Tung tree (Vernicia fordii),a member of the family Euphorbiaceae,is one of the important industrial oilseed plants in the world.The oil extracted from tung seeds is now widely used in production of paints,plasticizers,high-quality printing,resins,medicine,chemical regents and biodiesel.Tung oil is accumulated in tung seeds mainly in the form of triacylglycerol (TAG).In the progress of TAG synthesis,Diacylglycerol acyltransferases (DGAT) catalyzes the last and most committed step of TAG biosynthesis.It has been noted that DGAT2 is a potential contributor to the desired fatty acids accumulation in the TAG.For instance,RcDGAT2 isolated from castor bean (Ricinus communis) has been reported that could increase hydeoxy fatty acid from 17% to nearly 30% in transgenic Arabidopsis.Therefore,investigating the genes involved in triacylglycerol (TAG) biosynthesis provides us a better understanding of mechanisms regarding lipid biosyntheses.Further,it may lay the foundation for achieving improved varieties with high-value oil by genetic engineering in the future.In this study,we characterized the expression profiles of VfDGAT2 in different tung tissues/organs and seeds from different development stages.The oil content and α-eleostearic acid production during seed development were also examined.Expressional studies showed that VfDGAT2 was expressed in all tested tissues,including leaves,petioles,stems,petals,pistils,fruitlets and developing seeds,while highly expressed in developing seeds about 19-fold more than in leaves.VfDGAT2 showed temporal specific expression during seed development and maturation.Notably,we discovered that the expression of VfDGAT2 in developing seeds is consistent with oil accumulation and α-eleostearic acid production.The expression levels of VfDGAT2 was lower in the early stage of oil accumulation and α-eleostearic acid biosynthesis,and rapidly increased during the peak periods of fatty acid synthesis,then decreased during accumulation completion period at the end of September.Finally,the expression vector of pBI121-VfDGAT2 was constructed and transferred into yeast,the expression level of VfDGAT2 in yeast transformants was examined and the content of fatty acids was tested.The results showed that total fatty acids content of VfDGAT2 transformants was 7.8-fold more than that of the control,indicating that VfDGAT2 contributed to fatty acids accumulation.All these data suggested that VfDGAT2 plays a significant role in TAG synthesis and may be a key target for tung genetic engineering programmes in the future.