Scholarlink

Key message <p><b>Plant-specific HD2s have been characterized; </b><Emphasis Type="BoldItalic">HDT1</Emphasis><b> orthologs were dicot-specific. AtHDT4 interacts with AtILR3 to increase Cd tolerance.</b></p> Abstract <p>The plant-specific histone deacetylase 2 (HD2) family is crucial for growth and stress responses, yet its evolutionary origins and functional diversification remain largely unknown. Here, we systematically elucidated the evolutionary trajectories of <i>HDT</i> homologs. We found the emergence of <i>HDT1</i> orthologs as a dicot-specific innovation, characterized by unique motif acquisition and accompanied by relaxed purifying selection. Synteny analysis indicated that the duplication events establishing the <i>HDT1</i> and <i>HDT3</i> lineages were associated with whole-genome duplications (WGDs) specific to the dicot lineage. In contrast, the expansion of the <i>HDT</i> gene family in monocots appears to rely primarily on local duplication mechanisms, such as tandem duplications. Codon usage analysis revealed distinct species-specific preferences: lycophytes, bryophytes, and algae exhibited higher frequencies of G3s, C3s, GC3, CBI, Nc, and overall GC content, suggesting potential adaptive evolution or optimization for translational efficiency. Functional validation demonstrated that <i>AtHDT4</i> contributes to the plant response to cadmium (Cd) stress. Specifically, <i>AtHDT4</i> expression was significantly upregulated under CdCl₂ treatment. Compared with wild-type (WT) plants, the <i>hdt4</i> mutant exhibited markedly reduced activities of key antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Inductively coupled plasma mass spectrometry (ICP-MS) analyses confirmed that <i>AtHDT4</i> regulates Cd accumulation. Furthermore, <i>AtILR3</i> expression was significantly downregulated in the <i>hdt4</i> mutant, implicating it in the Cd stress response. As anticipated, direct protein–protein interaction between AtHDT4 and AtILR3 was verified. This study not only uncovers the critical role of <i>AtHDT4</i> in mediating plant responses to Cd stress but also provides a broader evolutionary perspective on the functional diversification and specialization of <i>HDT</i> homologs across plant lineages.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Exploring the evolution of the histone deacetylase 2 (HD2) gene family in plants and the role of AtHDT4 in cadmium stress response in Arabidopsis thaliana

  • 期刊论文

  • 发表日期：

    2026年3月19日

查看全文
  • Min Jiang,
  • Peng Li,
  • Zhengqiong Sun

摘要

Key message

Plant-specific HD2s have been characterized; HDT1 orthologs were dicot-specific. AtHDT4 interacts with AtILR3 to increase Cd tolerance.

Abstract

The plant-specific histone deacetylase 2 (HD2) family is crucial for growth and stress responses, yet its evolutionary origins and functional diversification remain largely unknown. Here, we systematically elucidated the evolutionary trajectories of HDT homologs. We found the emergence of HDT1 orthologs as a dicot-specific innovation, characterized by unique motif acquisition and accompanied by relaxed purifying selection. Synteny analysis indicated that the duplication events establishing the HDT1 and HDT3 lineages were associated with whole-genome duplications (WGDs) specific to the dicot lineage. In contrast, the expansion of the HDT gene family in monocots appears to rely primarily on local duplication mechanisms, such as tandem duplications. Codon usage analysis revealed distinct species-specific preferences: lycophytes, bryophytes, and algae exhibited higher frequencies of G3s, C3s, GC3, CBI, Nc, and overall GC content, suggesting potential adaptive evolution or optimization for translational efficiency. Functional validation demonstrated that AtHDT4 contributes to the plant response to cadmium (Cd) stress. Specifically, AtHDT4 expression was significantly upregulated under CdCl₂ treatment. Compared with wild-type (WT) plants, the hdt4 mutant exhibited markedly reduced activities of key antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Inductively coupled plasma mass spectrometry (ICP-MS) analyses confirmed that AtHDT4 regulates Cd accumulation. Furthermore, AtILR3 expression was significantly downregulated in the hdt4 mutant, implicating it in the Cd stress response. As anticipated, direct protein–protein interaction between AtHDT4 and AtILR3 was verified. This study not only uncovers the critical role of AtHDT4 in mediating plant responses to Cd stress but also provides a broader evolutionary perspective on the functional diversification and specialization of HDT homologs across plant lineages.