Study On The Mechanism Of Foeniculum VuLgare Mill Essential Oil Promoting The Growth Of Arabidopsis Thaliana

BackgroundTraditional Chinese medicine is widely used,and the demand is soaring.Illegal merchants use chemical pesticides excessively to increase the output of traditional Chinese medicine to obtain higher benefits.Excessive use of chemical pesticides poses a serious threat to the environment,soil and human health.Therefore,in order to solve the overuse of chemical pesticides,it is urgent to find green and pollution-free plant growth regulators.As the vegetative organ of plants,the root affects the growth and development of plants by absorbing water and nutrients.At the same time,the root is also the medicinal part of most rhizome medicinal materials.A good root configuration can promote the absorption of soil nutrients and water by plants and the exertion of plant ecological functions.The change of root structure is very important to the yield,economic value and stress response of traditional Chinese medicine.Therefore,by regulating the root configuration,affecting the root development and further affecting the plant growth,to achieve the purpose of increasing production and reducing the use of chemical pesticides.The regulation of plant secondary metabolites on root development is of great significance for improving crop yield and stress resistance.The study of its regulation mechanism provides another possible way for the development of plant-derived growth regulators.Volatile organic compounds（VOC_S）,as secondary metabolites of plants,can easily penetrate the plant cell wall and combine with carriers on the cell membrane.As internal signals of plants,VOC_Sis perceived by plants to transmit and communicate among various tissues and organs of plants and regulate plant development.Among them,epigenetic regulation plays an important role in the process of plant growth and development.H3K9ac（Histone lysine acetylation at the 9th position）is the most studied in plants.It can make the chromatin structure more open and promote gene expression,and participate in the formation of meristematic tissue,embryo and embryo development,flower development and other processes during plant growth and development.Therefore,explore the mechanism of VOC_Spromoting plant growth based on multi-omics,and provide new insights for improving the development and utilization of plant secondary metabolism.ObjectBy exploring the effects of different concentrations of fennel volatile oil on the growth of Arabidopsis thaliana（above-ground leaves and underground roots）,and through the joint analysis of multi-omics（transcriptomics and epigenetics）,this paper attempts to clarify the molecular mechanism of plant growth and development mediated by volatile oil,and analyze the apparent regulatory mechanism behind its biological phenomenon and the potential regulatory relationship with the expression of related genes,It lays a theoretical foundation for the development of new green plant growth regulators.Method1.The volatile oil of fennel was extracted by steam distillation,and the minimum inhibitory concentration of the volatile oil of fennel was obtained in the previous experiment;2.GC-MS analysis of the chemical composition and content of the volatile oil of Fennel;3.Determine the effect of volatile oil of fennel with different concentrations on the aboveground and underground parts of Arabidopsis thaliana;4.Through RNA-seq analysis,information about the expression of related genes was obtained;5.Western blot was used to determine the modification level of H3K9ac after the treatment of Arabidopsis thaliana with different concentrations of fennel volatile oil;6.The key regulatory pathway of volatile oil from fennel to promote the growth of Arabidopsis thaliana was analyzed by the combination of RNA-seq and Ch IP-seq;7.Explore the effect of the monomer compound of the volatile oil of fennel on the growth of Arabidopsis thaliana,and further reveal the main components of the volatile oil that play a role in promoting growth.Results1.According to the GC-MS test results of the volatile oil of fennel,the volatile oil of fennel contains 18 chemical components,including anisole,4-Allylanisole,d-limonene,fenvalenoneγ-Terpinene;2.When Arabidopsis thaliana is treated with different concentrations of volatile oil,it can promote the growth and development of its underground roots.When the concentration is1.09 mg m L^-1,the promotion effect is most significant;3.Western blot showed that the acetylation level of Arabidopsis thaliana increased after the treatment of volatile oil;4.In the analysis of ChIP-seq data,the genes up-regulated by H3K9ac were mainly concentrated in the promoter region and the transcription starting site of the gene,and the H3K9ac modification level increased after the treatment of Arabidopsis thaliana with volatile oil;5.After the Arabidopsis thaliana was treated with the volatile oil monomer of fennel,d-limonene and 4-Allylanisole showed a strong growth promotion effect.ConclusionThe volatile oil of fennel can promote the growth and development of Arabidopsis thaliana,especially the underground root,which can significantly promote the development of taproot and lateral root.Volatile oil can be used as a signal molecule to influence the acetylation process of histone H3,and further regulate growth and development by regulating plant signal and hormone transduction pathways and affecting the production of other metabolites.As a mixture,the chemical components of the volatile oil are mainly aromatic compounds and terpenes,among which the monomers of the volatile oil d-limonene and 4-Allyl anisole play an important role in promoting the growth and development of Arabidopsis thaliana.