Transcriptome analysis of tea () leaves in response to ammonium starvation and recovery.

The tea plant is a kind of ammonium-preferring crop, but the mechanism whereby ammonium (NH ) regulate its growth is not well understood. The current study focused on the effects of NH on tea plants. Transcriptomic analysis was performed to investigate the early- and late-stage NH deprivation and resupply in tea plants shoots. Through short- and long-term NH deficiency, the dynamic response to NH stress was investigated. The most significant effects of NH deficiency were found to be on photosynthesis and gene ontology (GO) enrichment varied with the length of NH deprivation. Enriched KEGG pathways were also different when NH was resupplied at different concentrations which may indicate reasons for tolerance of high NH concentration. Using weighted gene co-expression network analysis (WGCNA), modules related to significant tea components, tea polyphenols and free amino acids, were identified. Hence, NH could be regarded as a signaling molecule with the response of catechins shown to be higher than that of amino acids. The current work represents a comprehensive transcriptomic analysis of plant responses to NH and reveals many potential genes regulated by NH in tea plants. Such findings may lead to improvements in nitrogen efficiency of tea plants.