Scholarlink

<p>Flower color is a crucial ornamental trait in <i>Hydrangea macrophylla</i>. Anthocyanins, a class of flavonoids, are the primary pigments responsible for its coloration, and their synthesis is regulated by a series of structural genes and transcription factors. Among these, the basic helix-loop-helix (bHLH) transcription factors have been identified as one of the key regulators of anthocyanin biosynthesis. However, a systematic investigation of the bHLH transcription factors in relation to flower coloration in <i>H. macrophylla</i> has not been conducted. This study aims to identify bHLH transcription factors and elucidate their molecular mechanisms in regulating anthocyanin synthesis in <i>H. macrophylla</i>. Based on full-length transcriptome data and phylogenetic analysis, three candidate bHLH transcription factors associated with anthocyanin synthesis were identified and designated as <i>HmbHLH1</i>, <i>HmbHLH12</i>, and <i>HmbHLH42</i>. Subcellular localization studies revealed that all three bHLH transcription factors were localized to both the nucleus and cytoplasm. HmbHLH1 and HmbHLH42 exhibited transcriptional activation activity and promoted anthocyanin accumulation, while HmbHLH12 had the opposite effect. <i>HmbHLH42</i> was highly expressed in the sepals, and virus-induced gene silencing of <i>HmbHLH42</i> in sepals resulted in a significant reduction in both anthocyanin content and the expression of structural genes in the anthocyanin biosynthesis pathway. Further analysis showed that <i>HmbHLH42</i> expression was induced by light signals, which in turn promoted anthocyanin accumulation in sepals of <i>H. macrophylla</i>. These results suggest that HmbHLH42 is a key transcription factor regulating the expression of structural genes involved in anthocyanin biosynthesis in the sepals of <i>H. macrophylla</i>. This study establishes a foundation for elucidating the molecular mechanisms governing anthocyanin accumulation in the sepals of <i>H. macrophylla</i>. By revealing how light regulates anthocyanin metabolism in hydrangea petals, our findings provide new insights into the physiological basis of color variation and offer valuable implications for future breeding programs.</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

HmbHLH42, a Light-induced Transcription Factor, Positively Regulates Anthocyanin Biosynthesis in Sepals of Hydrangea Macrophylla

  • 期刊论文

  • 发表日期：

    2025年12月5日

查看全文
  • Xiaoyu Qu,
  • Youwei Fan,
  • Yibing Wan,
  • Chun Liu,
  • Yaxin Wang,
  • Yuzhe Wang,
  • Suxia Yuan

摘要

Flower color is a crucial ornamental trait in Hydrangea macrophylla. Anthocyanins, a class of flavonoids, are the primary pigments responsible for its coloration, and their synthesis is regulated by a series of structural genes and transcription factors. Among these, the basic helix-loop-helix (bHLH) transcription factors have been identified as one of the key regulators of anthocyanin biosynthesis. However, a systematic investigation of the bHLH transcription factors in relation to flower coloration in H. macrophylla has not been conducted. This study aims to identify bHLH transcription factors and elucidate their molecular mechanisms in regulating anthocyanin synthesis in H. macrophylla. Based on full-length transcriptome data and phylogenetic analysis, three candidate bHLH transcription factors associated with anthocyanin synthesis were identified and designated as HmbHLH1, HmbHLH12, and HmbHLH42. Subcellular localization studies revealed that all three bHLH transcription factors were localized to both the nucleus and cytoplasm. HmbHLH1 and HmbHLH42 exhibited transcriptional activation activity and promoted anthocyanin accumulation, while HmbHLH12 had the opposite effect. HmbHLH42 was highly expressed in the sepals, and virus-induced gene silencing of HmbHLH42 in sepals resulted in a significant reduction in both anthocyanin content and the expression of structural genes in the anthocyanin biosynthesis pathway. Further analysis showed that HmbHLH42 expression was induced by light signals, which in turn promoted anthocyanin accumulation in sepals of H. macrophylla. These results suggest that HmbHLH42 is a key transcription factor regulating the expression of structural genes involved in anthocyanin biosynthesis in the sepals of H. macrophylla. This study establishes a foundation for elucidating the molecular mechanisms governing anthocyanin accumulation in the sepals of H. macrophylla. By revealing how light regulates anthocyanin metabolism in hydrangea petals, our findings provide new insights into the physiological basis of color variation and offer valuable implications for future breeding programs.