Comparative transcriptome analysis reveals the potential molecular mechanism involved in fatty acids biosynthesis of Juglans regia

Juglans regia is high-nutrient deciduous fruit trees rich in fatty acids. Here, comparative transcriptome analysis was performed in the roots, stems, and leaves of J. regia as well as determination of fatty acid. The results of gas chromatography-mass spectrometry analysis showed that the total content of fatty acids were the significantly highest in the stems. A total of 86,033 unigenes from J. regia transcriptome. RNA-seq analysis showed that 55,190, 49,263, 34,279, 42,044, 17,866, and 30,633 differentially expressed genes (DEGs) were annotated using Nr, Nt, Swiss-Prot, GO, COG and KEGG databases, respectively. On this basis, 122 DEGs were identified to be involved in the biosynthetic pathways of fatty acid. Most of the genes were upregulated in the stems than in other organs. Among these genes, the expression level of 16 genes had significant correlation with fatty acid content in different organs of walnut and quantitative real time PCR verified the expression profile of these genes, indicating that these 16 genes were closely related to fatty acid synthesis. This study provided a basis for further studies on fatty acid synthesis at the molecular level and could help for clarifying the function of key genes in the fatty acid metabolic pathway in walnut.