Transcription FactorTaDof1Improves Nitrogen and Carbon Assimilation Under Low-Nitrogen Conditions in Wheat

摘要

A single transcription factor is known to coordinate expression of a set of metabolites in a biochemical pathway; its use therefore can be a functional strategy in generating plants with desired traits.Triticum aestivum Dof1(TaDof1) transcription factor is mainly associated with improved nitrogen assimilation in plants. In the current research, the transgenic wheat overexpressingTaDof1transcription factor, under a constitutive promoter, was developed byAgrobacterium-mediated transformation. The two elite wheat cultivars (Galaxy and Faisalabad-2008) were selected for transformation study. The T(0)plants were subjected to screening using selection medium containing herbicide BASTA. PCR results confirmed that only 8 out of 31 plants possessed the completeTaDof1cassette. A transformation efficiency of 0.46% for Galaxy and 0.08% for Faisalaad-2008 was obtained. The quantitative RT-PCR was performed on T(1)plants grown under nitrogen-limiting conditions. A substantial rise in the expression of citrate synthase (CS), isocitrate dehydrogenase (ICDH), phosphoenolpyruvate carboxylase (PEPC), and pyruvate kinase (PK) genes regulated byTaDof1was observed after 4 weeks of nitrogen stress in T(1)plants. The maximum fold increase of 464 was recorded for ICDH. Our findings indicate a cooperative modification of nitrogen and carbon metabolisms since they are intimately linked together. Overexpression ofTaDof1in wheat resulted in a significant increase in various agronomic traits. Furthermore, various physiological and biochemical markers (chlorophyll, protein, and soluble sugar contents) exhibited a profound change inTaDof1transgenic plants in comparison with wild type plants. The results clearly depict the merits of employing transcription factors in engineering plant metabolisms.