Numbers and locations of native bacteria on field-grown wheat roots quantified by fluorescence in situ hybridization (FISH)

Watt, Michelle, Hugenholtz, Philip, White, Rosemary and Vinall, Kerry (2006) Numbers and locations of native bacteria on field-grown wheat roots quantified by fluorescence in situ hybridization (FISH). Environmental Microbiology, 8 5: 871-884. doi:10.1111/j.1462-2920.2005.00973.x


Author Watt, Michelle
Hugenholtz, Philip
White, Rosemary
Vinall, Kerry
Title Numbers and locations of native bacteria on field-grown wheat roots quantified by fluorescence in situ hybridization (FISH)
Journal name Environmental Microbiology   Check publisher's open access policy
ISSN 1462-2912
1462-2920
Publication date 2006-05
Sub-type Article (original research)
DOI 10.1111/j.1462-2920.2005.00973.x
Volume 8
Issue 5
Start page 871
End page 884
Total pages 4
Place of publication Oxford, U.K.
Publisher Wiley-Blackwell Publishing
Language eng
Formatted abstract
Native bacteria, Pseudomonas and filamentous bacteria were quantified and localized on wheat roots grown in the field using fluorescence in situ hybridization (FISH). Seminal roots were sampled through the season from unploughed soil in a conservation farming system. Such soils are spatially heterogeneous, and many roots grow slowly through hard soil with cracks and pores containing dead roots remnant from previous crops. Root and rhizosphere morphology, and contact with soil particles were preserved, and autofluorescence was avoided by observing sections in the far-red with Cy5 and Cy5.5 fluorochromes. Spatial analyses showed that bacteria were embedded in a stable matrix (biofilm) within 11 μm of the root surface (range 2-30 μm) and were clustered on 40% of roots. Half the clusters colocated with axial grooves between epidermal cells, soil particles, cap cells or root hairs; the other half were not associated with visible features. Across all wheat roots, although variable, bacteria averaged 15.4 × 105 cells per mm3 rhizosphere, and of these, Pseudomonas and filaments comprised 10% and 4%, respectively, with minor effects of sample time, and no effect of plant age. Root caps were most heavily colonized by bacteria along roots, and elongation zones least heavily colonized. Pseudomonas varied little with root development and were 17% of bacteria on the elongation zone. Filamentous bacteria were not found on the elongation zone. The most significant factor to rhizosphere populations along a wheat root, however, was contact with dead root remnants, where Pseudomonas were reduced but filaments increased to 57% of bacteria (P < 0.001). This corresponded with analyses of root remnants showing they were heavily colonized by bacteria, with 48% filaments (P < 0.001) and 1.4%Pseudomonas (P = 0.014). Efforts to manage rhizosphere bacteria for sustainable agricultural systems should continue to focus on root cap and mucilage chemistry, and remnant roots as sources of beneficial bacteria
Keyword Microbial communities
Oxidizing bacteria
Soil bacteria
Targeted oligonucleotide probes
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: ERA 2012 Admin Only
School of Chemistry and Molecular Biosciences
 
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Created: Tue, 29 Nov 2011, 10:35:24 EST by Hong Lee on behalf of School of Chemistry & Molecular Biosciences