The WRKY6 transcription factor affects seed oil accumulation and alters fatty acid compositions inArabidopsis thaliana

In rapeseed, the oil content of the seed not only supplies energy for seed germination and seedling development but also provides essential dietary nutrients for humans and livestock. Recent studies have revealed that many transcription factors (TFs) regulate the accumulation of fatty acids (FAs) during seed development.WRKY6, a WRKY6 family TF, was reported to serve a function in the plant senescence processes, pathogen defense mechanisms and abiotic stress responses. However, the precise role ofWRKY6in influencing FA accumulation in seeds is still unknown. In this study, we demonstrate thatWRKY6has a high expression level in developing seeds and plays an essential role in regulating the accumulation of FAs in developing seeds ofArabidopsis. Mutation ofWRKY6resulted in significant increase in seed size, accompanied by an increase in FA content and changes in FA composition. Ultrastructure analyses showed that the absence ofWRKY6resulted in more and higher percentage of oil body in the cell of mature seeds. Quantitative real-time PCR analysis revealed changes in the expression of several genes related to photosynthesis and FA biosynthesis inwrky6mutants at 10 or 16 days after pollination. These results reveal a novel function ofWRKY6influencing seed oil content and FAs compositions. This gene could be used as a promising gene resource to improve FA accumulation and seed yield inBrassica napusthrough genetic manipulation.