los factores ambientales más importantes que limitan la productividad de los cultivos. Estrategias para mejorar el crecimiento de los cultivos bajo condiciones de estrés abiótico incluyen la mejora convencional, la selección asistida por marcadores, la ingeniería genética y la aplicación de biorreguladores naturales o sintéticos. Los biorreguladores naturales son hormonas vegetales como el ácido abscísico (ABA), citoquininas, giberelinas y ácido jasmónico, mientras que los biorreguladores sintéticos son productos químicos que mejoran el crecimiento de plantas en condiciones de campo. Safeners son biorreguladores sintéticos que selectivamente protegen a las plantas del cultivo pero no a las malas hierbas de los herbicidas, induciendo de forma coordinada todas las vías de detoxificación de herbicidas. Además de su papel directo en la detoxificación, algunos safeners también pueden mejorar el crecimiento de plantas en particular bajo condiciones de estrés abiótico. He evaluado diversos biorreguladores sintéticos candidatos, solos o en combinación con ABA para seleccionar las combinaciones que mejoren el crecimiento y la productividad del arroz en condiciones de sequía o salinidad moderada, pero a largo plazo, optimizado en una cámara de crecimiento. Cyprosulfamide solo o en combinación con ABA se ha encontrado que promueve el crecimiento del arroz bajo estrés por salinidad, dando lugar a una floración temprana y a la aparición de tallos nuevos. Estas respuestas eran ausentes o mucho más limitadas en las plantas no tratadas sometidas a estrés. Experimentos para desentrañar las bases moleculares de la actividad de cyprosulfamide resultaron en la identificación de genes que son potencialmente responsables de la mejora del rendimiento de las plantas de arroz bajo estrés por salinidad. El análisis proteómico de las plantas de arroz sin tratar y las tratadas con cyprosulfamide y / o ABA en presencia o ausencia de estrés por salinidad nos ha permitido identificar genes de respuesta a estrés con funciones relacionadas con la defensa, la detoxificación, la energía, el metabolismo, la fotosíntesis, el plegamiento de proteínas y el transporte de proteínas, entre otros. Curiosamente, muchas proteínas que eran moduladas por la exposición a estrés por salinidad también eran moduladas por cyprosulfamide o cyprosulfamide más ABA. Nosotros proponemos que el safener cyprosulfamide induce genes responsables de estrés abiótico y adapta a las plantas para soportar las condiciones de estrés abiótico. Tres genes que codifican late embryogenesis abundant group 3 protein (OsLEA3), putative fumarylacetoacetate hydrolase (FAH) y mitochondrial import inner membrane translocase (TIM) fueron inducidas fuertemente por el estrés de salinidad, así como por cyprosulfamide o cyprosulfamide más ABA en la ausencia de estrés. También se vió una correlación positiva entre los perfiles de expresión genética determinada por la reacción en cadena de la polimerasa en tiempo real o cuantitativa con transcriptasa inversa (qRT-PCR) y los datos de proteómica.Abiotic stresses such as drought and salinity are important environmental factors that limit crop productivity. Strategies to improve the growth of crops under abiotic stress conditions include conventional breeding, marker-assisted breeding, genetic engineering and the application of natural and synthetic bioregulators. Natural bioregulators include plant hormones such as abscisic acid (ABA), cytokinins, gibberellins and jasmonic acid, whereas synthetic bioregulators are chemical products that improve plant growth under field conditions. Safeners are synthetic bioregulators that selectively protect crop plants but not weeds from herbicides by coordinately inducing entire herbicide detoxification pathways. In addition to their direct role in detoxification, some safeners can also improve plant growth particularly under abiotic stress conditions. I evaluated a number of potential synthetic bioregulators alone or in combination with ABA to select the combinations that improved rice growth and productivity under mild but long-term drought and salinity stress conditions optimized in a growth chamber. Cyprosulfamide alone or in combination with ABA was found to promote rice growth under salinity stress, resulting in earlier flowering and the appearance of new tillers. These responses were either absent or much more limited in untreated plants under stress. Experiments to unravel the molecular basis of cyprosulfamide activity resulted in the identification of genes that were potentially responsible for the improved performance of rice plants under salinity stress. Proteomic analysis of untreated rice plants and those treated with cyprosulfamide and/or ABA in the presence or absence of salinity stress allowed us to identify stress-response genes with roles in defense, detoxification, energy, metabolism, photosynthesis, protein folding and protein transport among others. Interestingly, many proteins that were modulated by exposure to salinity stress were also modulated by cyprosulfamide or cyprosulfamide plus ABA. We propose that cyprosulfamide induces abiotic stress-response genes and pre-adapts the plants to withstand abiotic conditions. Three genes encoding a late embryogenesis abundant group 3 protein (OsLEA3), a putative fumarylacetoacetate hydrolase (FAH) and a mitochondrial import inner membrane translocase (TIM) were strongly upregulated by salinity stress as well as by cyprosulfamide or cyprosulfamide plus ABA in the absence of stress. There was good agreement between gene expression profiles determined by quantitative real-time reverse transcriptase polymerase chain reaction and the proteomic data

Spatially-explicit effects of small-scale clear-cutting on soil fungal communities in Pinus sylvestris stands

Clear-cutting is a common silvicultural practice. Although temporal changes in the soil fungal community after clear-cutting have been widely investigated, little is known about stand-level variations in the spatial distribution of soil fungi, particularly at the clear-cut edge. We performed spatial soil sampling in three clear-cuts (0.5 ha), edge habitats, and surrounding forests 8 years after clear-cutting to examine the impact of clear-cutting on the soil fungal community (diversity, composition, guilds, and biomass) and soil properties in a managed Pinus sylvestris forest in northern Spain. Our analyses showed small differences in the composition of the soil fungal community between edge, forest, and clear-cut zones, with <4 % of the species strictly associated with one or two zones. The richness, diversity, and evenness of the fungal community in the edge zone was not significantly different to that in the forest or clear-cut zones, although the clear-cut core had approximately a third fewer ectomycorrhizal species than the edge or the forest. Saprotrophic fungi were widespread across the clear-cut–forest gradient. Soil fungal biomass varied significantly between zones, ranging from 4 to 5 mg g?1 dry soil in the forest and at the forest edge to 1.7 mg g?1 dry soil in the clear-cut area. Soil organic matter, pH, nitrogen, and phosphorus did not differ significantly between edge, forest, and clear-cutting zones and were not significantly related to the fungal community composition. Overall, our study showed that small-scale clear-cut treatments are optimal to guarantee, in the medium-term, soil fungal communities within harvested areas and at the forest edge that are comparable to soil fungal communities in the forest, even though the amount of fungal biomass in the clear-cut zone is lower than at the forest edge or in the forest.Agradecemos a Ayco Tack sus comentarios constructivos y útiles observaciones sobre el primer borrador del artículo. Damos las gracias a José Antonio Lucas Santolaya, Maria Jesús García Serrano y José María Barrio, gestores de la Junta de Castilla y León, por su contribución al diseño de las claras y por facilitar la recolección de las mismas. También damos las gracias a los propietarios de Pinar Grande y a los miembros del Instituto Micológico Europeo (IME): Ayuntamiento de Soria y Mancomunidad de los 150 pueblos de Soria por su ayuda en el diseño del experimento.Forest managementSilvicultureForest edgeSaprotrophSpatial changesEctomycorrhizal fungiPublishe