Root nitrate uptake in sugarcane (Saccharum spp.) is modulated by transcriptional and presumably posttranscriptional regulation of the NRT2.1/NRT3.1 transport system

Author(s)

Lima, Joni E. ; Serezino, Luis H. D. ; Alves, Melissa K. ; Tagliaferro, Andre L. ; Vitti, Marielle ; Creste, Silvana ; Riano-Pachon, Diego M. ; dos Santos, Renato, V ; Figueira, Antonio

• Document type: Journal article
• Source: Molecular Genetics and Genomics; v. 297, n. 5, p. 19-pg., 2022-07-26.

Abstract

Key message Nitrate uptake in sugarcane roots is regulated at the transcriptional and posttranscriptional levels based on the physiological status of the plant and is likely a determinant mechanism for discrimination against nitrate. Sugarcane (Saccharum spp.) is one of the most suitable energy crops for biofuel feedstock, but the reduced recovery of nitrogen (N) fertilizer by sugarcane roots increases the crop carbon footprint. The low nitrogen use efficiency (NUE) of sugarcane has been associated with the significantly low nitrate uptake, which limits the utilization of the large amount of nitrate available in agricultural soils. To understand the regulation of nitrate uptake in sugarcane roots, we identified the major canonical nitrate transporter genes (NRTs-NITRATE TRANSPORTERS) and then determined their expression profiles in roots under contrasting N conditions. Correlation of gene expression with N-15-nitrate uptake revealed that under N deprivation or inorganic N (ammonium or nitrate) supply in N-sufficient roots, the regulation of ScNRT2.1 and ScNRT3.1 expression is the predominant mechanism for the modulation of the activity of the nitrate high-affinity transport system. Conversely, in N-deficient roots, the induction of ScNRT2.1 and ScNRT3.1 transcription is not correlated with the marked repression of nitrate uptake in response to nitrate resupply or high N provision, which suggested the existence of a posttranscriptional regulatory mechanism. Our findings suggested that high-affinity nitrate uptake is regulated at the transcriptional and presumably at the posttranscriptional levels based on the physiological N status and that the regulation of NRT2.1 and NRT3.1 activity is likely a determinant mechanism for the discrimination against nitrate uptake observed in sugarcane roots, which contributes to the low NUE in this crop species. (AU)

• FAPESP's process: 13/15989-8 - Physiological, biochemical and molecular characterizaiton of nitrate transport during n uptake and remobilization in sugarcane (Saccharum spp.)
• Grantee: Antonio Vargas de Oliveira Figueira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/02702-2 - Physiological characterization and gene expression profile of transportation during acquisition and nitrate remobilization in sugarcane (Saccharum spp.)
• Grantee: Luís Henrique Damasceno Serezino
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 10/11313-1 - Identification, physiological characterization and gene expression profilling of sugarcane (Saccharum spp.) cultivars contrasting for nitrogen use efficiency
• Grantee: Joni Esrom Lima
• Support Opportunities: Scholarships in Brazil - Post-Doctoral