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冬性植物红菜薹在不同温度处理下花青素积累的分子机制

Molecular Characterization of Anthocyanin Accumulation under Different Temperatures in Winter Plant Hongcaitai (Brassica rapa L.)

  • 摘要: 芸薹属植物红菜薹(Brassica rapa)是一种常见的蔬菜,它的花茎和叶柄表皮中均积累有花青素。为了解红菜薹中花青素合成的分子机制,进行了花青素含量的测定和花青素合成相关基因的表达分析。研究结果表明,叶柄表皮中的花青素含量显著高于叶片(去主脉)的花青素含量。同时,叶柄表皮花青素合成相关基因的表达水平高于叶柄(去表皮)和叶片(去主脉)的表达水平,这表明红菜薹中花青素的合成调控发生在转录水平。BrMYBA1仅在叶柄表皮中表达,但BrbHLH1BrWD40在叶片和叶柄表皮中均能检测到表达。因此,BrMYBA1的转录激活可能与红菜薹的花青素合成相关。连续低温处理时,红菜薹叶柄表皮中的花青素含量逐渐增加,而该组织中花青素合成的结构基因表达水平逐渐降低。

     

    Abstract: Hongcaitai (Brassica rapa) is a vegetable that accumulates anthocyanins in both floral stems and leaf petioles. To understand the mechanism underlying the regulation of anthocyanin biosynthesis in B. rapa, anthocyanin accumulation and expression patterns of anthocyanin biosynthesis genes in seedlings of Hongcaitai were investigated. Anthocyanin content in epidermal tissues of petioles were significantly higher than those in leaves with excised mid-veins. Expression levels of all anthocyanin biosynthesis pathway genes were significantly higher in epidermal tissues of petioles than those detected in either endodermal tissues of petioles or in leaves, suggesting that anthocyanin biosynthesis was regulated at the transcriptional level. Transcripts of BrMYBA1 were exclusively expressed in the petiole epidermis; whereas, transcripts of BrbHLH1 and BrWD40 were detected in both leaves and petiole epidermal tissues. This suggests that activation of BrMYBA1 was likely responsible for anthocyanin pigmentation in Hongcaitai. Following cold treatment, seedlings demonstrated increased accumulation of anthocyanins in petiole epidermal tissues, while the transcription of anthocyanin pathway genes was reduced in petiole epidermal tissues.

     

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