Functional Analysis Of EgMYB108 Transcription Factor In The Metabolism Of Very-Long Chain Fatty Acids (VLCFAs) In Oil Palm (Elaeis Guineensis Jacq.) Mesocarp

Oil palm(Elaeis guineensis Jacq.)is an important tropical woody oil crop.Its pulp and kernel are rich in oil,and it is known as "the king of oil in the world".MYB is a super transcription factor family commonly found in animals,plants,fungi and protozoa.It has many members and complex functions.In this study,bioinformatics was used to comprehensively analyze the physicochemical properties,structure and other aspects of EgMYB108 transcription factor,and it was determined that EgMYB108 was the most common R2R3-MYB transcription factor in the MYB family of plants,and phyletic analysis showed that EgMYB108 had a very close relationship with Phoenix dactylifera Pd MYB108.The subcellular localization of EgMYB108 was detected by transient tobacco,and the localization and function of EgMYB108 were confirmed in the nucleus.The potential target genes of EgMYB108 were identified by comparing the fatty acid differences between EgMYB108 overexpressed oil palm transgenic embryoid and wild-type embryoid.The identified downstream target genes were related to the biosynthesis of very long chain fatty acids(VLCFA).The presumed target genes were further quantitatively analyzed by qRT-PCR to confirm their expression patterns in the transgenic lines.In the EgMYB108 transient oil palm protoplasm experiment,the expression levels of target genes EgKCS5 and EgLACS4 increased significantly with the overexpression of EgMYB108.In dual luciferase assays and yeast one-hybrid assay,EgMYB108 can directly activate the promoter of target genes and regulate related expression.In addition,the interaction between EgMYB108 and downstream target genes was determined by EMSA.At the same time,the expression levels of EgMYB108 and target genes EgKCS5 and EgLACS4 were increased during the mature stage of oil palm fruit,which was consistent with the accumulation of lipid.These experimental results demonstrate that EgKCS5 and EgLACS4,regulated by EgMYB108,promote the synthesis of ultra-long chain fatty acids and affect the anabolism of oils.Studying the function of EgMYB108 plays an important role in revealing the regulatory pathway of lipid metabolism,which provides an important research basis for future studies on lipid anabolism.