| abstract |
The present invention provides, inter alia, an isolated polynucleotide comprising a region encoding a chloroplast transit peptide and a glyphosate resistant 5-enolpyruvylshikimate phosphate synthase (EPSPS) 3′ of the peptide, the said region being under expression control of a plant operable promoter, with the provisos that the said promoter is not heterologous with respect to the said region, and the chloroplast transit peptide is not heterologous with respect to the said synthase. The polynucleotide may comprise the following components in the 5′ to 3′ direction of transcription: (i) at least one transcriptional enhancer being that enhancing region which is upstream from the transcriptional start of the sequence from which the enhancer is obtained and which enhancer per se does not function as a promoter either in the sequence in which it is endogenously comprised or when present heterologously as part of a construct; (ii) the promoter from the rice EPSPS gene; (iii) the rice genomic sequence which encodes the rice EPSPS chloroplast transit peptide; (iv) the genomic sequence which encodes the rice EPSPS; (v) a transcriptional terminator; wherein the rice EPSPS coding sequence is modified in that a first position is mutated so that the residue at this position is Ile rather than Thr and a second position is mutated so that the residue at this position is Ser rather than Pro, the mutations being introduced into EPSPS sequences which comprise the following conserved region GNAGTAMRPLTAAV (SEQ ID NO:49) in the wild type enzyme such that modified sequence reads GNAGIAMRSLTAAV (SEQ ID NO:50). |