#PlantTOR
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Great work by Busche et al. (2026) on how #PlantTOR can reduce #plasmodesmata (PD) transport in plants by promoting the expression of PD-localized callose binding proteins (PDCBs), which drive #callose deposition at PD through the PP2A-ABI5-PDCB1/2 signaling axis 🌱.
🔗 www.science.org/doi/10.1126/...
Fig. 4. Glucose-TOR signaling drives callose deposition at PD through the PP2A-ABI5- PDCB signaling axis. (A and B) TOR and PP2A antagonistically regulate callose deposition at PD in leaves. Callose deposits in cell walls were stained with aniline blue and visualized using confocal fluorescence microscopy. Inhibiting TOR with Torin2 (T2) significantly decreased PD callose (n ≥ 27, P < 10−2), whereas inhibiting PP2A with either CAN or OA significantly increased PD callose (n ≥ 27, P < 10−7). Representative images shown in (B). (C and D) Overexpressing the transcription factor ABI5 is sufficient to significantly increase callose deposition at PD compared to mock controls (35SPRO:GFP) (n ≥ 27, P < 10−7). (E and F) Silencing ABI5 is sufficient to reduce callose deposition at PD compared to mock controls (n ≥ 16, P < 10−1). Oppositely, silencing DSE1 increases PD callose, as expected (n ≥ 27, P < 10−7). (G) Glucose-TOR-ABI5 signaling induces PDCB1 and PDCB2 expression. Wild-type (WS) and abi5-1 mutant seedlings were grown to quiescence and then supplied with glucose or glucose and Torin2. mRNA levels of ABI5, PDCB1, and PDCB2 were then quantified using RT-dPCR. (H) Model summarizing how TOR can reduce PD transport by driving callose deposition at PD through a PP2A-ABI5- PDCB1/2 signaling axis. a.u., arbitrary units.
September 7, 2026 at 3:33 PM
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Great work by Tian et al. (2026) on how #PlantTOR regulates the protein abundance of EBS, a bivalent #histone reader, by phosphorylating it at Ser195/Ser196 to modulate the floral transition of #Arabidopsis in response to nitrogen availability 🌱💮.
🔗 www.pnas.org/doi/10.1073/...
Fig 6E. A working model of nitrogen–TOR mediated EBS phosphorylation and degradation in regulating floral transition. Under normal conditions, Target of Rapamycin (TOR) is stimulated and phosphorylates EARLY BOLTING IN SHORT DAYS (EBS), thereby stabilizing EBS and its chromatin association leading to the repression of FLOWERING LOCUS T (FT) transcription and floral inhibition. Nitrogen starvation inhibits TOR activity, resulting in reduced EBS phosphorylation and subsequent degradation likely via autophagy activation, which in turn reactivate FT and trigger floral transition
July 8, 2026 at 3:34 PM
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Great work by Wang et al. (2026) on how exogenous sucrose alleviates shade-induced inhibition of leaf development in #Arabidopsis by activating #PlantTOR and stabilizing phytochrome A (PHYA), thereby regulating #cytokinin and leaf development-related genes 🌱.
🔗 www.nature.com/articles/s41...
Fig. 6d | Proposed model illustrating how exogenous sucrose regulates true leaf development under canopy shade through the TOR and phyA signaling networks. Under shade, TOR activity is reduced, and phyA accumulates in the nucleus, where it is targeted for degradation by COP1/SPA. Exogenous sucrose activates TOR, which interacts with phyA, disrupting its interaction with COP1/SPA and enhancing phyA stability. Accumulated phyA regulates the transcription of downstream genes, including cytokinin biosynthesis and metabolism genes, thereby increasing active cytokinin levels, enhancing cytokinin signaling, and ultimately promoting true leaf development. Modified Fig. 1 | TOR and phyA are involved in sucrose-rescued leaf development under canopy shade. a The first true leaf area of Col-0 under simulated white light (WL) and shade (SH) treatment (scale bar, 2 mm). b The leaf primordium area and GUS staining intensity of pCYCB1;1::GUS seedlings under WL and SH (scale bar, 0.1 mm). In a–g, data are presented as mean values +/- SD. Numbers above the bars indicate n, the number of independent seedlings analyzed. The letters above the scatter indicate significant differences (P < 0.05) determined by two-way ANOVA, followed by Tukey’s multiple comparison test. Sor: sorbitol (30 mM; black dots); Suc: sucrose (30 mM; red dots); Suc + Torin 2: sucrose (30 mM) plus Torin 2 (5 μM; blue dots). For exact P values, see Source Data. Modified Fig. 3 | Sucrose–TOR signaling increases the protein level of PHYA under shade. a, b The protein levels of PHYA in Col-0 (a) or 35S::PHYA-YFP/phyA-211 (b) with sorbitol, sucrose or sucrose plus Torin 2 treatment under white light (WL) and shade (SH). c The protein levels of PHYA in Col-0, tor-es, raptor1-2, and lst8-1 with sorbitol or sucrose treatment under SH. In a–c and f–g, western blot band intensities were quantified using ImageJ and normalized to β-tubulin protein levels. Data are presented as mean values +/- SD (n = 3 independent biological replicates). The letters above the scatter indicate significant differences (P < 0.05) determined by one-way ANOVA (a, b) or two-way ANOVA (c, f, g), followed by Tukey’s multiple comparison test. For exact P values, see Source Data.
April 21, 2026 at 7:11 PM
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Summary of the special issue on #PlantTOR, #SnRK1 and #T6P that was edited by Wahl, Hanson and Menand (2026). 🌱⚡
"The plant energy management machinery: an essential hub for stress resilience and developmental dynamics with great potential for crop improvement"
🔗 academic.oup.com/jxb/article/...
Fig. 1. The core energy management machinery, comprising SnRKs, TORC, and the T6P pathway, and its interactions with multiple signals through complex feedback regulation to regulate growth and resilience trade-offs. The cover depicts a whiteboard illustration of the original concept behind the workshop ‘Plant Energy Management: Molecular Mechanisms and Signalling,’ held at UPSC, Sweden, in August 2024. The aim was to expand upon the original TOR meeting by focusing on the inputs and outputs of the core energy management machinery in a species-agnostic manner. (Credit: Benoît Menand, Johannes Hanson, and Vanessa Wahl.) Link: https://academic.oup.com/jxb/issue/77/5
March 2, 2026 at 7:11 PM
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Great preprint by Liu, Blanford et al. (2025) on how trehalose 6-phosphate #T6P stimulates plant cell growth via #PlantTOR and is required for sucrose-induced TOR activation in #Arabidopsis by suppressing #SnRK1 in a dose-dependent manner, thereby mediating the antagonistic TOR–SnRK1 relationship.
Fig. 3. Trehalose 6-phosphate (T6P) is required for sucrose-mediated TOR activation. a) Exogenous T6P induces stronger TOR activation than sucrose during resupply of starved suspension cells. Starved suspension cells derived from an Arabidopsis S6K1-HA OX seedlings were resupplied with 0.5% of basal sucrose plus 100 μM sucrose or 100 μM T6P (0–2 h). Representative immunoblots show S6K1-HA, phosphorylated S6K1-HA (pS6K1-HA), phosphorylated RPS6 (pRPS6), and RPS6 at the indicated time points. Phos-tag gels separate phospho-S6K1-HA. Ponceau S serves as loading control. Band intensities were quantified using GelAnalyzer 23.1.1 and normalized to total protein. pRPS6/RPS6 ratios (n=3) were quantified for TOR activity (Šídák's Multiple Comparisons Test: *, P < 0.05; **, P < 0.01; ***, P < 0.001). b) Endogenous T6P is essential for TOR activation. In WT seedlings, sucrose resupply robustly activates TOR, whereas tps1 mutants show only weak activation. 3-d-old seedlings germinated on ½ MS (1% sucrose) (long-day conditions) were transferred to ½ MS liquid medium and starved for 4 d in dark. Seedlings were then resupplied with 1% sucrose ± 1 μM Torin2. Samples at 0.5–4 h. Representative immunoblots and quantified TOR activity (described as in a) are shown. c) Modulating T6P alters sucrose-mediated TOR activation. Arabidopsis lines overexpressing otsA (encoding E. coli T6P synthase) accelerates and otsB (encoding T6P phosphatase) delays TOR activation relative to WT. 3-d-old WT, otsA and otsB seedlings germinated on ½ MS (1% sucrose) (long-day conditions) were transferred to ½ MS liquid medium and starved for 4 d in dark. Seedlings were then resupplied with 1% sucrose . Samples at 0.5–4 h. Representative immunoblots and quantified TOR activity (described as in a) are shown. Fig. 4f. Trehalose 6-phosphate (T6P) activates Target of Rapamycin (TOR) by suppressing Sucrose non-fermenting-1-related protein kinase 1 (SnRK1). Purified SnRK1α1 suppresses TOR activity, and T6P reverses this inhibition in a dose-dependent manner. IP-TOR incubated with SnRK1α1 alone or with GRIK1 and EIF4EBP1 substrate ± T6P (0.1–1 mM). TOR activities were quantified at right. Similar results were shown with S6K1 (Supplementary Fig. 8).
December 16, 2025 at 4:06 PM
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Great work by O’Leary et al. (2025) on how Gln-driven #PlantTOR signaling occurs during the early development of pea embryos (i.e. cell division phase), but is unexpectedly inactive during #legume seed storage protein biosynthesis. #Pisum #glutamine

🔗 nph.onlinelibrary.wiley.com/doi/10.1111/...
Fig. 8 Hypothetical model showing the reciprocal regulation of target of rapamycin (TOR) and abscisic acid (ABA) signaling during the transition from the cell division to the cell expansion phase of legume seed development. The activators of TOR observed in this paper are shown, but further molecular and hormonal influences on the developmental transition are omitted for simplicity. The bottom panel extends a basic model by Weber et al. (2005) to show the approximate timing of relative changes in three established signaling metabolites: Glc, glucose; Suc, sucrose; and Gln, glutamine. Sucrose levels are known to be correlated with the signaling metabolite T6P. Fig. 5. Glutamine (Gln) activates target of rapamycin (TOR) in developing pea cotyledons. (a) The in vivo RPS6-Ser240 phosphorylation status in pea embryos throughout development. Replicate immunoblots are shown in Supporting Information Fig. S5. (b) The relative RPS6-Ser240 phosphorylation signal is plotted, and the fresh weight of the embryos is plotted against days after pollination (DAP). Error bars represent the standard error of the mean. (c–e) RPS6-Ser240 phosphorylation was assessed in 90–130 mg pea embryos incubated for 2 or 4 h with or without Gln (62.5 mM) and sucrose (142 mM) (c), Gln (62.5 mM) and glucose (100 mM) (d) or individual amino acids (62.5 mM) and NH4NO3 (20 mM) (e). Two biological replicates are shown. Replicate immunoblots are shown in Fig. S6.
October 16, 2025 at 9:24 PM
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Great preprint by Upadhyaya et al. (2025) on using a #multiomics approach to study #PlantTOR signaling in the unicellular green alga #Chromochloris zofingiensis, particularly showing the upregulation of #AminoAcid biosynthesis pathways during TOR inhibition with AZD8055.
#Algae #Phosphoproteomics 🔗⬇️
Fig. 8. Summary of the mechanism of TOR inhibition-dependent accumulation of amino acids in Chromochloris zofingiensis. TOR inhibition by AZD8055 induces the expression of transcription factors G2- like, HSF, and bHLH, which bind to amino acid biosynthesis and nitrogen metabolism genes to potentially regulate their transcription. This process, which is independent of glucose-TOR signaling, leads to an accumulation of amino acids during TOR inhibition. Glucose addition via hexokinase1 (HXK1) also upregulates amino acid biosynthesis. Fig. 1. TOR inhibition prevents glucose-driven growth and suppresses photosynthesis in the green alga Chromochloris zofingiensis. (A) Representative C. zofingiensis (WT) cultures over the 96 h experiment with the following treatments: control, TOR inhibition by 1 µM AZD8055, 100 mM glucose addition, and 100mM glucose + 1 µM AZD treatment. (B) Cell density and (C) maximum PSII photosynthetic efficiency (Fv/Fm). For (B) and (C), datapoints represent biological replicates with lines representing means (n = 3). (D) PCA of WT 1 h and 24 h transcriptome, proteome, and metabolome with treatments: control, 1 µM AZD, 15 mM glucose, 15 mM glucose + 1 µM AZD, and 15 mM sorbitol as an osmotic control. For the transcriptome, normalized log2-transformed counts of 500 genes with highest variance were considered. For the proteome and the metabolome, the raw intensity values were log2-transformed, and proteins or metabolites with highest variance were used to calculate and plot the PCA. Modified Fig. 2. Phosphoproteomics of TOR-inhibited Chromochloris zofingiensis identifies novel TOR players. (B) The log2 fold changes of TOR-dependent phosphosites between TOR inhibition by 1 µM AZD, 15 mM glucose addition, 15 mM glucose + 1 µM AZD, and 15 mM sorbitol-treated C. zofingiensis (WT) cultures at 1 h and 24 h from cluster 4 were labelled according to their protein symbols and phosphorylated Ser/Thr residue on the left and by their ortholog name identified on the right. The phosphopeptides were labelled if they are known conserved TOR targets as “known targets” and if they are unknown as “novel targets”. RbcL, MAPK, PP2C, PP2C, and SnRK2 were identified as putative novel conserved TOR targets. White boxes in the heatmap indicate that the phosphopeptides were not detected. Data represent means of fold changes log2 intensities of phosphopeptides (n = 3-4 biological replicates).
October 2, 2025 at 4:27 PM
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Great work by Wang et al. (2025) on how #PlantTOR dynamically regulates the translation of a chromatin-associated complex for growth (CACG) in #Arabidopsis, which represses the expression of stress-responsive genes to coordinate plant growth and stress tolerance 🌱⚖️🏜️.
🔗 www.nature.com/articles/s41...
Fig. 6 | Working model for the role of the nutrient–TOR–CACG axis in balancing plant growth and stress tolerance. In the presence of adequate nutrients, TOR is active and promotes the translation of CACG mRNAs. The pyrimidine-rich motifs present in the 5′ UTRs of CACG mRNAs facilitate target selection by TOR. The CACG complex directly binds to numerous stress-responsive genes marked by histone acetylation, thereby repressing their transcription, which contributes to plant growth and development. Conversely, under nutrient-deficient conditions, TOR becomes inactive, leading to decreased translation of CACG mRNAs. This results in the alleviation of the repression of stress-response genes, causing reduced growth but increased stress tolerance. The nutrient–TOR–CACG axis is crucial for balancing plant growth with stress tolerance, promoting survival and reproductive success in variable environmental conditions. conditions. Image partially created in BioRender. He, X. Fig. 1 | Identification of a multi-subunit protein complex involved in nutrient-responsive growth. a) Protein–protein interaction networks were generated from mass spectrometry data using Cytoscape. The edges show the interactions identified by AP–MS. CACG subunits are shown in pink, while COMPASS subunits and the INO80 complex (INO80-C) are shown in blue. b) Interactions among CACG subunits as determined by Y2H and pull-down assays. Interactions revealed by Y2H assays are shown in yellow, those shown by pull-down assays in red and those confirmed by both methods in orange. Protein names in bold denote those analysed through pull-down assays. c) Detection of a high-molecular-weight complex by gel filtration. Proteins extracted from Flag-tagged GTE1, DP1, EMB1967 and CP2 transgenic plants were separated in a Superose 6 column (10/300 GL; GE Healthcare Life Sciences) and were detected by immunoblotting. d) Immunoblot analysis of protein levels in the indicated Flag-tagged transgenic plants under different nutrient conditions. Twelve-day-old plants grown in solid MS medium were transferred to liquid MS, H2O or reduced concentrations of MS for 4 days. The actin protein level is shown as a loading control. e) Fresh weight of wild-type plants irrigated with water or liquid MS medium (n = 24). The values are means ± s.d. f) Immunoblot analysis of protein levels in the indicated Flag-tagged transgenic plants irrigated with water or liquid MS medium. The actin protein level is shown as a loading control. g) Morphological phenotypes of 20-day-old wild-type and mutant plants (top) and 12-day-old wild-type and mutant plants (bottom). Scale bars, 1 cm. The experiments in c, d and f were repeated independently twice and showed similar results. Modified Fig. 4 | The CACG complex suppresses the expression of stress-responsive genes to coordinate plant growth and stress tolerance. g) Morphological phenotypes of wild-type plants and CACG mutants under control, drought stress and rehydration conditions. Twelve-day-old plants grown in solid MS medium were transferred to soil and subsequently subjected to drought treatment until the Col-0 plants began to show mortality. The phenotypes are shown before and three days after rehydration with MS. Plants watered with MS serve as the control. h) The survival rate of wild-type plants and CACG mutants under drought stress conditions (n = 24). Each bar shows the mean ± s.d. from three independent biological replicates. P values were determined using two-tailed Student’s t-tests. i) Immunoblot analysis of the protein levels of CACG components under the indicated conditions. TOR activity was monitored by the phosphorylation state of S6K. The actin protein level is shown as a loading control. The experiments were independently repeated twice and showed similar results. j) Statistical analysis of pS6K protein levels. Actin was used as a loading control. Each black dot represents an independent biological replicate.
September 26, 2025 at 8:26 PM
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Great work by Li et al. (2025) on identifying the regulatory loop between #PlantTOR complex (TORC) via its RAPTOR1B subunit (Ser897) and the CBL4/CBL10–CIPK24 module in #Arabidopsis, which regulates the balance between plant growth and #SaltStress response ⚖️.
#PlantScience

🔗 doi.org/10.1093/plce...
Figure 1. Target of rapamycin complex (TORC) activity is rapidly repressed by salt stress. A) Dose dependance of salt-mediated TOR repression. 35S:S6K1-HA seedlings were treated with different NaCl concentrations for 4 h. Band intensity in the immunoblots indicates the level of total protein (anti-HA in lower panel) or T449-phosphorylated form of S6K1 (anti-p-T449 in upper panel). B) Quantification of relative p-T449 intensity in A). The data represent the ratio of intensity of p-T449 over S6K1-HA, and the value for the sample “0 mM NaCl” was set as 1. C) Time course of salt-mediated TOR repression. 35S:S6K1-HA seedlings were treated with 200 mM NaCl for indicated times. D) Quantification of relative p-T449 intensity in C). The value at 0 min was set as 1. E) TORC activity was restored following salt recovery treatment. 35S:S6K1-HA seedlings were treated with 200 mM NaCl for 15 min, and then transferred to the recovery medium for indicated times. Rec, recovery. F) Quantification of relative p-T449 intensity in E). In B), D), and F), the data represent the ratio of intensity of p-T449 over S6K1-HA, data are means±SEM, n=3 (biologically independent experiments). Different letters in B) and D) represent significant difference between samples by one-way ANOVA (P<0.05, Supplementary Data Set 1). In F), *P<0.05 (one-way ANOVA, Supplementary Data Set 1) Figure 6.The salt-tolerant phenotype shown in raptor1b mutant is abolished in the absence of SOS2/Calcineurin B-Like (CBL)-Interacting Protein Kinase 24 (CIPK24). A) Representative images of Col-0, cipk24, raptor1-2, and raptor1-2cipk24 mutant under normal or salt conditions in post-germination assays. Scale bar: 1 cm. B) Chlorophyll content per 4 seedlings measured at the end of the assay shown in A). Quantitative data are mean±SD of three biological repeats. Statistical analyses were performed by one-way ANOVA. (***P<0.001, ****P<0.0001, n.s., not significant). C) Working model for target of rapamycin complex (TORC), abscisic acid (ABA), and CBL–CIPK signaling pathways to orchestrate growth and salt stress response under changing salinity status. In response to salt stress, ABA pathway and CBL–CIPK pathway dominate, suppressing TORC by phosphorylating RAPTOR1B and slowing down the growth to facilitate stress adaptation. Upon the removal of salt stress, TORC rapidly activates to suppress the ABA- and CBL–CIPK-mediated salt stress response network and promotes plant growth.
July 2, 2025 at 4:15 PM
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Great #preprint by Chen et al. (2025) on revealing the role of #SalicylicAcid (SA) in controlling central metabolic regulators #SnRK1 and #PlantTOR to coordinate plant immunity and growth by differential phosphorylation of #Arabidopsis NPR1, a key SA receptor (Ser-557 and Ser-55/59, respectively)🤯.
Figure 7H. Proposed model in which central metabolic regulators SNF1-RELATED KINASE 1 (SnRK1) and TARGET OF RAPAMYCIN (TOR) govern plant immunity through differential phosphorylation of NONEXPRESSER OF PR GENES 1 (NPR1), the central plant immune regulator of salicylic acid (SA)-mediated defense responses, uncovering a mechanistic link to SA signaling and NPR1 activation in coordinating defense and growth. Under normal growth conditions (left), NPR1 is phosphorylated at Ser-55 and Ser-59 (Ser-55/59) by active TOR (bright green) and sequestered in the cytoplasm via oligomerization, while SnRK1 (dim red) is inhibited by nutrient availability. During immune responses (right), SA activates SnRK1 (bright red), leading to TOR inhibition and Ser-55/59 dephosphorylation. SA-triggered redox changes also facilitate nuclear translocation of NPR1. SnRK1 then phosphorylates NPR1 at Ser-557, partially activating it and priming it for subsequent PTMs. Ub, ubiquitination.
June 19, 2025 at 3:53 PM
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Great work by Mallén-Ponce et al. (2025) on how they identified #dihydroxyacetone phosphate (DHAP) as a key metabolite regulating the activation of #PlantTOR in the green alga #Chlamydomonas reinhardtii in response to #CO2 availability and light signals 🌅.
@ibvf-sevilla.bsky.social #PlantScience ⬇️
Fig 3E. Proposed model for the regulation of target of rapamycin (TOR) activity by dihydroxyacetone phosphate (DHAP) in the model green alga Chlamydomonas reinhardtii. Photosynthesis provides reducing power [NADPH (reduced form of nicotinamide adenine dinucleotide phosphate)] and energy [ATP (adenosine 5′-triphosphate)] for CO2 fixation and the biosynthesis of organic carbon compounds. DHAP is synthesized in the chloroplast and exported to the cytoplasm through the TPT3 transporter. The abundance of cytoplasmic DHAP is transmitted to TOR to modulate its activity. Figure S3. Schematic diagram of central carbon metabolism in the model green alga Chlamydomonas reinhardtii. The Calvin Benson Bassham (CBB), tricarboxylic acid (TCA) and glutamine synthetase-glutamate synthase (GS-GOGAT) cycles, gluconeogenesis, glycolysis and lipid synthesis are shown. The effect of dihydroxyacetone (DHA), dimethyl-alpha-ketoglutarate (DMKG), L-methionine sulfoximine (MSX) or cerulenin on central metabolism is also shown. The fatty acid synthase (FAS) inhibitor cerulenin and the GS inhibitor MSX are indicated with red lines whereas the metabolic input of DHA and DMKG as precursors of DHAP and AKG, respectively, are indicated with blue arrows. The DHAP chloroplast-to-cytosol transporter triose-phosphate-translocator 3 (TPT3) is shown in pink. Enzyme abbreviations are as follows: PRK, phosphoribulokinase; RuBisCo, ribulose 1,5-bisphosphate carboxylase oxygenase; PGK, phosphoglucokinase; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; TK, triokinase; TPI, triosephosphate isomerase; FAS: fatty acid synthase; GS, glutamine synthetase; GOGAT, glutamate synthase; TPT3, triose-phosphatetranslocator 3; PDH, pyruvate dehydrogenase; CS, citrate synthase; ACO, aconitase; IL, isocitrate lyase; IDH, isocitrate dehydrogenase; ADH, alphaketoglutarate dehydrogenase; SCS, succinyl-CoA-synthase; SDH, succinicdehydrogenase; Fum, fumarase; MDH, malate dehydrogenase; DAK1, dihydroxyacetone kinase 1. Metabolite abbreviations: DHAP, dihydroxyacetone phosphate; Ru5P, ribulose 5-phosphate; RuBP, ribulose 1,5-bisphosphate; 3- PGA, 3-phosphoglycerate; GAP, glyceraldehyde 3-phosphate; Glc, glucose; Glc1P, glucose 1-phosphate; Glc6P, glucose 6-phosphate; AKG, alphaketoglutarate. Fig. 2. Effect of dihydroxyacetone (DHA), cerulenin, dimethyl-α-ketoglutarate (DMKG), or L-methionine sulfoximine (MSX) on TOR activity. (A) Immunoblot (upper panel) of P-RPS6/ RPS6 in Chlamydomonas cells treated with 2 mM DHA (0, 15, 30, and 60 min) over the night part of the diurnal cycle. Relative abundance (lower panel) of DHAP in cells treated with 2 mM DHA (0, 15, 30, and 60 min). (B) Immunoblot (upper panel) of P-RPS6/ RPS6 in cells treated with 20 μM cerulenin (0, 15, 30, and 60 min) over the day part of the diurnal cycle. Relative abundance (lower panel) of DHAP in cells treated with 20 μM cerulenin (0, 15, 30, and 60 min). (C) Immunoblot (upper panel) of P-RPS6/ RPS6 in cells treated with 2 mM DMKG (0, 15, 30, and 60 min) over the night part of the diurnal cycle. Relative abundance (lower panel) of DHAP in cells under the same conditions. (D) Immunoblot (upper panel) of P-RPS6/ RPS6 and relative abundance (lower panel) of Gln in cells treated or not with 5 mM MSX for 2 hours over the night part of the diurnal cycle and then reilluminated for 30 min. (E) Immunoblot (upper panel) of P-RPS6/ RPS6 and relative abundance (lower panel) of Gln and DHAP in cells treated or not with 5 mM MSX for 2 hours and then 2 mM DHA for 30 min over the day part of the diurnal cycle. Coomassie brilliant blue–stained gels were used as a loading control. Chlamydomonas cells were grown in TP medium. Error bars correspond to SD from at least three biological replicates. Asterisks represent significant differences according to one-way ANOVA: ***P < 0.001; **P < 0.01; *P < 0.05; not significant, ≥0.05. The statistical analyses described apply to all statistical analyses in this figure (detailed in table S8). White and black bars indicate light and dark phases, respectively.
April 22, 2025 at 3:02 PM
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Very interesting review by Liu, Hu et al. (2025) on the signaling landscape of #PlantTOR pathway (i.e. upstream signals and downstream effectors) and the physiological roles of #PlantTOR signaling in plant growth, development, and stress responses 🌱. www.annualreviews.org/content/jour...
Figure 2. Representative TOR-specific chemical inhibitors in the green plant lineage. The structures of ATP and TOR-specific chemical inhibitors docking to plant TOR complexes were predicted by using AlphaFold 3. For more detail, please refer to Supplemental Table 2. Abbreviations: Ath, Arabidopsis thaliana; FKBP12, FK506-binding protein 12; FRB, FKBP-rapamycin binding; LST8, lethal with SEC13 protein 8; TOR, target of rapamycin. Figure 3. Upstream signals and regulators of plant TOR signaling. The plant TORC integrates a variety of upstream signals to gate its own activity and function. Activation of TORC only occurs when glucose/energy, mineral nutrients, growth-related hormones, and favorable environmental conditions are all readily available. Conversely, low energy, nutrient scarcity, and stresses lead to TORC inhibition. Transporters depicted include AKT, Arabidopsis potassium (KC) transporter (65); AMT, ammonium (NH4 C) transporter (74); IRT, iron (Fe2C) transporter (24); NRT, nitrate (NO3 -) transporter (74); PHT, phosphate (PO4 3-) transporter (23); and SULTR, sulfate (SO4 2-) transporter (141). Positive regulators of TORC are depicted in orange; negative regulators are in light gray blue. Figure 4. Downstream targets and molecular functions of plant TOR signaling. Plant TORC orchestrates a myriad of cellular, molecular, and metabolic changes to balance anabolic and catabolic programs by directly or indirectly regulating key components. (a–e, left) Summary of plant TORC downstream substrates, regulators, and their related molecular functions. (Right) Illustration of the central dogma in the plant cell. ( f ) Summary of plant TORC-regulated hormone signaling pathways. Positive regulators are depicted in light green; negative regulators are in light gray-blue. Phosphorylation regulation is depicted by the phosphate group shown in pink, and the biological processes are shown in light cyan. Solid lines with triangle arrows (positive) and with vertical bars (negative) represent confirmed signaling regulation. The dashed line indicates that this regulation needs further experimental validation. Figure 5. Physiological roles of TOR signaling in plant growth, development, and stress adaptation. (a, i–vii) By integrating upstream signals and regulating multiple cellular processes, plant TOR signaling ultimately regulates every stage of an individual life cycle, from embryo development to senescence, and (b) participates in diverse stress adaptation and growth–defense trade-offs. The key upstream signals and regulators are shown. External and internal signals involved in TOR regulating plant growth, development, and stress adaptation processes are labeled in brown (activation signals) and blue (inhibition signals). Positive and negative regulators are labeled in orange and black, respectively. Black lines with triangle arrows (positive) and with vertical bars (negative) represent signaling regulation.
April 9, 2025 at 3:02 PM
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Great work by Zheng et al. (2025) on how employing pupylation-based proximity labeling (PUP-IT) unravels a comprehensive #interactome of #Arabidopsis TOR complex.
Newly identified #PlantTOR interactors, like PANK2, were also supported by #AlphaFold2.
advanced.onlinelibrary.wiley.com/doi/10.1002/...
Figure 1. Combining different treatments and baits determines different components of the TORC interactome. A) Scheme illustrating PUP-IT in the context of TOR signaling. PafA fused to the baits LST8-1, RAPTOR1, and ScFKBP labels individual and TOR complex associated protein interactors, while a GFP fusion acts as a control for unspecific interactions. B–E) Volcano plots showing proteins significantly enriched in LST8-1 B,D) and RAPTOR1 C,E) baits using constitutive B,C) or inducible D,E) FLAG::PUP(E) expression. F–G) Treatment-dependency of identified interactors using LST8-1 G) or RAPTOR1 H) baits and inducible FLAG::PUP(E) expression. Treatment-specific interactors are those only identified in one of the two treatments. H) Rapamycin response of WT and ScFKBP-producing seedlings (n = 10 seedlings). Bar height indicates group median. I) Volcano plot showing proteins significantly enriched in the ScFKBP bait using constitutive FLAG::PUP(E) expression. In all volcano plots, fold changes are calculated from n = 3 replicates using MsqRob2, p-values are corrected for multiple comparisons using the Benjamini–Hochberg FDR method. Different letters in panel (H) indicate statistically significant differences between groups based on a one-way ANOVA followed by a Tukey-HSD test (𝛼 = 0.05). Figure 2. Identification of phosphorylated direct interactors of the TOR complex and in silico corroboration using AlphaFold2. A,B) Phosphorylated proteins enriched in LST8-1 and RAPTOR1 against the GFP control after 4 h A) and 24 h B) of sucrose treatment and FLAG::PUP(E) induction. Phosphorylation sites previously associated with TOR are indicated in blue, new sites in proteins previously reported to be phosphorylated by TOR in turquoise. Fold changes are calculated from n = 3 replicates using MsqRob2, p-values are corrected for multiple comparisons using the Benjamini–Hochberg FDR method. C,D) The two significantly enriched motifs among the identified phosphorylation sites. The “SP” motif C) mirrors previous reports from TOR substrates, while the “RxxS” motif D) has previously been associated with TOR downstream interactor S6K1. E) Interactions of 20 proteins from the four shown groups with the TORC components TOR, LST8-1, and RAPTOR1 were predicted using AlphaFold2 multimer. Vertical lines indicate the median of the local interaction score (LIS) distribution by group. F) Predicted structures of the top-scoring interactions for each group: newly identified TORC interactor PANK2, TORC subunit RAPTOR1, senescence regulator S40-7, and KIN10 paralog KIN11. Models are colored by predicted local distance difference test (pLDDT), with values above 70 indicating high confidence predictions.
March 24, 2025 at 8:15 PM
tkozawa.bsky.social
Great work by Komiya, Pancha et al. (2025) on how #PlantTOR signaling regulates (floridean) starch degradation in extremophilic red microalga #Cyanidioschyzon merolae (rapamycin-sensitive SF12 strain), by modulating the phosphorylation status of α-glucan, water dikinase (CmGWD) at Ser264 residue.
March 21, 2025 at 8:48 PM
tkozawa.bsky.social
Great work by Urrea-Castellanos et al. (2025) on how RAPTOR1B, a subunit of #PlantTOR complex (TORC), post-transcriptionally regulates CONSTANS (CO), a component of the #photoperiod pathway to promote flowering, via #circadian clock-associated protein GIGANTEA (GI) 🌻.
🔗 www.pnas.org/doi/10.1073/...
Fig. 5. RAPTOR1B functions upstream of GIGANTEA (GI) to contribute to CONSTANS (CO) stability at dusk and thus promote the floral transition in Arabidopsis. (F) Proposed model for the role of RAPTOR during floral transition in long days (LD). The length of the light period is primarily sensed in leaves by the combined action of light signaling (mediated by PHYA and CRYs) and the circadian clock (driving gene expression of effector proteins, such GI and FKF1). This accounts for protein accumulation of CONSTANS at dusk, which in turn, upregulates the florigen, FT. FT protein travels from the leaves into the shoot apex via the vasculature to induce the expression of floral integrator genes (such SOC1) and flower promoting genes (such SPL3/4/5). GI, similar to CO, accumulates over the day and is degraded at night. Independent, or together with FKF1 in response to blue light-mediated by CRYs, GI helps to stabilize CONSTANS at dusk in LD. RAPTOR, which is part of the TORC, contributes to CO stability at dusk by promoting GI levels posttranscriptionally. TORC is known to be activated by light and sugars, suggesting that RAPTOR conveys nutrient status, in this case carbon availability, to regulate GI accumulation and thus fine-tune flowering via the photoperiod pathway. Remarkably, TOR is essential for sugar-mediated regulation of the circadian period, while GI integrates signals from the circadian clock, thus strengthening the potential crosstalk between these proteins.
February 4, 2025 at 6:19 PM
tkozawa.bsky.social
Great #preprint by Rawat and Laxmi (2025) on how salicylic acid (SA)-induced primary root growth inhibition in #Arabidopsis seedlings is regulated by the glucose-auxin-TOR-E2Fa module. #PlantTOR
🔗 www.biorxiv.org/content/10.1...
Figure 8. The interplay of glucose, auxin and TOR-E2Fa in mediating root growth repression by the defense hormone, salicylic acid (SA). A testable model for glucose and SA crosstalk. Glucose promotes root growth by stimulating auxin biosynthesis, signaling and transport. Both glucose and auxin activate TOR kinase, which, in turn, activate RPS6 and E2Fa, key players in cell cycle regulation. E2Fa binds to S-phase cell cycle gene promoters, upregulating their expression and promoting cell growth and proliferation. Conversely, SA appears to inhibit root growth by antagonizing auxin signaling and transport. Additionally, SA reduces the phosphorylation levels of both RPS6 and E2Fa, negatively impacting cell growth and proliferation processes, ultimately leading to root growth inhibition.
February 3, 2025 at 4:08 PM
tkozawa.bsky.social
Great work by Coronel et al. (2024) on how altering cytochrome c (CYTc) levels affected #SnRK1 activity in #Arabidopsis 🌱, indicating a molecular link between #mitochondrial function and #PlantTOR -mediated growth under normal and mannitol stress conditions.
🔗 onlinelibrary.wiley.com/doi/10.1111/...
Figure 6. Cytochrome c (CYTc) deficiency affects TOR pathway activity, downstream of SnRK1. (A) Western blot analysis of RPS6 phosphorylation in WT plants, cytc-1a and akin10-2 single mutants, and cytc-1a akin10-2 double mutants using anti-P-RPS6 antibodies. Extracts were prepared from seedlings grown for 3.5 days in 0.59 MS medium, followed by an extended night (16 h) for nutrient depletion and treatment with 20 mM glucose for 3 h to activate TOR (Xiong et al., 2013). Anti-RPS6 antibodies were used as a control of total RPS6 levels. Anti-Actin antibodies were used for the control of loading. The original uncropped image is shown in Figure S8. On the right, a quantification of P-RPS6 and total RPS6 band intensities relative to WT plants after normalisation with actin is shown. Different letters indicate significant differences (three independent experiments; P < 0.05; ANOVA). (B) Hypocotyl growth in WT plants, cytc-1a and akin10-2 single mutants, and cytc-1a akin10-2 double mutants grown as in (A) and supplemented with different concentrations of selective TOR inhibitor AZD-8055. Hypocotyl length was measured using ImageJ software. Asterisks indicate significant differences with WT (n = 20; P < 0.05; ANOVA). (C) Representative images of the experiment shown in (B). Bar: 0.5 cm. Figure 6D. Model of the connection between cytochrome c (CYTc) levels and plant growth and stress responses. Under normal conditions (left), CYTc, probably acting as an OXPHOS component, exerts repression on SnRK1 activity, thus allowing TOR activation and plant growth. A decrease in CYTc levels (right) derepresses SnRK1, leading to growth inhibition and the activation of autophagy and stress responses. Since stress conditions affect mitochondrial function, it can be envisaged that CYTc dependent processes are part of a signal that influences the balance between growth and stress responses through SnRK1.
December 17, 2024 at 10:43 PM
tkozawa.bsky.social
Great work by Liu et al. (2024) on how #PlantTOR kinase positively regulates plant #FattyAcid and lipid synthesis in #Nicotiana benthamiana leaves 🍃, #Arabidopsis seedlings 🌱 and #Brassica napus suspension cells.
PS. Relatively short periods were used for the assays.
academic.oup.com/plphys/advan...
Figure 7. Target of Rapamycin (TOR) kinase is a positive regulator of plant fatty acid and lipid synthesis. Plant TOR is activated by light and sugars. Once activated, TOR positively regulates fatty acid (FA) and lipid synthesis by upregulating genes involved in de novo fatty acid synthesis and downregulating genes associated with lipid turnover. Additionally, TOR promotes the biosynthesis of proteins, cell walls, DNA, RNA, and the other essential cellular components. TOR complex shown in the figure is comprising of LST8-1 (Lethal with SEC13 protein 8-1, in green), TOR (in purple) and RAPTOR1B (Regulatory-associated protein of TOR 1B, in yellow) and its 3D structure model is predicated by AlphaFold 3. Figure 1. Transient expression of TOR in Nicotiana benthamiana (N. benth) leaves increases the levels of total fatty acids (TFAs). A) Representative fluorescence confocal image of N. benth leaf samples taken 4 days after agroinfiltration with TOR-GFP. Bar = 50 µm. B) Immunoblotting with anti-GFP antibody shows TOR-GFP is detected in protein samples extracted from N. benth leaves 4 days after infiltration with agrobacterium containing plasmid TOR/pCHF3-hGFP (TOR-GFP), but not pCHF3-hGFP (Empty vector, EV). Ponceau S staining of PVDF membrane after protein transfer is shown as a protein loading control. M, protein markers. Multiple lanes for the same construct represent biological replicates. C) Transient expression of TOR for 4 days after agroinfiltration significantly elevates total fatty acids content in N. benth leaves after. Bar values represent mean ± SD (n = 6), with each data point represented by a dot. Asterisks denote a statistically difference from the EV (Student's t-test, **, P < 0.01). Figure 5. Suppression of TOR activity by Torin 2 in a Brassica napus suspension cell culture results in significant reduction in the accumulation of both total fatty acid (TFA) and triacylglycerol (TAG). A) TFA content in Brassica napus microspore-derived suspension cells cultured in medium supplemented without (−) or with (+) 1 μM Torin 2 for the indicated time periods. B) TAG content in the Brassica napus suspension cells in (A). In this figure, bar values represent mean ± SD (n = 4), with each data point represented by a dot. Asterisks denote statistically significant differences from the non-Torin 2 treatment controls (Student’s t-test, *, P < 0.05; ***, P < 0.001).
December 4, 2024 at 1:24 AM
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📜 Target of Rapamycin (TOR): A Master Regulator in Plant Growth, Development, and Stress Responses

🧑‍🔬 Yanlin Liu, Jun Hu, Yan Xiong, et al.

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🔗 www.annualreviews.org/content/jour...

#️⃣ #PlantScience #PlantDevelopment #PlantStress #PlantTOR
Target of Rapamycin (TOR): A Master Regulator in Plant Growth, Development, and Stress Responses | Annual Reviews
The target of rapamycin (TOR) is a central regulator of growth, development, and stress adaptation in plants. This review delves into the molecular intricacies of TOR signaling, highlighting its conse...
www.annualreviews.org
April 16, 2025 at 7:35 AM