Allelic variation of PmCBF03 contributes to the altitude and temperature adaptability in Japanese apricot (Prunus mume Sieb. et Zucc.).

Japanese apricot is an important subtropical deciduous fruit tree in China, widely distributed in different altitude areas. How does it adapt to the different temperature environments in these areas? In this study, we identified a low-temperature transcription factor PmCBF03 on chromosome 7 through adaptive analysis of populations at different altitudes, which has an early termination single nucleotide polymorphism mutation. There were two different types of variation, PmCBF03A type in high-altitude areas and PmCBF03T type in low-altitude areas. PmCBF03A gene increased the survival rate, Fv/Fm values, antioxidant enzyme activity, and expression levels of antioxidant enzyme genes, and reducing electrolyte leakage and accumulation of reactive oxygen species in transgenic Arabidopsis under low temperature and freezing stress. Simultaneously, PmCBF03A gene promoted the dormancy of transgenic Arabidopsis seeds than wild-type. Biochemical analysis demonstrated that PmCBF03A directly bound to the DRE/CRT element in the promoters of the PmCOR413, PmDAM6 and PmABI5 genes, promoting their transcription and enhanced the cold resistance and dormancy of the overexpressing PmCBF03A lines. While PmCBF03T gene is unable to bind to the promoters of PmDAM6 and PmABI5 genes, leading to early release of dormancy to adapt to the problem of insufficient chilling requirement in low-altitude areas.

Novel insights into the dissemination route of Japanese apricot (Prunus mume Sieb. et Zucc.) based on genomics.

Japanese apricot (Prunus mume) is an attractive fruit tree originating from China, and its cultivation history dates back 7000 years. In this study, we investigated the genetic diversity, population structure, and genetic relationship of Japanese apricots in different regions of China and Japan. The analyses of the genetic variation between wild and cultivated populations improved our understanding of the general mechanisms of domestication and improvement. A total of 146 accessions of Japanese apricot from different geographic locations were sequenced. The genetic diversity of wild and domesticated accessions (3.60 × 10-3 and 3.51 × 10-3 , respectively) from China was high, and the effect of artificial selection pressure on domesticated accessions was small; however, the genetic diversity of artificially bred accessions decreased significantly (2.68 × 10-3 ) compared to domesticated accessions, which had an obvious improvement bottleneck effect. The chloroplast genome results showed that 41 haplotypes were detected, and Japanese apricots from the Yunnan region had the most haplotypes and the highest genetic diversity. The results revealed the dissemination route of Japanese apricot, not only along the Yangtze River basin system (from southwest China to Hunan, Jiangxi, and Anhui, and finally to the Jiangsu, Zhejiang, and Shanghai areas). Additionally, we discovered a second route for Japanese apricot dispersion, which was mostly in the Pearl River basin system, from southwest China to Libo of Guizhou and then to the Guangdong, Fujian, and Taiwan areas. This also showed that Japanese-bred accessions originated from Zhejiang, China. In addition, selective sweep analysis showed that most of the high-impact single nucleotide polymorphisms were identified in genes related to glucose metabolism, aromatic compound metabolism, flowering time, dormancy, and resistance to abiotic stress during the domestication and improvement of Japanese apricot.

Transcriptome analysis revealed molecular basis of cold response in Prunus mume.

Japanese apricot (Prunus mume Sieb. et Zucc.) is a traditional woody flower and fruit tree restrictedly cultivated in northern area due to its inability to survive harsh winters and early springs. In the current study, RNA-seq and physiological assay were used to study the cold response of P. mume 'Xuemei'. A total of 4705 genes were identified as differentially expressed genes (DEGs) in the 21 pairwise comparisons among seven time points under 0 °C cold treatment, and 3678 of them showed differential levels compared with control at normal temperature. The gene expression profiles indicated that the number of upregulated genes increased with prolongation of treatment time throughout the whole 48 h. Hierarchical clustering suggested three obvious phases of the gene expression profiles. Gene ontology (GO) analysis of the 4705 DEGs resulted in 102 significantly enriched GO items in which the transcription activity was dominant. 225 DEGs were predicted to encode transcription factor (TF) genes. Some important TFs (ERF, CBF, WRKY, NAC, MYB, bHLH) were strongly induced during the whole cold treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that plant signal transduction pathways such as plant hormone and calcium (Ca2+) were notable. Metabolic pathways such as sugar metabolism, especially RFOs (raffinose family oligosaccharides) were activated, which was accompanied by the accumulation of soluble sugars. SOD and POD enzyme activities coupled with reactive oxygen species (ROS)-related gene expression profile implied a gradually induced ROS scavenging system under cold treatment. These results might shed light on the sensitivity to cold stress in Japanese apricot and provide new insights into hardiness studies in P. mume and its related species. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01376-2.

Comprehensive transcriptomic and metabolomic analysis revealed distinct flavonoid biosynthesis regulation during abnormal pistil development in Japanese apricot.

Japanese apricot is an imperative stone fruit plant with numerous processing importance. The failure of reproductive system is the most common cause of fruit loss, through which pistil abortion is the fundamental one. To understand this mechanism, we used a combination of transcriptomic and metabolomic approaches to investigate the biochemical and molecular basis of flavonoid biosynthesis. Due to the regulated expression of flavonoid pathway-related genes in plants, flavonoid biosynthesis is largely regulated at the transcriptional level. A total of 2272 differently expressed genes and 215 differential metabolites were found. The expression of the genes and metabolites encoding flavonoid biosynthesis was lower in abnormal pistils that are in line with the flavonoid quantification from abnormal pistils. Besides, a couple of genes were also detected related to MYB, MADS, NAC and bHLH transcription factors. Remarkably, we found 'hydroxycinnamoyl transferase (LOC103323133)' and flavonoid related metabolite '2-hydroxycinnamic acid' was lower expressed in abnormal pistil, proposing the cause of pistil abortion. Collectively, the present study delivers inclusive transcriptional and metabolic datasets that proposed valuable prospects to unravel the genetic mechanism underlying pistil abortion.

The analysis of genetic structure and characteristics of the chloroplast genome in different Japanese apricot germplasm populations.

BACKGROUND: Chloroplast (cp) genomes are generally considered to be conservative and play an important role in population diversity analysis in plants, but the characteristics and diversity of the different germplasm populations in Japanese apricot are still not clear. RESULTS: A total of 146 cp genomes from three groups of wild, domesticated, and bred accessions of Japanese apricot were sequenced in this study. The comparative genome analysis revealed that the 146 cp genomes were divided into 41 types, and ranged in size from 157,886 to 158,167 bp with a similar structure and composition to those of the genus Prunus. However, there were still minor differences in the cp genome that were mainly caused by the contraction and expansion of the IR region, and six types of SSR in which mono-nucleotide repeats were the most dominant type of repeats in the cp genome. The genes rpl33 and psbI, and intergenic regions of start-psbA, rps3-rpl22, and ccsA-ndhD, showed the highest nucleotide polymorphism in the whole cp genome. A total of 325 SNPs were detected in the 146 cp genomes, and more than 70% of the SNPs were in region of large single-copy (LSC). The SNPs and haplotypes in the cp genome indicated that the wild group had higher genetic diversity than the domesticated and bred groups. In addition, among wild populations, Southwest China, including Yunnan, Tibet, and Bijie of Guizhou, had the highest genetic diversity. The genetic relationship of Japanese apricot germplasm resources in different regions showed a degree of correlation with their geographical distribution. CONCLUSION: Comparative analysis of chloroplast genomes of 146 Japanese apricot resources was performed to analyze the used to explore the genetic relationship and genetic diversity among Japanese apricot resources with different geographical distributions, providing some reference for the origin and evolution of Japanese apricot.

miR169 and PmRGL2 synergistically regulate the NF-Y complex to activate dormancy release in Japanese apricot (Prunus mume Sieb. et Zucc.).

KEY MESSAGE: This study is the first to demonstrate that GA4-induced dormancy release is associated with the NF-Y complex, which interacts with gibberellin inhibitor RGL2 in Japanese apricot. Seasonal dormancy is not only vital for the survival in cold winter but also affects flowering of temperate fruit trees and the dormancy release depends on the accumulation of the cold temperatures (Chilling requirement-CR). To understand the mechanism of dormancy release in deciduous fruit crops, we compared miRNA sequencing data during the transition stage from paradormancy to dormancy release in the Japanese apricot and found that the miR169 family showed significant differentially up-regulated expression during dormancy induction and was down-regulated during the dormancy release periods. The 5' RACE assay and RT-qPCR validated its target gene NUCLEAR FACTOR-Y subunit A (NF-YA), which exhibited the opposite expression pattern. Further study showed that exogenous GA4 could inhibit the expression of the gibberellic acid (GA) signal transduction suppressor PmRGL2 (RGA-LIKE 2) and promote the expression of NF-Y. Moreover, the interaction between the NF-Y family and GA inhibitor PmRGL2 was verified by the yeast-two-hybrid (Y2H) system and a bimolecular fluorescence complementarity (BiFC) experiment. These results suggest that synergistic regulation of the NF-Y and PmRGL2 complex leads to the activation of dormancy release induced by GA4. These findings will help to elucidate the functional and regulatory roles of miR169 and NF-Y complex in seasonal bud dormancy induced by GA in Japanese apricot and provide new insights for the discovery of dormancy release mechanisms in woody plants.

Comprehensive transcriptome profiling to identify genes involved in pistil abortion of Japanese apricot.

Flower development exists as a key period in the angiosperms life cycle and the proper development is considered with its reproductive success. Pistil abortion is one of the widely distributed aspects of berry plants and its basic mechanism in Japanese apricot is quite unclear and needs thorough investigation. The present study was carried out to get a deep insight into the pistil abortion mechanism in Japanese apricot using a transcriptomic approach. A large number of DEGs were identified from different development stages of normal and abortive pistils. Pair-wise comparison analysis was performed as LY1 vs DQD1, LY2 vs DQD2, and LY3 vs DQD3 and produced 3590, 2085, and 2286 transcripts, respectively. The Gene Ontology (GO) showed that different metabolic processes, plant hormones, developmental processes, and photosystem-related genes were involved in pistil abortion. The pathway analysis revealed significant enrichment of plant hormone's signal transduction and circadian rhythm pathways. Furthermore, transcription factors such as MYB, MADS-box, and NAC family showed lower expression in abortive pistils. The current study presents a new strategy for advanced research and understanding of the pistil abortion process in Japanese apricot and provides a possible reference for other deciduous fruit trees.

Prunasin production using engineered Escherichia coli expressing UGT85A47 from Japanese apricot and UDP-glucose biosynthetic enzyme genes.

Japanese apricot, Prunus mume Sieb. et Zucc., biosynthesizes the l-phenylalanine-derived cyanogenic glucosides prunasin and amygdalin. Prunasin has biological properties such as anti-inflammation, but plant extraction and chemical synthesis are impractical. In this study, we identified and characterized UGT85A47 from Japanese apricot. Further, UGT85A47 was utilized for prunasin microbial production. Full-length cDNA encoding UGT85A47 was isolated from Japanese apricot after 5'- and 3'-RACE. Recombinant UGT85A47 stoichiometrically catalyzed UDP-glucose consumption and synthesis of prunasin and UDP from mandelonitrile. Escherichia coli C41(DE3) cells expressing UGT85A47 produced prunasin (0.64 g/L) from racemic mandelonitrile and glucose. In addition, co-expression of genes encoding UDP-glucose biosynthetic enzymes (phosphoglucomutase and UTP-glucose 1-phosphate uridiltransferase) and polyphosphate kinase clearly improved prunasin production up to 2.3 g/L. These results showed that our whole-cell biocatalytic system is significantly more efficient than the existing prunasin production systems, such as chemical synthesis.

Antiplatelet mechanism of an herbal mixture prepared from the extracts of Phyllostachys pubescens leaves and Prunus mume fruits.

BACKGROUND: Bamboo (Phyllostachys pubescens) leaves and Japanese apricot (Mume fructus) fruit are traditionally recognized to be safe herbs broadly used for food and medicinal purposes in Southeast Asia. Our group previously explored their antiplatelet effects. This study was designed to confirm inhibition effects of PM21 (a 2:1 mixture of bamboo leaf extract and Japanese apricot fruit extract) on platelet aggregation and evaluate its potency to use as an herbal remedy to prevent and/or treat the diseases caused by platelet aggregation and thrombus formation. METHODS: Washed platelets were prepared and platelet aggregation was induced by adding 5 µg/mL collagen. Anti-platelet effects of PM21 (75 mg/kg, 150 mg/kg, and 300 mg/kg for ex vivo and in vivo assays, and 50, 100, 200 µg/mL for in vitro assays) were evaluated. In ex vivo assays, PM21 was orally administered to rats daily after overnight fasting for 3 days and blood was collected 1 h after the final treatment. In vivo antithrombotic effect of PM21 was observed from a carrageenan induced mouse tail thrombosis model. RESULTS: In ex vivo assay, PM21 inhibited platelet aggregation significantly. PM21 showed a strong antithrombotic effect by reducing significantly the length of mouse tail thrombus. PM21 increased intracellular cAMP level and reduced the release of ATP, TXA2, and serotonin. PM21 also reduced intracellular concentration of calcium ion, fibrinogen binding to integrin αIIbß3, and phosphorylation of ERK2, p38, PLCγ2, and PI3 K. CONCLUSIONS: PM21 showed remarkable inhibitory effects on platelet aggregation and thrombus formation. Its inhibitory function seems to influence on GPVI binding to its ligand and subsequent initiation of a signaling cascade that involves activation of effector proteins and secretion of effector molecules, such as ATP, TXA2, serotonin, and Ca2+. PM21 also appears to exert its anti-platelet effect by deactivation of ERKs activation pathway as well as inhibition of fibrinogen binding to integrin αIIbß3.

Comparative proteomic and transcriptomic approaches to address the active role of GA4 in Japanese apricot flower bud dormancy release.

Hormones are closely associated with dormancy in deciduous fruit trees, and gibberellins (GAs) are known to be particularly important. In this study, we observed that GA4 treatment led to earlier bud break in Japanese apricot. To understand better the promoting effect of GA4 on the dormancy release of Japanese apricot flower buds, proteomic and transcriptomic approaches were used to analyse the mechanisms of dormancy release following GA4 treatment, based on two-dimensional gel electrophoresis (2-DE) and digital gene expression (DGE) profiling, respectively. More than 600 highly reproducible protein spots (P<0.05) were detected and, following GA4 treatment, 38 protein spots showed more than a 2-fold difference in expression, and 32 protein spots were confidently identified according to the databases. Compared with water treatment, many proteins that were associated with energy metabolism and oxidation-reduction showed significant changes after GA4 treatment, which might promote dormancy release. We observed that genes at the mRNA level associated with energy metabolism and oxidation-reduction also played an important role in this process. Analysis of the functions of the identified proteins and genes and the related metabolic pathways would provide a comprehensive proteomic and transcriptomic view of the coordination of dormancy release after GA4 treatment in Japanese apricot flower buds.

Genome-Wide Identification of the KNOX Gene Family in Japanese Apricot (Prunus mume Sieb. et Zucc.) and Functional Characterization of PmKNAT2 Genes.

The Knotted1-like Homeobox gene is crucial for plant morphological development and growth. Physicochemical characteristics, phylogenetic relationships, chromosomal localization, cis-acting elements, and tissue-specific expression patterns of the 11 PmKNOX genes found in the Japanese apricot genome in this study were examined. Proteins of 11 PmKNOX were soluble proteins with isoelectric points between 4.29 and 6.53, molecular masses between 15.732 and 44.011 kDa, and amino acid counts between 140 and 430. The identified PmKNOX gene family was split into three subfamilies by jointly constructing the phylogenetic tree of KNOX proteins in Japanese apricot and Arabidopsis thaliana. Combined outcomes of the analyzed conserved motifs and gene structures of the 11 PmKNOX genes from the same subfamily displayed comparable gene structure and motif patterns. The 11 PmKNOX members were distributed across six chromosomes, while two sets of PmKNOX genes were found to be collinear. Analysis of the 2000 bp promoter upstream of the coding region of the PmKNOX gene revealed that most PmKNOX genes might be involved in the physiological metabolism, growth and development processes of plants. The PmKNOX gene expression profile revealed that these genes were expressed at varying levels in different tissues, and most of them were linked to the meristems of leaf and flower buds, suggesting that PmKNOX may be involved in plants' apical meristems. In Arabidopsis thaliana, functional validation of PmKNAT2a and PmKNAT2b revealed that these two genes might be involved in regulating leaf and stem development. In addition to laying the groundwork for future research on the function of these genes, understanding the evolutionary relationships between members of the PmKNOX gene family provides opportunities for future breeding in Japanese apricots.

Bioinformatics Study of Aux/IAA Family Genes and Their Expression in Response to Different Hormones Treatments during Japanese Apricot Fruit Development and Ripening.

Auxin/indole-3-acetic acid (Aux/IAA) is a transcriptional repressor in the auxin signaling pathway that plays a role in several plant growth and development as well as fruit and embryo development. However, it is unclear what role they play in Japanese apricot (Prunus mume) fruit development and maturity. To investigate the role of Aux/IAA genes in fruit texture, development, and maturity, we comprehensively identified and expressed 19 PmIAA genes, and demonstrated their conserved domains and homology across species. The majority of PmIAA genes are highly responsive and expressed in different hormone treatments. PmIAA2, PmIAA5, PmIAA7, PmIAA10, PmIAA13, PmIAA18, and PmIAA19 showed a substantial increase in expression, suggesting that these genes are involved in fruit growth and maturity. During fruit maturation, alteration in the expression of PmIAA genes in response to 1-Methylcyclopropene (1-MCP) treatment revealed an interaction between auxin and ethylene. The current study investigated the response of Aux/IAA development regulators to auxin during fruit ripening, with the goal of better understanding their potential application in functional genomics.

Whole-genome analysis guided molecular mechanism of cyanogenic glucoside degradation by yeast isolated from Prunus mume fruit syrup.

Consumption of fermented Prunus mume fruit (maesil) sugar syrup raise a health concern due to the presence of the cyanogenic glucoside amygdalin. The goal of the present study was to investigate the amygdalin degradation potential and genome profile of the native microbes found in maesil syrup. The microbial profile analysis revealed that yeast is the predominant microorganism native to maesil syrup and that the isolated yeast cells showed a remarkable potential for amygdalin reduction (99.7%). Moreover, the reduction in amygdalin was inversely proportional to the growth of the isolated yeast. The whole-genome analysis revealed that the isolated yeast is Zygosaccharomyces rouxii (genome size 10 Mb, 39.25% of GC content). Of the 5250 genes (64.88%) predicted in the Z. rouxii genome, 5245 (99.90%) were annotated using NCBI Non-Redundant, UniProt, and InterProScan databases. The genome of the isolated Z. ruoxii harbored 2.03% of repeats and 0.68% of non-coding RNAs. Protein prediction indicated that ß-glycosidases and hydroxynitrile lyase may play a key role in amygdalin degradation. The predicted degradation initiated by ß-glycosidases that hydrolyze α-glucosidic bonds of amygdalin results in α-hydroxy nitriles (cyanohydrins) that are subsequently converted into carbonyl compounds (benzaldehyde) and hydrogen cyanide catalyzed by hydroxynitrile lyases. Present findings provide valuable data for constructing engineered microorganisms that can degrade amygdalin. Further analysis of Z. rouxii may elucidate the exact mechanism of amygdalin reduction in the production of maesil syrup.

Construction of the UDP-Glucose Biosynthetic Enzyme Gene Coexpression Plasmid for Prunasin Production in Escherichia coli.

Microbial production of bioactive glucosides using uridine diphosphate glucosyltransferase (UGT) is an efficient glucoside production method. Here, we describe a detailed method for the construction of a UDP-glucose biosynthetic enzyme gene coexpression plasmid, that is, pCDF-PGP and the microbial production of prunasin from racemic mandelonitrile using Escherichia coli possessing UGT85A47 obtained from Japanese apricot. Furthermore, this constructed vector can find application in the production of various other glucosides that utilize other UGTs and aglycons.

Analyzing Differentially Expressed Genes and Pathways Associated with Pistil Abortion in Japanese Apricot via RNA-Seq.

Reproduction is a critical stage in the flower development process, and its failure causes serious problems affecting fruit quality and yield. Pistil abortion is one of the main factors in unsuccessful reproduction and occurs in many fruit plants. In Japanese apricot, the problem of pistil abortion is very common and affects fruit quality and plant yield; however, its molecular mechanism is not clearly understood. Therefore, in the current study, we used RNA-Seq to identify the differentially expressed genes (DEGs) and pathways actively involved in pistil abortion. A total of 3882 differentially expressed genes were found after cutoff and pairwise comparison analysis. According to KEGG pathway analysis, plant hormone signaling transduction and metabolic pathways were found most significantly enriched in this study. A total of 60 transcription factor families such as MADS-box, NAC and TCP showed their role in this process. RT-qPCR assays confirmed that the expression levels were consistent with RNA-Seq results. This study provides an alternative to be considered for further studies and understanding of pistil abortion processes in Japanese apricot, and it provides a reference related to this issue for other deciduous fruit crops.

Subcritical Methanol Extraction of the Stone of Japanese Apricot Prunus mume Sieb. et Zucc.

The pits of Japanese apricot, Prunus mume Sieb. et Zucc., which are composed of stones, husks, kernels, and seeds, are unused by-products of the processing industry in Japan. The processing of Japanese apricot fruits generates huge amounts of waste pits, which are disposed of in landfills or, to a lesser extent, burned to form charcoal. Mume stones mainly consist of cellulose, hemicellulose, and lignin. Herein, we attempted to solubilize the wood-like carapace (stone) encasing the pit by subcritical fluid extraction with the aim of extracting useful chemicals. The characteristics of the main phenolic constituents were elucidated by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) analyses. The degrees of solubility for various treatments (190 °C; 3 h) were determined as follows: subcritical water (54.9%), subcritical 50% methanol (65.5%), subcritical 90% methanol (37.6%), subcritical methanol (23.6%), and subcritical isopropyl alcohol (14.4%). Syringaldehyde, sinapyl alcohol, coniferyl alcohol methyl ether, sinapyl alcohol methyl ether, 5-(hydroxymethyl)-2-furfural, and furfural were present in the subcritical 90% methanol extract. Coniferyl and sinapyl alcohols (monolignols) are source materials for the biosynthesis of lignin, and syringaldehyde occur in trace amounts in wood. Our current findings provide a solubilization method that allows the main phenolic constituents of the pits to be extracted under mild conditions. This technique for obtaining subcritical extracts shows great potential for further applications.

Carbon stable isotopic compositions of citric acid and malic acid in Japanese apricot liqueur decrease as the fruit ripens.

The carbon stable isotopic composition (δ13C) is often analyzed to quantify the addition of acidulants to Japanese apricot liqueur, but little is known about the variation in the δ13C values of the main organic acids arising from differences in the ripeness of Japanese apricots. We show that in Japanese apricot liqueur prepared using fruits at different stages of ripeness, the δ13C values of citric acid and malic acid ranged from -25.1‰ to -23.7‰ and from -22.3‰ to -19.7‰, respectively, and the δ13C values decreased as the fruit ripened. The average δ13C value of citric acid from liqueurs was 0.7‰ higher than that from fresh fruits, whereas the δ13C values of malic acid showed no isotope discrimination. The variation in δ13C values of the main organic acids in Japanese apricot liqueurs will help detect acidulant addition and control authenticity.

Component Profiling in Agricultural Applications Using an Adjustable Acupuncture Needle for Sheath-Flow Probe Electrospray Ionization/Mass Spectrometry.

In previous work, probe electrospray ionization/mass spectrometry (PESI/MS) and sheath-flow probe electrospray ionization/mass spectrometry (sfPESI/MS) were reported for the rapid and minimally invasive analysis of food. In this work, a modified version of sfPESI will be reported. The sample surface was pricked with an acupuncture needle inserted in the sfPESI probe that protruded from the terminus of the tip by 5 mm. The invasion depth of the needle into the sample was ∼1 mm. After sampling, the needle was retracted into the solvent-preloaded capillary with a protrusion length of 0.1-0.2 mm from the tip. A mass spectrum of the sample captured on the needle was obtained by applying a high voltage to the needle. This method could be applicable to profiling analyses of plants with the epicuticular wax covering on the surfaces that are difficult to analyze by sf-PESI. The on-site mass spectrometric analysis for a growing apricot in the field was performed to monitor the developing stage of the fruit.

Analysis of ethyl carbamate in plum wines produced in Korea.

Ethyl carbamate is naturally occurring compound, commonly found in many fermented foods and alcoholic beverages. During the process of plum wine production, ethyl carbamate can be formed. To this date, limited studies were conducted to monitor the ethyl carbamate in the plum wine brewed in-house. The objective of this study was to analyze the ethyl carbamates in plum wine, that were produced in differently: in-house and commercial production. A total of 33 plum wines were analyzed. The levels of ethyl carbamate ranged from N.D to 352.7 µg/kg in plum wines available in Korea. The current level of ethyl carbamate in plum wine was below the governmental regulation. However, continuous monitoring and further develop a strategy to reduce the level of ethyl carbamate in plum wine is in need, as the highest level of ethyl carbamate in plum wine is near the governmental standard (400 µg/kg).

Isolation and Role of PmRGL2 in GA-mediated Floral Bud Dormancy Release in Japanese Apricot (Prunus mume Siebold et Zucc.).

Bud dormancy release is regulated by gibberellins (GAs). DELLA proteins are highly conserved and act as negative regulators in GA signaling pathway. The present study established a relationship between PmRGL2 in Japanese apricot and GA4 levels during dormancy release of floral buds. Overexpression of PmRGL2 in poplar delayed the onset of bud dormancy and resulted in dwarf plants, relative to wild-type trees. PmRGL2 exhibited higher expression during ecodormancy and relatively lower expression during endodormancy. The relative level of GA4 exhibited an increasing trend at the transition from endodormancy to ecodormancy and displayed a similar expression pattern of genes related to GA metabolism, PmGA20ox2, PmGA3ox1, PmGID1b, in both Japanese apricot and transgenic poplar. These results suggests that PmRGL2 acts as an integrator and negative regulator of dormancy via a GA-signaling pathway. Moreover, an interaction between RGL2 and SLY1 in a yeast two hybrid (Y2H) system further suggests that SCF E3 ubiquitin ligases, such as SLY1, may be a critical factor in the regulation of RGL2 through an SCF SLY1 -proteasome pathway. Our study demonstrated that PmRGL2 plays a negative role in bud dormancy release by regulating the GA biosynthetic enzymes, GA20ox and GA3ox1 and the GA receptor, GID1b.