Study On The Metabolome And Molecular Mechanism Of Fasciated Plants Of Atractylodes Lancea

The rhizomes of Atractylodes lancea(Thunb.)DC.are commonly used traditional Chinese medicine.The stem-fasciated plants of A.lancea were detected in the process of germplasm investigation in the field of Yinshan,Hubei Province.Other symptoms included floral virescence,inflorescence abnormality were also observed.Nonetheless,the content of essential oil and main terpene component was significantly improved in stem-fasciated plants compared to normal ones.The reason resulting in the fasciation was then confirmed to be phytoplasma infection(Candidatus Phytoplasma asteris),which is belonged to 16SrI-B.The mechanism were investigated by transcriptome approach and showed that the gene expressions were varied.This study was designed to investigate the metabolic variation in fasciated plants of A.lancea by metabolome approach,clarify the key gene involving in MEP pathway of terpenoid biosynthesis,and identify the terpene synthase in A.lancea.The results will characterize the mechanisms of interaction between phytoplasma and the host plant and provide a scientific basis for the elucidating of effective component biosynthesis and quality enhancement of the cultivated medicinal materials.The main contents are as follows.1.The metabolome study of fasciated plants of A.lancea.The non-targeted metabolomics based on GC-MS was used to study the metabolic profile in the leaf and rhizome of fasciated and normal plants of A.lancea.The components were identified by virtue of mass library(NIST).The PCA and OPLS-DA were used to construct the discrimination model of samples.The chemical markers,including β-Sitosterol,2-aMannobiose,Maltose,Galactinol,Mthyl galactoside,Ribonic acid,D—galactose,D-(-)-tagatose,etc.,were successfully selected to be the potential biomarkers of fasciated plants of A.lancea.This results will provide a scientific basis for illuminating the metabolic variation and identification of fasciated plants of A.lancea.2.Cloning and analysis of the key gene involving in MEP pathway of terpenoids biosynthesis.The AlMCT,AlCMK,AlMDS,and AlHDS were cloned and the bioinformatics analysis were carried out.The results of tissue specific expression of those genes showed that AlMCT,AlMDS,and AlHDR were mainly expressed in leaves,and the other two genes were mainly expressed in rhizomes.3.Cloning,analysis,functional identification of AlTPS gene.The full length of AlTPS1 gene was cloned and the bioinformatics analysis were then carried out.The results suggested that the ORF of AlTPS1 gene was 1644 bp coding 547 amino acids.A phylogenetic tree was constructed and showed that AlTPS1 clustered in TPS-a subfamily with other angiosperm TPS gene.Heterologous expression in E.coli confirmed that the isolated AlTPS1 protein could catalyse FPP or GPP to form Zingiberene or linalool,geraniol,α-phellandrene,α-pinene,estragole.In conclusion,the metabolic profile and the potential biomarkers of fasciated plants of A.lancea were illuminated,then the key gene involving in MEP pathway of terpenoids biosynthesis and the terpene synthase AlTPS1 were characterized.This results will provide a scientific basis for the elucidating of effective component biosynthesis and regulation.Furthermore,this results will facilitate the utilization of fasciated plants of A.lancea to improve the quality of Atractylodis Rhizoma.