AUTHOR=Domínguez-Figueroa José , Carrillo Laura , Renau-Morata Begoña , Yang Lu , Molina Rosa-V , Marino Daniel , Canales Javier , Weih Martin , Vicente-Carbajosa Jesús , Nebauer Sergio G. , Medina Joaquín 

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

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.601558

DOI=10.3389/fpls.2020.601558

ISSN=1664-462X

ABSTRACT=<p>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 <italic>Arabidopsis</italic> DNA binding with one finger (DOF) transcription factor CDF3 in nitrate responses and shows that <italic>CDF3</italic> gene is induced under nitrate starvation. Moreover, knockout <italic>cdf3</italic> mutant plants exhibit nitrate-dependent lateral and primary root modifications, whereas <italic>CDF3</italic> overexpression plants show increased biomass and enhanced root development under both nitrogen poor and rich conditions. Expression analyses of <italic>35S::CDF3</italic> lines reveled that CDF3 regulates the expression of an important set of nitrate responsive genes including, <italic>glutamine synthetase-1</italic>, <italic>glutamate synthase-2</italic>, <italic>nitrate reductase-1</italic>, and nitrate transporters <italic>NRT2.1</italic>, <italic>NRT2.4</italic>, and <italic>NRT2.5</italic> as well as carbon assimilation genes like <italic>PK1</italic> and <italic>PEPC1</italic> 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 <italic>CDF3</italic>-overexpressing plants, but lower in <italic>cdf3-1</italic> in N limiting conditions. Moreover, overexpression of <italic>CDF3</italic> 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.</p>