Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, National Engineering Research Center of Sugarcane, College of Agriculture, Fujian Agriculture and Forestry University, 350002, Fuzhou, Fuzhou, Fujian Province, P. R. China.
Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, 100193, Beijing, P. R. China.
BMC Plant Biol. 2021 May 12;21(1):214. doi: 10.1186/s12870-021-02986-8.
Sugarcane (Saccharum officinarum) is one of the most valuable feedstocks for sugar production. In addition to the production of industrial raw materials such as alcohol, papermaking, the fiber of livestock feed, respectively, sugarcane can produce bioactive compounds such as anthocyanins. Elucidation of the anthocyanin biosynthesis pathway is critical for the molecular breeding of sugarcane varieties with favorable traits. We aimed to identify candidate genes involved in anthocyanin biosynthesis by transcriptomic and metabolomic analyses.
Three varieties of sugarcane displaying different colors were used in this study: FN15 (greed rind), ROC22 (red rind), and Badila (purple rind). Sample materials were subjected to metabolomic analysis using UPLC-Q-TOF/MS and RNA-seq analysis. The metabolomic profiling results showed Cyanidin, Cyanidin (6'-malonylglucoside), Cyanidin O-glucoside, and Peonidin O-glucoside were the main components responsible for the rind color. Then, through RNA-seq analysis, we identified a total of 3137, 3302, 3014 differentially expressed genes (DEGs) between the rind and pith tissues for the corresponding varieties Badila rind, ROC22, and FN15. We then compared the expression levels of genes among the rind tissues from the three varieties. We identified 2901, 2821, and 3071 DEGs between Badila rind vs. ROC22 rind, Badila rind vs. FN15 rind, ROC22 rind vs. FN15 rind, respectively. We identified two enriched pathways, including phenylpropanoid biosynthesis and flavonoid biosynthesis. Sequencing similarity search identified a total of 50 unigenes belonging to 15 enzyme families as putative genes involved in anthocyanin biosynthesis in sugarcane rind. Seven of them were identified as candidate genes related to anthocyanin biosynthesis in the rind of sugarcane through co-localization analysis with the anthocyanin content in sugarcane. In total, 25 unigenes were selected and subjected to RT-qPCR analysis, and qRT-PCR results were consistent with those obtained with the RNA-Seq experiments.
We proposed a pathway for anthocyanin biosynthesis in sugarcane rind. This is the first report on the biosynthesis of anthocyanin in sugarcane using the combined transcriptomic and metabolomic methods. The results obtained from this study will lay the foundation for breeding purple pith sugarcane varieties with high anthocyanin contents.
甘蔗（Saccharum officinarum）是生产糖的最有价值的原料之一。除了生产工业原料如酒精、造纸、牲畜饲料纤维外，甘蔗还可以产生花色苷等生物活性化合物。阐明花色苷生物合成途径对于具有优良性状的甘蔗品种的分子育种至关重要。我们旨在通过转录组和代谢组分析鉴定花色苷生物合成相关的候选基因。
本研究使用三种颜色不同的甘蔗品种：FN15（绿色皮）、ROC22（红色皮）和 Badila（紫色皮）。使用 UPLC-Q-TOF/MS 和 RNA-seq 分析对样品材料进行代谢组分析。代谢组学分析结果表明，矢车菊素、矢车菊素（6'-丙二酰葡萄糖苷）、矢车菊素 O-葡萄糖苷和芍药素 O-葡萄糖苷是导致皮色的主要成分。然后，通过 RNA-seq 分析，我们在相应品种 Badila 皮、ROC22 和 FN15 的皮与髓组织之间总共鉴定出 3137、3302 和 3014 个差异表达基因（DEGs）。然后，我们比较了三个品种的皮组织之间的基因表达水平。我们在 Badila 皮与 ROC22 皮、Badila 皮与 FN15 皮、ROC22 皮与 FN15 皮之间分别鉴定出 2901、2821 和 3071 个 DEGs。我们鉴定出两个富集途径，包括苯丙素生物合成和黄酮类生物合成。测序相似性搜索共鉴定出 50 个属于 15 种酶家族的 unigenes，它们可能是甘蔗皮花色苷生物合成相关的基因。其中 7 个通过与甘蔗皮花色苷含量的共定位分析被鉴定为与甘蔗皮花色苷生物合成相关的候选基因。总共选择了 25 个 unigenes进行 RT-qPCR 分析，qRT-PCR 结果与 RNA-Seq 实验一致。
我们提出了一个甘蔗皮花色苷生物合成途径。这是首次使用转录组和代谢组联合方法研究甘蔗花色苷的生物合成。本研究的结果将为培育高花色苷含量的紫色髓甘蔗品种奠定基础。
