Transcriptomic analysis revealed the mechanism of oil dynamic accumulation during developing Siberian apricot (Prunus sibirica L.) seed kernels for the development of woody biodiesel.

Jun Niu,Chengyu Fu,Zhixiang Zhang,Chengliang Fang,Denglong Ha,Haiyan Yu,Haiyan Yu,Xinyi Feng,Lin Qiu,Shanzhi Lin,Sufan Zhou,Xinyu Hou,Jiyong An,Haiyan Zhao,Libing Wang,Libing Wang,Zheng Xiang

doi:10.1186/s13068-015-0213-3

Abstract

BackgroundSiberian 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.ResultsWe 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.ConclusionsThis 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-015-0213-3) contains supplementary material, which is available to authorized users.

Highlights

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
There was a gradual increase in SASK oil content from 10 days after flowering (DAF) (4.00% ± 0.39%) to 60 DAF (50.68% ± 4.18%), followed by approximately 2% decline at 70 DAF, indicating that the optimal harvest time for obtaining the maximum SASK oil content was at 60 DAF
We found that the C18:1 relative proportion gradually increased from 10 DAF (34.37% ± 1.57%) to 70 DAF (67.41% ± 2.35%) with a remarkable elevated degree at 40 to 50 DAF, and the percentage of C18:2 exhibited a peak value (50.07% ± 2.87%) only at 30 DAF, but almost no significant alteration (23.29% to 38.45%) for the other different developing periods

Summary

Introduction

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. With the increasing energy demand and environmental pollution problems caused by the fossil fuels, the renewable and clean of energy sources have become an inevitable choice for sustainable development of society and economy. Woody seed oils with a notable advantage over conventional feedstocks have been used as potential raw materials for biodiesel production [2,3]. It is important to develop woody resources for biodiesel. Siberian apricot has been characterized as a novel potential raw material for biodiesel from the ten candidate oleiferous tree species [3]

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Conclusion