Correlation between squalene synthase promoter and WRKY transcription factor in Camellia oleifera

Tea oil obtained fromCamellia oleifera is a high-quality vegetable oil rich in squalene, a triterpenoid bioactive substance with several demonstrated health benefits. WRKY transcription factors in C. oleifera play essential roles in a wide range of physiological processes. To further develop C. oleifera as a functional material with genetic improvement, we constructed a tea oil seed transcriptome database and screened out the C.oleifera WRKY genes (CoWRKY) to determine their relation with squalene anabolism. Forty-one CoWRKY transcription factors were obtained, including five showing a potential association with squalene metabolism and regulating the expression of the squalene synthase gene (CoSQS). Through bioinformatics analysis of the CoSQS promoter, it was predicted that W-box components that may bind to CoWRKY were present at the – 293 bp position. Real-time polymerase chain reaction showed a significant positive correlation between the expression levels of the CoWRKY1 and CoSQS genes, further indicating their interaction, which was confirmed via a yeast one-hybrid assay. Overall, these results suggest that the CoWRKY1 transcription factor may bind to the W-box cis-acting element of the CoSQS promoter to positively regulate the synthesis of squalene in C. oleifera, offering new strategies for engineering strains with production of oil highly enriched in squalene.