Feng Jin-Ling, Yang Zhi-Jian, Chen Shi-Pin, El-Kassaby Yousry A, Chen Hui
College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
BMC Genomics. 2017 Jul 20;18(1):546. doi: 10.1186/s12864-017-3923-z.
Camellia species are ancient oilseed plants with a history of cultivation over two thousand years. Prior to oil extraction, natural seed drying is often practiced, a process affecting fatty acid quality and quantity. MicroRNAs (miRNA) of lipid metabolism associated with camellia seed natural drying are unexplored. To obtain insight into the function of miRNAs in lipid metabolism during natural drying, Illumina sequencing of C. oleifera and C. meiocarpa small-RNA was conducted.
A total of 274 candidate miRNAs were identified and 3733 target unigenes were annotated by performing a BLASTX. Through integrated GO and KEGG function annotation, 23 miRNA regulating 131 target genes were identified as lipid metabolism, regulating fatty acid biosynthesis, accumulation and catabolism. We observed one, two, and four miRNAs of lipid metabolism which were specially expressed in C. Meiocarpa, C. oleifera, and the two species collectively, respectively. At 30% moisture contents, C. meiocarpa and C. oleifer produced nine and eight significant differentially expressed miRNAs, respectively, with high fatty acid synthesis and accumulation activities. Across the two species, 12 significant differentially expressed miRNAs were identified at the 50% moisture content.
Sequencing of small-RNA revealed the presence of 23 miRNAs regulating lipid metabolism in camellia seed during natural drying and permitted comparative miRNA profiles between C. Meiocarpa and C. oleifera. Furthermore, this study successfully identified the best drying environment at which the quantity and quality of lipid in camellia seed are at its maximum.
山茶属植物是古老的油料作物，有着两千多年的栽培历史。在榨油之前，通常会进行自然种子干燥，这一过程会影响脂肪酸的质量和含量。与油茶种子自然干燥相关的脂质代谢微小RNA（miRNA）尚未得到研究。为了深入了解miRNA在自然干燥过程中脂质代谢的功能，对油茶树和小果油茶的小RNA进行了Illumina测序。
通过BLASTX共鉴定出274个候选miRNA，并注释了3733个靶标单基因。通过综合GO和KEGG功能注释，鉴定出23个调控131个靶基因的miRNA参与脂质代谢，调控脂肪酸的生物合成、积累和分解代谢。我们分别观察到在小果油茶、油茶树以及这两个物种中共同特异地表达的脂质代谢miRNA各有1个、2个和4个。在含水量为30%时，小果油茶和油茶树分别产生了9个和8个显著差异表达的miRNA，此时具有较高的脂肪酸合成和积累活性。在两个物种中，在含水量为50%时鉴定出12个显著差异表达的miRNA。
小RNA测序揭示了在自然干燥过程中，有23个miRNA调控油茶种子的脂质代谢，并实现了小果油茶和油茶树之间miRNA图谱的比较。此外，本研究成功确定了油茶种子脂质数量和质量达到最大值时的最佳干燥环境。
