Recognition of cyclic dinucleotides and folates by human SLC19A1.

Cyclic dinucleotides (CDNs) are ubiquitous signalling molecules in all domains of life1,2. Mammalian cells produce one CDN, 2'3'-cGAMP, through cyclic GMP-AMP synthase after detecting cytosolic DNA signals3-7. 2'3'-cGAMP, as well as bacterial and synthetic CDN analogues, can act as second messengers to activate stimulator of interferon genes (STING) and elicit broad downstream responses8-21. Extracellular CDNs must traverse the cell membrane to activate STING, a process that is dependent on the solute carrier SLC19A122,23. Moreover, SLC19A1 represents the major transporter for folate nutrients and antifolate therapeutics24,25, thereby placing SLC19A1 as a key factor in multiple physiological and pathological processes. How SLC19A1 recognizes and transports CDNs, folate and antifolate is unclear. Here we report cryo-electron microscopy structures of human SLC19A1 (hSLC19A1) in a substrate-free state and in complexes with multiple CDNs from different sources, a predominant natural folate and a new-generation antifolate drug. The structural and mutagenesis results demonstrate that hSLC19A1 uses unique yet divergent mechanisms to recognize CDN- and folate-type substrates. Two CDN molecules bind within the hSLC19A1 cavity as a compact dual-molecule unit, whereas folate and antifolate bind as a monomer and occupy a distinct pocket of the cavity. Moreover, the structures enable accurate mapping and potential mechanistic interpretation of hSLC19A1 with loss-of-activity and disease-related mutations. Our research provides a framework for understanding the mechanism of SLC19-family transporters and is a foundation for the development of potential therapeutics.

Nylon Fabric/GO Based Self-Powered Humidity Sensor Based on the Galvanic Cell Principle with High Air Permeability and Rapid-Response.

Flexible humidity sensors have received more and more attention in people's lives, and the problems of gas permeability and power supply issues of the device have long been areas in need of improvement. In this work, inspired by the high air permeability of daily wear clothing and galvanic batteries, a self-powered humidity sensor with high air permeability and fast response is designed. A nylon fabric/GO net (as a humidity sensitive layer and solid electrolyte) is obtained by spraying technique. This structure enables the sensor to have fast response/recovery (0.78 s/0.93 s, calculated at 90% of the final value), ultra-high response (0.83 V) and excellent stability (over 150 cycles) at 35 °C. Such sensors are useful for health monitoring, such as non-contact monitoring of human respiratory rate before and after exercise, and monitoring a level of humidity in the palms, arms, and fingers. This research provides an idea for developing a flexible wearable humidity sensor that is both breathable and self-powered and can also be mass-produced similar to wearable clothing.

Indole-3 acetic acid negatively regulates rose black spot disease resistance through antagonizing the salicylic acid signaling pathway via jasmonic acid.

MAIN CONCLUSION: IAA cooperates with JA to inhibit SA and negatively regulates rose black spot disease resistance. Black spot disease caused by the fungus Marssonina rosae is the most prevalent and severe ailment in rose cultivation, leading to the appearance of black spots on leaves and eventual leaf fall, significantly impacting the utilization of roses in gardens. Salicylic acid (SA) and jasmonic acid (JA) are pivotal hormones that collaborate with indole-3 acetic acid (IAA) in regulating plant defense responses; however, the detailed mechanisms underlying the induction of black spot disease resistance by IAA, JA, and SA remain unclear. In this study, transcript analysis was conducted on resistant (R13-54) and susceptible (R12-26) lines following M. rosae infection. In addition, the impact of exogenous interference with IAA on SA- and JA-mediated disease resistance was examined. The continuous accumulation of JA, in synergy with IAA, inhibited activation of the SA signaling pathway in the early infection stage, thereby negatively regulating the induction of effective resistance to black spot disease. IAA administration alleviated the inhibition of SA on JA to negatively regulate the resistance of susceptible strains by further enhancing the synthesis and accumulation of JA. However, IAA did not contribute to the negative regulation of black spot resistance when high levels of JA were inhibited. Virus-induced gene silencing of RcTIFY10A, an inhibitor of the JA signaling pathway, further suggested that IAA upregulation led to a decrease in disease resistance, a phenomenon not observed when the JA signal was inhibited. Collectively, these findings indicate that the IAA-mediated negative regulation of black spot disease resistance relies on activation of the JA signaling pathway.

The Marssonina rosae effector MrSEP43 suppresses rose immunity by targeting the orphan protein RcBROG.

Rose black spot disease, caused by Marssonina rosae (syn. Diplocarpon rosae), is one of the most widespread diseases of field-grown roses worldwide. Pathogens have been found to interfere with or stimulate plant immune response through the secreted effectors. However, the molecular mechanism involved in inhibition of rose immune response by M. rosae effectors remains poorly understood. In this study, we identified the effector MrSEP43, which played a pivotal role in promoting the virulence of M. rosae and enhancing rose susceptibility by reducing callose deposition, H2O2 accumulation, and the expression of defense genes in jasmonic acid signaling pathway. Through Y2H, BiFC, and LUC assays, MrSEP43 was proved to interact with the rose orphan protein RcBROG. RcBROG, which was a positive regulator of defense against M. rosae, enhanced rose resistance by increasing callose deposition, H2O2 accumulation, and expression of RcERF1 in the ethylene signaling pathway. Overall, our findings suggested that the virulence effector MrSEP43 from M. rosae specifically targeted the orphan protein RcBROG to suppress rose immune response to M. rosae. These results provided new insight into how M. rosae manipulated and successfully colonized rose leaves, and were essential for preventing the breakdown of resistance to rose black spot disease.

PfPIN5 promotes style elongation by regulating cell length in Primula forbesii Franch.

BACKGROUND AND AIMS: Style dimorphism is one of the polymorphic characteristics of flowers in heterostylous plants, which have two types of flowers: the pin morph, with long styles and shorter anthers, and the thrum morph, with short styles and longer anthers. The formation of dimorphic styles has received attention in the plant world. Previous studies showed that CYP734A50 in Primula determined style length and limited style elongation and that the brassinosteroid metabolic pathway was involved in regulation of style length. However, it is unknown whether there are other factors affecting the style length of Primula. METHODS: Differentially expressed genes highly expressed in pin morph styles were screened based on Primula forbesii transcriptome data. Virus-induced gene silencing was used to silence these genes, and the style length and anatomical changes were observed 20 days after injection. KEY RESULTS: PfPIN5 was highly expressed in pin morph styles. When PfPIN5 was silenced, the style length was shortened in pin and long-homostyle plants by shortening the length of style cells. Moreover, silencing CYP734A50 in thrum morph plants increased the expression level of PfPIN5 significantly, and the style length increased. The results indicated that PfPIN5, an auxin efflux transporter gene, contributed to regulation of style elongation in P. forbesii. CONCLUSIONS: The results implied that the auxin pathway might also be involved in the formation of styles of P. forbesii, providing a new pathway for elucidating the molecular mechanism of style elongation in P. forbesii.

Integrative Metabolomic and Transcriptomic Analyses Reveal the Mechanism of Petal Blotch Formation in Rosa persica.

Petal blotch is a specific flower color pattern commonly found in angiosperm families. In particular, Rosa persica is characterized by dark red blotches at the base of yellow petals. Modern rose cultivars with blotches inherited the blotch trait from R. persica. Therefore, understanding the mechanism for blotch formation is crucial for breeding rose cultivars with various color patterns. In this study, the metabolites and genes responsible for the blotch formation in R. persica were identified for the first time through metabolomic and transcriptomic analyses using LC-MS/MS and RNA-seq. A total of 157 flavonoids were identified, with 7 anthocyanins as the major flavonoids, namely, cyanidin 3-O-(6″-O-malonyl) glucoside 5-O-glucoside, cyanidin-3-O-glucoside, cyanidin 3-O-galactoside, cyanidin O-rutinoside-O-malonylglucoside, pelargonidin 3-O-glucoside, pelargonidin 3,5-O-diglucoside, and peonidin O-rutinoside-O-malonylglucoside, contributing to pigmentation and color darkening in the blotch parts of R. persica, whereas carotenoids predominantly influenced the color formation of non-blotch parts. Zeaxanthin and antheraxanthin mainly contributed to the yellow color formation of petals at the semi-open and full bloom stages. The expression levels of two 4-coumarate: CoA ligase genes (Rbe014123 and Rbe028518), the dihydroflavonol 4-reductase gene (Rbe013916), the anthocyanidin synthase gene (Rbe016466), and UDP-flavonoid glucosyltransferase gene (Rbe026328) indicated that they might be the key structural genes affecting the formation and color of petal blotch. Correlation analysis combined with weighted gene co-expression network analysis (WGCNA) further characterized 10 transcription factors (TFs). These TFs might participate in the regulation of anthocyanin accumulation in the blotch parts of petals by modulating one or more structural genes. Our results elucidate the compounds and molecular mechanisms underlying petal blotch formation in R. persica and provide valuable candidate genes for the future genetic improvement of rose cultivars with novel flower color patterns.

Comparative metabolomic analysis reveals nutritional properties and pigmentation mechanism of tea-scented rosehips.

BACKGROUND: The fruits of the genus Rosa, commonly known as rosehips, have attracted significant attention owing to their rich content of various bioactive compounds. However, their utility is generally secondary to the ornamental appeal of their flowers. This study aimed to explore the quality differences among tea-scented rosehips found in Yunnan, China, including those of Rosa odorata var. odorata (RO), Rosa odorata var. gigantea (RG), and Rosa yangii (RY). Morphological characteristics, chemical composition, and antioxidant activity of their fruits were evaluated. RESULTS: The study revealed significant variability in composition and biological activities based on fruit color. RO exhibited the highest levels of polyphenols, flavonoids, anthocyanins, carotenoids, and vitamin C, with the strongest antioxidant activity (10.99 µmol Trolox·g-1 ), followed by RG (7.91 µmol Trolox·g-1 ) and RY (6.52 µmol Trolox·g-1 ). This supports RO's potential as a functional food source. Untargeted metabolomics identified and quantified 502 metabolites, with flavonoids (171) and phenolic acids (147) as the main metabolites. The differential metabolites among the fruits are primarily enriched for flavonoid biosynthesis and phenylpropanoid biosynthesis pathways. Insights into color formation supported the role of anthocyanins, flavones, and flavonols in fruit color variation. CONCLUSION: Tea-scented rosehips offer vibrant colors and high nutritional value with potent biological activities. Rosa odorata var. odorata stands out as a functional food source owing to its rich bioactive compounds. These findings lay the groundwork for utilizing rosehips in functional foods, health supplements, and food additives, emphasizing the practical and beneficial applications of Rosa spp. independent of their ornamental value. © 2023 Society of Chemical Industry.

Highly Anion-Conductive Viologen-based Two-Dimensional Polymer Membranes as Nanopower Generators.

Two-dimensional polymers (2DPs) and their layer-stacked 2D covalent organic frameworks (2D COFs) membranes hold great potential for harvesting sustainable osmotic energy. The nascent research has yet to simultaneously achieve high ionic flux and selectivity, primarily due to inefficient ion transport dynamics. This is directly related to ultrasmall pore size (<3 nm), much smaller than the duple Debye length in the diluted electrolyte (6~20 nm), as well as low charge density (<4.5 mC m-2). Here, we introduce a π-conjugated viologen-based 2DP (V2DP) membrane possessing a large pore size of 4.5 nm, strategically enhancing the overlapping of the electric double layer, coupled with an exceptional positive surface charge density (~6 mC m-2). These characteristics enable the membrane to facilitate high anion flux while maintaining ideal selectivity. Notably, V2DP membranes realize an impressive current density of 5.5×103 A m-2, surpassing  previously nanofluidic membranes. In practical application scenario involving the mixing of artificial seawater and river water, the V2DP membranes exhibit a considerable ion transference number of 0.70 towards Cl-, contributing to an outstanding power density of ~55 W m-2. Theoretical calculations reveal that the large quantity of anion transport sites act as binding sites evenly located in the positively charged N-containing pyridine rings.

Liquid-liquid phase separation-related gene in gliomas: FABP5 is a potential prognostic marker.

BACKGROUND: The glioma is the most malignant human brain tumor. Early glioma detection and treatment are still difficult. New biomarkers are desperately required to aid in the evaluation of diagnosis and prognosis. METHODS: The single cell sequencing dataset scRNA-6148 for glioblastoma was obtained from the Chinese Glioma Genome Atlas database. Data were gathered for the transcriptome sequencing project. Genes involved in liquid-liquid phase separation (LLPS) were taken out of the DrLLPS database. To find the modules connected to LLPS, the weighted co-expression network was analyzed. Differential expression analysis was used to identify the differentially expressed genes (DEGs) in gliomas. Pseudo-time series analysis, gene set enrichment analysis (GSEA) and immune cell infiltration analysis were used to investigate the role of important genes in the immunological microenvironment. We examined the function of key glioma genes using polymerase chain reaction (PCR) testing, CCK-8 assays, clone generation assays, transwell assays and wound healing assays. RESULTS: FABP5 was identified as a key gene in glioblastoma by multiomics research. Pseudo-time series analysis showed that FABP5 was highly linked with the differentiation of many different types of cells. GSEA revealed that FABP5 was strongly linked to several hallmark pathways in glioblastoma. We looked at immune cell infiltration and discovered a significant link between FABP5, macrophages and T cell follicular helpers. The PCR experiment results demonstrated that FABP5 expression was elevated in glioma samples. Cell experiments showed that FABP5 knockdown dramatically decreased the viability, proliferation, invasion and migration of the LN229 and U87 glioma cell lines. CONCLUSIONS: Our study provides a new biomarker, FABP5, for glioma diagnosis and treatment.

Integration of chromatin accessibility and gene expression reveals new regulators of cold hardening to enhance freezing tolerance in Prunus mume.

Low temperature is one of the most important abiotic factors limiting the growth, development and geographical distribution of plants. Prunus mume is an attractive woody ornamental plant that blooms in early spring in Beijing. However, the molecular mechanisms underlying cold hardening to enhance freezing tolerance in Prunus genus remains elusive. This study examined the dynamic physiological responses induced by cold hardening, and identified freezing-tolerance genes by RNA-seq and ATAC-seq analyses. Cold hardening elevated the content of soluble substances and enhanced freezing resistance in P. mume. Transcriptome analysis indicated that the candidate differentially expressed genes (DEGs) were those enriched in Ca2+ signalling, mitogen-activated protein kinase (MAPK) cascade, abscisic acid signalling, and inducer of CBF expression 1 (ICE)-C-repeat binding factor (CBF) signalling pathways. The openness of gene chromatin positively correlated with the expression level of these genes. Thirteen motifs were identified in the open chromatin regions in the treatment group subjected to freezing after cold hardening. The chromatin opening of transcription start site at the proximal -177 region of cold-shock protein CS120-like (PmCSL) was markedly increased, while the expression level of PmCSL was significantly up-regulated. Overexpression of PmCSL in Arabidopsis significantly improved the freezing tolerance of transgenic plants. These findings provide new insights into the regulatory mechanism of freezing tolerance to improve breeding of cold-hardy P. mume plants.

Comparative Analysis of Single-Path and Multipath Adrenal Venous Sampling in Primary Aldosteronism.

Objective: To evaluate the safety and efficacy of adrenal venous sampling (AVS) via the cubital vein and femoral vein synchronously. Methods: A total of 200 patients with primary aldosteronism admitted to the First Hospital of Fujian Medical University were enrolled and randomly divided into a single-path AVS group (SP, N = 108) and a multipath AVS group (MP, N = 92). We analyzed the clinical characteristics, intubation success rate, procedure cost, total fluoroscopy time, complications, contrast dosage, and the number of catheters selected during AVS. A planar quadrant system was established to mark the direction of the adrenal opening, with the intersection of the right renal vein and the inferior vena cava defined as the origin. In digital subtraction angiography images, the RAV opening located in the 0-3 o'clock direction was the first quadrant (I), and the 3-6 o'clock direction was the third quadrant (III). Results: There was no statistical difference between the two groups at baseline. Multipath AVS had a significantly higher success rate of right-sided intubation than single-path AVS (success rate of right-sided intubation/%: SP 87.96 vs MP 95.65, P = 0.043). Total fluoroscopy time was significantly reduced (fluoroscopy time/min: SP 9.80 ± 4.07 vs MP 7.42 ± 3.48, P = 0.024) and the cost of the procedure was markedly lower (cost/yuan: SP 3,900.93 ± 1,191.12 vs MP 3,378.26 ± 399.40, P < 0.001). There was no significant difference in postoperative complications between the two groups. In the group I, the procedure was completed mainly with an MPA catheter (catheter selection/%: MPA 98.19 vs TIG 17.65, P < 0.001). In the group III, TIG catheters were used more frequently (catheter selection/%: MPA 1.81 vs TIG 82.35, P < 0.001). Conclusion: Multipath AVS via the cubital vein and femoral vein improves the success rate of AVS with comparable safety compared to single-path AVS. When the RAV is opened in the III quadrant, the TIG catheter improves the cannulation success rate. The multipath AVS method provides more catheter options. Patients diagnosed with PA at the First Hospital of Fujian Medical University from December 2019 to December 2021 were included. The collection of medical records of the included population was approved by the ethics committee (approval number: [2021] 311). This was a cross-sectional study in which some patients were treated surgically and some were treated with superselective adrenal artery embolization (SAAE). We conducted a cohort study of patients treated with SAAE. ClinicalTrials.gov Protocol Registration and Results System (PRS) receipt release date: January 11, 2022. This trial is registered with NCT05188872.

Molecular mechanism underlying selective inhibition of mRNA nuclear export by herpesvirus protein ORF10.

Viruses employ multiple strategies to inhibit host mRNA nuclear export. Distinct to the generally nonselective inhibition mechanisms, ORF10 from gammaherpesviruses inhibits mRNA export in a transcript-selective manner by interacting with Rae1 (RNA export 1) and Nup98 (nucleoporin 98). We now report the structure of ORF10 from MHV-68 (murine gammaherpesvirus 68) bound to the Rae1-Nup98 heterodimer, thereby revealing detailed intermolecular interactions. Structural and functional assays highlight that two highly conserved residues of ORF10, L60 and M413, play critical roles in both complex assembly and mRNA export inhibition. Interestingly, although ORF10 occupies the RNA-binding groove of Rae1-Nup98, the ORF10-Rae1-Nup98 ternary complex still maintains a comparable RNA-binding ability due to the ORF10-RNA direct interaction. Moreover, mutations on the RNA-binding surface of ORF10 disrupt its function of mRNA export inhibition. Our work demonstrates the molecular mechanism of ORF10-mediated selective inhibition and provides insights into the functions of Rae1-Nup98 in regulating host mRNA export.

Phylogeny of PmCCD Gene Family and Expression Analysis of Flower Coloration and Stress Response in Prunus mume.

The CCD gene family plays a crucial role in the cleavage of carotenoids, converting them into apocarotenoids. This process not only impacts the physiology and development of plants but also enhances their tolerance toward different stresses. However, the character of the PmCCD gene family and its role in ornamental woody Prunus mume remain unclear. Here, ten non-redundant PmCCD genes were identified from the P. mume genome, and their physicochemical characteristics were predicted. According to the phylogenetic tree, PmCCD proteins were classified into six subfamilies: CCD1, CCD4, CCD7, CCD8, NCED and CCD-like. The same subfamily possessed similar gene structural patterns and numbers of conserved motifs. Ten PmCCD genes were concentrated on three chromosomes. PmCCD genes exhibited interspecific collinearity with P. armeniaca and P. persica. Additionally, PmCCD genes had obvious specificity in different tissues and varieties. Compared with white-flowered 'ZLE', PmCCD1 and PmCCD4 genes were low-expressed in 'HJH' with yellow petals, which suggested PmCCD1 and PmCCD4 might be related to the formation of yellow flowers in P. mume. Nine PmCCD genes could respond to NaCl or PEG treatments. These genes might play a crucial role in salt and drought resistance in P. mume. Moreover, PmVAR3 and PmSAT3/5 interacted with PmCCD4 protein in yeast and tobacco leaf cells. This study laid a foundation for exploring the role of the PmCCD gene family in flower coloration and stress response in P. mume.

KNOX Genes Were Involved in Regulating Axillary Bud Formation of Chrysanthemum × morifolium.

Branching is an important agronomic and economic trait in cut chrysanthemums. The axillary meristem (AM) formation of the axillary buds of cut chrysanthemums has a decisive role in its branching characteristics. However, little is known about the regulation mechanism of axillary meristem formation in chrysanthemums at the molecular level. Members of the Homeobox gene family especially genes belonging to the class I KNOX branch play a key role in regulating the axillary bud growth and development processes of plants. In this study, three genes belonging to the class I KNOX branch, CmKNAT1, CmKNAT6, and CmSTM were cloned from chrysanthemums, and their functions in regulating axillary bud formation were examined. The subcellular localization test showed that these three KNOX genes were expressed in the nucleus, so all of them might function as transcription factors. The results of the expression profile analysis showed that these three KNOX genes were highly expressed in the AM formation stage of axillary buds. Overexpression of KNOX genes result in a wrinkled leaf phenotype in tobacco and Arabidopsis, which may be related to the excessive division of leaf cells, resulting in the proliferation of leaf tissue. Furthermore, overexpression of these three KNOX genes enhances the regeneration ability of tobacco leaves, indicating that these three KNOX genes may participate in the regulation of cell meristematic ability, thus promoting the formation of buds. In addition, the results of fluorescence quantitative testing showed that these three KNOX genes may promote the formation of chrysanthemum axillary buds by promoting the cytokinin pathway while inhibiting the auxin and gibberellin pathways. In conclusion, this study demonstrated that CmKNAT1, CmKNAT6, and CmSTM genes were involved in regulating axillary bud formation of Chrysanthemum × morifolium and preliminarily revealed the molecular mechanism of their regulation of AM formation. These findings may provide a theoretical basis and candidate gene resources for genetic engineering breeding of new varieties of cut chrysanthemums without lateral branches.

Genome-Wide Identification of the MAPK and MAPKK Gene Families in Response to Cold Stress in Prunus mume.

Protein kinases of the MAPK cascade family (MAPKKK-MAPKK-MAPK) play an essential role in plant stress response and hormone signal transduction. However, their role in the cold hardiness of Prunus mume (Mei), a class of ornamental woody plant, remains unclear. In this study, we use bioinformatic approaches to assess and analyze two related protein kinase families, namely, MAP kinases (MPKs) and MAPK kinases (MKKs), in wild P. mume and its variety P. mume var. tortuosa. We identify 11 PmMPK and 7 PmMKK genes in the former species and 12 PmvMPK and 7 PmvMKK genes in the latter species, and we investigate whether and how these gene families contribute to cold stress responses. Members of the MPK and MKK gene families located on seven and four chromosomes of both species are free of tandem duplication. Four, three, and one segment duplication events are exhibited in PmMPK, PmvMPK, and PmMKK, respectively, suggesting that segment duplications play an essential role in the expansion and evolution of P. mume and its gene variety. Moreover, synteny analysis suggests that most MPK and MKK genes have similar origins and involved similar evolutionary processes in P. mume and its variety. A cis-acting regulatory element analysis shows that MPK and MKK genes may function in P. mume and its variety's development, modulating processes such as light response, anaerobic induction, and abscisic acid response as well as responses to a variety of stresses, such as low temperature and drought. Most PmMPKs and PmMKKs exhibited tissue-specifific expression patterns, as well as time-specific expression patterns that protect them through cold. In a low-temperature treatment experiment with the cold-tolerant cultivar P. mume 'Songchun' and the cold-sensitive cultivar 'Lve', we find that almost all PmMPK and PmMKK genes, especially PmMPK3/5/6/20 and PmMKK2/3/6, dramatically respond to cold stress as treatment duration increases. This study introduces the possibility that these family members contribute to P. mume's cold stress response. Further investigation is warranted to understand the mechanistic functions of MAPK and MAPKK proteins in P. mume development and response to cold stress.

Analysis of Spatial-Temporal Variation in Floral Volatiles Emitted from Lagerstroemia caudata by Headspace Solid-Phase Microextraction and GC-MS.

Lagerstroemia caudata is a rare aromatic species native to southeastern China, but its floral scent properties and release dynamics remain unclear. This study is the first systematic analysis of spatial-temporal variation in volatile organic compounds (VOCs) emitted from L. caudata by headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS). Thirty-two VOCs were identified, 20 of which were detected for the first time. Aldehydes, alcohols, and monoterpenoids were the main VOC categories, each with different releasing rhythms. Total emission of VOCs was much higher in the full-blooming stage (140.90 ng g-1min-1) than in the pre-blooming (36.54 ng g-1min-1) or over-blooming (24.92 ng g-1min-1). Monoterpenoids, especially nerol, geraniol, and linalool, were the characteristic VOCs for full-blooming flowers. Daily emissions of nine compounds (nerol, geraniol, linalool, citronellol, ß-citral, (E)-citral, phenylethyl alcohol, 2-heptanol, 2-nonanol) correlated closely with the opening of L. caudata, presenting an apparent diurnal pattern of scent emission. Tissue-specific emission was found in most isolated floral parts. Stamen was the most significant source of floral VOCs, considering its high emission levels of total VOC (627.96 ng g-1min-1). Our results extend the information on floral VOCs of Lagerstroemia and provide a theoretical basis for breeding new cultivars with desirable floral scents.

Cytological, physiological and transcriptomic analysis of variegated Leaves in Primulina pungentisepala offspring.

BACKGROUND: Primulina pungentisepala is suitable for use as a potted plant because of its beautiful leaf variegation, which is significantly different in its selfed offspring. However, the mechanism of P. pungentisepala leaf variegation is unclear. In this study, two types of offspring showing the greatest differences were compared in terms of leaf structure, chlorophyll contents, chlorophyll fluorescence parameters and transcriptomes to provide a reference for studying the molecular mechanism of structural leaf variegation. RESULTS: Air spaces were found between water storage tissue, and the palisade tissue cells were spherical in the white type. The content of chlorophyll a and total chlorophyll (chlorophyll a + b) was significantly lower in the white type, but there were no significant differences in the content of chlorophyll b, chlorophyll a/b or chlorophyll fluorescence parameters between the white and green types. We performed transcriptomic sequencing to identify differentially expressed genes (DEGs) involved in cell division and differentiation, chlorophyll metabolism and photosynthesis. Among these genes, the expression of the cell division- and differentiation-related leucine-rich repeat receptor-like kinases (LRR-RLKs), xyloglucan endotransglycosylase/hydrolase (XET/H), pectinesterase (PE), expansin (EXP), cellulose synthase-like (CSL), VARIEGATED 3 (VAR3), and ZAT10 genes were downregulated in the white type, which might have promoted the development air spaces and variant palisade cells. Chlorophyll biosynthesis-related hydroxymethylbilane synthase (HEMC) and the H subunit of magnesium chelatase (CHLH) were downregulated, while chlorophyll degradation-related chlorophyllase-2 (CHL2) was upregulated in the white type, which might have led to lower chlorophyll accumulation. CONCLUSION: Leaf variegation in P. pungentisepala was caused by a combination of mechanisms involving structural variegation and low chlorophyll levels. Our research provides significant insights into the molecular mechanisms of structural leaf variegation.

The chromosome-level genome provides insight into the molecular mechanism underlying the tortuous-branch phenotype of Prunus mume.

Plant with naturally twisted branches is referred to as a tortuous-branch plant, which have extremely high ornamental value due to their zigzag shape and the natural twisting of their branches. Prunus mume is an important woody ornamental plant. However, the molecular mechanism underlying this unique trait in Prunus genus is unknown. Here, we present a chromosome-level genome assembly of the cultivated P. mume var. tortuosa created using Oxford Nanopore combined with Hi-C scaffolding, which resulted in a 237.8 Mb genome assembly being anchored onto eight pseudochromosomes. Molecular dating indicated that P. mume is the most recently differentiated species in Prunus. Genes associated with cell division, development and plant hormones play essential roles in the formation of tortuous branch trait. A putative regulatory pathway for the tortuous branch trait was constructed based on gene expression levels. Furthermore, after transferring candidate PmCYCD genes into Arabidopsis thaliana, we found that seedlings overexpressing these genes exhibited curled rosette leaves. Our results provide insights into the evolutionary history of recently differentiated species in Prunus genus, the molecular basis of stem morphology, and the molecular mechanism underlying the tortuous branch trait and highlight the utility of multi-omics in deciphering the properties of P. mume plant architecture.

Evidence for hexasomic inheritance in Chrysanthemum morifolium Ramat. based on analysis of EST-SSR markers.

Chrysanthemums (Chrysanthemum morifolium Ramat.) are ornamental flowers, which are famous worldwide. The mode of inheritance has great implications for the genetic analysis of polyploid species. However, genetic analysis of chrysanthemum has been hampered because of its controversial inheritance mode (disomic or hexasomic). To classify the inheritance mode of chrysanthemums, an analysis of three approaches was carried out in an F1 progeny of 192 offspring using 223 expressed sequence tag-simple sequence repeat (EST-SSR) markers. The analysis included segregation analysis, the ratio of simplex marker alleles linked in coupling to repulsion, as well as the transmission and segregation patterns of EST-SSR marker alleles. After segregation analysis, 204 marker alleles fit hexasomic inheritance and 150 marker alleles fit disomic inheritance, showing that marker alleles were inherited predominantly in a hexasomic manner. Furthermore, the results of the analysis of allele configuration and segregation behavior of five EST-SSR markers also suggested random pairing of chromosomes. Additionally, the ratio of simplex marker alleles linked in coupling to repulsion was 1:0, further supporting hexasomic inheritance. Therefore, it could be inferred that chrysanthemum is a complete or near-complete hexasome.

Effects of different photoperiods on flower opening, flower closing and circadian expression of clock-related genes in Iris domestica and I. dichotoma.

The circadian clock can entrain to forced light-dark cycles by adjusting the phases and periods of flower opening and closing in ephemeral flowers. The responses of circadian rhythms to the same light conditions differ from species. However, the differences in internal genetic mechanisms underlying the different responses between species remain unclear. Iris domestica and I. dichotoma have ephemeral flowers and significantly divergent flower opening and closing times. The effects of different photoperiods (continuous darkness, 4L20D, 8L16D, 12L12D, 16L8D, 20L4D and continuous white light) on flower opening and closing, and expression patterns of seven genes (CRYPTOCHROME 1, PHYTOCHROME B, LATE ELONGATED HYPOCOTYL, PSEUDO RESPONSE REGULATOR 95, PHYTOCHROME INTERACTING FACTOR 4-like, SMUX AUXIN UP RNA 64-like and senescence-associated gene 39-like) involved in the circadian regulation of flower opening and closing were compared between I. domestica and I. dichotoma. Flower opening and closing in the two species exhibited circadian rhythms under continuous darkness (DD), but showed arrhythmia in continuous white light (LL). In the two species, keeping robust rhythms, strong synchronicity, rapid progressions of flower opening and closing and reaching full opening stage required a dark period longer than 4 h. In light-dark cycles with dark periods longer than 4 h, flower opening and closing times of the two species delayed with the delay of dawn, and the degree to which flower opening time varies with the time of dawn was greater in I. dichotoma than in I. domestica. The arrhythmia of flower opening and closing under 20L4D and LL would result from the arrhythmic output signals rather than arrhythmia of oscillators and photoreceptors. The different responses of the two species to the change of photoperiods would be caused by the transcriptional differences of genes in the output pathway of circadian clock system rather than in the input pathway or oscillators.