Abstract
Abstract Glutamine synthetase type I (GSI)-like proteins are proposed to mediate nitrogen signaling and developmental fate by synthesizing yet unidentified metabolites. Theanine, the most abundant non-proteinogenic amino acid in tea plants, is the first identified metabolite synthesized by a GSI-like protein (CsTSI) in a living system. However, the roles of theanine in nitrogen signaling and development are little understood. In this study we found that nitrogen deficiency significantly reduced theanine accumulation and increased lateral root development in tea plant seedlings. Exogenous theanine feeding significantly repressed lateral root development of seedlings of tea plants and the model plant Arabidopsis. The transcriptomic analysis revealed that the differentially expressed genes in the roots under theanine feeding were enriched in the apoplastic pathway and H2O2 metabolism. Consistently, theanine feeding reduced H2O2 levels in the roots. Importantly, when co-treated with H2O2, theanine abolished the promoting effect of H2O2 on lateral root development in both tea plant and Arabidopsis seedlings. The results of histochemical assays confirmed that theanine inhibited reactive oxygen species accumulation in the roots. Further transcriptomic analyses suggested the expression of genes encoding enzymes involved in H2O2 generation and scavenging was down- and upregulated by theanine, respectively. Moreover, the expression of genes involved in auxin metabolism and signaling, cell division, and cell expansion was also regulated by theanine. Collectively, these results suggested that CsTSI-synthesized theanine is likely involved in the regulation of lateral root development, via modulating H2O2 accumulation, in response to nitrogen levels in tea plants. This study also implied that the module consisting of GSI-like protein and theanine-like metabolite is probably conserved in regulating development in response to nitrogen status in plant species.
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Claims 13
Claim · model-written summary
Nitrogen deficiency reduced theanine accumulation in tea seedlings.
Not reportedComparator
Verbatim
e0“nitrogen deficiency significantly reduced theanine accumulation and increased lateral root development in tea plant seedlings”
Claim · model-written summary
Nitrogen deficiency increased lateral root development in tea seedlings.
Not reportedComparator
Verbatim
e0“nitrogen deficiency significantly reduced theanine accumulation and increased lateral root development in tea plant seedlings”
Claim · model-written summary
Theanine feeding repressed lateral root development in tea seedlings.
- Taxon
- tea plantse0
- Treatment
- Exogenous theanine feedinge0
- Outcome
- lateral root developmente0
- Direction
- repressede0
Not reportedComparator
Verbatim
e0“Exogenous theanine feeding significantly repressed lateral root development of seedlings of tea plants and the model plant Arabidopsis”
Claim · model-written summary
Theanine feeding repressed lateral root development in Arabidopsis seedlings.
- Taxon
- Arabidopsis
Arabidopsise0 - Treatment
- Exogenous theanine feedinge0
- Outcome
- lateral root developmente0
- Direction
- repressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous theanine feeding significantly repressed lateral root development of seedlings of tea plants and the model plant Arabidopsis”
Claim · model-written summary
Root differentially expressed genes under theanine feeding were enriched in apoplastic and H2O2 metabolism pathways.
Verbatim
e0“differentially expressed genes in the roots under theanine feeding were enriched in the apoplastic pathway and H2O2 metabolism”
e1“seedlings of tea plants”
Claim · model-written summary
Theanine feeding reduced root H2O2 levels.
Not reportedComparator
Verbatim
e0“theanine feeding reduced H2O2 levels in the roots”
e1“seedlings of tea plants”
Claim · model-written summary
With H2O2 co-treatment, theanine abolished the promotion of lateral roots by H2O2 in tea.
Verbatim
e0“when co-treated with H2O2, theanine abolished the promoting effect of H2O2 on lateral root development in both tea plant and Arabidopsis seedlings”
Claim · model-written summary
With H2O2 co-treatment, theanine abolished the promotion of lateral roots by H2O2 in Arabidopsis.
- Taxon
- ArabidopsisArabidopsise0
- Treatment
- theaninee0
- Outcome
- lateral root developmente0
- Direction
- abolishede0
- Comparator
- H2O2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when co-treated with H2O2, theanine abolished the promoting effect of H2O2 on lateral root development in both tea plant and Arabidopsis seedlings”
Claim · model-written summary
Theanine inhibited root reactive oxygen species accumulation.
- Taxon
- tea plantse1
- Treatment
- theaninee0
- Outcome
- reactive oxygen species accumulatione0
- Direction
- inhibitede0
Not reportedComparator
Verbatim
e0“theanine inhibited reactive oxygen species accumulation in the roots”
e1“seedlings of tea plants”
Claim · model-written summary
Theanine downregulated genes encoding H2O2 generating enzymes.
- Taxon
- tea plantse1
- Treatment
- theaninee0
- Outcome
- expression of genes encoding enzymes involved in H2O2 generatione0
- Direction
- down-e0
Not reportedComparator
Verbatim
e0“expression of genes encoding enzymes involved in H2O2 generation and scavenging was down- and upregulated by theanine, respectively”
e1“seedlings of tea plants”
Claim · model-written summary
Theanine upregulated genes encoding H2O2 scavenging enzymes.
Not reportedComparator
Verbatim
e0“expression of genes encoding enzymes involved in H2O2 generation and scavenging was down- and upregulated by theanine, respectively”
e1“seedlings of tea plants”
Claim · model-written summary
Theanine regulated expression of genes involved in auxin metabolism and signaling, cell division and expansion.
- Taxon
- tea plantse1
- Treatment
- theaninee0
- Outcome
- expression of genes involved in auxin metabolism and signaling, cell division, and cell expansione0
Not reportedComparatorDirection
Verbatim
e0“expression of genes involved in auxin metabolism and signaling, cell division, and cell expansion was also regulated by theanine”
e1“seedlings of tea plants”
Claim · model-written summary
The authors propose that CsTSI-synthesized theanine regulates tea lateral roots via H2O2 in response to nitrogen.
Verbatim
e0“CsTSI-synthesized theanine is likely involved in the regulation of lateral root development, via modulating H2O2 accumulation, in response to nitrogen levels in tea plants”
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