Extensive Transcriptome Changes Underlying the Flower Color Intensity Variation in Paeonia ostii.
Extensive Transcriptome Changes Underlying the Flower Color Intensity Variation in Paeonia ostii.
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DOI：
10.3389/fpls.2015.01205
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发表时间：
2015
影响因子：
5.6
通讯作者：
Hu Y
中科院分区：
文献类型：
--
作者：
Gao L;Yang H;Liu H;Yang J;Hu Y
牡丹是一组传统的观赏植物，特别是在东亚，其中奥氏牡丹是最重要的祖先物种之一。P. ostii有不同颜色的花，从近白色，浅粉色到深粉色。然而，很少有研究已经完成，以解开植物花色强度变化的分子机制。通过对不同花色强度的口氏牡丹色素组成和转录组的比较分析，发现口氏牡丹花色素苷浓度与花色强度呈显著相关。通过RNA测序的转录组分析揭示了7187个基因在具有不同颜色强度的花之间差异表达。差异表达基因的功能富集分析揭示了多种途径可能负责的颜色强度的变化，在P. ostii，包括黄酮类化合物的生物合成，脂肪酸氧化，碳水化合物代谢，和葡萄糖介导的信号。特别是，虽然花色素苷生物合成基因的表达和花色素苷浓度之间显示出正相关性，但两种转录因子PoMYB 2和PoSPL 1似乎通过影响MYB-bHLH-WDR复合物的活化能力来负调节花色素苷积累，表现出它们的表达和花色素苷积累之间的负相关性。研究结果表明，虽然花色素苷的生物合成直接影响了口氏牡丹花的着色，但其他代谢途径和酶介导的信号通路也对口氏牡丹花颜色强度的变化有贡献，表明转录网络中存在复杂的协调变化。花色素苷抑制子基因的差异表达可能是导致口氏原花青素色素沉着强度变化的主要因素。
Tree peonies are a group of traditional ornamental plants, especially in East Asia, with Paeonia ostii as one of the most important ancestral species. P. ostii has flowers with varying colors, ranging from nearly white, light pink to deep pink. However, few studies have been done to unravel the molecular mechanisms underlying the flower color intensity variation in plants. Based on comparative analyses of the pigment composition and transcriptomes of P. ostii with different flower color intensities, we found that the anthocyanin concentration was significantly correlated with the flower color intensity in P. ostii. Transcriptome analysis by RNA-Sequencing revealed 7187 genes that were differentially expressed between flowers with different color intensities. Functional enrichment analysis of differentially expressed genes revealed multiple pathways possibly responsible for color intensity variation in P. ostii, including flavonoid biosynthesis, fatty acid oxidation, carbohydrate metabolism, and hormone-mediated signaling. Particularly, while anthocyanin biosynthesis genes showing positive correlations between their expression and anthocyanin concentration in flowers, two transcription factors, PoMYB2 and PoSPL1, seem to negatively regulate anthocyanin accumulation by affecting the activation capacity of the MYB-bHLH-WDR complex, exhibiting an inverse relationship between their expression and anthocyanin accumulation. Our results showed that, although anthocyanin biosynthesis had a direct effect on the pigmentation of the P. ostii flower, other metabolic and hormone-mediated signaling pathways were also contributed to the flower color intensity variation in P. ostii, suggesting complex coordinated changes in the transcriptional network. Differential expression of genes encoding anthocyanin repressors seems to be the major factor responsible for the intensity variation in anthocyanin pigmentation in P. ostii.