p-Hydroxyphenylpyruvate dioxygenase inhibitor-resistant plants.
The enzyme p-hydroxyphenylpyruvate dioxygenase (HPPD) catalyzes the formation of homogentisic acid, the aromatic precursor of plastoquinone and vitamin E. HPPD is the specific target of several herbicide families: isoxazoles, triketones and pyroxazoles. Its inhibition results in the depletion of the plant plastoquinone and vitamin E pools, leading to bleaching symptoms. These herbicides are very potent for the selective pre- and in some cases post-emergence control of a wide range of broadleaf and grass weeds in maize and rice. Their herbicidal potential raised interest in the development of highly resistant transgenic crops. This goal was first achieved by over-expression of a bacterial HPPD in crop plants, and an increased level of resistance was obtained by using a mutant enzyme. A second strategy based on bypassing HPPD in the production of homogentisate was then developed. Recently, a third strategy of resistance based on the increase of p-hydroxyphenylpyruvate substrate flux has been developed. This was achieved by the introduction of the yeast prephenate dehydrogenase gene (PDH) into transgenic plants already overexpressing HPPD. In addition to a high level of herbicide resistance, a massive accumulation of vitamin E, mainly tocotrienols, was observed in leaves of the transgenic HPPD-PDH plants.
Matringe
Michel
M
Laboratoire de Physiologie Cellulaire Végétale, CNRS (UMR 5168)-CEA-Université Joseph Fourier-INRA (UMR 1200), CEA-Grenoble, 38054 Grenoble Cedex 9, France. mmatringe@cea.fr
Sailland
Alain
A
Pelissier
Bernard
B
Rolland
Anne
A
Zink
Olivier
O
D015111:4-Hydroxyphenylpyruvate Dioxygenase / Q000037:antagonists & inhibitors / Q000235:genetics*; D004351:Drug Resistance / Q000235:genetics; D015870:Gene Expression; D005818:Genetic Engineering; D006540:Herbicides / Q000737:chemistry / Q000494:pharmacology*; D010944:Plants / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000201:enzymology; D011551:Pseudomonas fluorescens / Q000201:enzymology
D006540:Herbicides; D015111:4-Hydroxyphenylpyruvate Dioxygenase