Integrative GWAS and transcriptome analysis reveals genetic and molecular determinants of oil content and fatty acid composition in safflower
Safflower (Carthamus tinctorius L.) is a valuable oilseed crop known for its adaptability andrich oil content, especially oleic acid, which is highly valued for its nutritional benefits andstability. This study aimed to uncover the genetic factors that influence oil content, fatty acidcomposition, and seed yield in safflower by combining genome-wide association studies(GWAS) and transcriptome analysis. We evaluated 262 diverse safflower accessions using4,545 SNP markers to identify genetic associations with eight oil-related traits and seed yield.Our GWAS analysis pinpointed 65 significant genetic loci, with chromosome 10 showing ahigh concentration of markers associated with key oil traits. To complement the GWASfindings, we performed RNA sequencing (RNA-Seq) to examine gene expression differencesbetween safflower varieties with high and low oleic content. This transcriptome analysisrevealed 206 important genes involved in lipid metabolism, including those associated withfatty acid synthesis and oil accumulation, including DGAT1, DGAT2, CER, ABHD6, KACS1,KACS2, FAD2, FAD3, GDSL esterases/lipases, FabG, SAD, and EDR1. Additionally, severaltranscription factors were identified, suggesting their potential roles in regulating theseprocesses. To validate these RNA-Seq results, we performed RT-PCR analysis. Theconsistency between RT-PCR and RNA-Seq results confirms the validity of these findings.By integrating the results from GWAS and transcriptome analysis, our study provides newinsights into the genetic and molecular basis of oil production in safflower. These findingscan help guide the breeding of safflower varieties with improved oil quality and yield,benefiting both agriculture and industry.