Cloning Of Glutamine Synthetase Gene And Regulation Of GS Expression In Wheat Seedling Stage

Efficiency of N using depends on the absorption of nitrogen, assimilation and transfer reuse process. It is inseparable that Glutamine synthase and nitrogen metabolism in the growth process of wheat. The GS of Wheat have ten sequences and divided into four race. GS2 is closely related with nitrogen assimilation , GS1 is closely related to the transfer of reuse. nitrogen .The influence of different nitrogen disease-related, affect the GS of reusing and transfer function. in N uptake and assimilate. Therefore the research have the important meaning of GS of transgenic and improve optimization cultivation measures to improve nitrogen use to.According to different plants families function of GS gene conservative district sequence .We design primer of GS2 and GS1 won the homologous sequence .We that won the full length of GS2 and GS1 cDNA sequence information of the wheat combined with RACE. Sequence analysis showed that full length of GS1 is 1494bp,including 5’ UTR region of 74bp,3’ UTR region of 349bp and open reading frame of 1071bp which encoding a protein of 356 amino acid.The full length cDNA of GS2 is 1631bp. It contains 5’UTR of 104bp,3’UTR of 243bp,ORF of 1284bp.Its ORF encoded a protain of 427 amino acids.Use of sand-based hydroponic experiment, we use the leaf and root of wheat in the first leaf of rapid elongation, maturity and senescence: The transcription and translation is dynamic changes of GS in the first leaf and root of wheat. The form of nitrogen influence the GS and content of soluble protein on the leaves and roots. In the rapid elongation of the first leaf, a large number of GS2-mRNA and GS1-mRNA are transcriptionleaf in the leaves.Native-PAGE with activity staining i isozymes,three kind of GS are isolated from n the first leaf: GS isoenzyme activity: GS2> GS1> GSx. The results of western-blot showed that subunit of GS2 is 44kD and subunit of GS2 is 39kD in the leaves, content of subunit GS2> GS1. In the first leaf GS1-mRNA and leaf GS2-mRNA transcription reduced at maturity.GS2 and GSx activity are increased, The activity of GSx and GS2 is almost similar; GS1 activity decreased significantly, activity showed GS2> GSx> GS1; relative leaf elongation subunit decreased GS1, GS2 subunit content increased; GS activity and soluble protein content increased. In the senescence of leaves a large number of GS1-mRNA is transcription, The transcription of GS2-mRNA is Termination.GS1 isoenzyme activity increased, GS2 and GSx activity decreased significantly, activity showed GS1> GSx> GS2; GS activity increased slightly, soluble protein decreased. With maturation senescence and the rapid elongation first leaf, the GS1-mRNA of roots showed no significant change; root isozyme separation only GS1, its activity is weak in the mature leaves. only the expression of roots are only the 39kD subunit of the GS1, subunits The trends of isoenzyme activity is consistent. GS activity of the root did not change significantly when the slight decrease in leaf senescence. When mature of leaf the soluble protein content is lower. subunit expression and activity of soluble protein of leaf is much higher than the root.The forms of nitrogen influence the expression of GS subunit significantly in the leaves and roots. The results showed that nitrate can induce GS2-mRNA and isozyme expression of GS2 in the rapid elongation of leaves and inhibit the expression of the GS2 isoenzyme in the senescence of leaves. The subunit of GS1 was significantly higher than GS2 leaf senescence that; NO3—promote to have a higher GS activity for the leaves, but The content of soluble protein is low. Ammonium nitrogen can promote GS1-mRNA transcription in the roots. In the rapid elongation of first leaf ammonium promote GS1 subunit of root .ammonium is abundantly expressed in the first mature leaf. The urea to promote the expression of large subunit of GS1 in roots.The forms of nitrogen on root activity of GS was not obvious.