Superexpressão do gene OsDof25 e seus efeitos sobre a absorção e assimilação de amônio

Abstract

In order to increase the efficiency of use of nitrogen (NUE) in the crop production, rice plants (Oryza sativa L. cv Nipponbare) were transformed with the transcription factor OsDof25. Were also transformed plants with OsDof25 gene promoter fused to GUS and EGFP reporter genes to identify sites of expression and its possible correlation with protein transport and assimilation of N. The MultiSite Gateway ® cloning technology was used to produced six independent transformants lines regenerated from calli of rice . All transformed lines showed lower crop cycle , between ten and seven days compared to WT plants. The lines L#1.1 , L#5.1 L#9.6 and L#10.8 showed higher enzyme activities of nitrogen assimilation (GS and NADH - GOGAT), both in leaves when roots when grown with 2.0 mM NH4+, generating higher internal concentrations of total amino acids. An increase in the GDH activity in roots amination, which can be associated with the supply of 2-OG to maintain the GS / GOGAT cycle activity was also checked. However lowest ICDH activity , indicating greater internal homeostasis in glutamate levels . These results show that plants transformed with the gene OsDof25 are more efficient in ammonium assimilation.