Comparison between Metabolomics and Transcriptomics for Revealing the Composition and Formation Pathway of Aroma Compounds in "19 Xiang" Rice.

Using gas chromatography-mass spectrometry (GC-MS), a metabolomic analysis of volatile metabolites of "19 Xiang" milk-ripe stage endosperm grains grown in Longchuan City and Lianshan City, Guangdong Province was conducted. The effect of origin on the formation of aroma compounds in aromatic rice was also explored by identifying the genes related to the formation of aroma compounds using transcriptome technology. Multivariate statistical analysis was performed on the original data using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The results showed that the content of volatile substances in "19 Xiang" varied among grains planted in different places, exhibiting significant differences in the relative contents of 14 aroma substances. KEGG enrichment analysis revealed that the biosynthetic pathways of secondary metabolites significantly affected on the content of aroma substances. At the transcriptional level, taking the Lianshan group as the control, the samples of the Longchuan group had 56 significantly upregulated genes and 89 downregulated genes, which were mainly associated with biological processes such as catabolism of organic matter and polysaccharide metabolism. In conclusion, different planting environments greatly influence the content of aroma substances in aromatic rice, and carbohydrate metabolism activities and stress response-related mechanisms at the milking stage may be crucial factors regulating the content of aroma substances in the planting environment. [ABSTRACT FROM AUTHOR]