Rhizospheric solutions: Pseudomonas isolates counter Botrytis cinerea on tomato

La moisissure grise causée par Botrytis cinerea provoque des dégâts sur plus de 200 espèces de cultures dans le monde. B. cinerea sporule pour former une pourriture grise sur les feuilles, les tiges et les fruits. Pour lutter contre B. cinerea, des fongicides synthétiques sont utilisés. Ces derniers mettent en danger la santé humaine et environnementale en plus de la résistance qu'ils peuvent occasionner chez les souches de B. cinerea. Les alternatives écologiques sont des solutions appropriées pour contrôler la moisissure grise tout en maintenant l’équilibre environnemental. L’objectif de cette étude est d'évaluer l’effet des isolats de Pseudomonas issus de la rhizosphère de la tomate sur B. cinerea. Les résultats ont montré que les 76 isolats testés inhibent le développement de B. cinerea in vitro. Cinq isolats de Pseudomonas (Q6B, Q13B, Q7B, Q14B et Q1B) ont provoqué des niveaux d'inhibition significatifs allant de 65 à 73%. Par ailleurs, ces isolats ont également inhibé B. cinerea sur les feuilles et le fruit de la tomate. Pour tenter d'élucider les mécanismes d'action, les cinq isolats ont montré une production des métabolites antifongiques tels que les sidérophores, le cyanure d'hydrogène et d’autres enzymes. Les résultats de cette étude ont montré que les isolats de Pseudomonas Q6B, Q13B, Q7B, Q14B et Q1B ont une forte efficacité dans la lutte biologique contre B. cinerea et peuvent être utilisés pour une lutte écologique durable.Gray mold caused by Botrytis cinerea causes serious losses in more than 200 crop species worldwide. The necrotrophic fungus sporulates to effect a grey covering on leaves, stems and flowers. B. cinerea is controlled by chemical synthetic fungicides, endangering human and environmental health. Synthetic fungicides stimulate emergence of pathogen resistance. Organic alternatives which may be present or introduced into the edaphic environment are suitable solutions to control outbreaks. This study was done in order to elucidate the mode of action involved in the control of B. cinerea using fluorescent Pseudomonas isolates from tomato roots. The results show that all 76 isolates inhibit fungal growth during in vitro bioassay using dual culture technique. Five isolates of Pseudomonas (Q6B, Q13B, Q7B, Q14B and Q1B) cause significant inhibition levels ranging from 65 to 73%. These isolates inhibit fungal growth in both fruits and leaves. Each isolate tested produced antifungal metabolites (siderophores, hydrogen cyanide and enzymes). Results of this study show that all tested Pseudomonas isolates have a strong efficacy in biological control against B. cinerea and can be used for environmentally sustainable control

Solutions rhizosphériques : Isolats de Pseudomonas contre Botrytis cinerea de la tomate

Gray mold caused by Botrytis cinerea causes serious losses in more than 200 crop species worldwide. The necrotrophic fungus sporulates to effect a grey covering on leaves, stems and flowers. B. cinerea is controlled by chemical synthetic fungicides, endangering human and environmental health. Synthetic fungicides stimulate emergence of pathogen resistance. Organic alternatives which may be present or introduced into the edaphic environment are suitable solutions to control outbreaks. This study was done in order to elucidate the mode of action involved in the control of B. cinerea using fluorescent Pseudomonas isolates from tomato roots. The results show that all 76 isolates inhibit fungal growth during in vitro bioassay using dual culture technique. Five isolates of Pseudomonas (Q6B, Q13B, Q7B, Q14B and Q1B) cause significant inhibition levels ranging from 65 to 73%. These isolates inhibit fungal growth in both fruits and leaves. Each isolate tested produced antifungal metabolites (siderophores, hydrogen cyanide and enzymes). Results of this study show that all tested Pseudomonas isolates have a strong efficacy in biological control against B. cinerea and can be used for environmentally sustainable control.La moisissure grise causée par Botrytis cinerea provoque des dégâts sur plus de 200 espèces de cultures dans le monde. B. cinerea sporule pour former une pourriture grise sur les feuilles, les tiges et les fruits. Pour lutter contre B. cinerea, des fongicides synthétiques sont utilisés. Ces derniers mettent en danger la santé humaine et environnementale en plus de la résistance qu'ils peuvent occasionner chez les souches de B. cinerea. Les alternatives écologiques sont des solutions appropriées pour contrôler la moisissure grise tout en maintenant l’équilibre environnemental. L’objectif de cette étude est d'évaluer l’effet des isolats de Pseudomonas issus de la rhizosphère de la tomate sur B. cinerea. Les résultats ont montré que les 76 isolats testés inhibent le développement de B. cinerea in vitro. Cinq isolats de Pseudomonas (Q6B, Q13B, Q7B, Q14B et Q1B) ont provoqué des niveaux d'inhibition significatifs allant de 65 à 73%. Par ailleurs, ces isolats ont également inhibé B. cinerea sur les feuilles et le fruit de la tomate. Pour tenter d'élucider les mécanismes d'action, les cinq isolats ont montré une production des métabolites antifongiques tels que les sidérophores, le cyanure d'hydrogène et d’autres enzymes. Les résultats de cette étude ont montré que les isolats de Pseudomonas Q6B, Q13B, Q7B, Q14B et Q1B ont une forte efficacité dans la lutte biologique contre B. cinerea et peuvent être utilisés pour une lutte écologique durable

A global database of soil nematode abundance and functional group composition

As the most abundant animals on earth, nematodes are a dominant component of the soil community. They play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns.Peer reviewe

A global database of soil nematode abundance and functional group composition [Data paper]

Measurement(s)Abundance center dot Nematoda center dot environmental factorTechnology Type(s)Elutriative Centrifugation center dot computational modeling techniqueFactor Type(s)geographic locationSample Characteristic - OrganismNematodaSample Characteristic - Environmentsoil environment center dot climateSample Characteristic - LocationEarth (planet) Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.11925843 As the most abundant animals on earth, nematodes are a dominant component of the soil community. They play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns

A global database of soil nematode abundance and functional group composition

This study uses direct measurements of soil nematode abundance from 6,825 georeferenced locations around the world, covering all continents and all terrestrial biomes. We describe the data sources, methodology and data processing steps to transform the data into a version that can be used for, for example, geospatial modeling. To do so, the samples were aggregated to the 1-km2 pixel level, each pixel is linked to 73 global covariate layers. These include on soil physiochemical properties, and vegetation, climate, and topographic, anthropogenic, and spectral reflectance information

Soil nematode abundance and functional group composition at a global scale

Soil organisms are a crucial part of the terrestrial biosphere. Despite their importance for ecosystem functioning, few quantitative, spatially explicit models of the active belowground community currently exist. In particular, nematodes are the most abundant animals on Earth, filling all trophic levels in the soil food web. Here we use 6,759 georeferenced samples to generate a mechanistic understanding of the patterns of the global abundance of nematodes in the soil and the composition of their functional groups. The resulting maps show that 4.4 ± 0.64 × 1020 nematodes (with a total biomass of approximately 0.3 gigatonnes) inhabit surface soils across the world, with higher abundances in sub-Arctic regions (38% of total) than in temperate (24%) or tropical (21%) regions. Regional variations in these global trends also provide insights into local patterns of soil fertility and functioning. These high-resolution models provide the first steps towards representing soil ecological processes in global biogeochemical models and will enable the prediction of elemental cycling under current and future climate scenario