Transcriptomic analysis during fruit development of the oil palm revealed specific isozymes related to starch metabolism that control oil yield

Abstract

The oil palm (Elaeis guineensis Jacq.) produces a large amount of oil from the fruit. A recent study has shown that starch metabolism is essential for oil synthesis in fruit-producing species. Therefore, we detected gene expression changes related to starch metabolism genes throughout the maturity stages of oil palm fruit with different oil yields. Gene expression profiles were examined with three different oil yields (low, medium, and high) at six fruit development phases (4, 8, 12, 16, 20, and 22 weeks after pollination). Using RNA-seq analysis, we successfully identified and analyzed differentially expressed genes in oil palm mesocarps during development. The results showed that the transcriptome profile for each developmental phase was unique. Additionally, we found that starch synthesis and degradation occurred during fruit development and influenced oil production. Sucrose flux to the mesocarp tissue, rapid starch turnover, and high glycolytic activity have been identified as critical factors for oil production in oil palms. For starch metabolism and the glycolytic pathway, we identified specific enzyme isoforms (isozymes) that may control the oil production. This study provides valuable information for creating new high-oil-yielding palm varieties via breeding programs or genome editing approaches.