Microbial-faunal interactions in the rhizosphere and effects on plant growth

Bonkowski, Michael; Cheng, Weixin; Griffiths, Bryan S.; Alphei, Jörn; Scheu, Stefan

doi:10.1016/s1164-5563(00)01059-1

Cited by 173 publications

(91 citation statements)

References 94 publications

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“…However, not all groups of Betaproteobacteria decreased. A number of microcosm studies with different groups of protozoa have shown that bacterial nitrifyers generally strongly increase in presence of protozoa (Griffiths, 1989;Verhagen et al, 1993;Alphei et al, 1996;Bonkowski et al, 2000), potentially due to increased availability of ammonium released by protozoan grazing. However, there was no information available on which taxa of nitrifyers were affected.…”

Section: Discussionmentioning

confidence: 99%

Soil amoebae rapidly change bacterial community composition in the rhizosphere of Arabidopsis thaliana

Rosenberg¹,

Bertaux²,

Krome³

et al. 2009

The ISME Journal

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208

183

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We constructed an experimental model system to study the effects of grazing by a common soil amoeba, Acanthamoeba castellanii, on the composition of bacterial communities in the rhizosphere of Arabidopsis thaliana. Amoebae showed distinct grazing preferences for specific bacterial taxa, which were rapidly replaced by grazing tolerant taxa in a highly reproducible way. The relative proportion of active bacteria increased although bacterial abundance was strongly decreased by amoebae. Specific bacterial taxa had disappeared already two days after inoculation of amoebae. The decrease in numbers was most pronounced in Betaproteobacteria and Firmicutes. In contrast, Actinobacteria, Nitrospira, Verrucomicrobia and Planctomycetes increased. Although other groups, such as betaproteobacterial ammonia oxidizers and Gammaproteobacteria did not change in abundance, denaturing gradient gel electrophoresis with specific primers for pseudomonads (Gammaproteobacteria) revealed both specific changes in community composition as well as shifts in functional genes (gacA) involved in bacterial defence responses. The resulting positive feedback on plant growth in the amoeba treatment confirms that bacterial grazers play a dominant role in structuring bacteria-plant interactions. This is the first detailed study documenting how rapidly protozoan grazers induce shifts in rhizosphere bacterial community composition.

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Section: Discussionmentioning

confidence: 99%

Soil amoebae rapidly change bacterial community composition in the rhizosphere of Arabidopsis thaliana

Rosenberg¹,

Bertaux²,

Krome³

et al. 2009

The ISME Journal

Self Cite

208

183

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“…Heterotrophic naked filose and reticulose amoebae are common in soils and in freshwater and marine sediments, and are suspected to have an important role in most microbial ecosystems (for example, Old and Chakraborty, 1986;Bonkowski et al, 2000). Yet they remain very poorly understood; for the vast majority of described species, molecular data are still missing, and very few lineages have been studied extensively morphologically and/or ecologically.…”

Section: Introductionmentioning

confidence: 99%

Vampires in the oceans: predatory cercozoan amoebae in marine habitats

et al. 2013

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Vampire amoebae (vampyrellids) are predators of algae, fungi, protozoa and small metazoans known primarily from soils and in freshwater habitats. They are among the very few heterotrophic naked, filose and reticulose protists that have received some attention from a morphological and ecological point of view over the last few decades, because of the peculiar mode of feeding of known species. Yet, the true extent of their biodiversity remains largely unknown. Here we use a complementary approach of culturing and sequence database mining to address this issue, focusing our efforts on marine environments, where vampyrellids are very poorly known. We present 10 new vampyrellid isolates, 8 from marine or brackish sediments, and 2 from soil or freshwater sediment. Two of the former correspond to the genera Thalassomyxa Grell and Penardia Cash for which sequence data were previously unavailable. Small-subunit ribosomal DNA analysis confirms they are all related to previously sequenced vampyrellids. An exhaustive screening of the NCBI GenBank database and of 454 sequence data generated by the European BioMarKs consortium revealed hundreds of distinct environmental vampyrellid sequences. We show that vampyrellids are much more diverse than previously thought, especially in marine habitats. Our new isolates, which cover almost the full phylogenetic range of vampyrellid sequences revealed in this study, offer a rare opportunity to integrate data from environmental DNA surveys with phenotypic information. However, the very large genetic diversity we highlight within vampyrellids (especially in marine sediments and soils) contrasts with the paradoxically low morphological distinctiveness we observed across our isolates.

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“…In densely Table 2 Effect of N-fertilizer/application method and PGPM on root growth and rhizosphere pH, shoot nutrient content and dry matter (55 days after sowing) P values are in italics; NS no significant difference, P ≥ 0.1; P < 0.1 is italic; *P < 0.5; **P < 0.01; ***P < 0. [15,[35][36][37]. All tested fungal and bacterial PGPMs showed normal or improved growth activity on solid nutrient agar containing as high as 50 mM NH 4 -N and slightly inhibited growth at 250 mM H 4 -N except for B. amyloliquefaciens FZB42 and Penicillium sp.…”

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confidence: 99%

Densely rooted rhizosphere hotspots induced around subsurface NH4 +-fertilizer depots: a home for soil PGPMs?

Nkebiwe

Neumann

Müller

2017

Chem. Biol. Technol. Agric.

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Background: Populations of plant growth-promoting microorganisms (PGPMs) inoculated in natural soil typically decline over time due unfavourable biotic and/or abiotic factor(s). Improving subsurface root density may enhance PGPM establishment due to high concentrations of organic nutrients released as root exudates. Placing subsurface root-attracting NH 4 + -fertilizer depots may form such zones of dense localized rooting ("rhizosphere hotspots") that can enhance PGPM survival. Nevertheless, required soil conditions that favour formation of rhizosphere hotspots are unknown. This study aimed to investigate: (1) background soil N min effect on NH 4 + -depot-zone root growth; (2) PGPM tolerance to high NH 4 + concentrations (± nitrification inhibitor, DMPP); (3) ability to solubilize sparingly soluble inorganic phosphates; (4) and establishment in a subsurface NH 4 + -depot. Methods:We conducted a greenhouse rhizobox experiment using spring wheat (Triticum aestivum L.) to investigate the effect of background N min (0, 5, 20 and 60 mg N kg Conclusion:These results show the first promising effects of combining fertilizer placement and application of P-solubilizing PGPMs on plant growth.

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Microbial-faunal interactions in the rhizosphere and effects on plant growth

Cited by 173 publications

References 94 publications

Soil amoebae rapidly change bacterial community composition in the rhizosphere of Arabidopsis thaliana

Soil amoebae rapidly change bacterial community composition in the rhizosphere of Arabidopsis thaliana

Vampires in the oceans: predatory cercozoan amoebae in marine habitats

Densely rooted rhizosphere hotspots induced around subsurface NH4 +-fertilizer depots: a home for soil PGPMs?

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