Energy competition remodels the metabolic glucose landscape of psoriatic epidermal cells.

Rationale: Skin cells actively metabolize nutrients to ensure cell proliferation and differentiation. Psoriasis is an immune-disorder-related skin disease with hyperproliferation in epidermal keratinocytes and is increasingly recognized to be associated with metabolic disturbance. However, the metabolic adaptations and underlying mechanisms of epidermal hyperproliferation in psoriatic skin remain largely unknown. Here, we explored the role of metabolic competition in epidermal cell proliferation and differentiation in psoriatic skin. Methods: Bulk- and single-cell RNA-sequencing, spatial transcriptomics, and glucose uptake experiments were used to analyze the metabolic differences in epidermal cells in psoriasis. Functional validation in vivo and in vitro was done using imiquimod-like mouse models and inflammatory organoid models. Results: We observed the highly proliferative basal cells in psoriasis act as the winners of the metabolic competition to uptake glucose from suprabasal cells. Using single-cell metabolic analysis, we found that the "winner cells" promote OXPHOS pathway upregulation by COX7B and lead to increased ROS through glucose metabolism, thereby promoting the hyperproliferation of basal cells in psoriasis. Also, to prevent toxic damage from ROS, basal cells activate the glutathione metabolic pathway to increase their antioxidant capacity to assist in psoriasis progression. We further found that COX7B promotes psoriasis development by modulating the activity of the PPAR signaling pathway by bulk RNA-seq analysis. We also observed glucose starvation and high expression of SLC7A11 that causes suprabasal cell disulfide stress and affects the actin cytoskeleton, leading to immature differentiation of suprabasal cells in psoriatic skin. Conclusion: Our study demonstrates the essential role of cellular metabolic competition for skin tissue homeostasis.

Crosstalk between endothelial cells and dermal papilla entails hair regeneration and angiogenesis during aging.

INTRODUCTION: Tissues maintain their function through interaction with microenvironment. During aging, both hair follicles and blood vessels (BV) in skin undergo degenerative changes. However, it is elusive whether the changes are due to intrinsic aging changes in hair follicles or blood vessels respectively, or their interactions. OBJECTIVE: To explore how hair follicles and blood vessels interact to regulate angiogenesis and hair regeneration during aging. METHODS: Single-cell RNA-sequencing (scRNA-seq) analyses were used to identify the declined ability of dermal papilla (DP) and endothelial cells (ECs) during aging. CellChat and CellCall were performed to investigate interaction between DP and ECs. Single-cell metabolism (scMetabolism) analysis and iPATH were applied to analyze downstream metabolites in DP and ECs. Hair-plucking model and mouse cell organoid model were used for functional studies. RESULTS: During aging, distance and interaction between DP and ECs are decreased. DP interacts with ECs, with decreased EDN1-EDNRA signaling from ECs to DP and CTF1-IL6ST signaling from DP to ECs during aging. ECs-secreted EDN1 binds to DP-expressed EDNRA which enhances Taurine (TA) metabolism to promote hair regeneration. DP-emitted CTF1 binds to ECs-expressed IL6ST which activates alpha-linolenic acid (ALA) metabolism to promote angiogenesis. Activated EDN1-EDNRA-TA signaling promotes hair regeneration in aged mouse skin and in organoid cultures, and increased CTF1-IL6ST-ALA signaling also promotes angiogenesis in aged mouse skin and organoid cultures. CONCLUSIONS: Our finding reveals reciprocal interactions between ECs and DP. ECs releases EDN1 sensed by DP to activate TA metabolism which induces hair regeneration, while DP emits CTF1 signal received by ECs to enhance ALA metabolism which promotes angiogenesis. Our study provides new insights into mutualistic cellular crosstalk between hair follicles and blood vessels, and identifies novel signaling contributing to the interactions of hair follicles and blood vessels in normal and aged skin.

Two SEPALLATA MADS-Box Genes, SlMBP21 and SlMADS1, Have Cooperative Functions Required for Sepal Development in Tomato.

MADS-box transcription factors have crucial functions in numerous physiological and biochemical processes during plant growth and development. Previous studies have reported that two MADS-box genes, SlMBP21 and SlMADS1, play important regulatory roles in the sepal development of tomato, respectively. However, the functional relationships between these two genes are still unknown. In order to investigate this, we simultaneously studied these two genes in tomato. Phylogenetic analysis showed that they were classified into the same branch of the SEPALLATA (SEP) clade. qRT-PCR displayed that both SlMBP21 and SlMADS1 transcripts are preferentially accumulated in sepals, and are increased with flower development. During sepal development, SlMBP21 is increased but SlMADS1 is decreased. Using the RNAi, tomato plants with reduced SlMBP21 mRNA generated enlarged and fused sepals, while simultaneous inhibition of SlMBP21 and SlMADS1 led to larger (longer and wider) and fused sepals than that in SlMBP21-RNAi lines. qRT-PCR results exhibited that the transcripts of genes relating to sepal development, ethylene, auxin and cell expansion were dramatically changed in SlMBP21-RNAi sepals, especially in SlMBP21-SlMADS1-RNAi sepals. Yeast two-hybrid assay displayed that SlMBP21 can interact with SlMBP21, SlAP2a, TAGL1 and RIN, and SlMADS1 can interact with SlAP2a and RIN, respectively. In conclusion, SlMBP21 and SlMADS1 cooperatively regulate sepal development in tomato by impacting the expression or activities of other related regulators or via interactions with other regulatory proteins.

Overexpression of SlCRF6 in tomato inhibits leaf development and affects plant morphology.

Cytokinin response factors (CRFs) are transcription factors (TFs) that are specific to plants and have diverse functions in plant growth and stress responses. However, the precise roles of CRFs in regulating tomato plant architecture and leaf development have not been comprehensively investigated. Here, we identified a novel CRF, SlCRF6, which is involved in the regulation of plant growth via the gibberellin (GA) signaling pathway. SlCRF6-overexpressing (SlCRF6-OE) plants displayed pleiotropic phenotypic changes, including reduced internode length and leaf size, which caused dwarfism in tomato plants. This dwarfism could be alleviated by application of exogenous GA3. Remarkably, quantitative real-time PCR (qRTPCR), a dual luciferase reporter assay and a yeast one-hybrid (Y1H) assay revealed that SlCRF6 promoted the expression of SlDELLA (a GA signal transduction inhibitor) in vivo. Furthermore, transgenic plants displayed variegated leaves and diminished chlorophyll content, resulting in decreased photosynthetic efficiency and less starch than in wild-type (WT) plants. The results of transient expression assays and Y1H assays indicated that SlCRF6 suppressed the expression of SlPHAN (leaf morphology-related gene). Collectively, these findings suggest that SlCRF6 plays a crucial role in regulating tomato plant morphology, leaf development, and the accumulation of photosynthetic products.

Suppression of a hexokinase gene SlHXK1 in tomato affects fruit setting and seed quality.

Hexokinase is considered to be the key molecule in sugar signaling and metabolism. Here, we reported that silencing SlHXK1 resulted in a decrease in flower number, increased rate of flower dropping, abnormal thickening of the anther wall, and reduced pollen and seed viability. An anatomical analysis revealed the loss of small cells and abnormal thickening of anther walls in SlHXK1-RNAi lines. Treatment with auxin and 1-methylcyclopropene inhibited flower dropping from the pedicel abscission zone. qRT-PCR analysis revealed that the effect of SlHXK1 on abscission was associated with the expression levels of genes related to key meristem, auxin, ethylene, cell wall metabolism and programmed cell death. Pollen germination and pollen staining experiments showed that pollen viability was significantly reduced in the SlHXK1-RNAi lines. Physiological and biochemical analyses showed that hexokinase activity and starch content were markedly decreased in the transgenic lines. The expression of genes related to tomato pollen development was also suppressed in the transgenic lines. Although the RNAi lines eventually produced some viable seeds, the yield and quality of the seeds was lower than that of wild-type plants. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that SlHXK1 interacted with SlKINγ. Furthermore, SlPIF4 inhibited the transcriptional expression of SlHXK1. In conclusion, our results demonstrate that SlHXK1 may play important roles in pollen, anther, seed and the pedicel abscission zone by affecting starch accumulation or cell wall synthesis, as well as by regulating the number of the transcripts of genes that are involved in auxin, ethylene and cell wall degradation.

Overexpression of SlPRE3 alters the plant morphologies in Solanum lycopersicum.

KEY MESSAGE: Overexpression of SlPRE3 is detrimental to the photosynthesis and alters plant morphology and root development. SlPRE3 interacts with SlAIF1/SlAIF2/SlPAR1/SlIBH1 to regulate cell expansion. Basic helix-loop-helix (bHLH) transcription factors play crucial roles as regulators in plant growth and development. In this study, we isolated and characterized SlPRE3, an atypical bHLH transcription factor gene. SlPRE3 exhibited predominant expression in the root and moderate expression in the senescent leaves. Comparative analysis with the wild type revealed significant differences in plant morphology in the 35S:SlPRE3 lines. These differences included increased internode length, rolling leaves with reduced chlorophyll accumulation, and elongated yet fewer adventitious roots. Additionally, 35S:SlPRE3 lines displayed elevated levels of GA3 (gibberellin A3) and reduced starch accumulation. Furthermore, utilizing the Y2H (Yeast two-hybrid) and the BiFC (Bimolecular Fluorescent Complimentary) techniques, we identified physical interactions between SlPRE3 and SlAIF1 (ATBS1-interacting factor 1)/SlAIF2 (ATBS1-interacting factor 2)/SlPAR1 (PHYTOCHROME RAPIDLY REGULATED 1)/SlIBH1 (ILI1-binding bHLH 1). RNA-seq analysis of root tissues revealed significant alterations in transcript levels of genes involved in gibberellin metabolism and signal transduction, cell expansion, and root development. In summary, our study sheds light on the crucial regulatory role of SlPRE3 in determining plant morphology and root development.

Down-regulation of SlGT-26 gene confers dwarf plants and enhances drought and salt stress resistance in tomato.

Plant architecture, an important agronomic trait closely associated with yield, is governed by a highly intricate molecular network. Despite extensive research, many mysteries surrounding this regulation remain unresolved. Trihelix transcription factor family plays a crucial role in the development of plant morphology and abiotic stresses. Here, we identified a novel trihelix transcription factor named SlGT-26, and its down-regulation led to significant alterations in plant architecture, including dwarfing, reduced internode length, smaller leaves, and shorter petioles. The dwarf phenotype of SlGT-26 silenced transgenic plants could be recovered after spraying exogenous GA3, and the GA3 content were decreased in the RNAi plants. Additionally, the expression levels of gibberellin-related genes were affected in the RNAi lines. These results indicate that the dwarf of SlGT-26-RNAi plants may be a kind of GA3-sensitive dwarf. SlGT-26 was response to drought and salt stress treatments. SlGT-26-RNAi transgenic plants demonstrated significantly enhanced drought resistance and salt tolerance in comparison to their wild-type tomato counterparts. SlGT-26-RNAi transgenic plants grew better, had higher relative water content and lower MDA and H2O2 contents. The expression of multiple stress-related genes was also up-regulated. In summary, we have discovered a novel gene, SlGT-26, which plays a crucial role in regulating plant architecture and in respond to drought and salt stress.

Trihelix transcription factor SlGT31 regulates fruit ripening mediated by ethylene in tomato.

Trihelix proteins are plant-specific transcription factors that are classified as GT factors due to their binding specificity for GT elements, and they play crucial roles in development and stress responses. However, their involvement in fruit ripening and transcriptional regulatory mechanisms remains largely unclear. In this study, we cloned SlGT31, encoding a trihelix protein in tomato (Solanum lycopersicum), and determined that its relative expression was significantly induced by the application of exogenous ethylene whereas it was repressed by the ethylene-inhibitor 1-methylcyclopropene. Suppression of SlGT31 expression resulted in delayed fruit ripening, decreased accumulation of total carotenoids, and reduced ethylene content, together with inhibition of expression of genes related to ethylene and fruit ripening. Conversely, SlGT31-overexpression lines showed opposite results. Yeast one-hybrid and dual-luciferase assays indicated that SlGT31 can bind to the promoters of two key ethylene-biosynthesis genes, ACO1 and ACS4. Taken together, our results indicate that SlGT31 might act as a positive modulator during fruit ripening.

SlERF.J2 reduces chlorophyll accumulation and inhibits chloroplast biogenesis and development in tomato leaves.

Chlorophyll metabolism and chloroplast biogenesis in tomato (Solanum lycopersicum) leaves contribute to photosynthesis; however, their molecular mechanisms are poorly understood. In this study, we found that overexpression of SlERF.J2 (ethylene transcription factor) resulted in a decrease in leaf chlorophyll content and reduced accumulation of starch and soluble sugar. The slerf.j2 knockout mutant showed no apparent change. Further observation of tissue sections and transmission electron microscopy (TEM) showed that SlERF.J2 was involved in chlorophyll accumulation and chloroplast formation. RNA-seq of mature SlERF.J2-OE leaves showed that many genes involved in chlorophyll biosynthesis and chloroplast formation were significantly downregulated compared with those in WT leaves. Genome global scanning of the ERF TF binding site combined with RNA-seq differential gene expression and qRT-PCR detection analysis showed that COP1 was a potential target gene of SlERF.J2. Tobacco transient expression technology, a dual-luciferase reporter system and Y1H technology were employed to verify that SlERF.J2 could bind to the COP1 promoter. Notably, overexpression of SlERF.J2 in Nr mutants resulted in impaired chloroplast biogenesis and development. Taken together, our findings demonstrated that SlERF.J2 plays an essential role in chlorophyll accumulation and chloroplast formation, laying a foundation for enhancing plant photosynthesis.

A tomato HD-zip I transcription factor, VAHOX1, acts as a negative regulator of fruit ripening.

Homeodomain-leucine zipper (HD-Zip) transcription factors are only present in higher plants and are involved in plant development and stress responses. However, our understanding of their participation in the fruit ripening of economical plants, such as tomato (Solanum lycopersicum), remains largely unclear. Here, we report that VAHOX1, a member of the tomato HD-Zip I subfamily, was expressed in all tissues, was highly expressed in breaker+4 fruits, and could be induced by ethylene. RNAi repression of VAHOX1 (VAHOX1-RNAi) resulted in accelerated fruit ripening, enhanced sensitivity to ethylene, and increased total carotenoid content and ethylene production. Conversely, VAHOX1 overexpression (VAHOX1-OE) in tomato had the opposite effect. RNA-Seq results showed that altering VAHOX1 expression affected the transcript accumulation of a series of genes involved in ethylene biosynthesis and signal transduction and cell wall modification. Additionally, a dual-luciferase reporter assay, histochemical analysis of GUS activity and a yeast one-hybrid (Y1H) assay revealed that VAHOX1 could activate the expression of AP2a. Our findings may expand our knowledge about the physiological functions of HD-Zip transcription factors in tomato and highlight the diversities of transcriptional regulation during the fruit ripening process.

Anthocyanin accumulation and transcriptional regulation in purple flowering stalk (Brassica campestris L. var. purpurea Bailey).

KEY MESSAGE: 1. Purple flowering stalk (Brassica campestris L. ssp. chinensis L. var. purpurea Bailey) is a crop with the high-level anthocyanin. 2. Increased abundance of LBGs promoted the synthesis of anthocyanin. 3. TTG2 (WRKY) interacted with TTG1 (WD40), probably regulating anthocyanin accumulation by shaping a MBWW complex. Brassica crops are a class of nutrient-rich vegetables. Here, two Brassica Crops-Flowering Stalk cultivars, purple flowering stalk (Brassica campestris L. var. purpurea Bailey) and pakchoi (Brassica campestris ssp. chinensis var. communis) were investigated. HPLC-ESI-MS/MS analysis demonstrated that Cy 3-p-coumaroylsophoroside-5-malonylglucoside and Cy 3-diferuloylsophoroside-5-malonylglucoside were identified as the major anthocyanin in peel of purple flowering stalk. The transcript level of structural genes including C4H, CHS, F3H, DFR, ANS and UFGT, and regulatory genes such as TT8, TTG1, Bra004162, Bra001917 and TTG2 in peel of purple flowering stalk were significantly higher than that in peel of pakchoi. In addition, the TTG2(WRKY) interacted only with TTG1(WD40) and the interaction between TT8 (bHLH) and TTG1/Bra004162(MYB)/Bra001917(MYB) were identified. Else, the WD40-WRKY complex (TTG1-TTG2) could activate the transcript of TT12. Our study laid a foundation for the research on the anthocyanin accumulation in Brassica crops.

The AP2/ERF transcription factor SlERF.J2 functions in hypocotyl elongation and plant height in tomato.

KEY MESSAGE: Our findings indicated that the SlERF.J2-IAA23 module integrates hormonal signals to regulate hypocotyl elongation and plant height in tomato. Light and phytohormones can synergistically regulate photomorphogenesis-related hypocotyl elongation and plant height in tomato. AP2/ERF family genes have been extensively demonstrated to play a role in light signaling and various hormones. In this study, we identified a novel AP2/ERF family gene in tomato, SlERF.J2. Overexpression of SlERF.J2 inhibits hypocotyl elongation and plant height. However, the plant height in the slerf.j2ko knockout mutant was not significantly changed compared with the WT. we found that hypocotyl cell elongation and plant height were regulated by a network involving light, auxin and gibberellin signaling, which is mediated by regulatory relationship between SlERF.J2 and IAA23. SlERF.J2 protein could bind to IAA23 promoter and inhibit its expression. In addition, light-dark alternation can activate the transcription of SlERF.J2 and promote the function of SlERF.J2 in photomorphogenesis. Our findings indicated that the SlERF.J2-IAA23 module integrates hormonal signals to regulate hypocotyl elongation and plant height in tomato.

The AlkB Homolog SlALKBH10B Negatively Affects Drought and Salt Tolerance in Solanum lycopersicum.

ALKBH proteins, the homologs of Escherichia coli AlkB dioxygenase, constitute a single-protein repair system that safeguards cellular DNA and RNA against the harmful effects of alkylating agents. ALKBH10B, the first discovered N6-methyladenosine (m6A) demethylase in Arabidopsis (Arabidopsis thaliana), has been shown to regulate plant growth, development, and stress responses. However, until now, the functional role of the plant ALKBH10B has solely been reported in arabidopsis, cotton, and poplar, leaving its functional implications in other plant species shrouded in mystery. In this study, we identified the AlkB homolog SlALKBH10B in tomato (Solanum lycopersicum) through phylogenetic and gene expression analyses. SlALKBH10B exhibited a wide range of expression patterns and was induced by exogenous abscisic acid (ABA) and abiotic stresses. By employing CRISPR/Cas9 gene editing techniques to knock out SlALKBH10B, we observed an increased sensitivity of mutants to ABA treatment and upregulation of gene expression related to ABA synthesis and response. Furthermore, the Slalkbh10b mutants displayed an enhanced tolerance to drought and salt stress, characterized by higher water retention, accumulation of photosynthetic products, proline accumulation, and lower levels of reactive oxygen species and cellular damage. Collectively, these findings provide insights into the negative impact of SlALKBH10B on drought and salt tolerance in tomato plant, expanding our understanding of the biological functionality of SlALKBH10B.

Transcription and Metabolism Pathways of Anthocyanin in Purple Shamrock (Oxalis triangularis A.St.-Hil.).

Anthocyanins are water-soluble pigments that can impart various colors to plants. Purple shamrock (Oxalis triangularis) possesses unique ornamental value due to its purple leaves. In this study, three anthocyanins, including malvidin 3-O-(4-O-(6-O-malonyl-glucopyranoside)-rhamnopyranosyl)-5-O-(6-O-malonyl-glucopyranoside), delphinidin-3-O-rutinoside and malvidin-3,5-di-O-glucoside, were characterized with ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) in purple shamrock. To investigate the molecular mechanism of anthocyanin biosynthesis in green shamrock (Oxalis corymbosa) and purple shamrock, RNA-seq and qRT-PCR were performed, and the results showed that most of the anthocyanin biosynthetic and regulatory genes were up-regulated in purple shamrock. Then, dark treatment and low temperature treatment experiments in purple shamrock showed that both light and low temperature can induce the biosynthesis of anthocyanins.

Silencing of SlMYB50 affects tolerance to drought and salt stress in tomato.

High salinity and drought stresses often cause plants to produce ROS, including hydrogen peroxide (H2O2) and superoxide (O2-), which interfere with plant growth and affect crop yield. The transcription factors of the MYB family are involved in responses to biotic and abiotic stresses. Here, we isolated the R2R3-MYB transcription factor gene SlMYB50 and found that silencing of SlMYB50 increased resistance to PEG 6000, mannitol and salt. In addition, the resistance of transgenic tomatoes increased under high salt and drought stress. After stress treatment, the relative water content, chlorophyll content (critical for carbon fixation) and root vitality of the SlMYB50-RNAi lines were higher than those of the wild-type (WT). The opposite was true the water loss rate, relative conductivity, and MDA (as a sign of cell wall disruption). Under drought stress conditions, SlMYB50-silenced lines exhibited less H2O2 and less O2- accumulation, as well as higher CAT enzyme activity, than were exhibited by the WT. Notably, after stress treatment, the expression levels of chlorophyll-synthesis-related, flavonoid-synthesis-related, carotenoid-related, antioxidant-enzyme-related and ABA-biosynthesis-related genes were all upregulated in SlMYB50-silenced lines compared to those of WT. A dual-luciferase reporter system was used to verify that SlMYB50 could bind to the CHS1 promoter. In summary, this study identified essential roles for SlMYB50 in regulating drought and salt tolerance.

Hypermethylation in the promoter region of the ADRA1A gene is associated with opioid use disorder in Han Chinese.

Opioid use disorder is a chronic brain disease influenced by genetic and epigenetic factors, accounting for approximately 50% of the liability. Adrenergic signaling is involved in opioid use disorder. To demonstrate the associations between methylation alterations in the alpha-1-adrenergic receptor (ADRA1A) gene and opioid use disorder, in the present study, we first examined and compared the methylation levels of 97 CpG sites in the promoter region of the ADRA1A gene in the peripheral blood in 120 patients with heroin use disorder and 111 healthy controls. Correlations between methylation levels and duration of heroin/methadone use were then analyzed. Finally, the predicted binding transcription factors (TFs) and their target sequences in the promoter region of the ADRA1A gene, which include the selected CpG sites, were screened in the JASPAR database. Our results demonstrated that hypermethylation in the promoter region of the ADRA1A gene in the blood was associated with opioid use disorder. Correlations between methylation levels of several CpG sites and duration of heroin/methadone use were observed. TFs TFAP2A and RUNX1 were predicted to bind to the target sequences, which include the CpG sites selected in the current study, in the promoter region of the ADRA1A gene. Our findings further extend the associations between methylation alterations in the ADRA1A gene and opioid use disorder potentially through mechanisms of gene expression regulations in the ADRA1A gene.

SlJAZ10 and SlJAZ11 mediate dark-induced leaf senescence and regeneration.

During evolutionary adaptation, the mechanisms for self-regulation are established between the normal growth and development of plants and environmental stress. The phytohormone jasmonate (JA) is a key tie of plant defence and development, and JASMONATE-ZIM DOMAIN (JAZ) repressor proteins are key components in JA signalling pathways. Here, we show that JAZ expression was affected by leaf senescence from the transcriptomic data. Further investigation revealed that SlJAZ10 and SlJAZ11 positively regulate leaf senescence and that SlJAZ11 can also promote plant regeneration. Moreover, we reveal that the SlJAV1-SlWRKY51 (JW) complex could suppress JA biosynthesis under normal growth conditions. Immediately after injury, SlJAZ10 and SlJAZ11 can regulate the activity of the JW complex through the effects of electrical signals and Ca2+ waves, which in turn affect JA biosynthesis, causing a difference in the regeneration phenotype between SlJAZ10-OE and SlJAZ11-OE transgenic plants. In addition, SlRbcs-3B could maintain the protein stability of SlJAZ11 to protect it from degradation. Together, SlJAZ10 and SlJAZ11 not only act as repressors of JA signalling to leaf senescence, but also regulate plant regeneration through coordinated electrical signals, Ca2+ waves, hormones and transcriptional regulation. Our study provides critical insights into the mechanisms by which SlJAZ11 can induce regeneration.

The role of melatonin in tomato stress response, growth and development.

Melatonin has attracted widespread attention after its discovery in higher plants. Tomato is a key model economic crop for studying fleshy fruits. Many studies have shown that melatonin plays important role in plant stress resistance, growth, and development. However, the research progress on the role of melatonin and related mechanisms in tomatoes have not been systematically summarized. This paper summarizes the detection methods and anabolism of melatonin in tomatoes, including (1) the role of melatonin in combating abiotic stresses, e.g., drought, heavy metals, pH, temperature, salt, salt and heat, cold and drought, peroxidation hydrogen and carbendazim, etc., (2) the role of melatonin in combating biotic stresses, such as tobacco mosaic virus and foodborne bacillus, and (3) the role of melatonin in tomato growth and development, such as fruit ripening, postharvest shelf life, leaf senescence and root development. In addition, the future research directions of melatonin in tomatoes are explored in combination with the role of melatonin in other plants. This review can provide a theoretical basis for enhancing the scientific understanding of the role of melatonin in tomatoes and the improved breeding of fruit crops.

Genome-Wide Identification, Classification and Expression Analysis of m6A Gene Family in Solanum lycopersicum.

Advanced knowledge of messenger RNA (mRNA) N6-methyladenosine (m6A) and DNA N6-methyldeoxyadenosine (6 mA) redefine our understanding of these epigenetic modifications. Both m6A and 6mA carry important information for gene regulation, and the corresponding catalytic enzymes sometimes belong to the same gene family and need to be distinguished. However, a comprehensive analysis of the m6A gene family in tomato remains obscure. Here, 24 putative m6A genes and their family genes in tomato were identified and renamed according to BLASTP and phylogenetic analysis. Chromosomal location, synteny, phylogenetic, and structural analyses were performed, unravelling distinct evolutionary relationships between the MT-A70, ALKBH, and YTH protein families, respectively. Most of the 24 genes had extensive tissue expression, and 9 genes could be clustered in a similar expression trend. Besides, SlYTH1 and SlYTH3A showed a different expression pattern in leaf and fruit development. Additionally, qPCR data revealed the expression variation under multiple abiotic stresses, and LC-MS/MS determination exhibited that the cold stress decreased the level of N6 2'-O dimethyladenosine (m6Am). Notably, the orthologs of newly identified single-strand DNA (ssDNA) 6mA writer-eraser-reader also existed in the tomato genome. Our study provides comprehensive information on m6A components and their family proteins in tomato and will facilitate further functional analysis of the tomato N6-methyladenosine modification genes.