Oleosin Expression Patterns and Size of Oil Bodies as a Factor in Determining Oil Content in Safflower (Carthamus Tinctorius L.) Genotypes

The climate crisis and the Ukraine war have shown the vulnerability of various crop commodities. One of those badly affected is cooking oil, leading to a shortage in several countries. This coupled with the need for healthier cooking oil, increases proportionally with the world population and has resulted in escalated cooking oil prices. Thus, continued evaluation of alternative oil crops that can do well in marginal lands becomes a vital practice to undertake. Safflower is one of the marginalized oil crops with high-quality oil containing essential fatty acids beneficial to human health. Screening safflower genotypes for oil content is critical for its breeding and adoption in non-native areas. Therefore, this study delineates the relationship between oleosin genes and oil bodies in regulating the oil content of safflower seeds. Oleosin genes and oil bodies from the seeds of five safflower genotypes were isolated and quantified using qPCR and fluorescence microscope respectively, and evaluated against the seed oil content. The results showed an inverse relationship where smaller oil bodies were displayed by genotypes with high oil content. A high relative expression of oleosin genes was observed in genotypes with high oil content (Kenya-9819 and Gila). Of the eight Ctoleosin genes that were studied, it was observed that Ctoleosin genes (1, 4, 6, 7, and 8) were highly reliable in characterizing safflower genotypes based on the oil content. Kenya-9819 and Gila genotypes were found to have high oil potential and this was confirmed by a higher accumulation of the oleosin gene. A high correlation coefficient between oleosin, oil content, and oil body was also observed in this study. The findings suggest that selected oleosin genes and oil bodies are important traits to consider when characterizing oil seed crops for oil content.