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Fruit aroma of Japanese apricot is distinct, and the specific volatile compounds are not clearly known during fruit development and during post‐harvest stage. This study therefore aimed to explore the volatile compounds present during these stages. The volatile compounds were analysed by headspace solid‐phase microextraction and gas chromatography–mass spectrometry. OAV, PCA and electronic nose techniques were used to determine the characteristic aroma components. Enzyme‐linked immunoassay (ELISA) was also applied to determine the activity of enzymes. The results showed that in the cultivars 'Xiyeqing' a total of 52 components that included 20 terpenes, 15 aldehydes, 9 esters, 3 ketones and 5 other substances were detected during fruit development and post‐harvest stage. While in the cultivar 'Xiaoyezhugan' a total of 49 components that included 25 terpenes, 7 aldehydes, 11 esters, 1 alcohol, 3 ketones and 2 other substances were also detected during fruit development and post‐harvest stage. We concluded that the characteristic volatile compounds of mature Japanese apricot fruit were (+)‐limonene, linalool, damascenone, β‐damascenone and nonanal, finding the basis for the fruity, floral and sweet aroma of the Japanese apricot fruit. Further analysis indicated that low temperature inhibited the synthesis of esters and terpenes, and dark conditions were more favourable to the synthesis of volatile compounds than light conditions. Short‐term storage of Japanese apricot fruit at room temperature and dark conditions was conducive for the maintenance of volatile compounds, and low‐temperature storage was the most destructive to the fruit volatile compounds. These findings form a theoretical foundation for exploring the specific volatile compound of Japanese apricot and helped to determine the optimal storage condition of post‐harvest stage for Japanese apricot fruit. [ABSTRACT FROM AUTHOR]

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. Summary statement: The PmCBF03 allele variation is involved in regulating the low‐temperature adaptability of Japanese apricots at different altitudes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Self-incompatibility (SI) is a common strategy to avoid inbreeding and, consequently, keep genetic diversity within a species. In its mechanism, pollen rejection happens in the style when the single multiallelic locus (SFB in prunus species) of the haploid pollen matches one of the S-alleles existing in the diploid pistil. The SFB gene for the pollen S gene has been identified in many Prunus species. However, Japanese apricot is a species with a typical gametophytic self-incompatibility (GSI), and its SFB alleles available are limited, although they are required for studying GSI. Therefore, we used an AS-PCR amplification method, sequencing, and the pair primers SFB-C1F and Pm-Vb designed based on the conserved region of the Prunus SFB gene to identify SFB genotypes of 48 Japanese apricot (P. mume) accessions. Eleven novel SFB alleles were isolated from these accessions and shared typical structural features with SFB alleles from other Prunus species. These novel SFB alleles were uniquely expressed in pollen. Hence, we concluded that these 11 PmSFB were pollen S determinants of P. mume. This current study offers the novel SFB genes of the P. mume S locus, which could be a useful potential resource for studies on pollen SI mechanisms. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

SUMMARY: 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. Significance Statement: Japanese apricot was widely distributed in different regions of China. As for how to disseminate in different regions, there has been a great controversy in the academic circles. This study provided novel insight into the evolution and dissemination of Japanese apricot and a greater number of valuable genome resources for the genetic improvement and effective utilization of Japanese apricot. [ABSTRACT FROM AUTHOR]

Abstract Background MicroRNAs (miRNAs) are a class of endogenous, small, non-coding RNAs that regulate gene expression by mediating gene silencing at transcriptional and post-transcriptional levels in high plants. However, the diversity of miRNAs and their roles in floral development in Japanese apricot (Prunus mume Sieb. et Zucc) remains largely unexplored. Imperfect flowers with pistil abortion seriously decrease production yields. To understand the role of miRNAs in pistil development, pistil development-related miRNAs were identified by Solexa sequencing in Japanese apricot. Results Solexa sequencing was used to identify and quantitatively profile small RNAs from perfect and imperfect flower buds of Japanese apricot. A total of 22,561,972 and 24,952,690 reads were sequenced from two small RNA libraries constructed from perfect and imperfect flower buds, respectively. Sixty-one known miRNAs, belonging to 24 families, were identified. Comparative profiling revealed that seven known miRNAs exhibited significant differential expression between perfect and imperfect flower buds. A total of 61 potentially novel miRNAs/new members of known miRNA families were also identified by the presence of mature miRNAs and corresponding miRNA*s in the sRNA libraries. Comparative analysis showed that six potentially novel miRNAs were differentially expressed between perfect and imperfect flower buds. Target predictions of the 13 differentially expressed miRNAs resulted in 212 target genes. Gene ontology (GO) annotation revealed that high-ranking miRNA target genes are those implicated in the developmental process, the regulation of transcription and response to stress. Conclusions This study represents the first comparative identification of miRNAomes between perfect and imperfect Japanese apricot flowers. Seven known miRNAs and six potentially novel miRNAs associated with pistil development were identified, using high-throughput sequencing of small RNAs. The findings, both computationally and experimentally, provide valuable information for further functional characterisation of miRNAs associated with pistil development in plants.

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 SCFSLY1-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. [ABSTRACT FROM AUTHOR]

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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. [ABSTRACT FROM AUTHOR]

As with other self-incompatible Prunus species, cultivars of Japanese apricot ( Prunus mume Sieb. et Zucc.) display the S-RNase-based gametophytic self-incompatibility system. In this study, S-genotypes of ten Japanese apricot cultivars native to China were subjected to polyacrylamide gel electrophoresis (PAGE) analysis using an efficient Prunus S-RNase primer pair, Pru-C2 and PCE-R. In addition, three new S-RNase genes ( S, S and S -RNase) and six new SFB genes ( PmSFB14, PmSFB18, PmSFB22, PmSFB24, PmSFB31 and PmSFB34) were identified and their sequences were characterized and deposited in the GenBank database. [ABSTRACT FROM AUTHOR]

Abstract: Information on S-genotypes is essential for designing orchards of Japanese apricot (Prunus mume Sieb. et Zucc.) and for hybridization. However, this information is lacking for most cultivars grown in China. Thus, in this work, the S-genotypes of 24 Japanese apricot cultivars native to China were identified by sequencing the PCR products obtained from allele-specific polymerase chain reaction (AS-PCR). Seventeen S-RNase alleles were amplified, ten of them for the first time. The new S-RNase alleles were submitted to GenBank and denoted them as S 17, S 18, S 19, S 20, S 21, S 22, S 23, S 24, S 25 and S 26. Furthermore, the S-genotypes of four Japanese apricot cultivars were confirmed by field-testing cross-pollination. [Copyright &y& Elsevier]

Japanese apricot (Prunus mume) is remarkably valuable for its high ornamental and economic importance due to its distinctive features. Low temperature is a serious environmental constraint for this species, restricting its cultivation and dispersal in the north of China. To address this issue, breeding requires an understanding of the molecular mechanisms underlying responses to cold stress. We examined the leaf physiological and transcriptome profile by RNA sequencing in 'Bungo' scion cultivar grafted onto Prunus mume (cold-sensitive) and Prunus armeniaca (cold-tolerant) rootstocks at 4 °C for 0, 6, and 24 h. Our results revealed that the increased MDA concentration in the leaves of P. mume cultivar (cold-sensitive) suggests that cold stress might cause oxidative damage and increased sensitivity. Moreover, the cold-tolerant cultivar (P. armeniaca) considerably enhances the enzyme activities (i.e., SOD, POD, and CAT), as well as osmo-protectants (soluble sugars and proline) compared with sensitive cultivar, which helps plants to withstand oxidative damage caused by cold stress. Additionally, differentially expressed genes were shown to be enriched in plant hormone signal transduction, ribosome, MAPK signaling, and circadian rhythm pathway. After 24 h of cold stress, genes related to PYL4, histidine kinase 1, SAUR36, bHLH130, bHLH123, TIFY 6B-like, WRKY 40, WRKY 57, and 60S acidic ribosomal protein P1 were differentially expressed, implying that these DEGs involved in multiple pathways are involved in cold tolerance in Japanese apricot. This study improved our current understanding of the mechanism of cold tolerance in Japanese apricot, and the findings could be utilized for other related fruit species. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Prunus mume Sieb. et Zucc., P. armeniaca L., and P. salicina L. are economically important fruit trees in temperate regions. These species are taxonomically perplexing because of shared interspecific morphological traits and variation, which are mainly attributed to hybridization. The chloroplast is cytoplasmically inherited and often used for evolutionary studies. We sequenced the complete chloroplast genomes of P. mume, P. armeniaca, and P. salicina using Illumina sequencing followed by de novo assembly. The three chloroplast genomes exhibit a typical quadripartite structure with conserved genome arrangement, structure, and moderate divergence. The lengths of the genomes are 157,815, 157,797, and 157,916 bp, respectively. The length of the large single-copy region (LSC) region is 86,113, 86,283, and 86,122 bp, and the length of the SSC region is 18,916, 18,734, and 19,028 bp; the IR region is 26,393, 26,390, and 26,383 bp, respectively. Each of the three chloroplast genomes encodes 133 genes, including 94 protein-coding, 31 tRNA, and eight rRNA genes. Differential gene analysis for the three species revealed that trnY-ATA is a unique gene in P. armeniaca; in contrast, the gene trnI-TAT is only present in P. mume and P. salicina, though the position of the gene in these chloroplast genomes differs. Further comparative analysis of the complete chloroplast genome sequences revealed that the ORF genes and the sequences of linked regions rps16 and atpA, atpH and atpI, trnc-GCA and psbD, ycf3 and atpB, and rpL32 and ndhD are significantly different and may be used as molecular markers in taxonomic studies. Phylogenetic evolution analysis of the three species suggests that P. mume has a closer genetic relationship to P. armeniaca than to P. salicina. [ABSTRACT FROM AUTHOR]

Background: Long non-coding RNAs (lncRNAs) are transcripts more than 200 bp in length do not encode proteins. Up to the present, it has been reported that lncRNAs play an essential role in developmental processes through their regulatory functions. However, their characteristics, expression inheritance patterns, and functions in Prunus mume are quite unidentified. Results: In this present study, we exposed the specific characters of pistil development process between single pistil cv 'Qingjia No.2' (QJN2) and multiple pistils cv 'Da Yu' (DY). We found that early October is the key stage for pistil differentiation. The similarity epidermis was observed between two types of pistil. We also further investigated a complete pistil development lncRNA profiles through RNA-seq in Prunus mume. 2572 unique lncRNAs and 24,648 genes mapped to Prunus mume genome, furthermore, 591 novel lncRNAs were predicted. Both unique lncRNAs and novel lncRNAs are shorter in length than the mRNAs, and the overall expression level of lncRNAs was lower than mRNAs in Prunus mume. 186 known lncRNAs, 1638 genes and 89 novel lncRNAs were identified as significant differential expressed in QJN2 compared with DY. We predicted 421 target genes of differentially expressed known lncRNAs (DEKLs) and 254 target genes of differentially expressed novel lncRNAs (DENLs). 153 miRNAs were predicted interacted with 100 DEKLs while 112 miRNAs were predicted interacted with 55 DENLs. Further analysis of the DEKLs showed that the lncRNA of XR_514690.2 down-regulated its target ppe-miR172d, and up-regulated AP2, respectively. Meanwhile, the other lncRNA of TCONS_00032517 induced cytokinin negative regulator gene A-ARR expression via repressing its target miRNA ppe-miR160a/b in DY. At the same time we found that the AP2 expression was significantly up-regulated by zeatin (ZT) treatment in flower buds. Our experiments suggest that the two lncRNAs of XR_514690.2 and TCONS_00032517 might contribute the formation of multiple pistils in Prunus mume. Conclusion: This study shows the first characterization of lncRNAs involved in pistil development and provides new indications to elucidate how lncRNAs and their targets play role in pistil differentiation and flower development in Prunus mume. [ABSTRACT FROM AUTHOR]

The Japanese apricot (Prunus mume Sieb. et Zucc.), a deciduous tree within the Rosaceae family, is esteemed for its medicinal and ornamental attributes. In Chinese tradition, the 'Lve' group of the Japanese apricot, including varieties like 'Lve' and 'Xiaolve', is commonly employed for medicinal purposes and tea production. This study endeavors to delineate the chemical distinctions among four Japanese apricot varieties. Quantitative analysis, utilizing ultra-performance liquid chromatography (UPLC), was conducted on 'Lve', 'Xiaolve', 'Qingfeng', and 'Touguhong'. The research explores the chemical components of different floral organs and stages within the 'Xiaolve' cultivar, correlating them with hydroxyl radical (·OH) and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging rates. Results indicate significant variation in flower composition among the varieties. Notably, chlorogenic acid varies markedly, ranking highest in 'Xiaolve', followed by 'Touguhong', 'Lve' and 'Qingfeng', 'Qingfeng' exhibits elevated levels of hyperoside and quercetin. In the 'Xiaolve', stamens show heightened chlorogenic acid levels, while petals display increased flavonoids and catechins. Additionally, chemical components decrease with flowering stages. Correlations between chemical components in 'Xiaolve' and scavenging rates of OH and ABTS free radicals were observed. Molecular docking analysis reveals that chlorogenic acid binds to multiple antioxidant proteins, suggesting its dual role in scavenging free radicals and internal antioxidant activity. These findings form a theoretical foundation for exploring the medicinal potential of the 'Xiaolve', determining optimal harvest times, and unraveling underlying mechanisms. • Explored the differences in the chemical composition of different varieties of Japanese apricot. • The chemical composition of 'Xiaolve' blossom with it's antioxidant activity has strong correlation. • The best time to harvest Japanese apricot is the small bud stage. • The flavonoids contents of 'Xiaolve' cultivar are concentrated in the petals, pistils and stamens. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • The biochemical and molecular basis of flavonoid biosynthesis is studied using transcriptomic and metabolomics approaches • The expression of the genes and metabolites encoding flavonoid biosynthesis was lower in abnormal pistils • "Hydroxycinnamoyl transferase' and '2-hydroxycinnamic acid' was lower expressed might be the cause of pistil abortion [ABSTRACT FROM AUTHOR]

Abstract: The phenomenon of pistil abortion widely occurs in Japanese apricot and has seriously affected the yield in production. We used a combination of two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time of flight/time of flight (MALDI-TOF/TOF) approaches to identify the differentially expressed proteome between perfect and imperfect flower buds in Japanese apricot. More than 400 highly reproducible protein spots (P <0.05) were detected and 27 protein spots showed a greater than two-fold difference in their expression values. The proteins identified were classified into eight functional classifications and ten process categories, according to the Gene Ontology (GO). Acetyl-CoA produced by ATP citrate lyase (ACL) as a structural substance during formation of the cell wall could regulate pistil abortion in Japanese apricot. S-adenosylmethionine (SAM), xyloglucan endotransglucosylase/hydrolases (XTHs) and caffeoyl-CoA-O-methyl transferase (CCoAOMT) could promote cell wall formation in perfect flower buds of Japanese apricot, greatly contributing to pistil development. Spermidine hydroxycinnamoyl transferase (SHT) may be involved in the O-methylation of spermidine conjugates and could contribute to abnormal floral development. The identification of such differentially expressed proteins provides new targets for future studies that will assess their physiological roles and significance in pistil abortion. [Copyright &y& Elsevier]