Yellow horn (Xanthoceras sorbifolium Bunge) is an endemic oil-rich shrub that has been widely cultivated in northern China for bioactive oil production. However, little is known regarding the molecular mechanisms that contribute to oil content in yellow horn. In a recent study, researchers measured the oil contents of high- and low-oil yellow horn embryo tissues at four developmental stages and investigated the global gene expression profiles through RNA-seq.

The results found that at 40, 54, 68, and 81 days after anthesis, a total of 762, 664, 599, and 124 genes, respectively, were significantly differentially expressed between the high- and low-oil lines. Gene ontology (GO) enrichment analysis revealed some critical GO terms related to oil accumulation, including acyl-[acyl-carrier-protein] desaturase activity, pyruvate kinase activity, acetyl-CoA carboxylase activity, and seed oil body biogenesis. The identified differentially expressed genes also included several transcription factors, such as, AP2-EREBP family members, B3 domain proteins and C2C2-Dof proteins. Several genes involved in fatty acid (FA) biosynthesis, glycolysis/gluconeogenesis, and pyruvate metabolism were also up-regulated in the high-oil line at different developmental stages.

These findings indicate that the higher oil accumulation in high-oil yellow horn could be mostly driven by increased FA biosynthesis and carbon supply, i.e. a source effect.

 

 

Summary of the DEGs in pathways that are involved directly or indirectly in oil biosynthesis in high-oil yellow horn. Green represents up-regulated genes, red represents down-regulated genes, orange represents both up-regulated and down-regulated genes and blue represents non-differentially expressed genes. Dashed lines indicate multistep pathways.

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Reference
L Wang, C Ruan, L Liu, W Du, A Bao et al. (2018) Comparative RNA-Seq Analysis of High-and Low-Oil Yellow Horn During Embryonic Development Int. J. of Mol. Sci. doi: 10.3390/ijms19103071 [article]

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