Nutrition on bacteria by bacterial-feeding nematodes and consequences on the structure of soil bacterial community

Blanc, Coralie; Sy, Mame Ourèye; Djigal, Djibril; Brauman, Alain; Normand, Philippe; Villenave, Cécile

doi:10.1016/j.ejsobi.2006.06.003

Cited by 69 publications

(43 citation statements)

References 24 publications

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“…The whole composition of the soil microbial community drastically changed in the presence of protists (Bonkowski et al 2011;Ekelund et al 2009;Griffiths et al 1999;Koller et al 2013c;Rønn et al 2002;Rosenberg et al 2009) and bacterial-feeding nematodes (Blanc et al 2006;Djigal et al 2010;Djigal et al 2004;Postma-Blaauw et al 2005). Most published studies have a coarse taxonomic resolution limiting our ability to assess accurately grazing effects on microbial composition.…”

Section: Microbial Compositionmentioning

confidence: 95%

“…(amoeba), Neobodo designis (flagellate) and Colpoda steinii (Ciliate) on Pseudomonas fluorescens CHA0 and different exoproduct-deficient mutants was not similar among protists. The differences in growth rates of bacterivorous protist (Ekelund 1996;Weekers et al 1993) and nematode populations (Anderson and Coleman 1981;Blanc et al 2006;Venette and Ferris 1998) according to bacterial species suggest also that the digestibility and nutritional values of preys constitute an important trait involved in bacteriabacterivore interactions (Pussard et al 1994). …”

Section: Microbial Compositionmentioning

confidence: 99%

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Ecological importance of soil bacterivores for ecosystem functions

et al. 2015

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BackgroundBacterivores, mostly represented by protists and nematodes, are a key component of soil biodiversity involved in soil fertility and plant productivity. In the current context of global change and soil biodiversity erosion, it becomes urgent to suitably recognize and quantify their ecological importance in ecosystem functioning.ScopeUsing meta-analysis tools, we aimed at providing a quantitative synthesis of the ecological importance of soil bacterivores on ecosystem functions. We also intended to produce an overview of the ecological factors that are expected to drive the magnitude of bacterivore effects on ecosystem functions.ConclusionsBacterivores in soil contributed significantly to numerous key ecosystem functions. We propose a new theoretical framework based on ecological stoichiometry stressing the role of C:N:P ratios in soil, microbial and plant biomass as important parameters driving bacterivore-effects on soil N and P availability for plants, immobilization of N and P in the bacterial biomass, and plant responses in nutrition and growth

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Section: Microbial Compositionmentioning

confidence: 95%

Section: Microbial Compositionmentioning

confidence: 99%

Ecological importance of soil bacterivores for ecosystem functions

et al. 2015

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“…Prey selection is crucial for bacterivores, such as protozoa and nematodes, as the quality of ingested bacteria directly affects their fitness (Zubkov and Sleigh, 2000;Blanc et al, 2006;Jousset et al, 2006). In particular, amoebae were highly selective and preferentially consumed the non-toxic mutant in both the batch and rhizosphere experiment.…”

Section: Discussionmentioning

confidence: 99%

“…Predation significantly affects bacterial communities (Rønn et al, 2002;Blanc et al, 2006), and many bacteria evolved defence mechanisms such as the production of toxins. Toxic exoproducts protect bacteria by repelling predators, resulting in preyswitching towards more palatable prey (Jezbera et al, 2006;Liu et al, 2006), and at high toxin concentrations inhibit or even kill the predators (Matz et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Predators promote defence of rhizosphere bacterial populations by selective feeding on non-toxic cheaters

et al. 2009

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Soil pseudomonads increase their competitiveness by producing toxic secondary metabolites, which inhibit competitors and repel predators. Toxin production is regulated by cell-cell signalling and efficiently protects the bacterial population. However, cell communication is unstable, and natural populations often contain signal blind mutants displaying an altered phenotype defective in exoproduct synthesis. Such mutants are weak competitors, and we hypothesized that their fitness depends on natural communities on the exoproducts of wild-type bacteria, especially defence toxins. We established mixed populations of wild-type and signal blind, non-toxic gacS-deficient mutants of Pseudomonas fluorescens CHA0 in batch and rhizosphere systems. Bacteria were grazed by representatives of the most important bacterial predators in soil, nematodes (Caenorhabditis elegans) and protozoa (Acanthamoeba castellanii). The gacS mutants showed a negative frequency-dependent fitness and could reach up to one-third of the population, suggesting that they rely on the exoproducts of the wild-type bacteria. Both predators preferentially consumed the mutant strain, but populations with a low mutant load were resistant to predation, allowing the mutant to remain competitive at low relative density. The results suggest that signal blind Pseudomonas increase their fitness by exploiting the toxins produced by wild-type bacteria, and that predation promotes the production of bacterial defence compounds by selectively eliminating non-toxic mutants. Therefore, predators not only regulate population dynamics of soil bacteria but also structure the genetic and phenotypic constitution of bacterial communities.

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“…In fact, there exists a great diversity of feeding modes of protozoa and nematodes on bacteria, suggesting high competition and distinct niche partitioning of bacterivores (Weisse 2002;Bjørnlund et al 2006;Blanc et al 2006) and bacteria evolved sophisticated physical and chemical defence strategies to escape consumption by bacterivores which in their diversity are comparable to the strategies of plants to escape herbivore grazers aboveground (Bonkowski 2004;Huber et al 2004;Matz and Kjelleberg 2005;Pernthaler 2005;Young 2006;Montagnes et al 2007).…”

Section: Grazing Of Bacterivores Is Not Randommentioning

confidence: 99%

Rhizosphere fauna: the functional and structural diversity of intimate interactions of soil fauna with plant roots

2009

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For decades, the term "rhizosphere fauna" has been used as a synonym to denote agricultural pests among root herbivores, mainly nematodes and insect larvae. We want to break with this constrictive view, since the connection between plants and rhizosphere fauna is far more complex than simply that of resource and consumer. For example, plant roots have been shown to be neither defenceless victims of root feeders, nor passive recipients of nutrients, but instead play a much more active role in defending themselves and in attracting beneficial soil microorganisms and soil fauna. Most importantly, significant indirect feed-backs exist between consumers of rhizosphere microorganisms and plant roots. In fact, the majority of soil invertebrates have been shown to rely profoundly on the carbon inputs from roots, breaking with the dogma of soil food webs being mainly fueled by plant litter input from aboveground. In this review we will highlight areas of recent exciting progress and point out the black boxes that still need to be illuminated by rhizosphere zoologists and ecologists.

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Nutrition on bacteria by bacterial-feeding nematodes and consequences on the structure of soil bacterial community

Cited by 69 publications

References 24 publications

Ecological importance of soil bacterivores for ecosystem functions

Ecological importance of soil bacterivores for ecosystem functions

Predators promote defence of rhizosphere bacterial populations by selective feeding on non-toxic cheaters

Rhizosphere fauna: the functional and structural diversity of intimate interactions of soil fauna with plant roots

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