文摘
Glutamine synthetase (GS) in plants is a crucial enzyme for nitrogen assimilation and defending against biotic and abiotic stresses. In the present study, a full-length cDNA, designated HbGS2, was isolated from Hevea brasiliensis by amplification of cDNA ends method. HbGS2 was 1726 bp in length and contained a 1299-bp open reading frame encoding a putative protein of 433 amino acids. The predicted molecular mass of HbGS2 was 47.76 kilodalton with an isoelectric point (pI) of 8.06. Bioinformatics analysis showed that it contained the GS conserved elements and belonged to the plastidic member. Cis-regulatory element analysis showed the presence of stress-responsive elements and plastid-specific elements in the promoter region of HbGS2. Overproduction of recombinant HbGS2 protein gave the Escherichia coli cells or yeast more tolerance to heavy metal and hydrogen peroxide. The transcription level of HbGS2 and the activity of HbGS in Frey-Wyssling particles were significantly repressed by ethylene application. HbGS2 should be located in the Frey-Wyssling particles and may confer these organelles that are homologous to plastids a role in defending against various abiotic stresses.