Award details

Investigate the genetics and molecular basis of interaction between soil bacteria and fungi and crop plants in field soils

Reference	BBS/E/C/00031468
Principal Investigator / Supervisor	Professor Penny Hirsch
Co-Investigators / Co-Supervisors
Institution	Rothamsted Research
Department	Rothamsted Research Department
Funding type	Research
Value (£)	26,982
Status	Completed
Type	Institute Project
Start date	01/04/1997
End date	30/09/1997
Duration	6 months

Abstract

Details should only be considered in the context of PU information. Although it can be shown that different crop plants grown in the same soil, identical crops grown in different soils, and crops at different stages of growth have distinct microfloras, the factors responsible are not clear. Symbiotic and pathogenic rhizosphere microorganisms are known to respond to specific signal molecules in the root exudate of host or susceptible plants, but it is not known whether similar interactions are involved in colonization of roots by saprophytic microbes, or if they respond to the nutrients in the root exudates. This is of interest not only in understanding the microbial ecology of arable soils, but also because the rhizoflora may protect the plant from invasion by pests and pathogens, and may also improve nutrient supply. Bacterial response to signal molecules involves activation of genes following derepression of their promoters by the signal in conjunction with a bacterial sensor". Bacterial promoters induced by root exudates may control genes involved in root colonization. The project is to look for evidence of root exudate-inducible promoters in bacteria isolated from rhizospheres, and to analyze exudates for potential signal molecules. It also involves determination of exudate composition, to establish whether a response to the nutrients by rhizosphere bacteria is likely to be a significant factor in competition root colonization. The search for inducible genes involves mutagenesis of rhizosphere bacteria with a transposon that inserts at random throughout the genome, carries a selectable marker enabling selection of insertion mutants, and a promoterless gene (the "promoter probe") which is not expressed unless inserted in front of an active gene promoter, when a distinctive gene product is manifested. Expression of this gene only in the presence of root exudate indicates that the promoter probe is inserted in a gene involved in plant-microbe interactions. Similarly, important genes could also be repressed by exudate. Any promoter-probe insertions in genes induced or repressed by exudate can be used to assay fractions purified from exudate for the active components."

Summary

unavailable

Committee	Closed Committee - Plant & Microbial Sciences (PMS)
Research Topics	X – not assigned to a current Research Topic
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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