The Arabidopsis Transcription Factor CDF3 Is Involved in Nitrogen Responses and Improves Nitrogen Use Efficiency in Tomato

Abstract

Nitrate is an essential macronutrient and a signal molecule that regulates the expression of multiple genes involved in plant growth and development. Here, we describe the participation of Arabidopsis DNA binding with one finger (DOF) transcription factor CDF3 in nitrate responses and shows that CDF3 gene is induced under nitrate starvation. Moreover, knockout cdf3 mutant plants exhibit nitrate-dependent lateral and primary root modifications, whereas CDF3 overexpression plants show increased biomass and enhanced root development under both nitrogen poor and rich conditions. Expression analyses of 35S::CDF3 lines reveled that CDF3 regulates the expression of an important set of nitrate responsive genes including, glutamine synthetase-1, glutamate synthase-2, nitrate reductase-1, and nitrate transporters NRT2.1, NRT2.4, and NRT2.5 as well as carbon assimilation genes like PK1 and PEPC1 in response to N availability. Consistently, metabolite profiling disclosed that the total amount of key N metabolites like glutamate, glutamine, and asparagine were higher in CDF3-overexpressing plants, but lower in cdf3-1 in N limiting conditions. Moreover, overexpression of CDF3 in tomato increased N accumulation and yield efficiency under both optimum and limiting N supply. These results highlight CDF3 as an important regulatory factor for the nitrate response, and its potential for improving N use efficiency in crops.

Genetic Engineering and Genome Editing for Improving Nitrogen Use Efficiency in Plants

“…Some other genes associated with N metabolism were also transferred to trees. Unlike the studies in cereals [ 146 , 149 ] or tomato [ 154 ], overexpression of the ZmDof1 gene in poplar had no positive results [ 204 ], possibly due to different regulatory systems in annual and woody plants. The gene of Dof5 TF of the same TF family that regulates GS1 isoforms in maritime pine was also transferred to hybrid poplar plants [ 205 ].…”

“…The tissue-specific expression increased biomass, yield and NUE, whereas the constitutive expression had either neutral or negative effect due to downregulation of genes involved in photosynthesis. Overexpression of Arabidopsis TF CDF3 (DOF TF family) in tomato plants promoted a notable increase in the biomass of vegetative organs and fruits in both N-poor and -rich conditions [ 154 ]. The authors suggested that DOF genes could play similar functions in C/N metabolism in dicot and monocot species.…”

Ectopic Expression of Arabidopsis thaliana zDof1.3 in Tomato (Solanum lycopersicum L.) Is Associated with Improved Greenhouse Productivity and Enhanced Carbon and Nitrogen Use

“…Some zDof genes have been implicated in the regulation of primary metabolism by co-expression with genes involved in carbon and nitrogen metabolism in maize [ 26 ], wheat [ 27 ], and millet [ 28 , 29 ]. Furthermore, overexpression or suppression of native genes, or the ectopic expression of some zDof orthologues in A. thaliana [ 30 , 31 , 32 ], tomato [ 33 , 34 ], soybean [ 35 ], rice [ 36 ], tobacco [ 37 ], canola [ 38 ] and sweet potato [ 39 ] led to changes in carbon metabolism, nitrogen metabolism or both, suggesting direct involvement of some zDofs in coordinating the regulation of these pathways.…”

“…We wish to understand how the plant responds at all levels by using combined eco-physiology, metabolomics, and transcriptomic analyses. Attention was paid to nitrogen and carbon allocation because of their importance in determining crop yield and resilience, and evidence that some zDofs may regulate some aspects of these metabolic processes [ 33 , 34 , 39 , 40 , 41 , 42 ]. The second aim was to take advantage of growing genomic sequence resources to learn more about the evolutionary relatedness of AtzDof1.3 to other A. thaliana zDofs , and orthologues of tomato and other dicots.…”

Transcriptome Analysis of Two Near-Isogenic Lines with Different NUE under Normal Nitrogen Conditions in Wheat

“…In recent years, RNA-Seq analysis has been extensively used to explore the molecular mechanisms of NUE at the transcriptome level, researchers have identified genes and regulatory networks in plants [ 18 ]. For instance, the transcription factor CDF3 is induced by N starvation in Arabidopsis, which is an important modulating factor for the nitrate response and has the potential to improve NUE in crops [ 19 ]. Sinha et al [ 20 ] studied root and shoots transcriptome response to chronic N starvation using two rice genotypes differing in LN tolerance and identified the N-responsive genes that belonged to starch and chloroplast metabolism, which might serve as a resource in enhancing NUE.…”