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HHV-8 genotypes are distributed heterogeneously worldwide. The variable K1 gene and the conserved ORF26E region serve to genotype. The aim of the study was to characterize HHV-8 isolates from patients with AIDS, classical, and iatrogenic KS, primary effusion lymphoma and Castleman's disease and one organ donor from Argentina by analysis of ORFK1 and ORF26E regions. DNA was extracted from fresh or paraffin embedded biopsies, blood, and saliva samples and submitted to HHV-8 PCR. Phylogenetic analyses of ORFK1 showed that subtypes C (C1, C2, and C3), B1 and A (A1, A2, and A3) were present in 70.8%, 16.7%, and 12.5% of cases, respectively. Analyses of ORF26E fragment revealed that most strains (45.8%) were subtype A/C while the remaining fall into K, J, B2, R, and D subtypes. Linkage between ORFK1-ORF26E subtypes corresponded to reported relationships, except for one strain that clustered with B1 (K1 African) and D (ORF26E Asian-Pacific) subtypes. This research reveals predominance of subtype C, a broad spectrum of HHV-8 genotypes and reports the first isolation of the African B genotype in Argentina., (© 2017 Wiley Periodicals, Inc.)

Jasmonates, which include jasmonic acid (JA) and methyl jasmonate (MeJA), are compounds derived from linolenic acid. In recent years, the quality and phytochemical content of various fruits have been improved using plant growth regulators both before and after harvest. They play a significant role in improving the quality and biochemical composition of different fruit crops, including fruit peel colour, accumulation of anthocyanins, phenolic compounds, and antioxidant activities in the fruit. Further, the fruit ripening process is also accelerated by the application of jasmonate as it influences different physiological and molecular mechanisms of the plant system including regulation of the activities of different hormones during the entire period of fruit growth and development starting from fruit set to till ripening, activation of genes related to ripening, etc. In the case of apples, pre-harvest application of MeJA leads to enhanced fruit coloration by stimulating the anthocyanin biosynthesis gene MdUFGluT. The concentration of JA increases significantly during the early fruit development stage but then decreases sharply, reaching its lowest level when the fruits are fully ripe which signifies its role in initiating the fruit ripening process. Jasmonates can also induce the expression of genes related to ethylene synthesis and promote the production of ethylene gas. Application of jasmonates at the pre-climacteric stage increased the expression of 1-Aminocyclopropane-1-carboxylate synthase 1 (ACS 1) and 1-Aminocyclopropane-1-Carboxylic Acid Oxidase1 (ACO 1) genes. However, the accumulation of ACS1 mRNA decreased when Propyl Dihydro Jasmonate was applied at the climacteric stage, indicating that jasmonates influence system 2 ethylene synthesis pathway. In addition, these two compounds (MeJA and JA) are safe for human consumption; hence, can be applied at the commercial level to improve the fruit quality and ripening process in different fruit crops. This review provides an overview of the recent advancements in our understanding of the regulation of jasmonate biosynthesis, and the physiological and molecular mechanisms involved in the jasmonate-mediated fruit ripening process. [ABSTRACT FROM AUTHOR]

Schizophrenia is serious and prevalent psychotic condition in which patients misinterpret the real conditions and might cause combination of symptoms like hallucinations, delusions, and extremely disordered thinking and impaired behavior during daily functioning. People who are suffering from schizophrenia require lifelong treatment. The scientists are elucubrating round the clock to contribute novel pharmacological compounds in the hopes of improving the "quality of life" of schizophrenia patients. The antipsychotics drugs which are currently available in the market for management of schizophrenia needs reformulation into lipid vesicular nanocarrier systems with tremendous potential to provide superior platform as cutting-edge therapeutic strategies to target the brain via intranasal administration and thereby reduced the systemic adverse effects. The development of nanoformulation also provides sustained or prolonged drug delivery systems which might be helpful in reducing necessitate of frequent dosage administration. The transferosomes are types of vesicular nanocarriers which have been explored extensively in previous decades to address the flaws of conventional drug delivery systems and currently aregaining significant relevance in therapeutics owing to their capacity to conquer drug penetration challenges via biological membranes which acts by squeezing the vesicular structure into intercellular lipid barrier of biological membrane. The non-invasive intranasal delivery of drugs via nanotransferosomal vesicles acts as valuable tool for drugs with poor bioavailability. This review article addresses the risk factors for schizophrenia; key challenges faced with conventional medicines and the significance of nanotransferosomes in intranasal drug delivery for the management of schizophrenia which might advance the quality of living of patients suffering from schizophrenia. [ABSTRACT FROM AUTHOR]

Influenza virus (InfV) infection during pregnancy is a known risk factor for neurodevelopment abnormalities in the offspring, including the risk of schizophrenia, and has been shown to result in an abnormal behavioral phenotype in mice. However, previous reports have concentrated on neuroadapted influenza strains, whereas increased schizophrenia risk is associated with common respiratory InfV. In addition, no specific mechanism has been proposed for the actions of maternal infection on the developing brain that could account for schizophrenia risk. We identified two common isolates from the community with antigenic configurations H3N2 and H1N1 and compared their effects on developing brain with a mouse modified-strain A/WSN/33 specifically on the developing of dopaminergic neurons. We found that H1N1 InfV have high affinity for dopaminergic neurons in vitro, leading to nuclear factor kappa B activation and apoptosis. Furthermore, prenatal infection of mothers with the same strains results in loss of dopaminergic neurons in the offspring, and in an abnormal behavioral phenotype. We propose that the well-known contribution of InfV to risk of schizophrenia during development may involve a similar specific mechanism and discuss evidence from the literature in relation to this hypothesis.

1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is one of the key regulatory enzymes involved in the synthesis of the hormone ethylene and is encoded by a multigene family containing at least eight members in tomato (Lycopersicon esculentum). Increased ethylene production accompanies ripening in tomato, and this coincides with a change in the regulation of ethylene synthesis from auto-inhibitory to autostimulatory. The signaling pathways that operate to bring about this transition from so-called system-1 to system-2 ethylene production are unknown, and we have begun to address these by investigating the regulation of ACS expression during ripening. Transcripts corresponding to four ACS genes, LEACS1A, LEACS2, LEACS4, and LEACS6, were detected in tomato fruit, and expression analysis using the ripening inhibitor (rin) mutant in combination with ethylene treatments and the Never-ripe (Nr) mutant has demonstrated that each is regulated in a unique way. A proposed model suggests that system-1 ethylene is regulated by the expression of LEACS1A and LEACS6. In fruit a transition period occurs in which the RIN gene plays a pivotal role leading to increased expression of LEACS1A and induction of LEACS4. System-2 ethylene synthesis is subsequently initiated and maintained by ethylene-dependent induction of LEACS2.

Shiga toxin-producing Escherichia coli (STEC) has been associated with pathogenesis of hemolytic uremic syndrome (HUS) worldwide. The aim of the present study was to characterize the HUS cases reported in Mendoza and to determine their association with STEC infection. From July 1994 through June 1996 thirty-six patients with HUS were admitted to Hospital Pediátrico "Dr. HJ Notti" (Mean age 22.8 +/- 14.9 months, 44% females). The children developed HUS following an acute diarrheal illness in 94.4% of the cases. Bloody diarrhea was observed in 83.3% of them. Antimicrobial therapy had been administered to 69.4% of the patients. Most of the patients were well-nourished (88.9%), belong to middle-low socioeconomical condition (91.7%), from urban areas (72.2%) and they were mostly assisted during summer and the beginning of autumn. The acute stage of the disease occurred with presentation of pallor (100%), edema (25%), anuria (38.9%), oliguria (41.7%), hemolytic anemia (97.2%), thrombocytopenia (86.1%) and neurological involvement (41.7%). Twenty-five of them presented the full clinical syndrome. Peritoneal dialysis were performed in 50% and packed blood cell transfusion in 88.9%. The mean days of hospitalization was 15.1 +/- 9.2 [range 1-32]. A 91.7% of the patients recovered renal function, two developed chronic renal failure and one died. Cumulative evidence of STEC infection was found in 19 (86.4%) of 22 HUS patients. STEC O157:H7, biotype C was found in 8 (36.4%). The prevalent Stx type was Stx2 in STEC, free fecal Stx (STMF) and Stx-neutralizing antibodies (a-Stx). In Mendoza, as in the rest of Argentina E. coli O157:H7, biotype C, Stx2 producer is the most frequently detected pathogen in HUS cases.

Background: Sweet osmanthus (Osmanthus fragrans) is an ornamental evergreen tree species in China, whose flowers are sensitive to ethylene. The synthesis of ethylene is controlled by key enzymes and restriction enzymes, 1-aminocyclopropane-1-carboxylic acid synthase (ACS) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO), which are encoded by multigene families. However, the key synthase responsible for ethylene regulation in O. fragrans is still unknown. Objective: This study aims to screen the key ethylene synthase genes of sweet osmanthus flowers in response to ethylene regulation. Methods: In this study, we used the ACO and ACS sequences of Arabidopsis thaliana to search for homologous genes in the O. fragrans petal transcriptome database. These genes were also analyzed bioinformatically. Finally, the expression levels of O. fragrans were compared before and after senescence, as well as after ethephon and silver nitrate treatments. Results: The results showed that there are five ACO genes and one ACS gene in O. fragrans transcriptome database, and the phylogenetic tree revealed that the proteins encoded by these genes had high homology to the ACS and ACO proteins in plants. Sequence alignment shows that the OfACO1-5 proteins have the 2OG-Fe(II) oxygenase domain, while OfACS1 contains seven conserved domains, as well as conserved amino acids in transaminases and glutamate residues related to substrate specificity. Expression analysis revealed that the expression levels of OfACS1 and OfACO1-5 were significantly higher at the early senescence stage compared to the full flowering stage. The transcripts of the OfACS1, OfACO2, and OfACO5 genes were upregulated by treatment with ethephon. However, out of these three genes, only OfACO2 was significantly downregulated by treatment with AgNO3. Conclusion: Our study found that OfACO2 is an important synthase gene in response to ethylene regulation in sweet osmanthus, which would provide valuable data for further investigation into the mechanisms of ethylene-induced senescence in sweet osmanthus flowers. [ABSTRACT FROM AUTHOR]

Fleshy fruits of angiosperms are organs specialized for promoting seed dispersal by attracting herbivores and enticing them to consume the organ and the seeds it contains. Ripening can be broadly defined as the processes serving as a plant strategy to make the fleshy fruit appealing to animals, consisting of a coordinated series of changes in color, texture, aroma, and flavor that result from an intricate interplay of genetically and epigenetically programmed events. The ripening of fruits can be categorized into two types: climacteric, which is characterized by a rapid increase in respiration rate typically accompanied by a burst of ethylene production, and non-climacteric, in which this pronounced peak in respiration is absent. Here we review current knowledge of transcriptomic changes taking place in apple (Malus × domestica , climacteric) and grapevine (Vitis vinifera , non-climacteric) fruit during ripening, with the aim of highlighting specific and common hormonal and molecular events governing the process in the two species. With this perspective, we found that specific NAC transcription factor members participate in ripening initiation in grape and are involved in restoring normal physiological ripening progression in impaired fruit ripening in apple. These elements suggest the existence of a common regulatory mechanism operated by NAC transcription factors and auxin in the two species. [ABSTRACT FROM AUTHOR]

Fruit ripening is a complex and highly regulated process where tomato and strawberry have been the model species classically used for studying climacteric and non-climacteric fleshy fruit ripening types, respectively. Melon has emerged as an alternative ripening model because climacteric and non-climacteric cultivars exist, which makes it possible to dissect the regulation of ripening using a genetic approach. Several quantitative trait loci that regulate climacteric fruit ripening have been identified to date, and their combination in both climacteric and non-climacteric genetic backgrounds resulted in lines with different ripening behaviors, demonstrating that the climacteric intensity can be genetically modulated. This review discusses our current knowledge of the physiological changes observed during melon climacteric fruit ripening such as ethylene production, fruit abscission, chlorophyll degradation, firmness, and aroma, as well as their complex genetic control. From pioneer experiments in which ethylene biosynthesis was silenced, to the recent genetic edition of ripening regulators, current data suggest that the climacteric response is determined by the interaction of several loci under quantitative inheritance. The exploitation of the rich genetic diversity of melon will enable the discovery of additional genes involved in the regulation of the climacteric response, ultimately leading to breeding aromatic melon fruits with extended shelf life. [ABSTRACT FROM AUTHOR]

Human Herpesvirus 8 (HHV-8) has been classified by sequence analysis of open reading frame (ORF) K1, ORF K15, and variable sequence loci within the central constant region. The purpose of this study was to examine the molecular epidemiology of HHV-8 in an Irish population. This retrospective study included 30 patients who had HHV-8 DNA detected in plasma. Nested end-point PCR was used to characterise four regions of the HHV-8 genome, K1, T0.7 (K12), ORF 75, and K15. Sequencing data were obtained for 23 specimens from 19 patients. Phylogenetic analysis of ORF K1 demonstrated that subtypes A, B, C and F were present in 37%, 11%, 47% and 5%, respectively. For T0.7 and ORF 75, sequencing data were obtained for 12 patients. For T0.7, subtypes A/C, J, B, R and Q were present in 58%, 17%, 8%, 8%, and 8%, respectively. For ORF 75, subtypes A, B, C and D were present in 58%, 8%, 25%, and 8%, respectively. K15 sequences were determined for 13 patients. 69% had the P allele and 31% had the M allele. The data generated by this study demonstrate that a broad variety of HHV-8 subtypes are represented in patients exhibiting HHV-8-related disease in Ireland, a low prevalence country. The predominance of C and A K1 subtypes was as expected for a Western European population. The 31% prevalence for K15 subtype M was higher than expected for a Western European population. This may represent the changing and evolving epidemiology in Ireland due to altered migration patterns., (© 2024 The Authors. Journal of Medical Virology published by Wiley Periodicals LLC.)

The WRKY transcription factor (TF) genes form a large family in higher plants, with 72 members in Arabidopsis (Arabidopsis thaliana). The gaseous phytohormone ethylene (ET) regulates multiple physiological processes in plants. It is known that 1-aminocyclopropane-1-carboxylic acid (ACC) synthases (ACSs, EC 4.4.1.14) limit the enzymatic reaction rate of ethylene synthesis. However, whether WRKY TFs regulate the expression of ACSs and/or ACC oxidases (ACOs, EC 1.14.17.4) remains largely elusive. Here, we demonstrated that Arabidopsis WRKY22 positively regulated the expression of a few ACS and ACO genes, thus promoting ethylene production. Inducible overexpression of WRKY22 caused shorter hypocotyls without ACC treatment. A qRT-PCR screening demonstrated that overexpression of WRKY22 activates the expression of several ACS and ACO genes. The promoter regions of ACS5, ACS11, and ACO5 were also activated by WRKY22, which was revealed by a dual luciferase reporter assay. A follow-up chromatin immunoprecipitation coupled with quantitative PCR (ChIP-qPCR) and electrophoretic mobility shift assay (EMSA) showed that the promoter regions of ACS5 and ACO5 could be bound by WRKY22 directly. Moreover, wrky22 mutants had longer primary roots and more lateral roots than wild type, while WRKY22-overexpressing lines showed the opposite phenotype. In conclusion, this study revealed that WRKY22 acts as a novel TF activating, at least, the expression of ACS5 and ACO5 to increase ethylene synthesis and modulate root development., (© 2024 Scandinavian Plant Physiology Society.)

Tomato fruit ripening is a unique process of nutritional and energy metabolism. Target of rapamycin (TOR), a conserved serine/threonine protein kinase in eukaryotes, controls cell growth and metabolism by integrating nutrient, energy, and hormone signals. However, it remains unclear whether TOR participates in the modulation of tomato fruit ripening. Here, we showed that the manipulation of SlTOR by chemical or genetic methods greatly alters the process of tomato fruit maturation. Expression pattern analysis revealed that the transcripts of SlTOR declined as fruit ripening progressed. Moreover, suppression of SlTOR by TOR inhibitor AZD8055 or knock down of its transcripts by inducible RNA interference, accelerated fruit ripening, and led to overall effects on fruit maturity, including changes in colour and metabolism, fruit softening, and expression of ripening-related genes. Genome-wide transcription analysis indicated that silencing SlTOR reprogrammed the transcript profile associated with ripening, including cell wall and phytohormone pathways, elevated the expression of ethylene biosynthetic genes, and further promoted ethylene production. In contrast, the ethylene action inhibitor 1-MCP efficiently blocked fruit maturation, even following SlTOR inhibition. These results suggest that accelerated fruit ripening caused by SlTOR inhibition depends on ethylene, and that SlTOR may function as a regulator in ethylene metabolism. [ABSTRACT FROM AUTHOR]

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Summary: Ethylene (ETH) controls climacteric fruit ripening and can be triggered by osmotic stress. However, the mechanism regulating ETH biosynthesis during fruit ripening and under osmotic stress is largely unknown in apple (Malus domestica).Here, we explored the roles of SnRK2 protein kinases in ETH biosynthesis related to fruit ripening and osmoregulation. We identified the substrates of MdSnRK2‐I using phosphorylation analysis techniques. Finally, we identified the MdSnRK2‐I‐mediated signaling pathway for ETH biosynthesis related to fruit ripening and osmoregulation.The activity of two MdSnRK2‐I members, MdSnRK2.4 and MdSnRK2.9, was significantly upregulated during ripening or following mannitol treatment. Overexpression of MdSnRK2‐I increased ETH biosynthesis under normal and osmotic conditions in apple fruit. MdSnRK2‐I phosphorylated the transcription factors MdHB1 and MdHB2 to enhance their protein stability and transcriptional activity on MdACO1. MdSnRK2‐I also interacted with MdACS1 and increased its protein stability through two phosphorylation sites. The increased MdACO1 expression and MdACS1 protein stability resulted in higher ETH production in apple fruit. In addition, heterologous expression of MdSnRK2‐I or manipulation of SlSnRK2‐I expression in tomato (Solanum lycopersicum) fruit altered fruit ripening and ETH biosynthesis.We established that MdSnRK2‐I functions in fruit ripening and osmoregulation, and identified the MdSnRK2‐I‐mediated signaling pathway controlling ETH biosynthesis. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S), as a novel gaseous signalling molecule, has been extensively investigated in plants ranging from seed germination to senescence. Phytohormones, including stimulator (such as auxin: AUX; gibberellin: GA; cytokinin: CTK; and melatonin: MEL) and inhibitor (such as ethylene: ETH; abscisic acid: ABA; salicylic acid: SA; and jasmonic acid: JA) types, as universal regulators, play a key role in the plant growth, development, and response and adaptation to adverse environments. Now, phytohormones are considered to be the key targets for improving plant productivity and stress tolerance, which affect the production and quality of crop plants. These indicate the interaction of H2S with phytohormones in many physiological processes such as seed germination, seedling establishment, plant growth, development, and senescence, as well as response to environmental stress. However, the molecular mechanism of H2S–phytohormone interaction is not completely clear. In this review, the interaction of H2S with stimulator hormones (AUX, GA, and MEL) and inhibitor hormones (ETH, ABA, SA, and JA) in plants under physiological and stress conditions was discussed. The H2S–phytohormone interaction not only highlighted H2S-mediated phytohormone signaling in stomatal development and closure, fruit ripening, organ abscission, as well as heat, chilling, salt, cadmium, iron deficiency, and boron tolerance; but also focused on the phytohormone-mediated H2S signaling in seed germination, root development, stomatal closure, fruit ripening, organ abscission, as well as drought, chilling, and cadmium tolerance. The aim is to arouse the rapid development of the research on H2S, phytohormones, and their interaction in plant biology field, laying the foundation of acquiring transgenic crop plants with high yield, high quality, and multiple stress tolerance. [ABSTRACT FROM AUTHOR]

Background: The phytohormone ethylene controls many processes in plant development and acts as a key signaling molecule in response to biotic and abiotic stresses: it is rapidly induced by flooding, wounding, drought, and pathogen attack as well as during abscission and fruit ripening. In kiwifruit (Actinidia spp.), fruit ripening is characterized by two distinct phases: an early phase of system-1 ethylene biosynthesis characterized by absence of autocatalytic ethylene, followed by a late burst of autocatalytic (system-2) ethylene accompanied by aroma production and further ripening. Progress has been made in understanding the transcriptional regulation of kiwifruit fruit ripening but the regulation of system-1 ethylene biosynthesis remains largely unknown. The aim of this work is to better understand the transcriptional regulation of both systems of ethylene biosynthesis in contrasting kiwifruit organs: fruit and leaves. Results: A detailed molecular study in kiwifruit (A. chinensis) revealed that ethylene biosynthesis was regulated differently between leaf and fruit after mechanical wounding. In fruit, wound ethylene biosynthesis was accompanied by transcriptional increases in 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS), ACC oxidase (ACO) and members of the NAC class of transcription factors (TFs). However, in kiwifruit leaves, wound-specific transcriptional increases were largely absent, despite a more rapid induction of ethylene production compared to fruit, suggesting that post-transcriptional control mechanisms in kiwifruit leaves are more important. One ACS member, AcACS1, appears to fulfil a dominant double role; controlling both fruit wound (system-1) and autocatalytic ripening (system-2) ethylene biosynthesis. In kiwifruit, transcriptional regulation of both system-1 and -2 ethylene in fruit appears to be controlled by temporal up-regulation of four NAC (NAM, ATAF1/2, CUC2) TFs (AcNAC1–4) that induce AcACS1 expression by directly binding to the AcACS1 promoter as shown using gel-shift (EMSA) and by activation of the AcACS1 promoter in planta as shown by gene activation assays combined with promoter deletion analysis. Conclusions: Our results indicate that in kiwifruit the NAC TFs AcNAC2–4 regulate both system-1 and -2 ethylene biosynthesis in fruit during wounding and ripening through control of AcACS1 expression levels but not in leaves where post-transcriptional/translational regulatory mechanisms may prevail. [ABSTRACT FROM AUTHOR]

Chili pepper (Capsicum annuum) is one of the most important crops worldwide. Its fruits contain metabolites produced over the maturation process like capsaicinoids and carotenoids. This metabolic process produces internal changes in flavor, color, texture, and aroma in fruits to make them more attractive for seed dispersal organisms. The chiltepin (C. annuum L. var. glabriusculum) is a wild variety of the C. annuum L. species that is considered a source of genetic resources that could be used to improve the current chili crops. In this study, we performed a transcriptomic analysis on two fruit maturation stages: immature stage (green fruit) and mature stage (red fruit) of a wild and a cultivated pepper variety. We found 19,811 genes expressed, and 1,008 genes differentially expressed (DEGs) in at least one of the five contrast used; 730 DEGs were found only in one contrast, and most DEGs in all contrasts were downregulated. GO enrichment analysis showed that the majority of DEGs are related to stress responses. KEGG enrichment analysis detected differences in expression patterns in metabolic pathways related to phenylpropanoid biosynthesis, secondary metabolites, plant hormone signal transduction, carotenoid biosynthesis and sesquiterpenoid and triterpenoid biosynthesis. We selected 105 tomato fruit ripening-related genes, and found 53 pepper homologs differentially expressed related to shape, size, and secondary metabolite biosynthesis. According to the transcriptome analysis, the two peppers showed very similar gene expression patterns; differences in expression patterns of genes related to shape, size, ethylene and secondary metabolites biosynthesis suggest that changes produced by domestication of chilli pepper could be very specific to the expression of genes related to traits desired in commercial fruits. [ABSTRACT FROM AUTHOR]

The tomato (Solanum lycopersicum) ripening inhibitor (rin) mutation completely represses fruit ripening, as rin fruits fail to express ripening-associated genes and remain green and firm. Moreover, heterozygous rin fruits (rin/+) ripen normally but have extended shelf life, an important consideration for this perishable fruit crop; therefore, heterozygous rin has been widely used to breed varieties that produce red tomatoes with improved shelf life. We previously used CRISPR/Cas9 to produce novel alleles at the rin locus. The wild-type allele RIN encodes a MADS-box transcription factor and the novel allele, named as rinG2, generates an early stop codon, resulting in C-terminal truncation of the transcription factor. Like rin fruits, rinG2 fruits exhibit extended shelf life, but unlike rin fruits, which remain yellow-green even after long-term storage, rinG2 fruits turn orange due to ripening-associated carotenoid production. Here, to explore the potential of the rinG2 mutation for breeding, we characterized the effects of rinG2 in the heterozygous state (rinG2/+) compared to the effects of rin/+. The softening of rinG2/+ fruits was delayed compared to the wild type but to a lesser degree than rin/+ fruits. Lycopene and β-carotene levels in rinG2/+ fruits were similar to those of the wild type, whereas rin/+ fruits accumulated half the amount of β-carotene compared to the wild type. The rinG2/+ fruits produced lower levels of ethylene than wild-type and rin/+ fruits. Expression analysis revealed that in rinG2/+ fruits, the rinG2 mutation (like rin) partially inhibited the expression of ripening-associated genes. The small differences in the inhibitory effects of rinG2 vs. rin coincided with small differences in phenotypes, such as ethylene production, softening, and carotenoid accumulation. Therefore, rinG2 represents a promising genetic resource for developing tomato cultivars with extended shelf life. [ABSTRACT FROM AUTHOR]

BACKGROUND: A near‐isogenic line (NIL) of melon (SC10‐2) with introgression in linkage group X was studied from harvest (at firm‐ripe stage of maturity) until day 18 of postharvest storage at 20.5 °C together with its parental control ('Piel de Sapo', PS). RESULTS: SC10‐2 showed higher flesh firmness and whole fruit hardness but lower juiciness than its parental. SC10‐2 showed a decrease in respiration rate accompanied by a decrease in ethylene production during ripening, both of which fell to a greater extent than in PS. The introgression affected 11 volatile organic compounds (VOCs), the levels of which during ripening were generally higher in SC10‐2 than in PS. Transcriptomic analysis from RNA‐Seq revealed differentially expressed genes (DEGs) associated with the effects studied. For example, 909 DEGs were exclusive to the introgression, and only 23 DEGs were exclusive to postharvest ripening time. Major functions of the DEGs associated with introgression or ripening time were identified by cluster analysis. About 37 genes directly and/or indirectly affected the delay in ripening of SC10‐2 compared with PS in general and, more particularly, the physiological and quality traits measured and, probably, the differential non‐climacteric response. Of the former genes, we studied in more detail at least five that mapped in the introgression in linkage group (LG) X, and 32 outside it. CONCLUSION: There is an apparent control of textural changes, VOCs and fruit ripening by an expression quantitative trait locus located in LG X together with a direct control on them due to genes presented in the introgression (CmTrpD, CmNADH1, CmTCP15, CmGDSL esterase/lipase, and CmHK4‐like) and CmNAC18. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Reducing the negative effects of chilling injury (CI) in tomatoes after harvest is essential to ensure good quality and to minimize losses. CI is a postharvest disorder associated with the generation of reactive oxygen species (ROS) in the fruit. Therefore, antioxidant accumulation can counteract ROS, alleviating CI symptoms. In this sense, it has been confirmed that a brief hot‐water (HW) immersion promotes the synthesis of antioxidants. RESULTS: HW treatment at 52 °C for 5 min significantly reduced chilling‐associated decay, from 66.7% to 17.2% in breaker turning (BT) and from 55.8% to 9.8% in mature green (MG) 'BHN‐602' tomatoes stored at 5 °C for 2 weeks and from 26.7% to 6.7% in BT tomatoes stored at 5 °C for 1 week. Also, HW treatment significantly increased lycopene content by 17% in BT tomatoes stored at 5 °C for 2 weeks, as well as ascorbic acid by 11%, lipophilic phenolics by 18% and total phenolics by 6.5% in BT tomatoes stored at 12.5 °C for 1 week. Despite the increase of antioxidants, HW treatment did not enhance the sensory aromatic profile, color and antioxidant capacity. Interestingly, HW treatment reduced ripening time by 3 days in MG tomatoes stored at 5 °C for 2 weeks or at 12.5 °C for 1 week. CONCLUSION: HW treatment applied to MG or BT 'BHN‐602' tomatoes can alleviate the development of some CI symptoms, particularly decay, possibly by increasing antioxidants that scavenge ROS. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Summary: The gaseous plant hormone ethylene is produced by a fairly simple two‐step biosynthesis route. Despite this pathway's simplicity, recent molecular and genetic studies have revealed that the regulation of ethylene biosynthesis is far more complex and occurs at different layers. Ethylene production is intimately linked with the homeostasis of its general precursor S‐adenosyl‐l‐methionine (SAM), which experiences transcriptional and posttranslational control of its synthesising enzymes (SAM synthetase), as well as the metabolic flux through the adjacent Yang cycle. Ethylene biosynthesis continues from SAM by two dedicated enzymes: 1‐aminocyclopropane‐1‐carboxylic (ACC) synthase (ACS) and ACC oxidase (ACO). Although the transcriptional dynamics of ACS and ACO have been well documented, the first transcription factors that control ACS and ACO expression have only recently been discovered. Both ACS and ACO display a type‐specific posttranslational regulation that controls protein stability and activity. The nonproteinogenic amino acid ACC also shows a tight level of control through conjugation and translocation. Different players in ACC conjugation and transport have been identified over the years, however their molecular regulation and biological significance is unclear, yet relevant, as ACC can also signal independently of ethylene. In this review, we bring together historical reports and the latest findings on the complex regulation of the ethylene biosynthesis pathway in plants. [ABSTRACT FROM AUTHOR]

Summary: Fruit ripening is a developmental process that is spatio‐temporally tuned at multiple levels. Molecular dissections of the mechanisms underlying the ripening process have revealed a network encompassed by hormones, transcriptional regulators, epigenomic modifications and other regulatory elements that directly determine fruit quality and the postharvest commodity of fresh produce. Many studies have addressed the important roles of ethylene, abscisic acid (ABA) and other hormones in regulating fruit ripening. Recent studies have shown that some spontaneous mutants for tomato transcription factors (TFs) have resulted from loss‐of‐function or dominant‐negative mutations. Unlike in DNA methylation variation, the histone mark H3K27me3 may be conserved and prevents the transcriptional feedback circuit from generating autocatalytic ethylene. These observations of a network of partially redundant component indicate the need to improve our current understanding. Here, we focussed on the recent advances and future challenges in investigations of the molecular mechanisms of fruit ripening. We also identified several issues that still need to be addressed in future studies. [ABSTRACT FROM AUTHOR]

Summary: The gaseous plant hormone ethylene induces the ripening of climacteric fruit, including apple (Malus domestica). Another phytohormone, auxin, is known to promote ethylene production in many horticultural crops, but the regulatory mechanism remains unclear.Here, we found that auxin application induces ethylene production in apple fruit before the stage of commercial harvest, when they are not otherwise capable of ripening naturally.The expression of MdARF5, a member of the auxin response factor transcription factor (TF) family involved in the auxin signaling pathway, was enhanced by treatment with the synthetic auxin naphthaleneacetic acid (NAA). Further studies revealed that MdARF5 binds to the promoter of MdERF2, encoding a TF in the ethylene signaling pathway, as well as the promoters of two 1‐aminocyclopropane‐1‐carboxylic acid synthase (ACS) genes (MdACS3a and MdACS1) and an ACC oxidase (ACO) gene, MdACO1, all of which encode key steps in ethylene biosynthesis, thereby inducing their expression. We also observed that auxin‐induced ethylene production was dependent on the methylation of the MdACS3a promoter.Our findings reveal that auxin induces ethylene biosynthesis in apple fruit through activation of MdARF5 expression. [ABSTRACT FROM AUTHOR]

European pear (Pyrus communis L.) cultivars require a genetically pre-determined duration of cold-temperature exposure to induce autocatalytic system 2 ethylene biosynthesis and subsequent fruit ripening. The physiological responses of pear to cold-temperature-induced ripening have been well characterized, but the molecular mechanisms underlying this phenomenon continue to be elucidated. This study employed previously established cold temperature conditioning treatments for ripening of two pear cultivars, 'D'Anjou' and 'Bartlett'. Using a time-course transcriptomics approach, global gene expression responses of each cultivar were assessed at four stages of developmental during the cold conditioning process. Differential expression, functional annotation, and gene ontology enrichment analyses were performed. Interestingly, evidence for the involvement of cold-induced, vernalization-related genes and repressors of endodormancy release was found. These genes have not previously been described to play a role in fruit during the ripening transition. The resulting data provide insight into cultivar-specific mechanisms of cold-induced transcriptional regulation of ripening in European pear, as well as a unique comparative analysis of the two cultivars with very different cold conditioning requirements. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a slowly progressing neurodegenerative disorder that is coupled to both widespread protein aggregation and to loss of substantia nigra dopamine (DA) neurons, resulting in a wide variety of motor and non-motor signs and symptoms. Recent findings suggest that the PD process is triggered several years before there is sufficient degeneration of DA neurons to cause onset of overt motor symptoms. According to this concept, the number of DA neurons present in the substantia nigra at birth could influence the time from the molecular triggering event until the clinical diagnosis with lower number of neurons at birth increasing the risk to develop the disease. Conversely, the risk for diagnosis would be reduced if the number of DA neurons is high at birth. In this commentary, we discuss the genetic and epigenetic factors that might influence the number of nigral DA neurons that each individual is born with and how these may be linked to PD risk. [ABSTRACT FROM AUTHOR]

Enzyme biosensors are useful tools that can monitor rapid changes in metabolite levels in real-time. However, current approaches are largely constrained to metabolites within a limited chemical space. With the rising development of artificial metalloenzymes (ArM), a unique opportunity exists to design biosensors from the ground-up for metabolites that are difficult to detect using current technologies. Here we present the design and development of the ArM ethylene probe (AEP), where an albumin scaffold is used to solubilize and protect a quenched ruthenium catalyst. In the presence of the phytohormone ethylene, cross metathesis can occur to produce fluorescence. The probe can be used to detect both exogenous- and endogenous-induced changes to ethylene biosynthesis in fruits and leaves. Overall, this work represents an example of an ArM biosensor, designed specifically for the spatial and temporal detection of a biological metabolite previously not accessible using enzyme biosensors. Existing methods to detect ethylene in plant tissue typically require gas chromatography or use ethylene-dependent gene expression as a proxy. Here Vong et al. show that an artificial metalloenzyme-based ethylene probe can be used to detect ethylene in plants with improved spatiotemporal resolution. [ABSTRACT FROM AUTHOR]

European pears (Pyrus communis L.) require a range of cold-temperature exposure to induce ethylene biosynthesis and fruit ripening. Physiological and hormonal responses to cold temperature storage in pear have been well characterized, but the molecular underpinnings of these phenomena remain unclear. An established low-temperature conditioning model was used to induce ripening of 'D'Anjou' and 'Bartlett' pear cultivars and quantify the expression of key genes representing ripening-related metabolic pathways in comparison to non-conditioned fruit. Physiological indicators of pear ripening were recorded, and fruit peel tissue sampled in parallel, during the cold-conditioning and ripening time-course experiment to correlate gene expression to ontogeny. Two complementary approaches, Nonparametric Multi-Dimensional Scaling and efficiency-corrected 2-(ΔΔCt), were used to identify genes exhibiting the most variability in expression. Interestingly, the enhanced alternative oxidase (AOX) transcript abundance at the pre-climacteric stage in 'Bartlett' and 'D'Anjou' at the peak of the conditioning treatments suggests that AOX may play a key and a novel role in the achievement of ripening competency. There were indications that cold-sensing and signaling elements from ABA and auxin pathways modulate the S1-S2 ethylene transition in European pears, and that the S1-S2 ethylene biosynthesis transition is more pronounced in 'Bartlett' as compared to 'D'Anjou' pear. This information has implications in preventing post-harvest losses of this important crop. [ABSTRACT FROM AUTHOR]

Hinokitiol (β‐thujaplicin, volatile oil extracted from the wood of Hiba arborvitae [Thujopsis dolabrata var. hondae], cypress family) is a natural preservative, antimicrobial, and chelating agent, used to prevent decay and extend the shelf life of fruits and vegetables. In the present study, we used nonwoven rayon sheets impregnated with hinokitiol to conduct packaging studies. Mature green tomatoes var. "KEK‐1" were packaged under three packaging conditions, ie, modified atmosphere packaging (MAP), MAP + hinokitiol (MH), and perforated film package (as control), and their quality attributes were compared during storage. The packaging materials used were low‐density polyethylene (LDPE) film (40 μm) and fresh sheets of nonwoven rayon impregnated with hinokitiol. O2 in the MAP packaged tomatoes were retained throughout the storage period (3% to 5% O2). Results showed that MH had slightly improved quality attributes throughout the storage period when compared with MAP alone. Expression levels of LeACS, LeADH, and LeTBG4 genes were higher in 5 and 9 days of control when compared with MAP and MH. "KEK‐1" tomatoes had longer shelf life under MAP and MH packaging and maintained the quality at 15°C. Hence, the effect of the MAP with bioactive packaging treatments could be effective in the future application for the extension of shelf life and quality of fruits and vegetables. [ABSTRACT FROM AUTHOR]

Key message: The first transcriptome coupled to metabolite analyses reveals major trends during acerola fruit ripening and shed lights on ascorbate, ethylene signalling, cellular respiration, sugar accumulation, and softening key regulatory genes. Acerola is a fast growing and ripening fruit that exhibits high amounts of ascorbate. During ripening, the fruit experience high respiratory rates leading to ascorbate depletion and a quickly fragile and perishable state. Despite its growing economic importance, understanding of its developmental metabolism remains obscure due to the absence of genomic and transcriptomic data. We performed an acerola transcriptome sequencing that generated over 600 million reads, 40,830 contigs, and provided the annotation of 25,298 unique transcripts. Overall, this study revealed the main metabolic changes that occur in the acerola ripening. This transcriptional profile linked to metabolite measurements, allowed us to focus on ascorbate, ethylene, respiration, sugar, and firmness, the major metabolism indicators for acerola quality. Our results suggest a cooperative role of several genes involved in AsA biosynthesis (PMM, GMP1 and 3, GME1 and 2, GGP1 and 2), translocation (NAT3, 4, 6 and 6-like) and recycling (MDHAR2 and DHAR1) pathways for AsA accumulation in unripe fruits. Moreover, the association of metabolites with transcript profiles provided a comprehensive understanding of ethylene signalling, respiration, sugar accumulation and softening of acerola, shedding light on promising key regulatory genes. Overall, this study provides a foundation for further examination of the functional significance of these genes to improve fruit quality traits. [ABSTRACT FROM AUTHOR]

Main conclusion: The overexpression of SlbHLH22 functioned in controlling flowering time, accelerated fruit ripening, and produced more ethylene-producing phenotypes in tomato. Flowering and fruit ripening are two complex transition processes regulated by various internal and external factors that ultimately lead to fruit maturation and final seed dispersal. The basic helix–loop–helix (bHLH) transcription factor is the largest TF gene family in plants that controls various biological and developmental aspects, but the actual roles of these genes have not been fully studied. Here, we performed a functional characterization of the bHLH gene SlbHLH22 in tomato. SlbHLH22 was fully expressed in tomato flowers, while a moderate expression level was also observed in fruits at different developmental stages. Overexpression of the SlbHLH22 gene revealed that it is highly involved in controlling flowering time, through the activation of the SlSFT or SlLFY genes, and promoting fruit ripening and improved carotenoid accumulation. The expression patterns of carotenoid-related genes (SlPYS1) were also upregulated in transgenic tomato fruits. In transgenic tomato fruit, we observed clear changes in colour from green to orange with enhanced expression of the SlbHLH22 gene. SlbHLH22 was upregulated under exogenous ACC, IAA, ABA, and ethephon. Overexpression of SlbHLH22 also promotes ethylene production. Moreover, ethylene biosynthesis and perception genes (SlACO3, SlACS1, SlACS2, SlACS4, SlACS1a, SlEIN1, SlEIN2, SlEIN3, SlEIN4, SlETR2, SlETR3, SlSAM3, and SlSAMS) were upregulated. Ripening-related genes (SlAP2a, SlCNR, SlNOR, SlMYB, and SlTAG) were consistent in their expression pattern in transgenic plants. Finally, our study provides evidence that tomato bHLH genes play an important role in flowering, fruit ripening, and development. [ABSTRACT FROM AUTHOR]

Fruits result from complex biological processes that begin soon after fertilization. Among these processes are cell division and expansion, accumulation of secondary metabolites, and an increase in carbohydrate biosynthesis. Later fruit ripening is accomplished by chlorophyll degradation and cell wall lysis. Fruit maturation is an essential step to optimize seed dispersal, and is controlled by a complex network of transcription factors and genetic regulators that are strongly influenced by phytohormones. Abscisic acid (ABA) and ethylene are the major regulators of ripening and senescence in both dry and fleshy fruits, as demonstrated by numerous ripening-defective mutants, effects of exogenous hormone application, and transcriptome analyses. While ethylene is the best characterized player in the final step of a fruit's life, ABA also has a key regulatory role, promoting ethylene production and acting as a stress-related hormone in response to drought and pathogen attack. In this review, we focus on the role of ABA and ethylene in relation to the interconnected biotic and abiotic phenomena that affect ripening and senescence. We integrate and discuss the most recent data available regarding these biological processes, which are crucial for post-harvest fruit conservation and for food safety. [ABSTRACT FROM AUTHOR]

Banana fruit (Musa acuminate L.) ripening is a complex genetical process affected by multiple phytohormones and expression of various genes. However, whether plant hormone brassinosteroid (BR) is involved in this process remains obscure. In this work, three genes that encode BR core signaling components brassinazole resistant (BZR) proteins, namely MaBZR1 to MaBZR3, were characterized from banana fruit. MaBZR1‐MaBZR3 exhibited both nuclear and cytoplasmic localization and behaved as transcription inhibitors. Expression analysis showed that MaBZR1/2/3 were continuously decreased as fruit ripening proceeded, indicating their negative roles in banana ripening. Moreover, gel shift and transient expression assays demonstrated that MaBZR1/2 could suppress the transcription of ethylene biosynthetic genes, including MaACS1, MaACO13 and MaACO14, which increased gradually during the banana ripening, via specifically binding to CGTGT/CG sequence in their promoters. Importantly, exogenous application of BRs promotes banana ripening, which is presumably due to the accelerated expression of MaACS1 and MaACO13/14, and consequently the ethylene production. Our study indicates that MaBZR1/2 act as transcriptional repressors of ethylene biosynthetic genes during banana fruit ripening. [ABSTRACT FROM AUTHOR]

Upon exposure to abiotic stresses, plants activate early stress-signaling mechanisms within a few seconds to a few hours to counter the stress responses and bring tolerance. The most versatile signaling molecules involved during the early events of abiotic stress signaling are Ca2+ (calcium ion) and reactive oxygen species (ROS), 1O2, O2−, and H2O2. Initially, apoplastic Ca2+ activates plasma membrane-bound NADPH oxidase and generates H2O2, which acts as a second messenger and further leads to the activation of downstream signaling processes. Subsequently, H2O2 activates calcium-dependent protein kinase (CDPK) and mitogen activated protein kinase (MAPK) pathways, leading to stress tolerance through downstream signaling cascades. In addition, fast influx of Ca2+ from the apoplast to the cytosol further activates cytosolic CDPKs and respiratory burst oxidase D and regulates Ca2+ and ROS signaling. Sub-cellular organelles further produce ROS and Ca2+ to bring stress tolerance. Excessive ROS produced during these processes are quenched by ROS scavenging enzymes, whereas excessive Ca2+ is neutralized by the action of the calcium binding proteins CDPKs, CaMs, CMLs, and CBLs. The phytohormone ABA further regulates the production of H2O2, thus maintaining the positive feedback system for ROS production and stress tolerance. Additionally, CBL proteins modulate H2O2 production in the presence of NADPH oxidase via interaction with CIPK, thus maintaining a positive feedback mechanism in stress tolerance. Similarly, CaM proteins bind with MAPK and regulate stress tolerance by activating the MAPK cascade. [ABSTRACT FROM AUTHOR]

Flavor quality is import for determining consumer perception and acceptance of tomato products. In this study, 'Fendou' tomato fruit were harvested at six ripening stages and sampled to investigate the development of flavor-relevant compounds during vine ripening. Results showed that upon the initiation of ripening there was an increase in respiration rate and concomitant ethylene evolution that was associated with increased membrane permeability. In accordance with these physiological changes, flavor-relevant compounds demonstrated different expression patterns as fruit ripened, which contributed to 'red-ripe' flavor characteristics of red-ripe fruit. Based on correlation analysis between ethylene evolution and the flavor-relevant compounds during 'Fendou' tomato ripening and the other researchers' reports, the activation of System 2-dependent autocatalytic ethylene production plays an important role in the development of most flavor-relevant compounds during tomato vine ripening. Overall, our results suggested that most flavor-relevant compounds that accumulated the most during tomato fruit ripening at red stage could be under ethylene regulation and were among the most important contributors to the 'red-ripe' flavor. Due to the development of these compounds, the flavor quality at late ripening stages is different from that of fruit at early ripening stages. [ABSTRACT FROM AUTHOR]

Ethylene is a phytohormone involved in the regulation of several aspects of plant development and in responses to biotic and abiotic stress. The effects of exogenous application of ethylene to sugarcane plants are well characterized as growth inhibition of immature internodes and stimulation of sucrose accumulation. However, the molecular network underlying the control of ethylene biosynthesis in sugarcane remains largely unknown. The chemical reaction catalyzed by 1-aminocyclopropane-1-carboxylic acid synthase (ACS) is an important rate-limiting step that regulates ethylene production in plants. In this work, using a yeast one-hybrid approach, we identified three basic helix-loophelix (bHLH) transcription factors, homologs of Arabidopsis FBH (FLOWERING BHLH), that bind to the promoter of ScACS2 (Sugarcane ACS2), a sugarcane type 3 ACS isozyme gene. Protein-protein interaction assays showed that sugarcane FBH1 (ScFBH1), ScFBH2, and ScFBH3 form homo- and heterodimers in the nucleus. Gene expression analysis revealed that ScFBHs and ScACS2 transcripts are more abundant in maturing internodes during afternoon and night. In addition, Arabidopsis functional analysis demonstrated that FBH controls ethylene production by regulating transcript levels of ACS7, a homolog of ScACS2. These results indicate that ScFBHs transcriptionally regulate ethylene biosynthesis in maturing internodes of sugarcane. [ABSTRACT FROM AUTHOR]