Abstract: The present invention relates to a mutant p-hydroxyphenylpyruvate dioxygenase (HPPD) protein or a bioactive fragment thereof and an isolated polynucleotide comprising a nucleic acid sequence encoding the protein or fragment thereof, wherein the mutant p-hydroxyphenylpyruvate dioxygenase (HPPD) protein or a bioactive fragment thereof retains or enhances the property of catalyzing the conversion of p-hydroxyphenylpyruvate (HPP) to homogentisate and is significantly less sensitive to HPPD-inhibiting herbicides than a wild-type HPPD. The present invention also relates to a nucleic acid construct, an expression vector and a host cell comprising the polynucleotide, as well as to a method for producing a plant that has the property of catalyzing the conversion of p-hydroxyphenylpyruvate (HPP) to homogentisate and significantly reduced sensitivity to HPPD-inhibiting herbicides.