College of Biological Sciences and Biotechnology, College of Nature Conservation, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing, 10083 China.
Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 10091 China.
Biotechnol Biofuels. 2015 Feb 22;8:29. doi: 10.1186/s13068-015-0213-3. eCollection 2015.
Siberian apricot (Prunus sibirica L.) has emerged as a novel potential source of biodiesel in China, but the molecular regulatory mechanism of oil accumulation in Siberian apricot seed kernels (SASK) is still unknown at present. To better develop SASK oil as woody biodiesel, it is essential to profile transcriptome and to identify the full repertoire of potential unigenes involved in the formation and accumulation of oil SASK during the different developing stages.
We firstly detected the temporal patterns for oil content and fatty acid (FA) compositions of SASK in 7 different developing stages. The best time for obtaining the high quality and quantity of SASK oil was characterized at 60 days after flowering (DAF), and the representative periods (10, 30, 50, 60, and 70 DAF) were selected for transcriptomic analysis. By Illumina/Solexa sequencings, approximately 65 million short reads (average length = 96 bp) were obtained, and then assembled into 124,070 unigenes by Trinity strategy (mean size = 829.62 bp). A total of 3,000, 2,781, 2,620, and 2,675 differentially expressed unigenes were identified at 30, 50, 60, and 70 DAF (10 DAF as the control) by DESeq method, respectively. The relationship between the unigene transcriptional profiles and the oil dynamic patterns in developing SASK was comparatively analyzed, and the specific unigenes encoding some known enzymes and transcription factors involved in acetyl-coenzyme A (acetyl-CoA) formation and oil accumulation were determined. Additionally, 5 key metabolic genes implicated in SASK oil accumulation were experimentally validated by quantitative real-time PCR (qRT-PCR). Our findings could help to construction of oil accumulated pathway and to elucidate the molecular regulatory mechanism of increased oil production in developing SASK.
This is the first study of oil temporal patterns, transcriptome sequencings, and differential profiles in developing SASK. All our results will serve as the important foundation to further deeply explore the regulatory mechanism of SASK high-quality oil accumulation, and may also provide some reference for researching the woody biodiesel plants.
西伯利亚杏（Prunus sibirica L.）已成为中国生物柴油的一种新型潜在来源，但目前尚不清楚西伯利亚杏种仁（SASK）中油脂积累的分子调控机制。为了更好地开发 SASK 油作为木质生物柴油，有必要对其进行转录组分析，并鉴定参与不同发育阶段 SASK 油形成和积累的全部潜在基因。
我们首先检测了 7 个不同发育阶段 SASK 中油含量和脂肪酸（FA）组成的时间模式。开花后 60 天（DAF）是获得高质量和高数量 SASK 油的最佳时间，选择代表性时期（10、30、50、60 和 70 DAF）进行转录组分析。通过 Illumina/Solexa 测序，共获得约 6500 万个短读段（平均长度=96bp），然后通过 Trinity 策略组装成 124070 个 unigenes（平均大小=829.62bp）。通过 DESeq 方法，在 30、50、60 和 70 DAF（以 10 DAF 为对照）分别鉴定到 3000、2781、2620 和 2675 个差异表达基因。比较分析了发育中 SASK 中 unigene 转录谱与油动态模式的关系，确定了编码一些已知酶和参与乙酰辅酶 A（acetyl-CoA）形成和油积累的转录因子的特定基因。此外，通过定量实时 PCR（qRT-PCR）实验验证了与 SASK 油积累相关的 5 个关键代谢基因。我们的研究结果有助于构建油脂积累途径，阐明发育中 SASK 油脂产量增加的分子调控机制。
这是首次对 SASK 中油的时间模式、转录组测序和差异谱进行研究。我们的所有结果将为进一步深入研究 SASK 高油积累的调控机制提供重要基础，也可为木质生物柴油植物的研究提供一些参考。
