Cloning of 5-enolpyruvylshikimate-3-phosphate Synthase Genes EPSPS from the Upland Cotton and Its Expression in Different Cotton Tissues

5-Enolpyruvylshikimate-3-phosphate(EPSP) synthase is an enzyme of the shikimate pathway.It is the target enzyme of nonselective herbicide glyphosate.This enzyme is located in the chloroplasts of the higher plants.Primers were designed according to the assembled ESTs of Gossypium hirsutum,and a 1834 bp cDNA fragment of G.hirsutum cv.Coker 312 was obtained in this experiment.The frafment contains an ORF comprising of 1565 nucleotides which encodes 521 amino acid.A comparison of the deduced amino acid sequences of cotton and other higher plants genes reveals highly homology over the length of the entire mature protein.The site of transit peptides cleavage is deduced from a comparison to the known cleavage site in other plants.The enzyme,including 74 amino acid chloroplast transit peptides and 447 amino acid mature proteins,comprises conserved region of PEP binding sites and the characteristic sequence of catalytic activity sites.Semi-quantitative analysis of EPSP synthase expression showed that the gene expressed extensively in cotton roots,stems,leaves,and other organs,and leaf is the most highly expressed tissue.A genomic DNA sequence with 3344 bp clone containing an EPSP synthase was isolated from the upland cotton in this experiment,and the EPSPS gene contains eight introns and seven exons.