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Background: Grafting with dwarf rootstock is an efficient method to control plant height in fruit production. However, the molecular mechanism remains unclear. Our previous study showed that plants with Prunus mume (mume) rootstock exhibited a considerable reduction in plant height, internode length, and number of nodes compared with Prunus persica (peach) rootstock. The present study aimed to investigate the mechanism behind the regulation of plant height by mume rootstocks through transcriptomic and metabolomic analyses with two grafting combinations, 'Longyan/Mume' and 'Longyan/Peach'., Results: There was a significant decrease in brassinolide levels in plants that were grafted onto mume rootstocks. Plant hormone signal transduction and brassinolide production metabolism gene expression also changed significantly. Flavonoid levels, amino acid and fatty acid metabolites, and energy metabolism in dwarf plants decreased. There was a notable upregulation of PmLBD3 gene expression in plant specimens that were subjected to grafting onto mume rootstocks. Auxin signalling cues promoted PmARF3 transcription, which directly controlled this upregulation. Through its binding to PmBAS1 and PmSAUR36a gene promoters, PmLBD3 promoted endogenous brassinolide inactivation and inhibited cell proliferation., Conclusions: Auxin signalling and brassinolide levels are linked by PmLBD3. Our findings showed that PmLBD3 is a key transcription factor that regulates the balance of hormones through the auxin and brassinolide signalling pathways and causes dwarf plants in stone fruits., (© 2024. The Author(s).)

Gibberellins (GAs), enzymes that play a significant role in plant growth and development, and their levels in plants could be regulated by gibberellin-oxidases (GAoxs). As important fruit trees and ornamental plants, the study of the mechanism of plant architecture formation of the Prunus genus is crucial. Here, 85 GAox genes were identified from P. mume , P. armeniaca , P. salicina , and P. persica , and they were classified into six subgroups. Conserved motif and gene structure analysis showed that GAoxs were conserved in the four Prunus species. Collinearity analysis revealed two fragment replication events of PmGAox s in the P. mume genome. Promoter cis-elements analysis revealed 24 PmGAox s contained hormone-responsive elements and development regulatory elements. The expression profile indicated that PmGAox s have tissue expression specificity, and GA levels during the dormancy stage of flower buds were controlled by certain PmGAox s. After being treated with IAA or GA 3 , the transcription level of PmGA2ox8 in stems was significantly increased and showed a differential expression level between upright and weeping stems. GUS activity driven by PmGA2ox8 promoter was detected in roots, stems, leaves, and flower organs of Arabidopsis . PmGA2ox8 overexpression in Arabidopsis leads to dwarfing phenotype, increased number of rosette leaves but decreased leaf area, and delayed flowering. Our results showed that GAoxs were conserved in Prunus species, and PmGA2ox8 played an essential role in regulating plant height.

Background: The Prunus sibirica seeds with rich oils has great utilization, but contain amygdalin that can be hydrolyzed to release toxic HCN. Thus, how to effectively reduce seed amygdalin content of P. sibirica is an interesting question. Mandelonitrile is known as one key intermediate of amygdalin metabolism, but which mandelonitrile lyase (MDL) family member essential for its dissociation destined to low amygdalin accumulation in P. sibirica seeds still remains enigmatic. An integration of our recent 454 RNA-seq data, amygdalin and mandelonitrile content detection, qRT-PCR analysis and function determination is described as a critical attempt to determine key MDL and to highlight its function in governing mandelonitrile catabolism with low amygdalin accumulation in Prunus sibirica seeds for better developing edible oil and biodiesel in China., Results: To identify key MDL and to unravel its function in governing seed mandelonitrile catabolism with low amygdalin accumulation in P. sibirica. Global identification of mandelonitrile catabolism-associated MDLs, integrated with the across-accessions/developing stages association of accumulative amount of amygdalin and mandelonitrile with transcriptional level of MDLs was performed on P. sibirica seeds of 5 accessions to determine crucial MDL2 for seed mandelonitrile catabolism of P. sibirica. MDL2 gene was cloned from the seeds of P. sibirica, and yeast eukaryotic expression revealed an ability of MDL2 to specifically catalyze the dissociation of mandelonitrile with the ideal values of K m (0.22 mM) and V max (178.57 U/mg). A combination of overexpression and mutation was conducted in Arabidopsis. Overexpression of PsMDL2 decreased seed mandelonitrile content with an increase of oil accumulation, upregulated transcript of mandelonitrile metabolic enzymes and oil synthesis enzymes (involving FA biosynthesis and TAG assembly), but exhibited an opposite situation in mdl2 mutant, revealing a role of PsMDL2-mediated regulation in seed amygdalin and oil biosynthesis. The PsMDL2 gene has shown as key molecular target for bioengineering high seed oil production with low amygdalin in oilseed plants., Conclusions: This work presents the first integrated assay of genome-wide identification of mandelonitrile catabolism-related MDLs and the comparative association of transcriptional level of MDLs with accumulative amount of amygdalin and mandelonitrile in the seeds across different germplasms and developmental periods of P. sibirica to determine MDL2 for mandelonitrile dissociation, and an effective combination of PsMDL2 expression and mutation, oil and mandelonitrile content detection and qRT-PCR assay was performed to unravel a mechanism of PsMDL2 for controlling amygdalin and oil production in P. sibirica seeds. These findings could offer new bioengineering strategy for high oil production with low amygdalin in oil plants., (© 2024. The Author(s).)

The formation of multi-pistil flowers reduces the yield and quality in Japanese apricot (Prunus mume). However, the molecular mechanism underlying the formation of multi-pistil flowers remains unknown. In the current study, overexpression of PmKNAT2/6-a, a class I KNOTTED1-like homeobox (KNOX) member, in Arabidopsis (Arabidopsis thaliana) resulted in a multi-pistil phenotype. Analysis of the upstream regulators of PmKNAT2/6-a showed that AGAMOUS-like 24 (PmAGL24) could directly bind to the PmKNAT2/6-a promoter and regulate its expression. PmAGL24 also interacted with Like Heterochromatin Protein 1 (PmLHP1) to recruit lysine trimethylation at position 27 on histone H3 (H3K27me3) to regulate PmKNAT2/6-a expression, which is indirectly involved in multiple pistils formation in Japanese apricot flowers. Our study reveals that the PmAGL24 transcription factor, an upstream regulator of PmKNAT2/6-a, regulates PmKNAT2/6-a expression via direct and indirect pathways and is involved in the formation of multiple pistils in Japanese apricot., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

When compared with other phylogroups (PGs) of the Pseudomonas syringae species complex, P. syringae pv. syringae (Pss) strains within PG2 have a reduced repertoire of type III effectors (T3Es) but produce several phytotoxins. Effectors within the cherry pathogen Pss 9644 were grouped based on their frequency in strains from Prunus as the conserved effector locus (CEL) common to most P. syringae pathogens; a core of effectors common to PG2; a set of PRUNUS effectors common to cherry pathogens; and a FLEXIBLE set of T3Es. Pss 9644 also contains gene clusters for biosynthesis of toxins syringomycin, syringopeptin and syringolin A. After confirmation of virulence gene expression, mutants with a sequential series of T3E and toxin deletions were pathogenicity tested on wood, leaves and fruits of sweet cherry (Prunus avium) and leaves of ornamental cherry (Prunus incisa). The toxins had a key role in disease development in fruits but were less important in leaves and wood. An effectorless mutant retained some pathogenicity to fruit but not wood or leaves. Striking redundancy was observed amongst effector groups. The CEL effectors have important roles during the early stages of leaf infection and possibly acted synergistically with toxins in all tissues. Deletion of separate groups of T3Es had more effect in P. incisa than in P. avium. Mixed inocula were used to complement the toxin mutations in trans and indicated that strain mixtures may be important in the field. Our results highlight the niche-specific role of toxins in P. avium tissues and the complexity of effector redundancy in the pathogen Pss 9644., (© 2024 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd.)

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, PmCBF03 A type in high-altitude areas and PmCBF03 T type in low-altitude areas. PmCBF03 A 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, PmCBF03 A gene promoted the dormancy of transgenic Arabidopsis seeds than wild-type. Biochemical analysis demonstrated that PmCBF03 A 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 PmCBF03 A lines. While PmCBF03 T 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., (© 2024 John Wiley & Sons Ltd.)

Key Message: This study provides novel insights into the evolution, diversification, and functions of melatonin biosynthesis genes in Prunus species, highlighting their potential role in regulating bud dormancy and abiotic stresses. The biosynthesis of melatonin (MEL) in plants is primarily governed by enzymatic reactions involving key enzymes such as serotonin N-acetyltransferase (SNAT), tryptamine 5-hydroxylase (T5H), N-acetylserotonin methyltransferase (ASMT) and tryptophan decarboxylase (TDC). In this study, we analyzed Melatonin genes in four Prunus species such as Prunus avium (Pavi), Prunus pusilliflora (Ppus), Prunus serulata (Pser), and Prunus persica (Pper) based on comparative genomics approach. Among the four Prunus species, a total of 29 TDCs, 998 T5Hs, 16 SNATs, and 115 ASMTs within the genome of four Prunus genomes. A thorough investigation of melatonin-related genes was carried out using systematic biological methods and comparative genomics. Through phylogenetic analysis, orthologous clusters, Go enrichment, syntenic relationship, and gene duplication analysis, we discovered both similarities and variations in Melatonin genes among these Prunus species. Additionally, our study revealed the existence of unique subgroup members in the Melatonin genes of these species, which were distinct from those found in Arabidopsis genes. Furthermore, the transcriptomic expression analysis revealed the potential significance of melatonin genes in bud dormancy regulation and abiotic stresses. Our extensive results offer valuable perspectives on the evolutionary patterns, intricate expansion, and functions of PavMEL genes. Given their promising attributes, PavTDCs, PavT5H, PavNAT, and three PavASMT genes warrant in-depth exploration as prime candidates for manipulating dormancy in sweet cherry. This was done to lay the foundation for future explorations into the structural and functional aspects of these factors in Prunus species. This study offers significant insights into the functions of ASMT, SNAT, T5H, and TDC genes and sheds light on their roles in Prunus avium. Moreover, it established a robust foundation for further exploration functional characterization of melatonin genes in fruit species., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Salinity is a major abiotic stress factor that can significantly impact crop growth, and productivity. In response to salt stress, the plant Salt Overly Sensitive (SOS) signaling pathway regulates the homeostasis of intracellular sodium ion concentration. The SOS1, SOS2, and SOS3 genes play critical roles in the SOS pathway, which belongs to the members of Na + /H + exchanger (NHX), CBL-interacting protein kinase (CIPK), and calcineurin B-like (CBL) gene families, respectively. In this study, we performed genome-wide identifications and phylogenetic analyses of NHX, CIPK, and CBL genes in six Rosaceae species: Prunus persica, Prunus dulcis, Prunus mume, Prunus armeniaca, Pyrus ussuriensis × Pyrus communis, and Rosa chinensis. NHX, CIPK, and CBL genes of Arabidopsis thaliana were used as controls for phylogenetic analyses. Our analysis revealed the lineage-specific and adaptive evolutions of Rosaceae genes. Our observations indicated the existence of two primary classes of CIPK genes: those that are intron-rich and those that are intron-less. Intron-rich CIPKs in Rosaceae and Arabidopsis can be traced back to algae CIPKs and CIPKs found in early plants, suggesting that intron-less CIPKs evolved from their intron-rich counterparts. This study identified one gene for each member of the SOS signaling pathway in P. persica: PpSOS1, PpSOS2, and PpSOS3. Gene expression analyses indicated that all three genes of P. persica were expressed in roots and leaves. Yeast two-hybrid-based protein-protein interaction analyses revealed a direct interaction between PpSOS3 and PpSOS2; and between PpSOS2 and PpSOS1C-terminus region. Our findings indicate that the SOS signaling pathway is highly conserved in P. persica., (© 2023 The Authors. The Plant Genome published by Wiley Periodicals LLC on behalf of Crop Science Society of America. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Sargent's cherry trees ( Prunus sargentii Rehder) are widely planted as an ornamental, climate change-sensing species. This study investigated changes in the soil moisture content, fresh weight, photosynthesis and chlorophyll fluorescence properties, and the chlorophyll and proline content of four-year-old P. sargentii seedlings after 30 days of drought stress. In the trees subjected to drought stress treatment, soil moisture content decreased, and the fresh weight of the aboveground part of the plant decreased. However, there was no significant difference in the root growth of the dried plants. Among the photosynthesis parameters, P n MAX , E and g s showed a significant ( p   <  0.001) decrease after 15 days in dry-stressed seedlings, but there was no difference between treatments in WUE until 20 days, and there was a significant ( p   <  0.001) difference after 24 days. Chlorophyll fluorescence parameters, F v /F m , ΦPSII, R fd , NPQ, and P n MAX, also increased after 10 days in dry-stressed seedlings, but these changes did not reach statistical significance compared to the control treatment. These results may suggest that drought stress highly correlates with photosynthesis and chlorophyll fluorescence parameters. Chlorophyll content also significantly decreased in the seedlings under drought stress compared with the control treatment. The proline content decreased until the 10th day of drought stress treatment and increased after the 15th day, showing an increase of 10.9% on the 15th day and 57.1% on the 30th day, compared to the control treatment. These results suggest that photosynthesis, chlorophyll fluorescence parameters, and proline content can be used to evaluate drought stress in trees. The results of this study can contribute to the management of forests, such as the irrigation of trees when pore control ability and photosynthesis ability decrease., Competing Interests: The authors declare there are no competing interests., (©2023 Jin et al.)

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

Bud dormancy is crucial for winter survival and is characterized by the inability of the bud meristem to respond to growth-promotive signals before the chilling requirement (CR) is met. However, our understanding of the genetic mechanism regulating CR and bud dormancy remains limited. This study identified PpDAM6 (DORMANCY-ASSOCIATED MADS-box) as a key gene for CR using a genome-wide association study analysis based on structural variations in 345 peach (Prunus persica (L.) Batsch) accessions. The function of PpDAM6 in CR regulation was demonstrated by transiently silencing the gene in peach buds and stably overexpressing the gene in transgenic apple (Malus × domestica) plants. The results showed an evolutionarily conserved function of PpDAM6 in regulating bud dormancy release, followed by vegetative growth and flowering, in peach and apple. The 30-bp deletion in the PpDAM6 promoter was substantially associated with reducing PpDAM6 expression in low-CR accessions. A PCR marker based on the 30-bp indel was developed to distinguish peach plants with non-low and low CR. Modification of the H3K27me3 marker at the PpDAM6 locus showed no apparent change across the dormancy process in low- and non-low- CR cultivars. Additionally, H3K27me3 modification occurred earlier in low-CR cultivars on a genome-wide scale. PpDAM6 could mediate cell-cell communication by inducing the expression of the downstream genes PpNCED1 (9-cis-epoxycarotenoid dioxygenase 1), encoding a key enzyme for ABA biosynthesis, and CALS (CALLOSE SYNTHASE), encoding callose synthase. We shed light on a gene regulatory network formed by PpDAM6-containing complexes that mediate CR underlying dormancy and bud break in peach. A better understanding of the genetic basis for natural variations of CR can help breeders develop cultivars with different CR for growing in different geographical regions., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

Prunus mume, a woody perennial tree, is valued for its ornamental traits and has been cultivated for a long history. Low temperature is the main environmental factor restricting the distribution and affecting the growth of P. mume. In plants, some WRKY transcription factors have been reported to participate in regulating cold tolerance. However, there were few researches about functional characterization of WRKYs involving in P. mume cold response. Here, a cold-induced WRKY gene named as PmWRKY57 was cloned from a P. mume cultivar 'Guhong Zhusha.' PmWRKY57 protein harboring a WRKY domain and a C2H2 zinc finger motif belongs to Group IIc of WRKY family. The PmWRKY57 protein was located to the nucleus and has transcriptional activation activity. PmWRKY57-overexpresing Arabidopsis thaliana lines showed improved cold tolerance, compared to wild-type plants. Under cold treatment, the leaves of transgenic lines contained significantly lower malondialdehyde content, and higher levels of superoxide dismutase activity, peroxidase activity, and proline content than wild-type plants. Furthermore, the expression levels of cold-response genes such as AtCOR6.6, AtCOR47, AtKIN1, and AtRCI2A were up-regulated in leaves of transgenic A. thaliana compared to those in wild-type plants. This study characterized the function of PmWRKY57 in improving cold tolerance of plants., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

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

Low temperature is one of the most important abiotic factors limiting the growth, development and geographical distribution of plants. Prunus mume is an attractive woody ornamental plant that blooms in early spring in Beijing. However, the molecular mechanisms underlying cold hardening to enhance freezing tolerance in Prunus genus remains elusive. This study examined the dynamic physiological responses induced by cold hardening, and identified freezing-tolerance genes by RNA-seq and ATAC-seq analyses. Cold hardening elevated the content of soluble substances and enhanced freezing resistance in P. mume. Transcriptome analysis indicated that the candidate differentially expressed genes (DEGs) were those enriched in Ca2+ signalling, mitogen-activated protein kinase (MAPK) cascade, abscisic acid signalling, and inducer of CBF expression 1 (ICE)-C-repeat binding factor (CBF) signalling pathways. The openness of gene chromatin positively correlated with the expression level of these genes. Thirteen motifs were identified in the open chromatin regions in the treatment group subjected to freezing after cold hardening. The chromatin opening of transcription start site at the proximal -177 region of cold-shock protein CS120-like (PmCSL) was markedly increased, while the expression level of PmCSL was significantly up-regulated. Overexpression of PmCSL in Arabidopsis significantly improved the freezing tolerance of transgenic plants. These findings provide new insights into the regulatory mechanism of freezing tolerance to improve breeding of cold-hardy P. mume plants., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Knotted1 -like homeobox (KNOX) transcription factors are involved in plant development, playing complex roles in aerial organs. As Prunus species include important fruit tree crops of Italy, an exhaustive investigation of KNOX genes was performed using genomic and RNA-seq meta-analyses. Micropropagation is an essential technology for rootstock multiplication; hence, we investigated KNOX transcriptional behavior upon increasing 6-benzylaminopurine (BA) doses and the effects on GF677 propagules. Moreover, gene function in Prunus spp. was assessed by Gisela 6 rootstock transformation using fluorescence and peach KNOX transgenes. Based on ten Prunus spp., KNOX proteins fit into I-II-M classes named after Arabidopsis. Gene number, class member distribution, and chromosome positions were maintained, and exceptions supported the diversification of Prunus from Cerasus subgenera, and that of Armeniaca from the other sections within Prunus . Cytokinin (CK) cis-elements occurred in peach and almond KNOX promoters, suggesting a BA regulatory role in GF677 shoot multiplication as confirmed by KNOX expression variation dependent on dose, time, and interaction. The tripled BA concentration exacerbated stress, altered CK perception genes, and modified KNOX transcriptions, which are proposed to concur in in vitro anomalies. Finally, Gisela 6 transformation efficiency varied (2.6-0.6%) with the genetic construct, with 35S:GFP being more stable than 35S:KNOPE1 lines, which showed leaf modification typical of KNOX overexpression.

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 β-glycosidases and hydroxynitrile lyase may play a key role in amygdalin degradation. The predicted degradation initiated by β-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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Mutation is a source of genetic diversity widely used in breeding programs for the acquisition of agronomically interesting characters in commercial varieties of the Prunus species, as well as in the rest of crop species. Mutation can occur in nature at a very low frequency or can be induced artificially. Spontaneous or bud sport mutations in somatic cells can be vegetatively propagated to get an individual with the mutant phenotype. Unlike animals, plants have unlimited growth and totipotent cells that let somatic mutations to be transmitted to the progeny. On the other hand, in vitro tissue culture makes it possible to induce mutation in plant material and perform large screenings for mutant's selection and cleaning of chimeras. Finally, targeted mutagenesis has been boosted by the application of CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/Cas9 and Transcription activator-like effector nuclease (TALEN) editing technologies. Over the last few decades, environmental stressors such as global warming have been threatening the supply of global demand for food based on population growth in the near future. For this purpose, the release of new varieties adapted to such changes is a requisite, and selected or generated Prunus mutants by properly regulated mechanisms could be helpful to this task. In this work, we reviewed the most relevant mutations for breeding traits in Prunus species such as flowering time, self-compatibility, fruit quality, and disease tolerance, including new molecular perspectives in the present postgenomic era including CRISPR/Cas9 and TALEN editing technologies.

Background: Prunus mume is an early spring flower of Rosaceae, which owns high application value in gardens. Being an excellent ornamental trait, the double flower trait has always been one of the important breeding goals of plant breeders. However, the key regulatory genes of double flower traits of P. mume are still unclear at present., Results: The floral organs' morphological differences of 20 single and 20 double flower cultivars of P. mume were compared firstly. And it was found that double flower trait of P. mume were often accompanied by petaloid stamen, multiple carpels and an increase in the total number of floral organs. Then, transcriptome sequencing of two representative cultivars P. mume 'Danban Lve' and P. mume 'Xiao Lve' were conducted at 3 Stage of flower bud development with distinct morphological differentiation. 3256 differentially expression genes (DEGs) were detected, and 20 candidate genes for double flower trait of P. mume were screened out including hub genes PmAP1-1 and PmAG-2 based on DEGs function analysis and WGCNA analysis. And it was found that epigenetic and hormone related genes may also play an important role in the process of double flower., Conclusions: This study suggested that the double flower trait of P.mume is more like accumulation origin based on morphological observation. 20 genes and co-expression network related to the formation of double flower P. mume were preliminarily screened through transcriptomics analysis. The results provided a reference for further understanding of the molecular mechanism of double flower trait in P. mume., (© 2022. The Author(s).)

Prunus mume , a famous perennial ornamental plant and fruit tree in Asia, blooms in winter or early spring in the Yangtze River area. The flowering time directly determines its ornamental and economic value, so it is of great significance to study the molecular mechanism of flowering time. SQUAMOSA PROMOTER BINDING PROTEIN ( SBP ), often regulated by miR156 , is an important flowering regulator, although its function is unknown in P. mume . Here, 11 miR156 precursors were analyzed and located in five chromosomes of the P. mume genome. The expression pattern showed that PmSBP1 / 6 was negatively correlated with miR156 . The promoters of PmSBP1 / 6 were specifically expressed in the apical meristem. Overexpression of PmSBP1 / 6 in tobacco promoted flowering and changed the length ratio of pistil and stamen. Moreover, PmSBP1 also affected the number and vitality of pollen and reduced the fertility of transgenic tobacco. Furthermore, ectopic expression of PmSBP1/6 caused up-regulated expression of endogenous SUPPRESSOR OF OVEREXPRESSION OF CO1 ( NtSOC1 ). The yeast-one hybrid assay showed that PmSBP1 was bonded to the promoters of PmSOC1s . In conclusion, a miR156-PmSBP1-PmSOC1s pathway was formed to participate in the regulation of flowering time in P. mume , which provided references for the molecular mechanism of flowering time regulation and molecular breeding of P. mume.

The Gibberellic Acid Stimulated Arabidopsis/Gibberellin Stimulated Transcript (GASA/GAST) gene family is a group of plant-specific genes encoding cysteine-rich peptides essential to plant growth, development, and stress responses. Although GASA family genes have been identified in various plant species, their functional roles in Prunus mume are still unknown. In this study, a total of 16 PmGASA genes were identified via a genome-wide scan in Prunus mume and were grouped into three major gene clades based on the phylogenetic tree. All PmGASA proteins possessed the conserved GASA domain, consisting of 12-cysteine residues, but varied slightly in protein physiochemical properties and motif composition. With evolutionary analysis, we observed that duplications and purifying selection are major forces driving PmGASA family gene evolution. By analyzing PmGASA promoters, we detected a number of hormonal-response related cis-elements and constructed a putative transcriptional regulatory network for PmGASAs . To further understand the functional role of PmGASA genes, we analyzed the expression patterns of PmGASAs across different organs and during various biological processes. The expression analysis revealed the functional implication of PmGASA gene members in gibberellic acid-, abscisic acid-, and auxin-signaling, and during the progression of floral bud break in P. mume . To summarize, these findings provide a comprehensive understanding of GASA family genes in P. mume and offer a theoretical basis for future research on the functional characterization of GASA genes in other woody perennials.

SQUAMOSA Promoter-Binding Protein-Like ( SPL ) genes encode plant-specific transcription factors which bind to the SQUAMOSA promoter of the MADS-box genes to regulate its expression. It plays important regulatory roles in floral induction and development, fertility, light signals and hormonal transduction, and stress response in plants. In this study, 32 PySPL genes with complete SBP (squamosa promoter binding protein) conserved domain were identified from the genome of Prunus × yedoensis 'Somei-yoshino' and analyzed by bioinformatics. 32 PySPLs were distributed on 13 chromosomes, encoding 32 PySPL proteins with different physical and chemical properties. The phylogenetic tree constructed with Arabidopsis thaliana and Oryza sativa can be divided into 10 subtribes, indicating PySPLs of different clusters have different biological functions. The conserved motif prediction showed that the number and distribution of motifs on each PySPL is varied. The gene structure analysis revealed that PySPLs harbored exons ranging from 2 to 10. The predictive analysis of acting elements showed that the promoter of PySPLs contain a large number of light-responsive elements, as well as response elements related to hormone response, growth and development and stress response. The analysis of the PySPLs expressions in flower induction and flower organs based on qRT-PCR showed that PySPL06 /22 may be the key genes of flower development, PySPL01/06 and PySPL22 may play a role in the development of sepal and pistil, respectively. The results provide a foundation for the study of SPL transcription factors of Prunus × yedoensis 'Somei-yoshino' and provide more reference information of the function of SPL gene in flowering.

The application of the seed oil of Prunus mira Koehne (Tibetan name ཁམབུ།), a plant belonging to the Rosaceae family, for the treatment of alopecia has been recorded in Jingzhu Materia Medica (ཤེལ་གོང་ཤེལ་ཕྲེང་།) (the classic of Tibetan medicine) and Dictionary of Chinese Ethnic Medicine . This study aims to reveal the effective components and mechanism of hair growth promotion in the kernel of Prunus mira Koehne. Network pharmacology was used to predict the mechanism of action and effective components in the treatment of the kernel of Prunus mira Koehne. The contents of amygdalin in 12 batches of the kernel of Prunus mira Koehne were determined by HPLC. An animal model of the depilation of KM mice induced by sodium sulfide was created, and five effective components that promoted hair growth were initially screened. In the study of the effectiveness and mechanism of action, KM and C57BL/6 mice are selected as experimental objects, three screening tests for active components of the kernel of P. mira are performed, and three effective components are screened out from the eight components. HE staining was used to detect the number of hair follicles and the thickness of the dermis. RT-PCR and immunohistochemistry were used to evaluate the influence of the expression of indicators in the Wnt/β-catenin signaling pathway in skin, including β-catenin, GSK-3β, and mRNA and protein expression levels of Cyclin D 1 and LEF 1. The network pharmacology study showed 12 signaling pathways involving 25 targets in the treatment of alopecia by the kernel of Prunus mira Koehne. vitamin E (3.125 mg/cm 2 /d), β-sitosterol (0.061 mg/cm 2 /d), and linoleic acid (0.156 mg/cm 2 /d) in the kernel of Prunus mira Koehne can promote hair growth in mice, and the mechanism of action may be related to the Wnt/β-catenin pathway.

Background: Mei (Prunus mume) is the only woody plant in the genus Prunus with a floral fragrance, but the underlying mechanisms of aroma compound biosynthesis are unclear despite being a matter of considerable interest., Results: The volatile contents of the petals of two cultivars with significantly different aromas, Prunus mume 'Xiao Lve' and Prunus mume 'Xiangxue Gongfen', were characterised by GC-MS at different flowering periods, and a total of 44 volatile compounds were detected. Among these, the main substances forming the typical aroma of P. mume were identified as eugenol, cinnamyl acetate, hexyl acetate and benzyl acetate, with variations in their relative concentrations leading to sensory differences in the aroma of the two cultivars. We compiled a transcriptome database at key stages of floral fragrance formation in the two cultivars and used it in combination with differential analysis of floral volatiles to construct a regulatory network for the biosynthesis of key aroma compounds. The results indicated that PmPAL enzymes and PmMYB4 transcription factors play important roles in regulating the accumulation of key biosynthetic precursors to these compounds. Cytochrome P450s and short-chain dehydrogenases/reductases might also influence the biosynthesis of benzyl acetate by regulating production of key precursors such as benzaldehyde and benzyl alcohol. Furthermore, by analogy to genes with verified functions in Arabidopsis, we predicted that three PmCAD genes, two 4CL genes, three CCR genes and two IGS genes all make important contributions to the synthesis of cinnamyl acetate and eugenol in P. mume. This analysis also suggested that the downstream genes PmBGLU18-like, PmUGT71A16 and PmUGT73C6 participate in regulation of the matrix-bound and volatile states of P. mume aroma compounds., Conclusions: These findings present potential new anchor points for further exploration of floral aroma compound biosynthesis pathways in P. mume, and provide new insights into aroma induction and regulation mechanisms in woody plants., (© 2022. The Author(s).)

Background: Japanese apricot (Prunus mume Sieb. et Zucc.) is popular for both ornamental and processing value, fruit color affects the processing quality, and red pigmentation is the most obvious phenotype associated with fruit color variation in Japanese apricot, mutations in structural genes in the anthocyanin pathway can disrupt the red pigmentation, while the formation mechanism of the red color trait in Japanese apricot is still unclear.  RESULTS: One SNP marker (PmuSNP&#95;27) located within PmUFGT3 gene coding region was found highly polymorphic among 44 different fruit skin color cultivars and relative to anthocyanin biosynthesis in Japanese apricot. Meantime, critical mutations were identified in two alleles of PmUFGT3 in the green-skinned type is inactivated by seven nonsense mutations in the coding region, which leads to seven amino acid substitution, resulting in an inactive UFGT enzyme. Overexpression of the PmUFGT3 allele from red-skinned Japanese apricot in green-skinned fruit lines resulted in greater anthocyanin accumulation in fruit skin. Expression of same allele in an Arabidopsis T-DNA mutant deficient in anthocyanidin activity the accumulation of anthocyanins. In addition, using site-directed mutagenesis, we created a single-base substitution mutation (G to T) of PmUFGT3 isolated from green-skinned cultivar, which caused an E to D amino acid substitution and restored the function of the inactive allele of PmUFGT3 from a green-skinned individual., Conclusion: This study confirms the function of PmUFGT3, and provides insight into the mechanism underlying fruit color determination in Japanese apricot, and possible approaches towards genetic engineering of fruit color., (© 2022. The Author(s).)

In the present study, a facile, eco-friendly, and controlled synthesis of gold nanoparticles (Au NPs) using Prunus nepalensis fruit extract is reported. The biogenically synthesized Au NPs possess ultra-active intrinsic peroxidase-like activity for the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H 2 O 2 . Chemical analysis of the fruit extract demonstrated the presence of various bioactive molecules such as amino acids (l-alanine and aspartic acids), organic acids (benzoic acid and citric acid), sugars (arabinose and glucose), phenolic acid, and bioflavonoids (niacin and myo-inositol), which likely attributed to the formation of stable biogenic Au NPs with excellent peroxidase-mimicking activity. In comparison with the natural horseradish peroxidase (HRP) enzyme, the biogenic Au NPs displayed a 9.64 times higher activity with regard to the reaction velocity at 6% (v/v) H 2 O 2 , presenting a higher affinity toward the TMB substrate. The Michaelis-Menten constant ( K M ) values for the biogenic Au NPs and HRP were found to be 6.9 × 10 -2 and 7.9 × 10 -2 mM, respectively, at the same concentration of 100 pM. To investigate its applicability for biosensing, a monoclonal antibody specific for Mycobacterium bovis (QUBMA-Bov) was directly conjugated to the surface of the biogenic Au NPs. The obtained results indicate that the biogenic Au NPs-QUBMA-Bov conjugates are capable of detecting M. bovis based on a colorimetric immunosensing method within a lower range of 10 0 to 10 2 cfu mL -1 with limits of detection of ∼53 and ∼71 cfu mL -1 in an artificial buffer solution and in a soft cheese spiked sample, respectively. This strategy demonstrates decent specificity in comparison with those of other bacterial and mycobacterial species. Considering these findings together, this study indicates the potential for the development of a cost-effective biosensing platform with high sensitivity and specificity for the detection of M. bovis using antibody-conjugated Au nanozymes.

Histone deacetylases (HDACs) play important roles in plant growth, development, and stress response. However, the pattern of how they are expressed in response to cold stress in the ornamental woody plant Prunus mume is poorly understood. Here, we identify 121 RoHDACs from eight Rosaceae plants of which 13 PmHDACs genes are from P. mume . A phylogenetic analysis suggests that the RoHDACs family is classified into three subfamilies, HDA1/RPD3 , HD2, and SIR2 . We identify 11 segmental duplication gene pairs of RoHDACs and find, via a sequence alignment, that the HDACs gene family, especially the plant-specific HD2 family, has experienced gene expansion and contraction at a recent genome evolution history. Each of the three HDACs subfamilies has its own conserved domains. The expression of PmHDACs in mei is found to be tissue-specific or tissue-wide. RNA-seq data and qRT-PCR experiments in cold treatments suggest that almost all PmHDACs genes-especially PmHDA1/6/14 , PmHDT1 , and PmSRT1/2 -significantly respond to cold stress. Our analysis provides a fundamental insight into the phylogenetic relationship of the HDACs family in Rosaceae plants. Expression profiles of PmHDACs in response to cold stress could provide an important clue to improve the cold hardiness of mei.

Ulcerative colitis (UC) is a modern, refractory disease, and studies have shown that UC is closely associated with the gut microbiota and intestinal immune barrier. This study evaluated the protective effects and regulatory mechanism of Chinese dwarf cherry [ Cerasus humilis (Bge.) Sok.] fermentation juice (CFJ) on UC induced by dextran sulfate sodium (DSS). The results indicated that CFJ could significantly modulate the oxidative stress index in the serum and colon, observably reduce MPO and NO activity, and increase the SOD level. CFJ significantly downregulated the levels of TNF- α , IL-1 β and IL-6 and reduced inflammation caused by DSS. SIgA and short-chain fatty acids (SCFAs) levels were effectively improved in the CFJ group, especially the acetic acid and butyric acid levels. Intestinal flora analysis showed that DSS could enrich harmful bacteria such as Alistipes and Oribacterium and that CFJ could increase the abundance of beneficial bacteria ( Parasutterella , Bacteroides , Roseburia and Blautia ). SIgA in the colon was positively correlated with Lachnoclostridium , Blautia , Lachnospiraceae&#95;UCG-004 , Prevotellaceae&#95;NK3B31&#95;group and other beneficial bacteria. The results showed that DSS group rats had immunity and signalling pathway disorders and that CFJ could regulate immune disorders, mainly by regulating the expression of IgA pathway components. Taken together, our results demonstrated that CFJ could regulate changes in the gut microbiota, improve the expression of immune protein-related genes, further regulate intestinal mucosal immune function and maintain intestinal mucosal barrier homeostasis.

Root-knot nematodes (RKNs) are devastating parasites that invade thousands of plants. In this study, five RKN effectors, which might interact with Prunus sogdiana resistance protein PsoRPM3, were screened and identified. In situ hybridisation results showed that MiCal, MiGST&#95;N&#95;4, MiEFh and MiACPS are expressed in the subventral oesophageal glands (SvG), and MiTSPc hybridization signals are found in the dorsal esophageal gland (DG) of Meloidogyne incognita in the pre-J2. RT-qPCR data indicated that the expression of MiCal , MiGST&#95;N&#95;4 , MiEFh , and MiACPS genes are highly expressed in M. incognita of pra-J2 and J3/J4 stages. The expression of MiTSPc increased significantly in the female stage of M. incognita . Moreover, all effectors found in this study localize in the cytoplasm and nucleus when transiently expressed in plant cells. In addition, MiGST&#95;N&#95;4, MiEFh, MiACPS and MiTSPc can elicit the ROS burst and strong hypersensitive response (HR), as well as significant ion leakage. Our data suggest that MiGST&#95;N&#95;4, MiEFh, MiACPS and MiTSPc effectors may be involved in triggering the immune response of the host plant.

The almond crop has high economic importance on a global scale, but its sensitivity to salinity stress can cause severe yield losses. Salt-tolerant rootstocks are vital for crop economic feasibility under saline conditions. Two commercial rootstocks submitted to salinity, and evaluated through different parameters, had contrasting results with the survival rates of 90.6% for 'Rootpac 40' (tolerant) and 38.9% for 'Nemaguard' (sensitive) under salinity (Electrical conductivity of water = 3 dS m -1 ). Under salinity, 'Rootpac 40' accumulated less Na and Cl and more K in leaves than 'Nemaguard'. Increased proline accumulation in 'Nemaguard' indicated that it was highly stressed by salinity compared to 'Rootpac 40'. RNA-Seq analysis revealed that a higher degree of differential gene expression was controlled by genotype rather than by treatment. Differentially expressed genes (DEGs) provided insight into the regulation of salinity tolerance in Prunus. DEGs associated with stress signaling pathways and transporters may play essential roles in the salinity tolerance of Prunus. Some additional vital players involved in salinity stress in Prunus include CBL10, AKT1, KUP8, Prupe.3G053200 (chloride channel), and Prupe.7G202700 (mechanosensitive ion channel). Genetic components of salinity stress identified in this study may be explored to develop new rootstocks suitable for salinity-affected regions., (© 2022. The Author(s).)

Successive orchard plantings of almond and other Prunus species exhibit reduced growth and yield in many California soils. This phenomenon, known as Prunus replant disease (PRD), can be prevented by preplant soil fumigation or anaerobic soil disinfestation, but its etiology is poorly understood and its incidence and severity are hard to predict. We report here on relationships among physicochemical variables, microbial community structure, and PRD induction in 25 diverse replant soils from California. In a greenhouse bioassay, soil was considered to be "PRD-inducing" when growth of peach seedlings in it was significantly increased by preplant fumigation and pasteurization, compared to an untreated control. PRD was induced in 18 of the 25 soils, and PRD severity correlated positively with soil exchangeable-K, pH, %clay, total %N, and electrical conductivity. The structure of bacterial, fungal, and oomycete communities differed significantly between the PRD-inducing and non-inducing soils, based on PERMANOVA of Bray Curtis dissimilarities. Bacterial class MB-A2-108 of phylum Actinobacteria had high relative abundances among PRD-inducing soils, while Bacteroidia were relatively abundant among non-inducing soils. Among fungi, many ASVs classified only to kingdom level were relatively abundant among PRD-inducing soils whereas ASVs of Trichoderma were relatively abundant among non-inducing soils. Random forest classification effectively discriminated between PRD-inducing and non-inducing soils, revealing many bacterial ASVs with high explanatory values. Random forest regression effectively accounted for PRD severity, with soil exchangeable-K and pH having high predictive value. Our work revealed several biotic and abiotic variables worthy of further examination in PRD etiology., Competing Interests: The authors have declared that no competing interests exist.

Background: Flesh is prone to accumulate more anthocyanin in postharvest 'Friar' plum (Prunus salicina Lindl.) fruit stored at an intermediate temperature. However, little is known about the molecular mechanism of anthocyanin accumulation regulated by storage temperature in postharvest plum fruit., Results: To reveal the potential molecular regulation mechanism of anthocyanin accumulation in postharvest 'Friar' plum fruit stored at different temperatures (0 °C, 10 °C and 25 °C), the fruit quality, metabolite profile and transcriptome of its flesh were investigated. Compared to the plum fruit stored at 0 °C and 25 °C, the fruit stored at 10 °C showed lower fruit firmness after 14 days and reduced the soluble solids content after 21 days of storage. The metabolite analysis indicated that the fruit stored at 10 °C had higher contents of anthocyanins (pelargonidin-3-O-glucoside, cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside and quercetin-3-O-rutinose), quercetin and sucrose in the flesh. According to the results of weighted gene coexpression correlation network analysis (WGCNA), the turquoise module was positively correlated with the content of anthocyanin components, and flavanone 3-hydroxylase (F3H) and chalcone synthase (CHS) were considered hub genes. Moreover, MYB family transcription factor APL (APL), MYB10 transcription factor (MYB10), ethylene-responsive transcription factor WIN1 (WIN1), basic leucine zipper 43-like (bZIP43) and transcription factor bHLH111-like isoform X2 (bHLH111) were closely related to these hub genes. Further qRT-PCR analysis verified that these transcription factors were specifically more highly expressed in plum flesh stored at 10 °C, and their expression profiles were significantly positively correlated with the structural genes of anthocyanin synthesis as well as the content of anthocyanin components. In addition, the sucrose biosynthesis-associated gene sucrose synthase (SS) was upregulated at 10 °C, which was also closely related to the anthocyanin content of plum fruit stored at 10 °C., Conclusions: The present results suggest that the transcription factors APL, MYB10, WIN1, bZIP43 and bHLH111 may participate in the accumulation of anthocyanin in 'Friar' plum flesh during intermediate storage temperatures by regulating the expression of anthocyanin biosynthetic structural genes. In addition, the SS gene may play a role in anthocyanin accumulation in plum flesh by regulating sucrose biosynthesis., (© 2021. The Author(s).)

Cerasus humilis is a unique dwarf shrub and fruit color is an important trait in the species. In this study, we evaluated the transcriptomic and metabolomic profiles of the plant at different developmental stages to elucidate the mechanism underlying color formation. In a metabolomics analysis, 16 anthocyanin components were identified at four developmental stages, and high levels of cyanidin O -syringic acid and pelargonidin 3- O -beta-d-glucoside (callitephin chloride) were correlated with the reddening of the fruit peel. A co-expression analysis revealed that ANS and UFGT play key roles in pigmentation (PCC > 0.82). Additionally, transcriptome data showed that most anthocyanin biosynthetic genes and two MYB transcription factors were significantly up-regulated. QRT-PCR results for these differentially expressed genes were generally consistent with the high-throughput sequencing. Moreover, the overexpression of ChMYB1 (TRINITY&#95;DN21536&#95;c0&#95;g1) in apple calli could contribute to the accumulation of anthocyanin. It was also found that UFGT (TRINITY&#95;DN19893&#95;c1&#95;g5) and ChMYB1 (TRINITY&#95;DN21536&#95;c0&#95;g1) have similar expression patterns. These findings provide insight into the mechanisms underlying anthocyanin accumulation and coloration during fruit peel development, providing a basis for the breeding of anthocyanin-rich C. humilis cultivars.

Dynamic changes in flavonoid, total phenol, and antioxidant potential in different Prunus humilis accessions during fruit development stages were studied in order to provide a reference for the optimum harvest time for flavonoid extraction. 'Nongda 4', 'Nongda 5', 'DS-1' and '02-16' were selected as plant materials to determine the content of flavonoid, total phenol and antioxidant indices during six fruit development stages. Changes in total flavonoid content (TFC) and total phenol content (TPC) in different accessions of P. humilis were slightly different depending on the development stage of P. humilis fruit. TFC and TPC in 'Nongda 5' fruit showed a trend of continuous decline. There was a small increase in TFC and TPC from the young fruit stage to the stone hardening stage, followed by a decreasing trend, and then to the lowest level at the ripening stage of 'Nongda 4', 'DS-1', and '02-16' fruits. The trend of antioxidant capacity (ABTS, FRAP, DPPH) with the TFC and TPC of P. humilis fruit was basically the same, and the correlation analysis results showed that the TFC of P. humilis fruit was positively correlated with the antioxidant indices (P<0.01). Catechin (CC), rutin (RT), and quercetin-7-O-β-D-glucopyranoside (Q7G) were detected in all the fruit development stages of the four P. humilis fruits. Among them, catechin was the most abundant component, accounting for approximately 10%. Myricetin (MC) and quercetin (QC) were generally detected only in the early fruit development stage, but not in the later fruit development stage. Correlation analysis showed that the flavonoid components with TFC, TPC, and antioxidant indices differed between the different accessions. RT, CC, and liquiritigenin (LR) had a stronger correlation with TFC and antioxidant indices. Cyanidin-3-O-glucoside (C3G) was not detected until the coloring stage in two red P. humilis accessions ('Nongda 4' and 'DS-1'), and so it is better to choose a red P. humilis fruit to extract C3G at the ripening stage. Selecting an early stage of fruit development, especially the stone hardening stage, was important for extracting flavonoids, total phenols and other components. We believe that our results will provide basic information and reference for evaluation of fruit nutrition and health benefits, breeding of functional new varieties, and efficient utilization of P. humilis fruit., Competing Interests: The authors have declared that no competing interests exist.

Rhamnogalacturonan I (RG-I) enriched pectic polysaccharides were extracted from Cerasus humilis fruits (RPCF, RG-I: 74.46 %). Structural characterization including FTIR, XRD, NMR, HPAEC and SEM demonstrated that RPCF was a high-methoxy acetylated pectin macromolecule with abundant arabinose and galactose side chains (DM: 53.41 %, MW: 1098 kDa, (Ara + Gal)/Rha: 5.37 %). RPCF afforded additional lipid oxidation stability for emulsions, and exhibited significantly better emulsification performance than citrus pectin. In addition, RPCF formed a weak gel network that stabilized the emulsions (G' > G″). Interestingly, RPCF had behaviors that are divergent from those of commercial high-methoxy pectin because it demonstrated potential in forming sugar-free gels systems. Overall, Cerasus humilis is a new source of pectin rich in RG-I. RPCF can be used as a novel emulsifier with gelling and antioxidant effects, providing its alternative application as a natural emulsifier and rheological modifier in a wide range of products, including those with oil-in-water and low sugar., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

There is an increasing interest in polyphenols, plant secondary metabolites, in terms of fruit quality and diet, mainly due to their antioxidant effect. However, the identification of key gene enzymes and their roles in the phenylpropanoid pathway in temperate fruits species remains uncertain. Apricot ( Prunus armeniaca ) is a Mediterranean fruit with high diversity and fruit quality properties, being an excellent source of polyphenol compounds. For a better understanding of the phenolic pathway in these fruits, we selected a set of accessions with genetic-based differences in phenolic compounds accumulation. HPLC analysis of the main phenolic compounds and transcriptional analysis of the genes involved in key steps of the polyphenol network were carried out. Phenylalanine ammonia-lyase (PAL), dihydroflavonol-4-reductase (DFR) and flavonol synthase (FLS) were the key enzymes selected. Orthologous of the genes involved in transcription of these enzymes were identified in apricot: ParPAL1 , ParPAL2 , ParDFR , ParFLS1 and ParFLS2 . Transcriptional data of the genes involved in those critical points and their relationships with the polyphenol compounds were analyzed. Higher expression of ParDFR and ParPAL2 has been associated with red-blushed accessions. Differences in expression between paralogues could be related to the presence of a BOXCOREDCPAL cis-acting element related to the genes involved in anthocyanin synthesis ParFLS2 , ParDFR and ParPAL2 .

Background: Prunus pedunculata Pall, the deciduous shrub of Amygdalus subgenus in Rosaceae, is a new kind of desert oil-bearing tree. It has a long story of being planted in the West and North of China for sand fixation and desert control. In addition, the seeds of P. pedunculata are rich of oil, especially the monounsaturated fatty acid and polyunsaturated fatty acid. However, little is known about the molecular mechanisms of oil accumulation during the seed development of P. pedunculata., Results: The seeds of P. pedunculata from three independent plants at 10, 18, 24, 31, 39, 45, 59 and 73 days after flowering (DAF) were obtained and the oil compositions were evaluated. It showed that oleic acid was the dominant type of oil content in the mature seeds (from 32.724% at 10DAF to 72.06% at 73DAF). Next, transcriptome sequencing for the developing seeds produced 988.795 million high quality reads and TRINITY assembled 326,271 genes for the first transcriptome for P. pedunculata. After the assembled transcriptome was evaluated by BUSCO with 85.9% completeness, we identified 195,342, 109,850 and 121,897 P. pedunculata genes aligned to NR, GO and KEGG pathway databases, respectively. Then, we predicted 23,229 likely proteins from the assembled transcriptome and identified 1917 signal peptides and 5512 transmembrane related proteins. In the developing seeds we detected 91,362 genes (average FPKM > 5) and correlation analysis indicated three possible development stages - early (10 ~ 24DAF), middle (31 ~ 45DAF) and late (59 ~ 73DAF). We next analyzed the differentially expressed genes (DEGs) in the developing seeds. Interestingly, compared to 10DAF the number of DEGs was increased from 4406 in 18DAF to 27,623 in 73DAF. Based on the gene annotation, we identified 753, 33, 8 and 645 DEGs related to the fatty acid biosynthesis, lipid biosynthesis, oil body and transcription factors. Notably, GPAT, DGD1, LACS2, UBC and RINO were highly expressed at the early development stage, ω6-FAD, SAD, ACP, ACCA and AHG1 were highly expressed at the middle development stage, and LACS6, DGD1, ACAT1, AGPAT, WSD1, EGY2 and oleosin genes were highly expressed at the late development stage., Conclusions: This is the first time to study the developing seed transcriptome of P. pedunculata and our findings will provide a valuable resource for future studies. More importantly, it will improve our understanding of molecular mechanisms of oil accumulation in P. pedunculata.

Key Message: This study is the first to demonstrate that GA 4 -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 GA 4 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 GA 4 . 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.

In plants, fruit ripening is a coordinated developmental process that requires the change in expression of hundreds to thousands of genes to modify many biochemical and physiological signal cascades such as carbohydrate and organic acid metabolism, cell wall restructuring, ethylene production, stress response, and organoleptic compound formation. In Prunus species (including peaches, apricots, plums, and cherries), fruit ripening leads to the breakdown of complex carbohydrates into sugars, fruit firmness reductions (softening by cell wall degradation and cuticle properties alteration), color changes (loss of green color by chlorophylls degradation and increase in non-photosynthetic pigments like anthocyanins and carotenoids), acidity decreases, and aroma increases (the production and release of organic volatile compounds). Actually, the level of information of molecular events at the transcriptional, biochemical, hormonal, and metabolite levels underlying ripening in Prunus fruits has increased considerably. However, we still poorly understand the molecular switch that occurs during the transition from unripe to ripe fruits. The objective of this review was to analyze of the molecular bases of fruit quality in Prunus species through an integrated metabolic, genomic, transcriptomic, and epigenetic approach to better understand the molecular switch involved in the ripening process with important consequences from a breeding point of view.

The objective of the present study was to investigate the effectiveness of different 1-MCP treatment patterns on alleviating chilling injury (CI) of postharvest nectarine stored at 0 ± 1 °C. Nectarine fruits were subjected to the following treatments: Single-High dose 1-MCP treatment (S-H): 1 μL L -1 application before storage; Multi-low dose 1-MCP treatment: (M-L) Five 0.25 μL L -1 applications after 0, 5, 10, 15, and 20 d of storage; Multi-high dose 1-MCP treatment (M-H): Five 1 μL L -1 applications after 0, 5, 10, 15 and 20 d of storage. The results showed that although all 1-MCP treatments alleviated CI, M-H 1-MCP treatment is the most effective pattern in alleviating CI of nectarine fruit in S-H, M-L, and M-H 1-MCP treatments. Moreover, this study indicated that the reduction of CI in nectarine by 1-MCP application was related to its regulations of ROS and energy metabolism., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Oxidative damage in cells induced by reactive oxygen species (ROS) is a main factor in diabetes mellitus diseases progression. The composition of anthocyanins from Padus racemosa (APR) and the protective effects of APR on H 2 O 2 -induced rat insulinoma (INS-1) cells damage and streptozocin (STZ)-induced diabetes mice were investigated in this study. The main components of APR were cyanidin-cyanidin glucosyl-rutinoside, cyanidin-cyanidin xylosyl-rutinoside, cyanidin-xylosyl-glucoside and cyanidin-rutinoside, which were determined by liquid chromatography-mass spectrometry (LC/MS). APR could scavenge the 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical and superoxide radical in vitro. ROS level was decreased and the cell viability was increased in INS-1 cells after treated with APR. Cell apoptosis induced by H 2 O 2 in INS-1 cells was decreased after incubation with APR. APR could decrease the phosphorylation of p38 and the nuclear translocation of p65, which indicated that APR could inhibit the activation of p38 Mitogen-activated protein kinase (MAPK) and Nuclear factor kappa B (NF-κB) cell signaling pathways. Meanwhile, APR could effectively reduce the blood glucose and blood lipid in STZ-induced diabetic mice. These results suggested that APR might be a potential agent for diabetes mellitus diseases treatment., (© 2020 Wiley-VHCA AG, Zurich, Switzerland.)

Prunus sibirica and Prunus mume are closely related plant species that differ in cold tolerance. Hybrids of P. sibirica and true mume, belonging to the apricot mei group, inherited strong cold resistance from P. sibirica. These materials are favourable for research on the molecular mechanisms of cold resistance. However, no suitable reference genes have been identified for analysing gene expression patterns between P. sibirica and P. mume. Ten candidate reference genes were assessed, namely, actins (ACT2-1, ACT2-2, ACT2-3, ACT2-4), protein phosphatase 2A-1 (PP2A-1), ubiquitins (UBQ2, UBQ3), ubiquitin extension protein (UBQ1) and tubulins (TUB1, TUB2), with four distinct algorithms (geNorm, NormFinder, BestKeeper and RefFinder). UBQ2 was recognized as the best reference gene in stems and buds across materials (P. sibirica; 'Xiaohong Zhusha', 'Beijing Yudie', and 'Xiao Lve' for true mume; and 'Dan Fenghou', 'Fenghou', and 'Yanxing' for apricot mei) under cold stress. In addition, the temporal and spatial expression patterns of PmCBF6 and PmLEA10 among seven varieties during winter periods were analysed using UBQ2 as a reference gene. The expression differed significantly among cultivars, which may contribute to their differences in cold tolerance. This paper confirmed the strong cold tolerance of apricot mei. And the best internal reference gene suitable for seven varieties was selected: UBQ2. Based on the above results, the expression of PmCBF6 and PmLEA10 genes during wintering in seven varieties was analysed. The molecular mechanisms of cold resistance were found to be possibly different in different varieties of P. sibirica and P. mume.

Phytoplasmas are specialized small bacteria restricted to the phloem tissue and spread by hemipterans feeding on plant sieve tube elements. As for many other plant pathogens, it is known that phytoplasmas alter the chemistry of their hosts. Most research on phytoplasma-plant interactions focused on the induction of plant volatiles and phytohormones. Little is known about the influence of phytoplasma infections on the nutritional composition of phloem and consequences on vector behavior and development. The plum psyllid Cacopsylla pruni transmits 'Candidatus Phytoplasma prunorum', the causing agent of European Stone Fruit Yellows (ESFY). While several Prunus species are susceptible for psyllid feeding, they show different responses to the pathogen. We studied the possible modulation of plant-insect interactions by bacteria-induced changes in phloem sap chemistry. Therefore, we sampled phloem sap from phytoplasma-infected and non-infected Prunus persica and Prunus insititia plants, which differ in their susceptibility to ESFY and psyllid feeding. Furthermore, the feeding behavior and development of C. pruni nymphs was compared on infected and non-infected P. persica and P. insititia plants. Phytoplasma infection did not affect phloem consumption by C. pruni nymphs nor their development time. In contrast, the study revealed significant differences between P. insititia and P. persica in terms of both phloem chemistry and feeding behavior of C. pruni nymphs. Phloem feeding phases were four times longer on P. insititia than on P. persica, resulting in a decreased development time and higher mortality of vector insects on P. persica plants. These findings explain the low infestation rates of peach cultivars with plum psyllids commonly found in field surveys.

Amygdalus pedunculata Pall is a kind of desert woody oil plant, and its seeds are high in protein. The protein of Amygdalus pedunculata Pall (API) was identified by SDS-PAGE, 2-DE and MS. More than 300 proteins were identified. The improved solubility, emulsifying properties and foaming properties of API were observed in a pH range of 2.0-12.0 and a sodium chloride concentration of 0-1.0 M. The results showed that API had a good solubility (94.2%), bulk density (0.107 g/mL), oil absorption capacity (3.54 g/g), thermal stability (91.58 °C), emulsifying property (70 m 2 /g) and foaming property (83.7%). The conformation changes of API were studied by fluorescence and differential scanning calorimetry (DSC). The degree of denaturation of denaturants for API was guanidine hydrochloride > urea > SDS. These results showed that API has good processing performance and can be used as a new type of plant protein resource., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

'Friar' plum (Prunus salicina Lindl.) fruit were transferred to shelf life (25 °C) following different storage periods at low (0 °C) or intermediate (5 °C) temperature. The earliest flesh reddening appeared in plums during shelf life removed after 28 d at 0 °C and 14 d at 5 °C, respectively, in comparison with turning yellow in plums remained at 25 °C immediately after harvest. The flesh reddening developed rapidly thereafter. Anthocyanins, in particular, cyanidin 3-O-glucoside, significantly accumulated in the reddening tissue, and activities of enzymes associated with the phenylpropanoid pathway were considerably activated after the removal. The removal elicited extremely high ethylene production in plums, which might mediate the activation of the anthocyanin biosynthesis in response to cold stress signal. The results provided a potential approach for postharvest regulation of flesh color and accumulation of bioactive substances in plums, which could lead to attractive attributes and health-promoting effects on consumers., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Colorimetric and fluorescent detection of cyanide and hydrogen sulfide ions has been effected using a simple organic probe in H 2 O:DMSO (20:80, v/v) medium. The probe exhibits a colour change from pale-yellow to red upon addition of these analytes under normal light and fluorescent change from green to red under UV lamp. Other competitive ions show no observable colour or fluorescence change. The binding constants of cyanide and hydrogen sulfide ions with the probe determined using fluorescence titration data are found to be 2.1 × 10 4 and 1.6 × 10 4 M - 1 , respectively. The probe fluorimetrically detects the analytes in a wide pH range (4-10). 1 H and 13 C NMR studies suggest that the probe senses cyanide ion through deprotonation and nucleophilic addition mechanism and hydrogen sulfide ion via deprotonation mechanism. Detection limits of cyanide and hydrogen sulfide are determined to be 0.15 and 1 μM, respectively. The practical utility of the probe has been demonstrated by same dual mode detection of cyanide in food materials like bitter almond, cassava flour and sprouting potato., Competing Interests: Declaration of competing interest None., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Non-specific lipid transfer proteins (LTPs) are important allergens in fruits, pollen, vegetables, nuts and latex. Due to their compact structure, LTPs are highly resistant to heat treatment. Here, Art v 3 from mugwort pollen and Pru p 3 from peach were used as model allergens to in-depth investigate structural and immunological properties upon thermal treatment at different buffer conditions., Methods: Recombinant Art v 3 and Pru p 3 were purified from E. coli and incubated at 95 °C up to 120 min using sodium phosphate buffer pH 3.4 or 7.3. Physicochemical properties of allergens were analyzed in circular dichroism spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, size exclusion chromatography, and mass spectrometry. The crystal structure of Art v 3.0201 was determined to 1.9 Å resolution. IgG and IgE binding was investigated in ELISA using murine and LTP allergic patients' sera., Results: Highly pure and homogenous recombinant allergens were obtained from bacterial production. The crystal structure of Art v 3.0201 revealed an antiparallel four helix bundle with a C-terminal extension mediating an asymmetric, transient dimer interface and differently sized cavities. Both allergens showed high thermal stability at acidic conditions. In contrast, extensive heat treatment in neutral buffer induced irreversible structural changes due to lanthionine-based cysteine rearrangement. This fostered loss of the typical α-helical structure, increased molecular size and abrogation of IgG and IgE binding epitopes. Pru p 3 lost its structural integrity at shorter heat stress duration than Art v 3, which did however only partially affect the molecule's IgE binding epitopes., Conclusion: During thermal treatment, susceptibility to structural changes of the LTP-fold is highly dependent on the surrounding environment but also on intrinsic features of individual LTPs. This is a crucial fact to consider when processing LTP-containing food or food products as this will directly influence their allergenic potential., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

ATP-binding cassette (ABC) transporters constitute a large, diverse, and ubiquitous superfamily that is involved in a broad range of processes. The completion of genome sequencing provides an opportunity to understand the phylogenetic history of the ABC transporter superfamily among Rosaceae species. This study identified a total of 1323 ABC transporter genes from nine Rosaceae genomes: 191 from Malus domestica , 174 from Pyrus communis , 138 from Prunus persica , 118 from Prunus avium , 141 from Prunus dulcis , 122 from Fragaria vesca , 98 from Rubus occidentalis , 162 from Prunus mume , and 179 from Rosa chinensis . Their chemical characterization, phylogenetic analysis, chromosomal localization, gene structure, gene duplication, and tissue-specific expression were studied. Their subcellular localization, transmembrane structures, and protein motifs were predicted. All the ABC transporter genes were grouped into eight subfamilies on the basis of their phylogenetic relationships and structural features. Furthermore, cis-element and expression analysis of 10 potential phytohormone transporters in MdABCG subfamily genes were also performed. Loss of the W-box in the promoter region of MdABCG28 was found to reduce the gene expression level and was linked to the dwarfing phenotype in apple rootstocks. MdABCG28 overexpression promoted shoot growth of atabcg14 mutants in Arabidopsis.

Prunus mume, a traditional Chinese flower, is the only species of Prunus known to produce a strong floral fragrance, of which eugenol is one of the principal components. To explore the molecular mechanism of eugenol biosynthesis in P. mume, patterns of dynamic, spatial and temporal variation in eugenol were analysed using GC-MS. Coniferyl alcohol acetyltransferase (CFAT), a member of the BAHD acyltransferase family, catalyses the substrate of coniferyl alcohol to coniferyl acetate, which is an important substrate for synthesizing eugenol. In a genome-wide analysis, we found 90 PmBAHD genes that were phylogenetically clustered into five major groups with motif compositions relatively conserved in each cluster. The phylogenetic tree showed that the PmBAHD67-70 proteins were close to the functional CFATs identified in other species, indicating that these four proteins might function as CFATs. In this work, 2 PmCFAT genes, named PmCFAT1 and PmCFAT2, were cloned from P. mume 'Sanlunyudie', which has a strong fragrance. Multiple sequences indicated that PmCFAT1 contained two conserved domains, HxxxD and DFGWG, whereas DFGWG in PmCFAT2 was changed to DFGFG. The expression levels of PmCFAT1 and PmCFAT2 were examined in different flower organs and during the flowering stages of P. mume 'Sanlunyudie'. The results showed that PmCFAT1 was highly expressed in petals and stamens, and this expression increased from the budding stage to the full bloom stage and decreased in the withering stage, consistent with the patterns of eugenol synthesis and emission. However, the peak of gene expression appeared earlier than those of eugenol synthesis and emission. In addition, the expression level of PmCFAT2 was higher in pistils and sepals than in other organs and decreased from the budding stage to the blooming stage and then increased in the withering stage, which was not consistent with eugenol synthesis. Subcellular localization analysis indicated that PmCFAT1 and PmCFAT2 were located in the cytoplasm and nucleus, while enzyme activity assays showed that PmCFAT1 is involved in eugenol biosynthesis in vitro. Overall, the results suggested that PmCFAT1, but not PmCFAT2, contributed to eugenol synthesis in P. mume., Competing Interests: The authors have declared that no competing interests exist.

The aim of this research was to analyze sugars and phenolics of pollen obtained from 15 different 'Oblačinska' sour cherry clones and to assess the chemical fingerprint of this cultivar. Carbohydrate analysis was done using high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD), while polyphenols were analyzed by ultra-high-performance liquid chromatography-diode array detector-tandem mass spectrometry (UHPLC-DAD MS/MS) system. Glucose was the most abundant sugar, followed by fructose and sucrose. Some samples had high level of stress sugars, especially trehalose. Rutin was predominantly polyphenol in a quantity up to 181.12 mg/kg (clone III/9), with chlorogenic acid (up to 59.93 mg/kg in clone III/9) and p -coumaric acid (up to 53.99 mg/kg in clone VIII/1) coming after. According to the principal component analysis (PCA), fructose, maltose, maltotriose, sorbitol, and trehalose were the most important sugars in separating pollen samples. PCA showed splitting off clones VIII/1, IV/8, III/9, and V/P according to the quantity of phenolics and dissimilar profiles. Large differences in chemical composition of studied 'Oblačinska sour cherry' clone pollen were shown, proving that it is not a cultivar, but population. Finally, due to the highest level of phenolics, clones IV/8, XV/3, and VIII/1 could be singled out as a promising one for producing functional food and/or in medicinal treatments., Competing Interests: The authors declare no conflict of interest.