The nitrate inducible NAC transcription factor TaNAC2-5A controls nitrate response and increases wheat yield

Abstract

Nitrate is a major nitrogen resource for cereal crops; thus, understanding nitrate signaling in cereal crops is valuable for engineering crops with improved nitrogen use efficiency. Although several regulators have been identified in nitrate sensing and signaling in Arabidopsis (Arabidopsis thaliana), the equivalent information in cereals is missing. Here, we isolated a nitrateinducible and cereal-specific NAM, ATAF, and CUC (NAC) transcription factor, TaNAC2-5A, from wheat (Triticum aestivum). A chromatin immunoprecipitation assay showed that TaNAC2-5A could directly bind to the promoter regions of the genes encoding nitrate transporter and glutamine synthetase. Overexpression of TaNAC2-5A in wheat enhanced root growth and nitrate influx rate and, hence, increased the root's ability to acquire nitrogen. Furthermore, we found that TaNAC2-5A-overexpressing transgenic wheat lines had higher grain yield and higher nitrogen accumulation in aerial parts and allocated more nitrogen in grains in a field experiment. These results suggest that TaNAC2-5A is involved in nitrate signaling and show that it is an exciting gene resource for breeding crops with more efficient use of fertilizer.

Cytosolic Glutamine Synthetase Gln1;2 Is the Main Isozyme Contributing to GS1 Activity and Can Be Up-Regulated to Relieve Ammonium Toxicity

“…Regulation of GS may occur at levels of transcription, translation, subcellular localization, subunit assembly, and post-translational modification of the protein and its turnover (Thomsen et al, 2014;He et al, 2015;Seabra and Carvalho, 2015;Wang et al, 2015). While the regulation of GS gene expression has been studied in many cases, much less is known about responses at protein level.…”

Overexpression of TaNAC2D Displays Opposite Responses to Abiotic Stresses between Seedling and Mature Stage of Transgenic Arabidopsis

“…Transgenic wheat overexpressing TaNAC69 shows a conspicuous drought-tolerant phenotype (Xue et al, 2011). Recently, a new study reveals that TaNAC2-5A -overexpressing wheat plants produce a higher grain yield through acquired more nitrogen from fertilizer, suggesting that TaNAC2-5A participates in the wheat nitrate-signaling pathway (He et al, 2015). …”

Molecular and phenotypic characterization of transgenic wheat and sorghum events expressing the barley alanine aminotransferase

“…The metabolic network coordination between carbon and nitrogen can influence NUE. Exploiting these linkage strategies that addressed repletion of N metabolism with carbon skeletons such as 2-oxoglutarate and oxaloacetate from the TCA cycle have been promising as a strategy to boost mineral use efficiencies He et al 2015;Kurai et al 2011;McAllister and Good 2015;Shrawat et al 2008;Yanagisawa et al 2004).…”

“…Plants acquire nitrogen from the soil primarily as nitrate or ammonium via multiple specific transporters, into the root system (He et al 2015;Krapp et al 2014;Miller et al 2007;Xu et al 2012). The ammonium derived from nitrate reduction, or via direct uptake is assimilated into glutamine or glutamate by the GS/GOGAT cycle, the primary route for inorganic nitrogen assimilation (Lea and Miflin 2003).…”