Metabolomics Analysis of the Development Process of Camellia oleifera Seed Kernel

Purpose To understand the changes of kernel metabolites during the development of Camellia oleifera fruits.

Methods Using different developmental stages of C. oleifera kernels as materials, combined with liquid chromatography mass spectrometry (LC-MS/MS) metabolomics techniques, the metabolic changes of C. oleifera kernels during development were analyzed.

Results A total of 1006 differential metabolites were identified, belonging 15 categories, mainly including lipids and lipid-like molecules, phenylpropane and polyketones, organic acids and their derivatives, benzenoids, organic oxygen compounds, organoheterocyclic compounds, nucleosides, nucleotides and analogs. The annotated main metabolic pathways included metabolic pathways, biosynthesis of secondary metabolites, biosynthesis of plant secondary metabolites, biosynthesis of amino acids, and metabolism of 2-oxalic acid. There were significant differences in metabolites in the kernels of C. oleifera at different developmental stages. F1 and F2 periods had the least metabolites, only including 3-methyl-1-(2,4,6-trihydroxyphenyl)-1-butanone, L-glutathione, and sucrose, indicating slow growth of the kernels in the early stages. In F3 period, there were the largest number of kernel metabolites, especially the relative contents of phenylpropane and polyketones, benzenoids, lipids and lipid molecules, organic acids and their derivatives, and organic heterocyclic compounds changed obviously; the relative contents of melanin, tyrosine, phenylalanine, L-glutathione, 1-methylnenenebc guanine, 3,4-dihydro-2H-1-benzopyran-2-one, (S)-pinocenbrin, and kaempferol-3-O-rutoside were relatively high, indicating that it played an important role in the formation of kernels during the rapid expansion period of fruits. The metabolites in F4 and F5 periods gradually decreased, and the kernel entered the oil accumulation period.

Conclusion This study uses metabolomics methods to understand the changes in kernel metabolites during the development process of C. oleifera fruits, which can provide a theoretical basis for high-quality and high-yield cultivation and timely harvesting of C. oleifera fruits.