| 摘要 |
<p>#CMT# #/CMT# Rendering plants tolerant to a herbicide (I) by expressing an enzyme (II) that by-passes the metabolic pathway inhibited by (I) in them. #CMT# : #/CMT# Independent claims are also included for the following: (1) a polypeptide (III) with HPPO (4-hydroxyphenylpyruvate oxidase) activity; (2) a polypeptide (IV) with HPAH activity; (3) a polypeptide (V) with HPAC activity; (4) nucleic acids (A) that encode (III) - (V); (5) an expression cassette (EC) containing (A); (6) a cloning and/or expression vector containing an EC; (7) transformed plant cells, also plants and their seeds, that contain an EC; (8) transforming plants by incorporation of an EC into the genome; and (9) a selective weed control method that uses an inhibitor of HPPD (4-hydroxyphenylpyruvate dioxygenase) as a herbicide. #CMT#ACTIVITY : #/CMT# Herbicidal antidote. No biological data is given. #CMT#MECHANISM OF ACTION : #/CMT# 4-hydroxyphenylpyruvate oxidase; HPA 1-hydrolase. #CMT#USE : #/CMT# The method is used to impart resistance in plants to herbicides (e.g. isoxazoles or diketonitriles) that inhibit 4-hydroxyphenylpyruvate dioxygenase, making possible use of such herbicides for selective weed control in crops. #CMT#BIOTECHNOLOGY : #/CMT# Preferred Plants: Resistance to HPPD inhibitors is imparted by expressing HPPO, HPAH and/or HPAC. Preferred polypeptides: (III) - (V) are insensitive to HPPD inhibitors. (III) is a 561 amino acid (aa) sequence (S2) from Arthrobacter globiformis, or two of its mutants, (IV) is a 564 aa protein (S8) from Pseudomonas acidovorans and (V) is a 322 aa sequence (10) from P. acidovorans or two of its mutants. All proteins may be used in the form of homologs or fragments, and all sequences are given in the specification. Preferred Nucleic Acid: The nucleic acid are: (i) sequences that encode the proteins, or their homologs or fragments; or (ii) complements of (i). Preparation: (III) was purified from A. globiformis and sequences determined for its N-terminus and internal peptides. Primers based on these sequences were used to amplify a fragment of 937 base pairs (bp) and this was used, labeled with digoxigenein, to screen a cosmid library, so as to identify four cosmids with different restriction patterns. A 6.2 kb fragment from one cosmid was sequenced to identify a 1680 bp fragment, encoding HPPO. The 4-HPA (hydroxyphenylacetic acid) 1-hydrolase activity from P. acidovorans was isolated and processed as for the HPPO protein to produce a 536 bp probe for screening a cosmid library. Functional complementation of the failure of P. putida to grow on 4-HPA as sole carbon source (although it can grow on homogensitate (HGA)) was used to detect one clone containing a 5.2 kb fragment. This contained several genes - one designated hpaH and a second hpaC, both required for 4-HPA 1-hydrolase activity. Once these sequences have been isolated, they may be cloned and expressed in usual vector/host systems. #CMT#EXAMPLE : #/CMT# No suitable example is given.</p> |
