The Functional Diversity of the High-Affinity Nitrate Transporter Gene Family in Hexaploid Wheat: Insights from Distinct Expression Profiles
High-affinity nitrate transporters (NRT) are key components for nitrogen (N) acquisition and distribution within plants. However, insights on these transporters in wheat are scarce. This study presents a comprehensive analysis of the NRT2 and NRT3 gene families, where the aim is to shed light on the...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-12-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/25/1/509 |
| Summary: | High-affinity nitrate transporters (NRT) are key components for nitrogen (N) acquisition and distribution within plants. However, insights on these transporters in wheat are scarce. This study presents a comprehensive analysis of the NRT2 and NRT3 gene families, where the aim is to shed light on their functionality and to evaluate their responses to N availability. A total of 53 <i>NRT2s</i> and 11 <i>NRT3s</i> were identified in the bread wheat genome, and these were grouped into different clades and homoeologous subgroups. The transcriptional dynamics of the identified <i>NRT2</i> and <i>NRT3</i> genes, in response to N starvation and nitrate resupply, were examined by RT-qPCR in the roots and shoots of hydroponically grown wheat plants through a time course experiment. Additionally, the spatial expression patterns of these genes were explored within the plant. The <i>NRT2s</i> of clade 1, <i>TaNRT2.1-2.6</i>, showed a root-specific expression and significant upregulation in response to N starvation, thus emphasizing a role in N acquisition. However, most of the clade 2 <i>NRT2s</i> displayed reduced expression under N-starved conditions. Nitrate resupply after N starvation revealed rapid responsiveness in <i>TaNRT2.1-2.6</i>, while clade 2 genes exhibited gradual induction, primarily in the roots. <i>TaNRT2.18</i> was highly expressed in above-ground tissues and exhibited distinct nitrate-related response patterns for roots and shoots. The <i>TaNRT3</i> gene expression closely paralleled the profiles of <i>TaNRT2.1-2.6</i> in response to nitrate induction. These findings enhance the understanding of NRT2 and NRT3 involvement in nitrogen uptake and utilization, and they could have practical implications for improving nitrogen use efficiency. The study also recommends a standardized nomenclature for wheat <i>NRT2</i> genes, thereby addressing prior naming inconsistencies. |
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| ISSN: | 1661-6596 1422-0067 |