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Abstract <p><i>Aeonium</i> <i>arboreum</i> Webb &amp; Berthel ‘Blushing Beauty’ exhibits high sensitivity to drought stress. Previous transcriptome analysis revealed that the expression level of <i>AaNAC102</i> was significantly upregulated by short-term drought treatment. To elucidate the molecular mechanisms underlying drought tolerance, we cloned the <i>AaNAC102</i> gene from <i>Aeonium arboreum</i> ‘Blushing Beauty’. Bioinformatic analysis showed that <i>AaNAC102</i> contains an 804 bp open reading frame encoding 267 amino acids and belongs to the ATAF subfamily of NAC transcription factors. The promoter region harbors multiple predicted cis-acting elements associated with drought, light, and hormone responsiveness. Yeast two-hybrid assay confirmed that AaNAC102 exhibits strong transactivation activity. 20% (w/v) PEG 6000 was used to simulate drought stress in ‘Blushing Beauty’, and qRT-PCR analysis showed that the expression level of <i>AaNAC102</i> increased initially, peaked at 12 h of drought stress, and then declined within 0–24 h of stress. To investigate its function, we generated <i>Arabidopsis</i> <i>thaliana</i> lines overexpressing <i>AaNAC102</i> (OE) by the floral dip method. Physiological measurements indicated that, even under normal conditions, <i>Arabidopsis thaliana</i> lines overexpressing <i>AaNAC102</i> (OE) exhibited enhanced basal tolerance, characterized by significantly higher proline levels and elevated activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) compared with wild-type (WT) plants. After 12 h of drought stress, OE lines showed a significantly smaller increase in malondialdehyde (MDA) accumulation while maintaining higher proline content and antioxidant enzyme activities. By 24 h of stress, OE lines continued to exhibit lower MDA content and higher POD and CAT activities; however, their proline levels declined significantly compared to those of WT. Expression analysis of drought-responsive genes revealed that overexpression of <i>AaNAC102</i> significantly upregulated <i>AtP5CS</i>, <i>AtRD22</i>, and <i>AtRD29A</i> during the first 12 h of drought stress. 12–24 h, this upregulation diminished. By 24&#xa0;h, the expression levels of some genes, including <i>AtERD15</i>, <i>AtP5CS</i>, and <i>AtRD29A</i>, returned to WT levels, while those of others, such as <i>AtERD1</i>, <i>AtRD22</i>, and <i>AtDREB1A</i>, were significantly lower than those in WT. Together, these results demonstrate that AaNAC102 is a drought-responsive transcription factor that enhances short-term (0–12 h) adaptation to water deficit in transgenic <i>Arabidopsis</i> by transiently boosting the antioxidant system and activating downstream drought-responsive gene networks. This study provides novel insights into the molecular mechanisms of drought tolerance in succulent plants.</p>

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Cloning and Functional Characterization of the AaNAC102 Transcription Factor from Aeonium arboreum ‘Blushing Beauty’ in Response to Drought Stress

  • 期刊论文

  • 发表日期：

    2026年6月29日

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  • S. H. Li,
  • R. Zhao,
  • H. Z. Han,
  • L. H. Zhang,
  • N. Zhang,
  • F. Wang,
  • S. Y. Wei,
  • T. T. Lu

摘要

Abstract

Aeonium arboreum Webb & Berthel ‘Blushing Beauty’ exhibits high sensitivity to drought stress. Previous transcriptome analysis revealed that the expression level of AaNAC102 was significantly upregulated by short-term drought treatment. To elucidate the molecular mechanisms underlying drought tolerance, we cloned the AaNAC102 gene from Aeonium arboreum ‘Blushing Beauty’. Bioinformatic analysis showed that AaNAC102 contains an 804 bp open reading frame encoding 267 amino acids and belongs to the ATAF subfamily of NAC transcription factors. The promoter region harbors multiple predicted cis-acting elements associated with drought, light, and hormone responsiveness. Yeast two-hybrid assay confirmed that AaNAC102 exhibits strong transactivation activity. 20% (w/v) PEG 6000 was used to simulate drought stress in ‘Blushing Beauty’, and qRT-PCR analysis showed that the expression level of AaNAC102 increased initially, peaked at 12 h of drought stress, and then declined within 0–24 h of stress. To investigate its function, we generated Arabidopsis thaliana lines overexpressing AaNAC102 (OE) by the floral dip method. Physiological measurements indicated that, even under normal conditions, Arabidopsis thaliana lines overexpressing AaNAC102 (OE) exhibited enhanced basal tolerance, characterized by significantly higher proline levels and elevated activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) compared with wild-type (WT) plants. After 12 h of drought stress, OE lines showed a significantly smaller increase in malondialdehyde (MDA) accumulation while maintaining higher proline content and antioxidant enzyme activities. By 24 h of stress, OE lines continued to exhibit lower MDA content and higher POD and CAT activities; however, their proline levels declined significantly compared to those of WT. Expression analysis of drought-responsive genes revealed that overexpression of AaNAC102 significantly upregulated AtP5CS, AtRD22, and AtRD29A during the first 12 h of drought stress. 12–24 h, this upregulation diminished. By 24 h, the expression levels of some genes, including AtERD15, AtP5CS, and AtRD29A, returned to WT levels, while those of others, such as AtERD1, AtRD22, and AtDREB1A, were significantly lower than those in WT. Together, these results demonstrate that AaNAC102 is a drought-responsive transcription factor that enhances short-term (0–12 h) adaptation to water deficit in transgenic Arabidopsis by transiently boosting the antioxidant system and activating downstream drought-responsive gene networks. This study provides novel insights into the molecular mechanisms of drought tolerance in succulent plants.