Paradigm Genetics, Inc.

John W Rice

Sandy J Stewart

Beth Lanning

Lining Guo

Robert Ascenzi

John Richardson Crawford

Andreas S Kloti

Jorn Gorlach

Douglas C Boyes

Carol M Hamilton

Keith R Davis

Neil E Hoffman

Jeffrey P Woessner

Adel Zayed

Rao Mulpuri

Gordon Nye

Veeresh Sevala

John Milton Crawford, Jr

John M Crawford, Jr

Daniel N Riggsbee

Joseph Cameron Mitchell

Susanne Kjemtrup

The present inventors have discovered that serine acetyltransferase (SAT) is essential for plant growth. Specifically, the inhibition of SAT gene expression in plant seedlings results in reduced growth and altered pigmentation. Thus, SAT is useful as a target for the identification of herbicides. Accordingly, the present invention provides methods for the identification of herbicides by measuring the activity of an SAT in the presence and absence of a compound, wherein an alteration of SAT activity in the presence of the compound indicates the compound as a candidate for a herbicide.

Methods for the identification of inhibitors of serine acetyltransferase activity in plants

Assays, preferably high throughput assays, for determining cysteine concentration, cysteine synthase activity, and identifying herbicides, fungicides, bactericides, and insecticides. Cysteine concentration is quantitated by contacting cysteine with a coumarin dye capable of conjugating with cysteine but not to O-acetyl serine or sulfide; exciting the conjugate with UV light; and detecting fluorescent light emitted by the conjugate. Cysteine synthase activity is determined by combining O-acetyl-L-serine, sulfide and cysteine synthase to form a reaction mixture under conditions suitable for cysteine production; contacting the reaction mixture with an appropriate coumarin dye; subjecting the reaction mixture to UV light; and detecting fluorescent light emission.

Methods for measuring cysteine and determining cysteine synthase activity

Novel DNA and enzymes such as Plant Thioredoxin-Porphobilinogen Synthase (T-PPS) or Plant Porphobilinogen Synthase (PPS), together with novel compositions thereof and methods using such enyzmes are claimed.

Plant porphobilinogen synthase and fusion protein thereof

The invention is directed to methods and compositions for the determination of deoxyxylulose 5-phosphate synthase (DXPS) activity. The methods and compositions of the invention are amenable to high-throughput screening assays for the identification of inhibitors and enhancers of DXPS activity. Such compounds have use in the modulation of plant and microbial growth. The compositions of the invention are DXPS fragments and chimeric polypeptides that have increased solubility as compared to the wild-type DXPS polypeptide. These DXPS fragments and chimeric polypeptides can be recombinantly expressed and purified in quantities suitable for high-throughput screening assays. The assays of the invention are based on the detection of substrates of DXPS that remain after a DXPS reaction.

Methods for determining deoxyxylulose 5-phosphate synthase activity

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Pittsboro, NC, United States of America

John W Rice