Visualization of metabolite distribution based on matrix-assisted laser desorption/ionization-mass spectrometry imaging of tea seedlings (Camellia sinensis)

Abstract

Tea seedlings (Camellia sinensis) have a well-developed root system with a strong taproot and lateral roots. Compared with ordinary cuttings, tea has stronger vitality and environmental adaptability, thus facilitating the promotion of good varieties. However, there is less of detailed research on the rooting and germination process of tea seeds. In this study, matrix-assisted laser desorption ionization time-of-flight-mass spectrometry was used to conduct non-targeted spatial mass spectrometry imaging of the main organs during growth of tea seedlings. A total of 1234 compounds were identified, which could be divided into 24 classes. Among them, theanine, as the most prominent nitrogen compound, was synthesized rapidly at the early stage of embryo germination, accounting for > 90% of the total free amino acids in the radicle, and it was then transferred to each meristem region through the mesocolumnar sheath, indicating that theanine-based nitrogen flow plays a decisive role in organ formation during the development of tea seedlings. Nutrients stored in the cotyledon were rapidly hydrolyzed to dextrin and 3-phosphoglyceraldehyde at the early stages of germination, and subsequently converted to other forms that provided carbon and energy for development, such as raffinose and d-galactose (glucose), which were mainly distributed in the growing zones of the root apex and the apical meristems of the stem. This study provides a new perspective on the synthesis and metabolism of substances during the development of tea seedlings and contributes to a better understanding of the biological characteristics of tea varieties.

Acknowledgements

The authors are grateful for financial support from the National Key Research and Development Program of China (2022YFF1003103) and the Scientific Research Projects of University in Anhui Province (2023AH051044).

Author contributions

Q.C. and X.W. participated in the research design and reviewed the manuscript. M.F. conducted the experiments, analyzed the data, and drafted the manuscript. L.T., D.Z., Y.G., and C.S. processed part of the experimental data. S.Z. and Z.Z. revised the manuscript. All authors have read and approved the final manuscript.

Data availability statement

All relevant data are available within the article and its supplementary data.

Conflict of interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Supplementary data

Supplementary data are available at Horticulture Research online.

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