Comprehensive mining of storage oil related genes in developing seed of Abelmoschus esculentus

Abstract Okra (Abelmoschus esculentus), famous for its desired nutritional and medicinal values, could accumulate approximately 20% (w/w) seed oil dominated with unsaturated fatty acids (UFAs). However, the mechanism of oil biosynthesis and metabolic regulation in its seeds remains poorly understood. Here, storage oil profiles and transcriptome of okra seeds at different developmental stages were analyzed. Seed oil accumulated at a high rate during 21 to 28 days after flowering (DAF). Total of 136.6 million clean reads were obtained and 109,171 unigenes were assembled from the seed transcriptome. Differentially expressed genes among three developing stages of seeds were functionally annotated into the storage lipid metabolism pathway. Comparative analysis was performed for structural genes and transcription factor genes that participate in fatty acid biosynthesis, triacylglycerol assembly, oil body formation, and triacylglycerol degradation. A complex regulating network was built accordingly. Additionally, expressions of 12 key functional genes responsible for okra oil accumulation were examined by quantitative real-time PCR (qRT-PCR), demonstrating that RNA-sequencing data were reliable. This study will facilitate further investigation of molecular mechanism responsible for unsaturated fatty acid biosynthesis and oil accumulation in plant seed, providing valued reference for creating new okra varieties with better lipid composition and high oil yield.