Responses of tea plants (Camellia sinensis) with different low‐nitrogen tolerances during recovery from nitrogen deficiency

Abstract

BACKGROUND: Tea plants have high nitrogen (N) consumptions, whereas molecular and physiological responses of tea plants to N recovery are still unclear. RESULTS: By using non-invasive micro-test technology (NMT), 15 N tracer technique, ultra-performance liquid chromatography (UPLC), and transcriptome sequencing technology, we investigated the N recovery-induced changes in N absorptions, N tissue distributions, contents of free amino acids (FAAs), and global transcription of the low-N tolerant and intolerant tea genotypes [i. e. Wuniuzao (W) and Longjing43 (L)]. The results showed that the phenotype of Wuniuzao was better than that of Longjing43 under low-N condition. The N absorption and utilization of Wuniuzao were superior to Longjing43 under N recovery. The γ-aminobutyric acid (GABA) ratio (N recovery/N deficiency) in the root of Wuniuzao was significantly higher than that of Longj-ing43, while the glutamic acid ratio in the root of Wuniuzao was significantly lower than that of Longjing43. This findings suggested that Wuniuzao tended to enhance the GABA synthesis, while Longjing43 tended to inhibit the GABA synthesis under N recovery. The key genes in response to N recovery in Wuniuzao included N transport (AMT and NRT), N transformation (NR, NirA, and GAD), and amino acid transport (GAT) genes. In addition, some ribosome and flavonoid biosynthesis genes might help to maintain proteome homeostasis. CONCLUSION:The N absorption and transport, and the conversion abilities of key amino acids (Glu and GABA) might improve the adaptability of tea plants to N recovery, which provided a basis for the breeding of N efficient tea varieties.

Metabolome and RNA-seq Analysis of Responses to Nitrogen Deprivation and Resupply in Tea Plant (Camellia sinensis) Roots

“…Specifically, N deficiency caused pyruvate metabolism to be reprogrammed in soybean (Fataftah et al, 2018). The timing of N resupply can influence the N response and recovery capability of tea plant, as reported previously, AMTs and NRTs in tea plant played leading roles in restoration from N deficiency at 1 and 24 h post N resupply, respectively (Ruan et al, 2021), and pear root can also recover from nitrate deficiency at 24 h post nitrate resupply (Chen et al, 2018).…”

“…Additionally, the absorption rate of NH 4 + by tea plant was reported to higher than that of NO 3 − in N resupply (Ruan et al, 2021). Gene co-expression analysis also showed that compared with NRT, AMT1;1 was more closely related to TS (Figure 7B).…”

“…N forms (Ruan et al, 2007;Yang et al, 2020) and supply levels (Dong et al, 2019) could produce significant regulatory effects on the growth and metabolism in tea plant. And the responses to N conditions may vary from low-N tolerance or sensitive tea cultivars (Ruan et al, 2021), sampling tissues (Zhang et al, 2021), and sampling time points (Liu et al, 2020). Effective NH 4 + absorption, assimilation, transport, and reutilization enabled tea plant's desire for ammonium (Tang et al, 2020), NH 4 + can be assimilated into glutamate, and then converted into theanine.…”

Genome-Wide Identification and Characterization of GARP Transcription Factor Gene Family Members Reveal Their Diverse Functions in Tea Plant (Camellia sinensis)

“…Interestingly, although NIGT1/HRS1/HHO genes have been characterized as NO 3 – -induced genes ( Sawaki et al, 2013 ; Maeda et al, 2018 ), 6 out of 8 CsNIGT1/HRS1/HHO genes were significantly upregulated in response to NH 4 + treatment, indicating that CsNIGT1s are also involved in the tea plant response to NH 4 + treatment and might play important roles in nitrogen absorption and utilization in tea plant. Recently, numerous differentially expressed genes were identified via transcriptome sequencing in tea plant in response to nitrogen treatment ( Li et al, 2017 ; Ruan et al, 2021 ), and our results could provide valuable candidate genes for further studies on the transcriptional regulatory mechanism of the tea plant response to nutrients. Additionally, in this study, we found that the expression levels of several CsNIGT1/HRS1/HHO and CsPHR1/PHL1 genes were also regulated by stress treatments.…”

Identification, Phylogenetic and Expression Analyses of the AAAP Gene Family in Liriodendron chinense Reveal Their Putative Functions in Response to Organ and Multiple Abiotic Stresses

“…Overexpression of GmProT1 and 2 can affect the synthesis and response of proline and alleviate the damage of salt and drought stress to plants [37]. GsGAT gene expression levels increase the ability of Glu to convert to GABA and transport GABA to maintain high nitrogen availability in Camellia sinensis [38].…”