Metabolomic Analyses Provide New Insights into Signaling Mechanisms for Nutrient Uptake by Lateral Roots of Pruned Tea Plant (Camellia sinensis)

Pruning is an important plant management practice in tea cultivation. However, the mechanism underlying the dynamics of nutrient uptake by roots of pruned tea is unknown. This study investigated the metabolic alterations in lateral roots of pruned tea to unveil the mechanism of nutrient uptake. Elemental analysis revealed that pruning significantly increases the uptake of nutrients by lateral roots. Metabolic profiling showed significant metabolic variations in lateral roots of pruned tea. Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis revealed that flavonoid biosynthesis, phenylpropanoid biosynthesis, and amino acid metabolism were differentially regulated in lateral roots. Caffeine metabolism was significantly hindered, while ethylene signaling was significantly induced in lateral roots of pruned plants. In addition, intermediates in the tricarboxylic acid (TCA) cycle were upregulated, indicating high rates of the TCA cycle. Therefore, pathways related to phenylpropanoid biosynthesis, TCA cycle, ethylene biosynthesis, and metabolism of amino acids contribute to higher nutrient uptake by lateral roots of the tea plant.