Overexpressing the ZmDof1 gene in Populus does not improve growth and nitrogen assimilation under low-nitrogen conditions

摘要

Genetic engineering of nitrogen assimilation has received considerable attention for its improvement of nitrogen use efficiency in crops. Overexpression of maize Dof1 (ZmDof1), a plant-specific transcription factor, has been reported to promote nitrogen assimilation and growth under low-nitrogen conditions in transgenic Arabidopsis and rice. The present study explored its application in Populus by overexpressing the ZmDof1 gene. Contrary to the results in Arabidopsis and rice, introduction of the ZmDof1 gene did not improve growth of transgenic Populus under different low-nitrogen conditions both in vitro and in greenhouse. Expressions of genes that are involved in nitrogen assimilation and carbon fixation were not induced in ZmDof1-transgenic Populus. Nitrogen/carbon concentrations and photosynthesis rate were not increased in the ZmDof1-transgenic Populus. The results in transgenic Populus overexpressing the ZmDof1 gene indicated that ZmDof1 did not play an important role in nitrogen assimilation under low nitrogen condition in woody Populus plants as it did in annual Arabidopsis and rice plants.