Identification of Fatty Acid Components and Key Genes for Synthesis during the Development of Pecan Fruit

Abstract

Carya illinoinensis (Wangenh.) K. Koch, a species native to North America, is one of the most famous fruit oil trees worldwide. Fatty acids are essential energy storage substances in the human body. Transcriptome sequencing of pecan kernels was used to screen the key genes of fatty acid synthesis in pecan fruit development. The dynamic changes in the fatty acid fractions of the pecan kernels in different periods were analyzed using GC-MS. This study shows that oil accumulation in seeds follows an ‘M’-shaped bimodal curve, according to the proportion of fatty acid components, from big to small, for oleic acid, linoleic acid, palmitic acid, stearic acid, and linolenic acid. A total of 83.82 Gb of clean data was annotated using the RNA-seq of pecan fruits at distinct stages after flowering, 5376 new genes were discovered, and 2761 new genes were annotated in at least one database. SAD and FAD2 were significantly upregulated at 80–95 and 95–110 days, and downregulated at 110–130 days after flowering. These differently expressed genes (DEGs) were enriched in fatty acid biosynthesis, elongation, and concentration. This study aims to reveal the pecan high-oil synthesis mechanism of unsaturated fatty acids for the genetic improvement of pecan in potential genetic resources in order to promote the work of breeding pecan.