Deciphering the mechanism of E3 ubiquitin ligases in plant responses to abiotic and biotic stresses and perspectives on PROTACs for crop resistance.

With global climate change, it is essential to find strategies to make crops more resistant to different stresses and guarantee food security worldwide. E3 ubiquitin ligases are critical regulatory elements that are gaining importance due to their role in selecting proteins for degradation in the ubiquitin-proteasome proteolysis pathway. The role of E3 Ub ligases has been demonstrated in numerous cellular processes in plants responding to biotic and abiotic stresses. E3 Ub ligases are considered a class of proteins that are difficult to control by conventional inhibitors, as they lack a standard active site with pocket, and their biological activity is mainly due to protein-protein interactions with transient conformational changes. Proteolysis-targeted chimeras (PROTACs) are a new class of heterobifunctional molecules that have emerged in recent years as relevant alternatives for incurable human diseases like cancer because they can target recalcitrant proteins for destruction. PROTACs interact with the ubiquitin-proteasome system, principally the E3 Ub ligase in the cell, and facilitate proteasome turnover of the proteins of interest. PROTAC strategies harness the essential functions of E3 Ub ligases for proteasomal degradation of proteins involved in dysfunction. This review examines critical advances in E3 Ub ligase research in plant responses to biotic and abiotic stresses. It highlights how PROTACs can be applied to target proteins involved in plant stress response to mitigate pathogenic agents and environmental adversities.

Advances in the Multifaceted Functions of Cys2/His2-Type Zinc Finger Proteins in Distinctive Plant Characters.

Recent research findings established the cruciality of Cys2/His2-type Zinc Finger Proteins (C2H2-ZFPs) in plant growth and their relevance in coping with various stressors. Nevertheless, the complex structure of the C2H2-ZFPs network and the molecular mechanisms of response to stress in adversity have received considerable attention and now require more in-depth examination. This paper reviews the structural characteristics, classification, and recent functional research advances of C2H2-ZFPs. In addition, it systematically introduces the roles of these proteins across diverse facets of plant biology, encompassing growth and development, responses to biotic and abiotic stresses, and laying the foundation for future functional studies of C2H2-ZFPs.

Yarrowia lipolytica increased the activities of disease defense related enzymes and anti-fungal compounds in asparagus (Asparagus officinalis).

Fungal diseases pose significant threats to the production of asparagus, resulting in economic losses and decreased crop quality. The potential of the yeast Yarrowia lipolytica as a biocontrol agent against Fusarium proliferatum, a common pathogen of asparagus, was investigated in this study. The effects of Y. lipolytica treatment on decay incidence, disease index, and activities of major disease defense-related enzymes were investigated. In addition, we examined the levels of antifungal compounds such as total phenols, flavonoids, and lignin in asparagus plants exposed to Y. lipolytica. The results showed that Y. lipolytica treatment significantly reduced decay incidence and disease index caused by F. proliferatum when compared to the control group. Furthermore, Y. lipolytica-treated plants showed increased activity of disease defense-related enzymes, indicating that defense responses were activated. The activities of all evaluated enzymes were significantly higher in Y. lipolytica-treated asparagus, indicating an improved ability to combat fungal pathogens. Furthermore, Y. lipolytica treatment increased the content of antifungal compounds such as total phenols, flavonoids, and lignin, which are known to possess antimicrobial properties. These findings highlight the potential of Y. lipolytica as a biocontrol agent for fungal diseases in asparagus crops. The ability of Y. lipolytica to reduce disease incidence, boost disease defense-related enzymes, and increase antifungal compound content provides valuable insights into its efficacy as a natural and sustainable approach to disease management. However, further investigations are needed to optimize application methods and determine its efficacy under field conditions.

Revisiting the current and emerging concepts of postharvest fresh fruit and vegetable pathology for next-generation antifungal technologies.

Fungal infections of fresh fruits and vegetables (FFVs) can lead to safety problems, including consumer poisoning by mycotoxins. Various strategies exist to control fungal infections of FFVs, but their effectiveness and sustainability are limited. Recently, new concepts based on the microbiome and pathobiome have emerged and offer a more holistic perspective for advancing postharvest pathogen control techniques. Understanding the role of the microbiome in FFV infections is essential for developing sustainable control strategies. This review examines current and emerging approaches to postharvest pathology. It reviews what is known about the initiation and development of infections in FFVs. As a promising concept, the pathobiome offers new insights into the basic mechanisms of microbial infections in FFVs. The underlying mechanisms uncovered by the pathobiome are being used to develop more relevant global antifungal strategies. This review will also focus on new technologies developed to target the microbiome and members of the pathobiome to control infections in FFVs and improve safety by limiting mycotoxin contamination. Specifically, this review stresses emerging technologies related to FFVs that are relevant for modifying the interaction between FFVs and the microbiome and include the use of microbial consortia, the use of genomic technology to manipulate host and microbial community genes, and the use of databases, deep learning, and artificial intelligence to identify pathobiome markers. Other approaches include programming the behavior of FFVs using synthetic biology, modifying the microbiome using sRNA technology, phages, quorum sensing, and quorum quenching strategies. Rapid adoption and commercialization of these technologies are recommended to further improve the overall safety of FFVs.

Continual Reinforcement Learning for Quadruped Robot Locomotion.

The ability to learn continuously is crucial for a robot to achieve a high level of intelligence and autonomy. In this paper, we consider continual reinforcement learning (RL) for quadruped robots, which includes the ability to continuously learn sub-sequential tasks (plasticity) and maintain performance on previous tasks (stability). The policy obtained by the proposed method enables robots to learn multiple tasks sequentially, while overcoming both catastrophic forgetting and loss of plasticity. At the same time, it achieves the above goals with as little modification to the original RL learning process as possible. The proposed method uses the Piggyback algorithm to select protected parameters for each task, and reinitializes the unused parameters to increase plasticity. Meanwhile, we encourage the policy network exploring by encouraging the entropy of the soft network of the policy network. Our experiments show that traditional continual learning algorithms cannot perform well on robot locomotion problems, and our algorithm is more stable and less disruptive to the RL training progress. Several robot locomotion experiments validate the effectiveness of our method.

Recent advances in Penicillium expansum infection mechanisms and current methods in controlling P. expansum in postharvest apples.

One of the most significant challenges associated with postharvest apple deterioration is the blue mold caused by Penicillium expansum, which leads to considerable economic losses to apple production industries. Apple fruits are susceptible to mold infection owing to their high nutrient and water content, and current physical control methods can delay but cannot completely inhibit P. expansum growth. Biological control methods present promising alternatives; however, they are not always cost effective and have application restrictions. P. expansum infection not only enhances disease pathogenicity, but also inhibits the expression of host-related defense genes. The implementation of new ways to investigate and control P. expansum are expected with the advent of omics technology. Advances in these techniques, together with molecular biology approaches such as targeted gene deletion and whole genome sequencing, will lead to a better understanding of the P. expansum infectious machinery. Here, we review the progress of research on the blue mold disease caused by P. expansum in apples, including physiological and molecular infection mechanisms, as well as various methods to control this common plant pathogen.

Development and validation of a simple and rapid HILIC-MS/MS method for the quantification of low-abundant lysoglycerophospholipids in human plasma.

Lysoglycerophospholipids (Lyso-GPLs) are an essential class of signaling lipids with potential roles in human diseases, such as cancer, central nervous system diseases, and atherosclerosis. Current methods for the quantification of Lyso-GPLs involve complex sample pretreatment, long analysis times, and insufficient validation, which hinder the research of Lyso-GPLs in human studies, especially for Lyso-GPLs with low abundance in human plasma such as lysophosphatidic acid (LPA), lysophosphatidylinositol (LPI), lysophosphatidylglycerol (LPG), lysophosphatidylserine (LysoPS), lyso-platelet-activating factor (LysoPAF), and cyclic phosphatidic acid (cPA). Herein, we report the development and validation of a simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of Lyso-GPLs with low abundance in plasma. Protein precipitation using MeOH for Lyso-GPL extraction, quick separation (within 18 min) based on hydrophilic interaction liquid chromatography (HILIC), and sensitive MS detection under dynamic multiple reaction monitoring (dMRM) mode enabled efficient quantification of 22 Lyso-GPLs including 2 cPA, 4 LPG, 11 LPA, 2 LysoPS, and 3 LysoPAF in 50 µL of human plasma. The present method showed good linearity (goodness of fit, 0.99823-0.99995), sensitivity (lower limit of quantification, 0.03-14.06 ng/mL), accuracy (73-117%), precision (coefficient of variation ≤ 28%), carryover (≤ 17%), recovery (80-110%), and stability (83-123%). We applied the method in an epidemiological study and report concentrations of 18 Lyso-GPLs in 567 human plasma samples comparable to those of previous studies. Significant negative associations of LysoPAF C18, LysoPAF C18:1, and LysoPAF C16 with homeostatic model assessment for insulin resistance (HOMA-IR) level were observed; this indicates possible roles of LysoPAF in glucose homeostasis. The application of the present method will improve understanding of the roles of circulating low-abundant Lyso-GPLs in health and diseases.

Ethnic, Botanic, Phytochemistry and Pharmacology of the Acorus L. Genus: A Review.

The genus Acorus, a perennial monocotyledonous-class herb and part of the Acoraceae family, is widely distributed in the temperate and subtropical zones of the Northern and Southern Hemispheres. Acorus is rich in biological activities and can be used to treat various diseases of the nervous system, cardiovascular system, and digestive system, including Alzheimer's disease, depression, epilepsy, hyperlipidemia, and indigestion. Recently, it has been widely used to improve eutrophic water and control heavy-metal-polluted water. Thus far, only three species of Acorus have been reported in terms of chemical components and pharmacological activities. Previously published reviews have not further distinguished or comprehensively expounded the chemical components and pharmacological activities of Acorus plants. By carrying out a literature search, we collected documents closely related to Acorus published from 1956 to 2022. We then performed a comprehensive and systematic review of the genus Acorus from different perspectives, including botanical aspects, ethnic applications, phytochemistry aspects, and pharmacological aspects. Our aim was to provide a basis for further research and the development of new concepts.

A simple and rapid method for extraction and measurement of circulating sphingolipids using LC-MS/MS: a targeted lipidomic analysis.

Sphingolipids are a class of lipids with high structural diversity and biological pleiotropy. Mounting evidence supports a role for sphingolipids in regulating pathophysiology of cardiometabolic diseases, and they have been proposed as potential cardiometabolic biomarkers. Current methods for quantifying sphingolipids require laborious pretreatment and relatively large sample volumes, and cover limited species, hindering their application in epidemiological studies. Herein, we applied a time-, labor-, and sample-saving protocol simply using methanol for plasma sphingolipid extraction. It was compared with classical liquid-liquid extraction methods and showed significant advantages in terms of simplicity, sphingolipid coverage, and sample volume. By coupling the protocol with liquid chromatography using a wide-span mobile phase polarity parameter and tandem mass spectrometry operated in dynamic multiple reaction monitoring mode, 37 sphingolipids from 8 classes (sphingoid base, sphingoid base phosphate, ceramide-1-phosphate, lactosylceramide, hexosylceramide, sphingomyelin, ceramide, and dihydroceramide) were quantified within 16 min, using only 10 µL of human plasma. The current method showed good performance in terms of linearity (R2 > 0.99), intra- and interbatch accuracy (70-123%) and precision (RSD < 12%), matrix effect (91-121%), recovery (96-101%), analyte chemical stability (deviation < 19%), and carryover (< 16%). We successfully applied this method to quantify 33 detectable sphingolipids from 579 plasma samples of an epidemiological study within 10 days. The quantified sphingolipid concentrations were comparable with previous studies. Positive associations of ceramide C22:0/C24:0 and their precursors with homeostasis model assessment of insulin resistance suggested that the synthesis of the ceramides might be involved in insulin resistance. This novel method constitutes a simple and rapid approach to quantify circulating sphingolipids for epidemiological studies using targeted lipidomic analysis, which will help elucidate the sphingolipid-regulated pathways underlying cardiometabolic diseases.

Serum branched-chain amino acids modifies the associations between air pollutants and insulin resistance.

Growing evidence supports that air pollution exposure has become a risk factor of type II diabetes mellitus through the induction of insulin resistance (IR), but the presented findings did not provide a consistent relationship between air pollution exposure and IR in the temporal scale and the magnitude. Reported associated with IR and air pollution exposure, branched-chain amino acids (BCAAs) in blood might modify the association between air pollution exposure and IR. We took advantage of an existing panel study on elderly people who were healthy or with pre-diabetes. Amino acids were analyzed from the serum samples using a UPLC-QQQ-MS, and the homeostasis model assessment of insulin resistance (HOMA-IR) values were calculated to represent the levels of IR in each visit. Exposures to PM2.5, NO2, SO2, CO, O3, and black carbon (BC) were estimated using data from a monitoring station. Linear mixed-effects models were applied to estimate the associations between the air pollution and HOMA-IR, as well as the modifying effects of BCAAs. We found significantly higher concentrations of BCAAs in the pre-diabetic subjects than healthy ones. The concentrations of BCAAs were all significantly associated with HOMA-IR. For subjects with high-level BCAAs, HOMA-IR was positively associated with an IQR increase in PM2.5, NO2, BC, and CO at lag day 2 and in PM2.5, SO2, NO2, BC, and CO at lag day 7. While for subjects with low-level BCAAs, there was no significant association observed at any lag day except for CO at lag day 5. The study provided evidence that circulating BCAAs may modify the relationship between air pollution exposure and the level of insulin resistance in humans.

Securing fruit production: Opportunities from the elucidation of the molecular mechanisms of postharvest fungal infections.

Fruit-based diets have been adopted by the public worldwide because of their nutritional value. Many advances have also been made in the elucidation of host-pathogen interaction in the postharvest phase of fruits, in the hope of improving the management of diseases caused by pathogenic molds. In this study, we presented the molecular mechanisms by which pathogenic mold infects fruit in the postharvest phase, and focused on the knowledge gained from recent molecular techniques such as differential analysis of gene expression, targeted insertion, and mutagenesis. Current postharvest pathogenic fungal control strategies were then examined on the basis of their mechanisms for altering the infection process in order to explore new perspectives for securing fruit production. We found that biotechnological advances have led to an understanding of the new basic molecular processes involved in fruit fungal infection and to the identification of new genes, proteins and key factors that could serve as ideal targets for innovative antifungal strategies. In addition, the most commonly used steps to evaluate an approach to disrupt the fruit fungal infection process are mainly based on the inhibition of mycelial growth, spore germination, disruption of Adenosine triphosphate (ATP) synthesis, induction of oxidative stress, cell wall membrane damage, and inhibition of key enzymes. Finally, the alteration of the molecular mechanisms of signaling and response pathways to infection stimulation should also guide the development of effective control strategies to ensure fruit production.

Unravelling the fruit microbiome: The key for developing effective biological control strategies for postharvest diseases.

Fruit-based diets are recognized for their benefits to human health. The safety of fruit is a global concern for scientists. Fruit microbiome represents the whole microorganisms that are associated with a fruit. These microbes are either found on the surfaces (epiphytes) or in the tissues of the fruit (endophytes). The recent knowledge gained from these microbial communities is considered relevant to the field of biological control in prevention of postharvest fruit pathology. In this study, the importance of the microbiome of certain fruits and how it holds promise for solving the problems inherent in biocontrol and postharvest crop protection are summarized. Research needs on the fruit microbiome are highlighted. Data from DNA sequencing and "meta-omics" technologies very recently applied to the study of microbial communities of fruits in the postharvest context are also discussed. Various fruit parameters, management practices, and environmental conditions are the main determinants of the microbiome. Microbial communities can be classified according to their structure and function in fruit tissues. A critical mechanism of microbial biological control agents is to reshape and interact with the microbiome of the fruit. The ability to control the microbiome of any fruit is a great potential in postharvest management of fruits. Research on the fruit microbiome offers important opportunities to develop postharvest biocontrol strategies and products, as well as the health profile of the fruit.

Biological control as an alternative to synthetic fungicides for the management of grey and blue mould diseases of table grapes: a review.

Grey and blue mould diseases are among the most important diseases of grapes worldwide. They are causing extensive decay in postharvest grapes. Chemical fungicides remain the primary treatment for managing these diseases. However, consumer's interest in organic produce, restrictions on chemical use by some countries, and concerns about human and environmental safety have driven research to identify safe and effective alternatives. Among several alternative approaches, the use of biological control agents (BCAs) is getting more acceptance and has been comprehensively studied. This review summarizes the use of BCAs as a postharvest treatment to control the postharvest grey and blue mould of grapes. The review also emphasizes the economic importance of these two major postharvest diseases of grapes. In addition, other non-chemical postharvest treatments, the advantage of an integrated approach and finally problems, challenges, and future trends of the BCAs are described. Several yeasts that have a promising result to control grey and blue mould disease of grapes are thoroughly reviewed. The current market share of BCAs and their future directions on commercialization are also suggested in this review. Biocontrols can be a potential control method for postharvest diseases of fruits and vegetables in place of chemical fungicides. Antagonistic yeasts have high ability to suppress fungal growth. Integrated approach utilizes a combination approaches, which often results in a synergistic effect to control the diseases. USA and Europe are currently the largest markets for biocontrol products.

A rapid and high-throughput approach to quantify non-esterified oxylipins for epidemiological studies using online SPE-LC-MS/MS.

Oxylipins are highly bioactive lipid mediators derived from polyunsaturated fatty acids (PUFAs) and have fundamental roles in a diverse set of homeostatic and inflammatory processes. Current targeted methods of analyzing oxylipins require long runtimes and laborious sample preparation, limiting their application to epidemiological studies. Here, we report the development of an online solid-phase extraction-liquid chromatography-triple quadrupole mass spectrometry (online SPE-LC-MS/MS) method to quantify 49 non-esterified oxylipins and PUFAs, including prostanoids, leukotrienes, lipoxins, resolvins, hydroxy PUFAs, epoxy PUFAs, and their PUFA precursors, in 50-µL samples of human serum. The new method was validated in terms of linearity, lower limits of quantification, recovery, precision, and matrix effects. The limits of quantification were in the range of 0.18 to 9 pg for oxylipins. A single 11.5-min analysis enabled the accurate (80-120% recovery), precise, and reproducible (RSD < 15%) quantification of 32 analytes at three spiked concentrations (0.1, 1, 5 ng/mL), demonstrating the suitability of this method for large-scale epidemiological studies. We successfully applied it to rapidly analyze a total of 565 serum samples from prediabetic and healthy individuals in a nested case-control panel study. Oxylipin concentrations were quantified within a range similar to those of previously published articles. Application of this approach to both healthy and prediabetic subjects found that several circulating hydroxy PUFAs, including LTB4, 12-HEPE, 15(S)-HETE, and 17-HDHA, were negatively associated with fasting glucose levels, indicating decreased anti-inflammatory activity and impaired glucose tolerance in diabetes progression. This new approach provides a means for high-throughput analyses of non-esterified oxylipins for epidemiological studies and will help unravel the intricate interactions of the oxylipin cascade and accelerate our understanding of the biological regulation of these important lipid mediators in human disease.

Recent trends in detecting, controlling, and detoxifying of patulin mycotoxin using biotechnology methods.

Patulin (PAT) is a mycotoxin that can contaminate many foods and especially fruits and fruit-based products. Therefore, accurate and effective testing is necessary to enable producers to comply with regulations and promote food safety. Traditional approaches involving the use of chemical compounds or physical treatments in food have provided practical methods that have been used to date. However, growing concerns about environmental and health problems associated with these approaches call for new alternatives. In contrast, recent advances in biotechnology have revolutionized the understanding of living organisms and brought more effective biological tools. This review, therefore, focuses on the study of biotechnology approaches for the detection, control, and mitigation of PAT in food. Future aspects of biotechnology development to overcome the food safety problem posed by PAT were also examined. We find that biotechnology advances offer novel, more effective, and environmental friendly approaches for the control and elimination of PAT in food compared to traditional methods. Biosensors represent the future of PAT detection and use biological tools such as aptamer, enzyme, and antibody. PAT prevention strategies include microbial biocontrol, the use of antifungal biomolecules, and the use of microorganisms in combination with antifungal molecules. PAT detoxification aims at the breakdown and removal of PAT in food by using enzymes, microorganisms, and various adsorbent biopolymers. Finally, biotechnology advances will be dependent on the understanding of fundamental biology of living organisms regarding PAT synthesis and resistance mechanisms.

20-Hydroxy-3-Oxolupan-28-Oic Acid Attenuates Inflammatory Responses by Regulating PI3K⁻Akt and MAPKs Signaling Pathways in LPS-Stimulated RAW264.7 Macrophages.

20-Hydroxy-3-oxolupan-28-oic acid (HOA), a lupane-type triterpene, was obtained from the leaves of Mahonia bealei, which is described in the Chinese Pharmacopeia as a remedy for inflammation and related diseases. The anti-inflammatory mechanisms of HOA, however, have not yet been fully elucidated. Therefore, the objective of this study was to characterize the molecular mechanisms of HOA in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. HOA suppressed the release of nitric oxide (NO), pro-inflammatory cytokine tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) in LPS-stimulated RAW264.7 macrophages without affecting cell viability. Quantitative real-time reverse-transcription polymerase chain reaction (RT-qPCR) analysis indicated that HOA also suppressed the gene expression of inducible NO synthase (iNOS), TNF-α, and IL-6. Further analyses demonstrated that HOA inhibited the phosphorylation of upstream signaling molecules, including p85, PDK1, Akt, IκBα, ERK, and JNK, as well as the nuclear translocation of nuclear factor κB (NF-κB) p65. Interestingly, HOA had no effect on the LPS-induced nuclear translocation of activator protein 1 (AP-1). Taken together, these results suggest that HOA inhibits the production of cytokine by downregulating iNOS, TNF-α, and IL-6 gene expression via the downregulation of phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinases (MAPKs), and the inhibition of NF-κB activation. Our findings indicate that HOA could potentially be used as an anti-inflammatory agent for medical use.

Integration of proteome and transcriptome data reveals the mechanism involved in controlling of Fusarium graminearum by Saccharomyces cerevisiae.

BACKGROUND: It has been reported that antagonistic microorganisms could effectively control the infection of Fusarium graminearum. However, there is limited information on the control of F. graminearum by Saccharomyces cerevisiae, while the possible control mechanisms involved through proteomic and transcriptomic techniques have also not been reported. RESULTS: The results of this study showed that S. cerevisiae Y-912 could significantly inhibit the growth of F. graminearum Fg1, and the spore germination rate and germ tube length of F. graminearum Fg1 were also significantly inhibited by S. cerevisiae Y-912. Proteomic analysis revealed that differentially expressed proteins which were made of some basic proteins and enzymes related to basal metabolism, such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate mutase (PGAM), enolase (ENO), fructose diphosphate aldolase (FBA) and so on, were all down-regulated. The transcriptomics of F. graminearum control by S. cerevisiae was also analyzed. CONCLUSION: The control mechanism of S. cerevisiae Y-912 on F. graminearum Fg1 was a very complex material and energy metabolic process in which the related proteins and genes involved in the glycolytic pathway, tricarboxylic acid (TCA) cycle and amino acid metabolism were all down-regulated. © 2019 Society of Chemical Industry.

CDK4 protein is degraded by anaphase-promoting complex/cyclosome in mitosis and reaccumulates in early G1 phase to initiate a new cell cycle in HeLa cells.

CDK4 regulates G1/S phase transition in the mammalian cell cycle by phosphorylating retinoblastoma family proteins. However, the mechanism underlying the regulation of CDK4 activity is not fully understood. Here, we show that CDK4 protein is degraded by anaphase-promoting complex/cyclosome (APC/C) during metaphase-anaphase transition in HeLa cells, whereas its main regulator, cyclin D1, remains intact but is sequestered in cytoplasm. CDK4 protein reaccumulates in the following G1 phase and shuttles between the nucleus and the cytoplasm to facilitate the nuclear import of cyclin D1. Without CDK4, cyclin D1 cannot enter the nucleus. Point mutations that disrupt CDK4 and cyclin D1 interaction impair the nuclear import of cyclin D1 and the activity of CDK4. RNAi knockdown of CDK4 also induces cytoplasmic retention of cyclin D1 and G0/G1 phase arrest of the cells. Collectively, our data demonstrate that CDK4 protein is degraded in late mitosis and reaccumulates in the following G1 phase to facilitate the nuclear import of cyclin D1 for activation of CKD4 to initiate a new cell cycle in HeLa cells.

DNA replication initiator Cdc6 also regulates ribosomal DNA transcription initiation.

RNA-polymerase-I-dependent ribosomal DNA (rDNA) transcription is fundamental to rRNA processing, ribosome assembly and protein synthesis. However, how this process is initiated during the cell cycle is not fully understood. By performing a proteomic analysis of transcription factors that bind RNA polymerase I during rDNA transcription initiation, we identified that the DNA replication initiator Cdc6 interacts with RNA polymerase I and its co-factors, and promotes rDNA transcription in G1 phase in an ATPase-activity-dependent manner. We further showed that Cdc6 is targeted to the nucleolus during late mitosis and G1 phase in a manner that is dependent on B23 (also known as nucleophosmin, NPM1), and preferentially binds to the rDNA promoter through its ATP-binding domain. Overexpression of Cdc6 increases rDNA transcription, whereas knockdown of Cdc6 results in a decreased association of both RNA polymerase I and the RNA polymerase I transcription factor RRN3 with rDNA, and a reduction of rDNA transcription. Furthermore, depletion of Cdc6 impairs the interaction between RRN3 and RNA polymerase I. Taken together, our data demonstrate that Cdc6 also serves as a regulator of rDNA transcription initiation, and indicate a mechanism by which initiation of rDNA transcription and DNA replication can be coordinated in cells.

Exogenous trehalose enhanced the biocontrol efficacy of Hanseniaspora uvarum against grape berry rots caused by Aspergillus tubingensis and Penicillium commune.

BACKGROUND: Primarily, chemical pesticides are commonly used to control preharvest and postharvest diseases of fruits and vegetables. However, there is strong public concern regarding the human and environmental health problems that might emanate from the residues of these chemical pesticides. As a result, biocontrol is often preferred due to its safety for humans and animals. The microbial antagonists employed often encounter variable climatic conditions, which affect their efficacy. In this study, the biocontrol efficacy of Hanseniaspora uvarum enhanced with trehalose against Aspergillus tubingensis and Penicillium commune in grapes was investigated. RESULTS: H. uvarum Y3 pretreated with 2.0% w/v trehalose in nutrient yeast dextrose broth (NYDB) before used significantly inhibited the incidence of decay and lesion diameter without affecting the sensory qualities of the grapes stored at either 4 °C or 20 °C. There was also a significant (P < 0.05) increase in the population dynamics of H. uvarum that was pretreated with 2% trehalose compared to that of H. uvarum alone. The in vitro assay on spore germination revealed an inhibition of A. tubingensis and P. commune by 85.6% and 87.0% respectively. Scanning electron microscopy results showed that both untreated H. uvarum and H. uvarum pre-treated with the 2% w/v trehalose before use inhibited fungal mycelium and development of grape rot. CONCLUSION: The biocontrol efficacy of H. uvarum was enhanced against grape rot caused by A. tubingensis and P. commune. The findings indicate the potential applicability of trehalose in the enhancement of H. uvarum. © 2018 Society of Chemical Industry.