Genetic Insights into the Extremely Dwarf Hibiscus syriacus var. micranthus: Complete Chloroplast Genome Analysis and Development of a Novel dCAPS Marker.

This study explored the chloroplast (cp) genomes of three Hibiscus syriacus (HS) specimens endemic to Korea possessing unique ornamental and conservation values: the dwarf H. syriacus var. micranthus (HSVM), renowned for its small stature and breeding potential; HS 'Tamra', a cultivar from Korea's southernmost islands, noteworthy for its distinctive beauty; and HS Natural Monument no. 521 (N.M.521), a specimen of significant lifespan and height. Given the scarcity of evolutionary studies on these specimens, we assembled and analyzed their cp genomes. We successfully assembled genomes spanning 160,000 to 160,100 bp and identified intraspecific variants. Among these, a unique ATA 3-mer insertion in the trnL-UAA region was identified in HSVM, highlighting its value as a genetic resource. Leveraging this finding, we developed a novel InDel dCAPS marker, which was validated across 43 cultivars, enhancing our ability to distinguish HSVM and its derivatives from other HS cultivars. Phylogenetic analysis involving 23 Malvaceae species revealed that HSVM forms a clade with woody Hibiscus species, closely associating with N.M.520, which may suggest a shared ancestry or parallel evolutionary paths. This investigation advances our understanding of the genetic diversity in Korean HS and offers robust tools for accurate cultivar identification, aiding conservation and breeding efforts.

Wound healing effect of polydeoxyribonucleotide derived from Hibiscus sabdariffa callus via Nrf2 signaling in human keratinocytes.

There has been a growing interest in skin recovery in both the medical and cosmetics fields, leading to an increasing number of studies reporting diverse materials being utilized for this purpose. Among them, polydeoxyribonucleotide (PDRN) is known for its efficacy in skin repair processes, while Hibiscus sabdariffa (HS) is recognized for its antioxidant, hypolipidemic, and wound healing properties, including its positive impact on mammalian skin and cells. We hypothesized that these characteristics may have a germane relationship during the healing process. Consequently, we induced calli from HS and then extracted PDRN for use in treating human keratinocytes. PDRN (5 µg/mL) had considerable wound healing effects and wrinkle improvement effects. To confirm its function at the molecular level, we performed real-time polymerase chain reaction, western blotting, and immunocytochemistry. Furthermore, genes related to wound healing (MMP9, Nrf2, KGF, VEGF, SOD2, and AQP3) were significantly upregulated. Additionally, the protein expression of MMP9, AQP3, and CAT, which are closely related to wound healing and antioxidant cascades, was considerably enhanced. Based on cellular morphology and molecular-level evidence, we propose that PDRN from calli of HS can improve wound healing in human keratinocytes. Furthermore, its potential to serve as a novel material in cosmetic products is demonstrated.

Study on the causes of changes in colour during Hibiscus syriacus flowering based on transcriptome and metabolome analyses.

BACKGROUND: The flower colour of H. syriacus 'Qiansiban' transitions from fuchsia to pink-purple and finally to pale purple, thereby enhancing the ornamental value of the cultivars. However, the molecular mechanism underlying this change in flower colour in H. syriacus has not been elucidated. In this study, the transcriptomic data of H. syriacus 'Qiansiban' at five developmental stages were analysed to investigate the impact of flavonoid components on flower colour variation. Additionally, five cDNA libraries were constructed from H. syriacus 'Qiansiban' during critical blooming stages, and the transcriptomes were sequenced to investigate the molecular mechanisms underlying changes in flower colouration. RESULTS: High-performance liquid chromatography‒mass spectrometry detected five anthocyanins in H. syriacus 'Qiansiban', with malvaccin-3-O-glucoside being the predominant compound in the flowers of H. syriacus at different stages, followed by petunigenin-3-O-glucoside. The levels of these five anthocyanins exhibited gradual declines throughout the flowering process. In terms of the composition and profile of flavonoids and flavonols, a total of seven flavonoids were identified: quercetin-3-glucoside, luteolin-7-O-glucoside, Santianol-7-O-glucoside, kaempferol-O-hexosyl-C-hexarbonoside, apigenin-C-diglucoside, luteolin-3,7-diglucoside, and apigenin-7-O-rutinoside. A total of 2,702 DEGs were identified based on the selected reference genome. Based on the enrichment analysis of differentially expressed genes, we identified 9 structural genes (PAL, CHS, FLS, DRF, ANS, CHI, F3H, F3'5'H, and UFGT) and 7 transcription factors (3 MYB, 4 bHLH) associated with flavonoid biosynthesis. The qRT‒PCR results were in good agreement with the high-throughput sequencing data. CONCLUSION: This study will establish a fundamental basis for elucidating the mechanisms underlying alterations in the flower pigmentation of H. syriacus.

Unique properties of titanium dioxide quantum dots assisted regulation of growth and biochemical parameters of Hibiscus sabdariffa plants.

Owing to the uniqueness of quantum dots (QDs) as a potential nanomaterial for agricultural application, hence in the present study, titanium dioxide quantum dots (TiO2 QDs) were successfully synthesized via sol-gel technique and the physico-chemical properties of the prepared TiO2 QDs were analyzed. Based on the results, the TiO2 QDs showed the presence of anatase phase of TiO2. TEM examination revealed spherical QDs morphology with an average size of 7.69 ± 1.22 nm. The large zeta potential value (-20.9 ± 2.3 mV) indicate greater stability of the prepared TiO2 QDs in aqueous solutions. Moreover, in this work, the application of TiO2 QDs on Hibiscus sabdariffa plants was conducted, where H. sabdariffa plants were foliar sprayed twice a week in the early morning with different concentrations of TiO2 QDs (0, 2, 5, 10, 15 and 30 ppm) to evaluate their influence on these plants in terms of morphological indexes and biochemical parameters. The results exhibited an increasing impact of the different used concentrations of TiO2 QDs on morphological indexes, such as fresh weight, dry weight, shoot length, root length, and leaf number, and physio-biochemical parameters like chlorophyll a, chlorophyll b, carotenoid contents, total pigments and total phenolic contents. Remarkably, the most prominent result was recorded at 15 ppm TiO2 QDs where plant height, total protein and enzymatic antioxidants like catalase and peroxidase were noted to increase by 47.6, 20.5, 29.5 and 38.3%, respectively compared to control. Therefore, foliar spraying with TiO2 QDs positively serves as an effective strategy for inducing optimistic effects in H. sabdariffa plants.

An extract of Hibiscus sabdariffa improves short-term memory in rats with experimental diabetic hyperglycemia.

BACKGROUND: Calyxes of Hibiscus sabdariffa (Hs) contain anthocyanins, that normalize blood glucose levels (BGL) in diabetic patients. Diabetes also causes memory alterations, which could hypothetically decrease with the consumption of Hs. OBJECTIVES: To investigate the effect of dietary supplementation with a Hs extract on working memory and BGL in rats. METHODS: Diabetic hyperglycemia (DHG) was induced with streptozotocin (STZ, 55 mg/kg i.p.) in Wistar rats. After 72 h DHG was confirmed, and the consumption of Hs extract began (50 mg/Kg/day). BGL and body weight (BW) were measured at 10, 20 and 30 days after DHG induction in controls and treated animals. Learning and short-term memory were evaluated after 30 days with Novel Object Recognition Test (NOR) and Barnes Maze (BM). The gross hippocampal structure was histologically analyzed. RESULTS: STZ-treated animals presented low BW and persistent DHG (BGL <300 mg/dL). Diabetic animals consuming the Hs extract had a dual response: some showed BGL comparable to controls, while others had levels comparable to diabetic animals not consuming extract. Diabetic animals that consumed the Hs extract had a better performance in NOR and BM than the diabetic animals not consuming the extract. At the histological level, hippocampal morphological differences were observed between diabetic animals that consumed the extract and those that did not. DISCUSSION: The Hs extract used here could be a good co-adjuvant in the treatment of DHG, aimed at mitigating memory deficits and high BGL. These beneficial effects could be attributed to the anthocyanin content in the extract.

Contrasting plant-induced changes in heavy metals dynamics: Implications for phytoremediation strategies in estuarine wetlands.

Wetland plants play a crucial role in regulating soil geochemistry, influencing heavy metal (HM) speciation, bioavailability, and uptake, thus impacting phytoremediation potential. We hypothesized that variations in HM biogeochemistry within estuarine soils are controlled by distinct estuarine plant species. We evaluated the soils (pH, redox potential, rhizosphere pH, HM total concentration, and geochemical fractionation), plant parts (shoot and root), and iron plaques of three plants growing in an estuary affected by Fe-rich mine tailings. Though the integration of multiple plant and soil analysis, this work emphasizes the importance of considering geochemical pools of HM for predicting their fate. Apart from the predominance of HM associated with Fe oxides, Typha domingensis accumulated the highest Cr and Ni contents in their shoots (> 100 mg kg-1). In contrast, Hibiscus tiliaceus accumulated more Cu and Pb in their roots (> 50 mg kg-1). The differences in rhizosphere soil conditions and root bioturbation explained the different potentials between the plants by altering the soil dynamics and HM's bioavailability, ultimately affecting their uptake. This study suggests that Eleocharis acutangula is not suitable for phytoextraction or phytostabilization, whereas Typha domingensis shows potential for Cr and Ni phytoextraction. In addition, we first showed Hibiscus tiliaceus as a promising wood species for Cu and Pb phytostabilization.

First Report of Hibiscus Chlorotic Ringspot Virus infecting Hibiscus rosa-sinensis in Italy.

Hibiscus chlorotic ringspot virus (HCRSV) belongs to the Betacarmovirus genus of the Tombusviridae family and is a positive-sense monopartite single-stranded RNA virus. HCRSV was first described in a hibiscus variety imported into the United States from El Salvador. The HCRSV natural host range is limited to species belonging to Malvaceae family, in particular Hibiscus rosa-sinensis, H. manihot, H. diversifolius and H. syriacus. In September 2023, leaf mottle and chlorotic spots were observed on the leaves of two H. rosa-sinensis plants located in a public garden of Ercolano (Naples city, Southern Italy). Two leaves, one from each symptomatic plant, were pooled and submitted to double-stranded RNA extraction using a Viral Gene-Spin Viral DNA/RNA Extraction Kit (iNtRON, Korea), followed by cDNA library preparation with the TruSeq Stranded Total RNA (Illumina, USA). Sequencing on the Illumina NovaSeq 6000 platform (Illumina, USA) with 150-bp paired-end reads yielded 22,578,913 raw reads. 21,413,571 clean reads were obtained by quality control on the sequencing data was performed with the software FastQC (v. 0.11.5). Then low quality bases and adapters were removed with the software BBDuk in the BBTools package setting a minimum read quality of 25 and minimum read length of 35 bp. The resulted filtered reads were used to assembly viral genome by using two different algorithms (Metaspades and RNAViral) implemented in SPAdes (v. 3.15.3). Of the total contigs de novo assembled, the two algorithms implemented identified respectively 340 and 559 contigs related to viruses. BLASTn analysis of the contigs identify one coting of 3965 nt covering 97% to 100% of the whole genome sequence of nine HCRSV isolates, with percentage of identity of 87.8-95.2%. No other plant viruses or viroids have been identified during bioinformatic analysis. To confirm the result, a full-length genomic sequence of the Italian HCRSV isolate (named Ita-1), was obtained by reverse transcription polymerase chain reaction (RT-PCR) using specific primers designed on the sequence of the assembled contigs. The PCR products were sequenced using the Sanger method (Microsynth Seqlab, Germany) in both directions. The obtained full-length genomic sequence of the HCRSV isolate (Acc. No. OR981792) was 3910 nt in length. Maximum-likelihood phylogenetic trees inferred from the whole genome sequence showed that Ita-1 clustered closely with HCRSV isolates. The leaf samples were further analyzed using a HCRSV ELISA kit (Agdia, USA). Healthy H. rosa-sinensis leaves were taken as a negative control and buffer solution as a blank control. The results showed a positive reaction for the two symptomatic plants (OD = 1.345 ± 0.010 at 405 nm) relative to the negative (OD = 0.097) and blank (OD = 0.065) controls. Overall, the results of serological and molecular analyses supported that symptoms observed in H. rosa-sinensis were strictly associated to HCRSV infection. Four viruses have been reported in H. rosa-sinensis in Italy so far: eggplant mottled dwarf nucleorhabdovirus (EMDV), hibiscus latent Fort Pierce virus (HLFPV), hibiscus latent ringspot virus (HLRSV), hibiscus latent Singapore virus (HLSV). To our knowledge, this is the first report of HCRSV in H. rosa-sinensis in Italy, where probably infected plants were accidentally introduced. At present, HCRSV has been reported in three continents (Asia, Oceania and North America) and the number of countries where the virus has been detected is likely to increase rapidly as a result of increased surveillance and availability of diagnostic methods. This study will help the management of viral diseases on H. rosa-sinensis in Italy.

First report of Hibiscus latent Singapore virus and Hibiscus latent Fort Pierce virus infecting Lantana camara in China.

Hibiscus latent Singapore virus (HLSV) and Hibiscus latent Fort Pierce virus (HLFPV) both belong to the genus Tobamovirus in the family Virgaviridae. The genomes of both HLSV and HLFPV consist of a linear positive sense single-stranded RNA of about 6.3 kb. HLSV is the causal agent of hibiscus leaf crinkle disease. Infections of HLSV in hibiscus (Hibiscus rosa-sinensis) have so far only been reported in Singapore, Japan and Malaysia (Srinivasan et al., 2002; Yoshida et al., 2018; Yusop et al., 2021). In 2017, leaf curling and chlorosis symptoms of lantana (Lantana camara) plants were found in Chenshan Botanical Garden, Shanghai, China. To detect potential virus(es) in these lantana samples, leaves from one lantana plant were collected and total RNA was extracted with RNAiso Plus (TaKaRa). A cDNA library was prepared by TruSeq RNA Sample Prep Kit (Illumina) after removing ribosomal RNA by Ribo-ZeroTM rRNA Removal Kit (Epicentre). The paired-end sequencing was then performed on an Illumina NovaSeq 6000. A total of 61,085,018 high quality reads were obtained and de novo assembly by StringTie revealed 124,516 contigs (greater than 50 bp, N50=719 bp) with an average length of 537 bp. BLASTx analyses in the National Center for Biotechnology Information (NCBI) database showed that 1 long contig of 6,305 bp, assembled of 1794 clean reads, shared significant nucleotide similarities with the genomic sequence of HLSV, and 1 contig of 6,271 bp, assembled of 3174 clean reads, shared significant similarities with the genomic sequence of HLFPV, yielding an average coverage of the whole genome at 42.65 and 75.83 per million reads, respectively. To obtain the complete genome of the viral RNA in this lantana sample, eleven overlapping regions covering the entire HLSV viral genome, and nine overlapping regions covering the entire HLFPV viral genome were amplified by reverse transcription-PCR (RT-PCR) and sequenced. In addition, the exact 5' and 3' ends of the genomic RNA of each virus were determined by rapid amplification of the cDNA ends (RACE) (Wang et al. 2020). The complete genome of the identified HLSV, deposited in GenBank: MZ020960, is 6,486 nt in length and shows 98.4% nucleotide sequence identity with HLSV Singapore isolate (GenBank: AF395898). Similar to other HLSV isolates, this virus isolate possesses an internal poly(A) tract of 87 nucleotides, which is crucial to virus replication (Niu et al., 2015). The complete genome of the Lantana HLFPV isolate is 6,463 nt (GenBank MZ020961) including a 73 nt internal poly(A) tract, and has 98.4% nt identity to HLFPV-Japan (AB917427). In two other lantana plants from the same site, the presence of HLSV and HLFPV was confirmed by RT-PCR using the primer pairs (5'-GCATCTGCATAACACGGTTG-3'/5'-ACGTTGTAGTAGACGTTGTTGTAG-3' and 5'-GGACCTTGCTAATCCGCTAAAGTTG-3'/5'-GGTCCATGTCCATCCAGATGCAATC-3'). In addition to the HLSV and HLFPV genomes, BLASTx analysis of three contigs of 3,006 bp, 2,845 bp and 2,200 bp, assembled of 1328, 352 and 2280 clean reads respectively, showed high identity to RNAs 1 (MG182148), 2 (DQ412731) and 3 (KY794710) of cucumber mosaic virus. To the best of our knowledge, this is the first report of L. camara as a new natural host of HLSV and HLFPV, and first identification of a mixed infection of HLSV and HLFPV.

Genomic insights into a Pseudomonas amygdali isolate from Hibiscus rosa-sinensis.

The taxonomy of Pseudomonas has been extensively studied, yet the determination of species is currently difficult because of recent taxonomic changes and the lack of complete genomic sequence data. We isolated a bacterium causing a leaf spot disease on hibiscus (Hibiscus rosa-sinensis). Whole genome sequencing revealed similarity to Pseudomonas amygdali pv. tabaci and pv. lachrymans. The genome of this isolate (referred to as P. amygdali 35-1) shared 4987 genes with P. amygdali pv. hibisci, but possessed 204 unique genes and contained gene clusters encoding putative secondary metabolites and copper resistance determinants. We predicted this isolate's type III secretion effector (T3SE) repertoire and identified 64 putative T3SEs, some of which are present in other P. amygdali pv. hibisci strains. Assays showed that the isolate was resistant to copper at a concentration of 1.6 mM. This study provides an improved understanding of the genomic relatedness and diversity of the P. amygdali species.

The utility of Hibiscus sabdariffa L. to prepare metal oxides NPs for clinical application on osteoporosis supported by theoretical study.

Green synthesis of metal oxides as a treatment for bone diseases is still exploring. Herein, MgO and Fe2O3 NPs were prepared from the extract of Hibiscus sabdariffa L. to study their effect on vit D3, Ca+2, and alkaline phosphatase enzyme ALP associated with osteoporosis. Computational chemistry was utilized to gain insight into the possible interactions. These oxides were characterized by X-ray diffraction, SEM, FTIR, and AFM. Results revealed that green synthesis of MgO and Fe2O3 NPs was successful with abundant. MgO NPs were in vitro applied on osteoporosis patients (n = 35) and showed a significant elevation of vit D3 and Ca+2 (0.0001 > p < 0.001) levels, compared to healthy volunteers (n = 25). Thus, Hibiscus sabdariffa L. is a good candidate to prepare MgO NPs, with a promising enhancing effect on vit D3 and Ca+2 in osteoporosis. In addition, interactions of Fe2O3 and MgO NPs with ALP were determined by molecular docking study.

Effects of Rhizopus-arrhizus-31-Assisted Pretreatment on the Extraction and Bioactivity of Total Flavonoids from Hibiscus manihot L.

The Hibiscus manihot L. (HML) Medic, an edible hibiscus of the Malvaceae family, is abundant with flavonoids. The study investigated how Rhizopus-arrhizus-31-assisted pretreatment affects the extraction and bioactivity of flavonoids from HML. The fiber structure of the fermented flavonoid sample (RFF) appears looser, more porous, and more disordered than the unfermented flavonoid sample (RUF). RFF demonstrates milder conditions and yields higher extraction rates. According to the Box-Behnken response surface optimization experiment, the optimal conditions for RFF include a material-liquid ratio of 1:41 g/mL, a 2 h extraction time, a 57% ethanol concentration, and an extraction temperature of 800 °C, resulting in a 3.69% extraction yield, which is 39.25% higher than that of RUF. Additionally, RFF exhibits greater activity than RUF in the radical-scavenging system. The IC50 values for DPPH, OH, and ABTS radicals are 83.43 µg/mL and 82.62 µg/mL, 208.38 µg/mL and 175.99 µg/mL, and 108.59 µg/mL and 75.39 µg/mL for RUF and RFF, respectively. UPLC-QTOF-MS analysis of the active components in the HML flavonoid sample revealed significant differences in the chromatograms of RUF and RFF, indicating that biofermentation led to substantial changes in composition and content from HML.

Fractionation and physicochemical characterization of dietary fiber of kenaf (Hibiscus cannabinus L.) seed.

BACKGROUND: Kenaf seeds are underutilized kenaf plant by-products, containing essential nutrients including dietary fiber (DF), which can be potentially utilized as food ingredients. The present study aimed to evaluate the physicochemical characteristics of kenaf seed fiber fractions extracted from kenaf seed. RESULTS: Defatted kenaf seed powder yielded four DF fractions: alkali-soluble hemicellulose (146.4 g kg-1 ), calcium-bound pectin (10.3 g kg-1 ) and acid-soluble pectin (25.4 g kg-1 ) made up the soluble fibre fraction, whereas cellulose (202.2 g kg-1 ) comprised the insoluble fraction. All fractions were evaluated for their physicochemical properties. The DF fractions contained glucose, mannose, xylose and arabinose, and a small amount of uronic acid (1.2-2.7 g kg-1 ). The isolated pectin fractions had a low degree of esterification (14-30%). All the isolated DF fractions had high average molecular weights ranging from 0.3 to 4.3 × 106 g mol-1 . X-ray diffractogram analysis revealed that the fractions consisted mainly of an amorphous structure with a relative crystallinity ranging from 31.6% to 44.1%. The Fourier-transform infrared spectroscopy spectrum of kenaf seed and its DF fractions showed typical absorption of polysaccharides, with the presence of hydroxyl, carboxyl, acetyl and methyl groups. Scanning electron microscopy analysis demonstrated that the raw material with the rigid structure resulted in soluble and insoluble DF fractions with more fragile and fibrous appearances, respectively. The soluble DF demonstrated greater flowability and compressibility than the insoluble fractions. CONCLUSION: These findings provide novel information on the DF fractions of kenaf seeds, which could be used as a potential new DF for the food industry. © 2023 Society of Chemical Industry.

Hibiscus Sabdariffa L. Extract as a Natural Additive in Food Packaging Biodegradable Films to Improve Antioxidant, Antimicrobial, and Physicochemical Properties.

In this study, biodegradable active films were prepared from potato starch and polyvinyl alcohol at different proportions, mixed with acetone extract of Hibiscus sabdariffa L. (HS) and using glycerol as a plasticizer. Functional properties, antimicrobial, and antioxidant capacity were evaluated. Potato starch films with a proportion of polyvinyl alcohol up to 50% and HS extract had significant antioxidant capacity and antibacterial effect against most of the analyzed strains. Adding polyvinyl alcohol (PVOH) and HS extract improved the mechanical performance and reduced water vapor permeability of the materials. The active biobased films with HS extract presented good physicochemical, antimicrobial, and antioxidant properties. These materials are considered as suitable for food packaging, and the active compounds in the roselle extract are a natural antibacterial option for the food area. The materials based entirely on biodegradable products are an excellent alternative when developing and marketing biobased materials, minimizing the environmental impact of food packaging.

Physiological and transcriptional mechanisms associated with cadmium stress tolerance in Hibiscus syriacus L.

BACKGROUND: Cadmium (Cd) pollution of soils is a global concern because its accumulation in plants generates severe growth retardation and health problems. Hibiscus syriacus is an ornamental plant that can tolerate various abiotic stresses, including Cd stress. Therefore, it is proposed as a plant material in Cd-polluted areas. However, the molecular mechanisms of H. syriacus tolerance to Cd are not yet understood. RESULTS: This study investigated the physiological and transcriptional response of "Hongxing", a Cd2+-tolerant H. syriacus variety, grown on a substrate containing higher concentration of Cd (400 mg/kg). The Cd treatment induced only 28% of plant mortality, but a significant decrease in the chlorophyll content was observed. Malondialdehyde content and activity of the antioxidant enzymes catalase, peroxidase, and superoxide dismutase were significantly increased under Cd stress. Transcriptome analysis identified 29,921 differentially expressed genes (DEGs), including 16,729 down-regulated and 13,192 up-regulated genes, under Cd stress. Functional enrichment analyses assigned the DEGs mainly to plant hormone signal transduction, transport, nucleosome and DNA processes, mitogen-activated protein kinase signaling pathway, antioxidant process, fatty acid metabolism, and biosynthesis of secondary metabolites. Many MYB, EP2/ERF, NAC, WRKY family genes, and genes containing metal binding domains were up-regulated, implying that they are essential for the Cd-stress response in H. syriacus. The most induced genes were filtered out, providing valuable resources for future studies. CONCLUSIONS: Our findings provide insights into the molecular responses to Cd stress in H. syriacus. Moreover, this study offers comprehensive and important resources for future studies toward improving the plant Cd tolerance and its valorization in phytoremediation.

Embryological observations on seed abortion in Hibiscus syriacus L. and physiological studies on nutrients, enzyme activity and endogenous hormones.

Under natural conditions, most Hibiscus syriacus L. individuals form very few mature seeds or the mature seeds that do form are of poor quality. As a result, seed yield is poor and seeds have low natural germinability. These phenomena strongly hinder utilization of the excellent germplasm resources of H. syriacus. The study has shown that pollen activity and stigma receptivity were high on the day of anthesis, and the pistils and stamens were fertile. Pollen release and stigma receptivity were synchronous. But in styles following self and cross-pollination, pollen tube abnormalities (distortion and twisting of the pollen tubes) and callose deposition were observed. Cross-pollinated pollen tubes elongated faster and fewer pollen tube abnormalities were observed compared with self-pollinated pollen tubes. And during embryo development, abnormalities during the heart-shaped embryo stage led to embryo abortion. Imbalance in antioxidant enzyme activities and low contents of auxin and cytokinin during early stages of embryo development may affect embryo development. Therefore, a low frequency of outcrossing and mid-development embryo abortion may be important developmental causes of H. syriacus seed abortion. Nutrient deficiencies, imbalance in antioxidant enzyme activities, and a high content of abscisic acid at advanced stages of seed development may be physiological causes of seed abortion.

Comparative taxonomical, biological and pharmacological potential of healthy and geminivirus infected leaves of Hibiscus rosa-sinensis L.: First report.

In the present research project, the first report on comparative analysis of the taxonomical, biological and pharmacological potential of healthy and geminivirus infected Hibiscus rosa sinensis (L.) leaves of the family Malvaceae was done by using different micro and macroscopic techniques. First of all, leaves were characterized for Cotton leaf curl Multan virus (CLCuMuV) and its associated betasatellite (Cotton leaf curl Multan Betasatellite; CLCuMB). Different morphological parameters like shape and size of stem, leaves, seeds and roots, presence and absence of ligule, distance between nodes and internodes and type of inflorescence etc. were analyzed. CLCuMuV infected H. rosa-sinensis revealed systematic symptoms of infection like chlorosis of leaves, stunted growth, decrease in size of roots, shoots and distortion etc. Anatomical investigation was performed under light ad scanning electron microscope. Different anatomical features like length and shape of guard cells, subsidiary cells, presence or absence of stomata, secretory ducts and trichomes were examined. In both plant samples anomocytic types of stomata and elongated, non-glandular and pointed tip trichomes were present, but the size (especially length and width) of trichomes and other cells like epidermal, subsidiary, and guard cells were highest in virus infected plants likened to healthy one. In the antibacterial activity, the maximum antibacterial potentail was seen in methanolic extract of K. pneumonea while antifungal activity was shown by methanolic extract of A. solani. Plants interact with different biological entities according to environmental conditions continuously and evolved. These types of interactions induce changes positively and negatively on plant metabolism and metabolites production. Many plant viruses also attacked various host plants consequently alter their secondary metabolism. To overcome such virus infected plants produces many important and different types of secondary plant metabolites as a defense response. Subsequent analysis of this n-hexane plant extract using Gas chromatography mass spectroscopy technique revealed that Hibiscus eluted contained 10 main compounds in Healthy sample and 13 compounds in infected one. Presence of essential secondary metabolites were also analyzed by FTIR analysis. The present study provides a comprehensive and novel review on taxonomy (morphology, anatomy) and antimicrobial potential of both healthy and geminivirus infected H. rosa-sinensis.

Screening the possible anti-cancer constituents of Hibiscus rosa-sinensis flower to address mammalian target of rapamycin: an in silico molecular docking, HYDE scoring, dynamic studies, and pharmacokinetic prediction.

One of the most common malignancies diagnosed and the leading cause of death for cancer-stricken women globally is breast cancer. The molecular subtype affects therapy options because it is a complex disorder with multiple subtypes. By concentrating on receptor activation, mTOR (mammalian target of rapamycin) can be employed as a therapeutic target. The goal of this work was to screen a number of inhibitors produced from Hibiscus rosa-sinensis for possible target to inhibit the mTOR and to determine which has the greatest affinity for the receptor. Primarily, the ionization states of the chosen compounds were predicted using the ChemAxon web platform, and their pKa values were estimated. Given the significance of interactions between proteins in the development of drugs, structure-based virtual screening was done using AutoDock Vina. Approximately 120 Hibiscus components and ten approved anti-cancer drugs, including the mTOR inhibitor everolimus, were used in the comparative analysis. By using Lipinski's rule of five to the chosen compounds, the ADMET profile and drug-likeness characteristics were further examined to assess the anti-breast cancer activity. The compounds with the highest ranked binding poses were loaded using the SeeSAR tool and the HYDE scoring to give interactive, desolvation, and visual ΔG estimation for ligand binding affinity assessment. Following, the prospective candidates underwent three replicas of 100 ns long molecular dynamics simulations, preceded with MM-GBSA binding free energy calculation. The stability of the protein-ligand complex was determined using root mean square deviation (RMSD), root mean square fluctuation (RMSF), and protein-ligand interactions. The results demonstrated that the best mTOR binding affinities were found for stigmastadienol (107), lupeol (66), and taraxasterol acetate (111), which all performed well in comparison to the control compounds. Thus, bioactive compounds isolated from Hibiscus rosa-sinensis could serve as lead molecules for the creation of potent and effective mTOR inhibitors for the breast cancer therapy.

Effect of dietary supplementation with Diuripres® on blood pressure, vascular health, and metabolic parameters in individuals with high-normal blood pressure or stage I hypertension: The CONDOR randomized clinical study.

Our aim was to evaluate if a nutritional intervention with a dietary supplement (Diuripres®) containing magnesium, standardized extract of orthosiphon, hawthorn, and hibiscus could positively affect blood pressure (BP), vascular health, and metabolic parameters in 60 individuals with high-normal BP or stage I hypertension. Participants followed a low-fat low-sodium Mediterranean diet for 4 weeks before being randomly allocated to 8-week treatment with two pills each day of either Diuripres® or placebo. Diuripres® significantly decreased systolic BP compared to placebo after 4 weeks (3.1 ± 0.8 mmHg; p < 0.05) and more consistently after 8 weeks (3.4 ± 0.9 mmHg; p < 0.05). At 8-week follow-up, after correction for multiple testing, dietary supplementation with Diuripres® was associated with significant improvements in diastolic BP (-3.1 ± 0.6 mmHg; p < 0.05), aortic BP (-4.3 ± 0.4 mmHg; p < 0.05), and high-sensitivity C-reactive protein (hs-CRP; 0.04 ± 0.01 mg/dL; p < 0.05) in comparison with baseline. The reductions in diastolic BP (--3.8 ± 0.7 mmHg; p < 0.05), aortic BP (-5.2 ± 1.0 mmHg; p < 0.05), and hs-CRP (-0.03 ± 0.01 mg/dL; p < 0.05) were also significant compared to placebo. Therefore, our study shows that dietary supplementation with Diuripres® may be useful in individuals with high-normal BP or stage I hypertension.

Residues of sulfoxaflor and its metabolites in floral and extrafloral nectar from Hibiscus rosa-sinensis L. (Malvaceae) with or without co-application of tebuconazole.

Systemic pesticide exposure through nectar is a growing global concern linked to loss of insect diversity, especially pollinators. The insecticide sulfoxaflor and the fungicide tebuconazole are currently widely used systemic pesticides which are toxic to certain pollinators. However, their metabolisms in floral or extrafloral nectar under different application methods have not yet been well studied. Hibiscus rosa-sinensis was exposed to sulfoxaflor and tebuconazole via soil drenching and foliar spraying. Sulfoxaflor, tebuconazole, and their main metabolites in floral and extrafloral nectar, soil, and leaves were identified and quantified using liquid chromatography coupled with triple quadrupole mass spectrometry (LC-QqQ MS). The chemical compositions of unexposed and contaminated H. rosa-sinensis floral nectar or extrafloral nectar were compared using regular biochemical methods. The activities of two pesticide detoxifying enzymes, glutathione-s-transferase and nitrile hydratase, in H. rosa-sinensis nectar were examined using LC-MS and spectrophotometry. The floral nectar proteome of H. rosa-sinensis was analysed using high-resolution orbitrap-based MS/MS analysis to screen for sulfoxaflor and tebuconazole detoxifying enzymes. H. rosa-sinensis can absorb sulfoxaflor and tebuconazole through its roots or leaf surfaces and secrete them into floral nectar and extrafloral nectar. Both sulfoxaflor and tebuconazole and their major metabolites were present at higher concentrations in extrafloral nectar than in floral nectar. X11719474 was the dominant metabolite of sulfoxaflor in the nectars we studied. Compared with soil application, more sulfoxaflor and tebuconazole remained in their original forms in floral nectar and extrafloral nectar after foliar application. Sulfoxaflor and tebuconazole exposure did not modify the chemical composition of floral or extrafloral nectar. No active components, including proteins in the nectar, were detected to be able to detoxify sulfoxaflor.

First Report of Sclerotinia sclerotiorum Causing Hibiscus rosa-sinensis Stem Rot in Guangxi, China.

Hibiscus rosa-sinensis, native to the south of China, is currently planted as an important landscaping tree species in more than 100 countries around the world. Since 2012, an unknown stem rot disease of H. rosa-sinensis has occurred sporadically in a few green belts of Nanning, Guangxi, China. In February 2023, the incidence rate of the disease in the southern part of the city (108°38'E, 22°77'N) reached 5-8%. The pathogen mainly infected the stems near the soil line and aboveground stems. Initially, brown spots appeared and developed into long strips of large spots around the stem, slightly sunken. Later, the diseased tissue cortex presented longitudinal cracks and the vascular bundle tissue was exposed like silk hemp. White mycelium appeared on the diseased stem surfaces under high humidity conditions, eventually maturing into hard black sclerotia (1.5 to 11.0 mm in length). The leaves turned yellow and the whole plant finally died. For fungal isolation, seven diseased plants distributed within 800 square meters were collected, and 35 symptomatic stem sections were surface disinfect with alcohol for 30s, 0.08% NaClO for 1 min, triple rinsed with sterile distilled water, and cultured in potato dextrose agar (PDA) medium at 28℃. Sclerotinia-like colonies were consistently isolated from all diseased tissues and four isolates (Z1-Z4) were purified (Bolton et al. 2006). Irregular white immature sclerotia were produced after 5 to 7 days on the edges of the plates and turned black after 7 to 14 days, with a size of 1.8 to 4.6 × 1.2 to 3.4 mm (avg. 3.3 × 2.4 mm, n = 20). For molecular characterization, three gene regions (ITS, CaM and Mcm7) were amplified (White et al. 1990; Carbone et al. 1999; Schmitt et al. 2009) and sequenced (GenBank accession nos.: ITS: OR016764 to OR016767; CaM: OR257811 to OR257814; Mcm7: OR345318 to OR345321). The sequences of three analyzed DNA fragments shared 100% identity with sequences of Sclerotinia sclerotiorum strains (accession nos. JN013184, AF341304, KF545468). To fullfill Koch's postulates, healthy H. rosa-sinensis nursery stocks at the six months stage were individually planted in plastic pots at 25±3℃. The base of the stem and upper three branches of each plant were wounded with a sterile needle and inoculated with 5-mm discs of mycelium grown on PDA, then the inoculation sites of stem bases were covered with one layer nursery substrate and those of branches were wrapped with transparent tape to maintain the humidity. Three plants were inoculated with each isolate. As a control, three plants were inoculated with PDA discs. All the inoculated plants with mycelial discs developed characteristic symptoms 5 to 8 days after inoculation. The inoculation sites appeared white mycelium and the leaves sagged and wilted. Later, black sclerotia appeared on the diseased stem and the whole plant withered, while the control plants remained symptomless. Fungal cultures reisolated from symptomatic plants were morphologically identical with the cultures used as inoculum. Sclerotinia sclerotiorum has only been reported from H. rosa-sinensis in Taiwan (Tai 1979). The pathogen is a widely distributed fungus, causing many economically important diseases on various plants (Hossain et al. 2023). To our knowledge, this is the first report of S. sclerotiorum causing H. rosa-sinensis stem rot in Chinese Mainland, laying the foundation for monitoring its occurrence and spread.