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Background <p>Peanut (<i>Arachis hypogaea</i> L.) is a prominent legume and oilseed crop cultivated globally for its economic significance and nutritional value. With the growing demand for edible oil and protein, peanut cultivation needs to be expanded into salinized land. However, salt stress in such soils severely limits peanut growth and productivity. The Na⁺/H⁺ antiporter (<i>NHX</i>) gene family plays a crucial role in plant salt tolerance by regulating ion homeostasis. Genome-wide identification of peanut <i>NHX</i> genes and systematic profiling of their expression patterns under salt stress are essential for enhancing peanut salt tolerance through molecular breeding.</p> Results <p>In this study, we conducted a genome-wide analysis of the <i>NHX</i> gene family in cultivated peanut and identified 73 <i>AhNHX</i> genes. Based on NHX protein sequences from <i>Arabidopsis thaliana</i>, <i>Glycine max</i>, <i>Medicago sativa</i>, <i>Medicago truncatula</i>, and <i>Phaseolus vulgaris</i>, a phylogenetic tree was constructed, and the 73 <i>AhNHX</i> genes were divided into three clades. Furthermore, analysis of gene structure and conserved motifs revealed that intron size, intron number, and motif number differed significantly among subfamilies. Collinearity analysis indicated that segmental duplication events were the primary driver of <i>AhNHX</i> family expansion. The <i>dN</i>/<i>dS</i> ratio was less than one, implying that the <i>AhNHX</i> gene family experienced strong purifying selection during long‑term evolution. Expression profiling across 22 tissues showed that 27 <i>AhNHX</i> genes exhibited tissue‑specific expression patterns. Under salt stress, transcript levels of multiple <i>AhNHX</i> genes were differentially regulated between the salt‑tolerant variety (HY33) and the salt‑sensitive variety (HY9115). Based on representative features in gene structure, protein sequence, evolutionary lineage, and salt‑induced upregulation, 12 genes (<i>AhNHX11</i>, <i>12</i>, <i>19</i>, <i>23</i>, <i>34</i>, <i>38</i>, <i>43</i>, <i>44</i>, <i>48</i>, <i>54</i>, <i>57</i>, and <i>73</i>) were identified as candidates for further functional characterization.</p> Conclusions <p>This study provides comprehensive insights into the AhNHX gene family and pinpoints candidate genes for improving salt tolerance in peanut via molecular breeding.</p>

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Genome-wide identification and salt stress-induced expression analysis of the NHX gene family in peanut (Arachis hypogaea L.)

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年5月26日

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  • Xuhong Zhao,
  • Dongwei Cui,
  • Na Chen,
  • Xiao Jiang,
  • Lijuan Pan,
  • Jing Xu,
  • Xiangzhen Yin,
  • Junqing Ma,
  • Feifei Wan,
  • Xiaoli Zhang,
  • Xiaoyuan Chi

摘要

Background

Peanut (Arachis hypogaea L.) is a prominent legume and oilseed crop cultivated globally for its economic significance and nutritional value. With the growing demand for edible oil and protein, peanut cultivation needs to be expanded into salinized land. However, salt stress in such soils severely limits peanut growth and productivity. The Na⁺/H⁺ antiporter (NHX) gene family plays a crucial role in plant salt tolerance by regulating ion homeostasis. Genome-wide identification of peanut NHX genes and systematic profiling of their expression patterns under salt stress are essential for enhancing peanut salt tolerance through molecular breeding.

Results

In this study, we conducted a genome-wide analysis of the NHX gene family in cultivated peanut and identified 73 AhNHX genes. Based on NHX protein sequences from Arabidopsis thaliana, Glycine max, Medicago sativa, Medicago truncatula, and Phaseolus vulgaris, a phylogenetic tree was constructed, and the 73 AhNHX genes were divided into three clades. Furthermore, analysis of gene structure and conserved motifs revealed that intron size, intron number, and motif number differed significantly among subfamilies. Collinearity analysis indicated that segmental duplication events were the primary driver of AhNHX family expansion. The dN/dS ratio was less than one, implying that the AhNHX gene family experienced strong purifying selection during long‑term evolution. Expression profiling across 22 tissues showed that 27 AhNHX genes exhibited tissue‑specific expression patterns. Under salt stress, transcript levels of multiple AhNHX genes were differentially regulated between the salt‑tolerant variety (HY33) and the salt‑sensitive variety (HY9115). Based on representative features in gene structure, protein sequence, evolutionary lineage, and salt‑induced upregulation, 12 genes (AhNHX11, 12, 19, 23, 34, 38, 43, 44, 48, 54, 57, and 73) were identified as candidates for further functional characterization.

Conclusions

This study provides comprehensive insights into the AhNHX gene family and pinpoints candidate genes for improving salt tolerance in peanut via molecular breeding.