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Bindschedler, Saskia
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Bindschedler, Saskia
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saskia.bindschedler@unine.ch
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Voici les éléments 1 - 8 sur 8
- PublicationAccès libreExploiting the fungal highway: development of a novel tool for the in situ isolation of bacteria migrating along fungal mycelium(2015)
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- PublicationAccès libreTracing soil carbon cycle and the origin of needle fibre calcite(2009)
; ; - PublicationAccès libreFungal implication in secondary calcium carbonate accumulation in soils and caves(2009)
; ; ; Verrecchia, Eric P. - PublicationAccès libreGains of Bacterial Flagellar Motility in a Fungal World
; ; ; ; The maintenance of energetically costly flagella by bacteria in non-water-saturated media, such as soil, still presents an evolutionary conundrum. Potential explanations have focused on rare flooding events allowing dispersal. Such scenarios, however, overlook bacterial dispersal along mycelia as a possible transport mechanism in soils. The hypothesis tested in this study is that dispersal along fungal hyphae may lead to an increase in the fitness of flagellated bacteria and thus offer an alternative explanation for the maintenance of flagella even in unsaturated soils. Dispersal along fungal hyphae was shown for a diverse array of motile bacteria. To measure the fitness effect of dispersal, additional experiments were conducted in a model system mimicking limited dispersal, using Pseudomonas putida KT2440 and its nonflagellated (ΔfliM) isogenic mutant in the absence or presence of Morchella crassipes mycelia. In the absence of the fungus, flagellar motility was beneficial solely under conditions of water saturation allowing dispersal, while under conditions limiting dispersal, the nonflagellated mutant exhibited a higher level of fitness than the wild-type strain. In contrast, in the presence of a mycelial network under conditions limiting dispersal, the flagellated strain was able to disperse using the mycelial network and had a higher level of fitness than the mutant. On the basis of these results, we propose that the benefit of mycelium-associated dispersal helps explain the persistence of flagellar motility in non-water-saturated environments. - PublicationAccès libreBacterial farming by the fungus Morchella crassipes(The Royal Society of London, )
; ; ; ; The interactions between bacteria and fungi, the main actors of the soil microbiome, remain poorly studied. Here, we show that the saprotrophic and ectomycorrhizal soil fungus Morchella crassipes acts as a bacterial farmer of Pseudomonas putida, which serves as a model soil bacterium. Farming by M. crassipes consists of bacterial dispersal, bacterial rearing with fungal exudates, as well as harvesting and translocation of bacterial carbon. The different phases were confirmed experimentally using cell counting and 13C probing. Common criteria met by other non-human farming systems are also valid for M. crassipes farming, including habitual planting, cultivation and harvesting. Specific traits include delocalization of food production and consumption and separation of roles in the colony (source versus sink areas), which are also found in human agriculture. Our study evidences a hitherto unknown mutualistic association in which bacteria gain through dispersal and rearing, while the fungus gains through the harvesting of an additional carbon source and increased stress resistance of the mycelium. This type of interaction between fungi and bacteria may play a key role in soils. - PublicationAccès libreCalcitic nanofibres in soils and caves: a putative fungal contribution to carbonatogenesis
; ; Verrechia, Eric PThe origin of soil mineralized nanofibres remains controversial. It is attributed to either biogenic factors or physicochemical processes. Scanning electron microscope and transmission electron microscope observations show that nanofibres could originate from the breakdown of fungal hyphae, especially its cell wall. It is hypothesized that during the decay of organic matter, cell wall microfibrils are released in the soil where they are exposed to mineralizing pore fluids, leading to their calcitic pseudomorphosis and/or are used as a template for calcite pre-cipitation. When associated with needle fibre calcite bundles, nanofibres could indicate the relict of an organic sheath in which calcite has precipitated. This paper emphasizes the important roles of both organic matter and fungi in carbonatogenesis, and consequently in the soil carbon cycle.