Promotes Triacylglycerol Biosynthesis in Oil Tea () Seeds through Transcriptional Activation by WRINKLED1.

oil, a nutritionally rich edible oil derived from seeds, is predominantly stored as triacylglycerol (TAG) during fruit maturation. However, a limited understanding of the genetic and regulatory mechanisms governing oil accumulation has hindered efforts to optimize its yield. In this study, three diacylglycerol acyltransferase () genes were identified and characterized, wherein emerged as the primary contributor to seed TAG biosynthesis, functioning within the endoplasmic reticulum and increasing seed oil content by 64.4% in transgenic plant. Through weighted gene coexpression network analysis, we identified WRINKLED1 (CoWRI1) as a candidate transcriptional regulator of . Both genes exhibited significant upregulation during seed maturation. Mechanistically, CoWRI1 activated by directly binding to AW-box motifs in its promoter, thereby promoting TAG accumulation. Additionally, expression was suppressed by salicylic acid, methyl jasmonate, and darkness, suggesting that phytohormones and environmental signals modulate TAG accumulation through the WRI1- pathway. These findings provide an important basis for improving oil production through biotechnological manipulation of and genes.