Materials and methods for the enhancement of effective root nodulation in legumes
AssigneeThe University of Tennessee Research Corporation
InventorsJohn T. Loh, Gary Stacey
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Abstract
The subject invention relates to compounds and compositions which induce transcripts of the nolA gene in nitrogen-fixing bacteria, such as Bradyrhizobium japonicum. Novel bacterial strains which are insensitive too NolA, soil inoculants comprising NolA insensitive bacteria and/or nolA inducers, and methods of increasing nitrogen fixation in legumes are also disclosed.
Claims21
A method of producing a nodulation inoculant containing reduced amounts of cell density factor (CDF) comprising the addition of iron to growth medium for a nodulation inoculant in amounts sufficient to reduce the concentration of CDF.
A method of screening an extract or cell culture supernatant for the presence of an IND-1, IND-2, CDF, or CDF-like compound comprising:
- a) obtaining an extract or cell culture supernatant;
- b) contacting a host cell transformed with one or more genetic constructs containing a reporter enzyme selected from the group consisting of nolA-lacZ, nodY-lacZ, nodC-lacZ, or nodD-lacZ with said extract or cell culture supernatant;
- and
- c) analyzing the contacted host cell for the modulation or expression of said nolA-lacZ, nodY-lacZ, nodC-lacZ, or nodD-lacZ reporter enzyme.
An isolated compound selected from the group consisting of IND-2 and CDF.
A composition comprising a soil additive or conditioner and a compound selected from the group consisting of IND-1, IND-2, and CDF
The composition according to claim 22, wherein the compound is IND-1 (bis-ethyl-hexyl-ester phthalate).
An isolated bacterial cell defective in recognition of NolA inducer compounds.
The isolated bacterial cell according to claim 21, wherein said bacterial cell contains a defect in the nwsB gene.
A method of suppressing the nodulation activity of indigenous nodulating bacterial cells comprising the addition of one or more NolA inducers to soil containing said indigenous nodulating bacterial cells.
Dependencies are inferred from the claim text.