Abstract:A full-length cDNA of rice （Oryza sativa L.） glutathione synthetase （GS） gene was obtained by 5＇- RACE （rapid amplification of 5 ＇-complementary DNA ends）, and the gene was named as OsGS （GeneBank accession No.： AY453405）. The 1 892 bp cDNA contained an open reading flame （ORF） encoding a polypeptide of 540 amino acid residues with a predicted signal peptide of chloroplast. The alignment of OsGS cDNA with the mapped genome sequences office indicated that OsGS is located in the short arm office chromosome 12, and the transcript region （6 321 bp） of this gene consists of 12 extrons and 11 introns. The transcriptions of OsGS in rice under normal and stress conditions were studied by RT-PCR method. The results showed that, under normal conditions, the transcriptions of Os GS could be detected in roots, leaves of one-week old seedlings and roots of heading rice, but not in leaves, stems and spikes of heading rice. This result indicated that the expression of Os GS conforms to a spatio-temporal pattern. Under stress conditions, the expression of OsGS in the leaves of heading rice demonstrated that the transcription of OsGS was strongly induced by heat shock （40℃）, cadmium and drought; but not by salt, low temperature and wound. Further transcription analysis showed that OsGS expression was strongly induced by mild and medium drought stress for 4 hours. In addition, the exogenous ABA could induce the transcription of OsGS in the leaves of flowering rice, suggesting that the response of OsGS to drought might be mediated by ABA-dependent pathway.
