The GC-TOF/MS-based Metabolomic analysis reveals altered metabolic profiles in nitrogen-deficient leaves and roots of tea plants (Camellia sinensis)

Zheng-He Lin,Qi-Chun Ruan,Xiao-Mei You,Chang-Song Chen,Zhi-Hui Chen,Rui-Yang Shan,Xin-Lei Li,Qiu-Sheng Zhong

doi:10.1186/s12870-021-03285-y

Zheng-He Lin, Qi-Chun Ruan + Show 6 more

Open Access

https://doi.org/10.1186/s12870-021-03285-y

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Abstract

BackgroundNitrogen (N) fertilizer is commonly considered as one of the most important limiting factors in the agricultural production. As a result, a large amount of N fertilizer is used to improve the yield in modern tea production. Unfortunately, the large amount of N fertilizer input has led to increased plant nitrogen-tolerance and decreased amplitude of yield improvement, which results in significant N loss, energy waste and environment pollution. However, the effects of N-deficiency on the metabolic profiles of tea leaves and roots are not well understood.ResultsIn this study, seedlings of Camellia sinensis (L.) O. Kuntze Chunlv 2 were treated with 3 mM NH4NO3 (Control) or without NH4NO3 (N-deficiency) for 4 months by sandy culture. The results suggested that N-deficiency induced tea leaf chlorosis, impaired biomass accumulation, decreased the leaf chlorophyll content and N absorption when they were compared to the Control samples. The untargeted metabolomics based on GC-TOF/MS approach revealed a discrimination of the metabolic profiles between N-deficient tea leaves and roots. The identification and classification of the altered metabolites indicated that N deficiency upregulated the relative abundances of most phenylpropanoids and organic acids, while downregulated the relative abundances of most amino acids in tea leaves. Differentially, N-deficiency induced the accumulation of most carbohydrates, organic acids and amino acids in tea roots. The potential biomarkers screened in N-deficient leaves compared to Control implied that N deficiency might reduce the tea quality. Unlike the N-deficient leaves, the potential biomarkers in N-deficient roots indicated an improved stress response might occur in tea roots.ConclusionsThe results demonstrated N deficiency had different effects on the primary and secondary metabolism in tea leaves and roots. The findings of this study will facilitate a comprehensive understanding of the N-deficient tea plants and provide a valuable reference for the optimized N nutrient management and the sustainable development in the tea plantations.

Highlights

Nitrogen (N) fertilizer is commonly considered as one of the most important limiting factors in the agricultural production
The results suggested that N-deficiency impaired the seedling growth of tea plants, decreased the N absorption and the leaf Chl content significantly, leading to leaf chlorosis
Based on the untargeted metabolomics approach, the study demonstrated that N-deficiency induced metabolic alteration in both leaves and roots of tea plants

Summary

Introduction

Nitrogen (N) fertilizer is commonly considered as one of the most important limiting factors in the agricultural production. A large amount of N fertilizer is used to improve the yield in modern tea produc‐ tion. The large amount of N fertilizer input has led to increased plant nitrogen-tolerance and decreased amplitude of yield improvement, which results in significant N loss, energy waste and environment pollution. Nitrogen (N) nutrient is pivotal for the growth of tea plants (Camellia sinensis L.). Lin et al BMC Plant Biol (2021) 21:506 is indispensable for the biosynthesis of amino acids. The quality of tea leaves, such as mellowness and freshness, are determined by an appropriate level of free amino acids [2]. Apart from the amino acids, the biosynthesis of the quality-related chemical components of tea, such catechin, caffeine and aroma compounds, require a balance of C/N in tea leaves [3]. The nutrient status of N significantly influences the yield and quality of tea leaves [4]

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