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Summary: Branch number is one of the most important agronomic traits of fruit trees such as peach. Little is known about how LncRNA and/or miRNA modules regulate branching through transcription factors.Here, we used molecular and genetic tools to clarify the molecular mechanisms underlying brassinosteroid (BR) altering plant branching.We found that the number of sylleptic branch and BR content in pillar peach ('Zhaoshouhong') was lower than those of standard type ('Okubo'), and exogenous BR application could significantly promote branching. PpTCP4 expressed great differentially comparing 'Zhaoshouhong' with 'Okubo'. PpTCP4 could directly bind to DWARF2 (PpD2) and inhibited its expression. PpD2 was the only one differentially expressed key gene in the path of BR biosynthesis. At the same time, PpTCP4 was identified as a target of miR6288b‐3p. LncRNA1 could act as the endogenous target mimic of miR6288b‐3p and repress expression of miR6288b‐3p. Three deletions and five SNP sites of lncRNA1 promoter were found in 'Zhaoshouhong', which was an important cause of different mRNA level of PpTCP4 and BR content. Moreover, overexpressed PpTCP4 significantly inhibited branching.A novel mechanism in which the lncRNA1‐miR6288b‐3p‐PpTCP4‐PpD2 module regulates peach branching number was proposed. [ABSTRACT FROM AUTHOR]

Expansins (EXPs) loosen plant cell walls and are involved in diverse developmental processes through modifying cell-walls; however, little is known about the role of PpEXPs in peach fruit. In this study, 26 PpEXP genes were identified in the peach genome and grouped into four subfamilies, with 20 PpEXPAs, three PpEXPBs, one PpEXPLA and two PpEXPLBs. The 26 PpEXPs were mapped on eight chromosomes. The primary mode of gene duplication of the PpEXPs was dispersed gene duplication (DSD, 50%). Notably, cis-elements involved in light responsiveness and MeJA-responsiveness were detected in the promoter regions of all PpEXPs, while ethylene responsive elements were observed in 12 PpEXPs. Transcript profiling of PpEXPs in the peach fruit varieties of MF (melting), NMF (non-melting) and SH (stony hard) at different stages showed that PpEXPs displayed distinct expression patterns. Among the 26 PpEXPs, 15 PpEXPs were expressed in the fruit. Combining the expressing patterns of PpEXPs in fruits with different flesh textures, PpEXPA7, PpEXPA13 and PpEXPA15 were selected as candidate genes, as they were highly consistent with the patterns of previous reported key genes (PpPGM, PpPGF and PpYUC11) in regard to peach fruit texture. The genes with different expression patterns between MF and NMF were divided into 16 modules, of which one module, with pink and midnightblue, negatively correlated with the phenotype of fruit firmness and was identified as PpEXPA1 and PpEXPA7, while the other module was identified as PpERF in the pink module, which might potentially effect fruit texture development by regulating PpEXPs. These results provide a foundation for the functional characterization of PpEXPs in peach. [ABSTRACT FROM AUTHOR]

Controlling the tree size of fruit species such as peach can reduce the amount of labor and input needed for orchard management. The phytohormone gibberellin (GA) positively regulates tree size by inducing degradation of the GA signaling repressor DELLA. The N-terminal DELLA domain in this protein is critical for its GA-dependent interaction with the GA receptor GID1 and the resulting degradation of the DELLA protein, which allows for growth-promoting GA signaling. In this study, a DELLA family member, PpeDGYLA, contains a DELLA domain but has amino acid changes in three conserved motifs (DELLA into DGYLA, LEQLE into LERLE, and TVHYNP into AVLYNP). In the absence or presence of GA3, the PpeDGYLA protein did not interact with PpeGID1c and was stable in 35S-PpeDGYLA peach transgenic callus. The overexpression of PpeDGYLA in both polar and Arabidopsis showed an extremely dwarfed phenotype, and these transgenic plants were insensitive to GA3 treatment. PpeDGYLA could interact with PpeARF6-1 and -2, supposed growth-promoting factors. It is suggested that the changes in the DELLA domain of PpeDGYLA may, to some extent, account for the severe dwarf phenotype of poplar and Arabidopsis transgenic plants. In addition, our study showed that the DELLA family contained three clades (DELLA-like, DELLA, and DGLLA). PpeDGYLA clustered into the DGLLA clade and was expressed in all of the analyzed tissues. These results lay the foundation for the further study of the repression of tree size by PpeDGYLA. [ABSTRACT FROM AUTHOR]

Branch number is an important agronomic trait in peach (Prunus persica) trees because plant architecture affects fruit yield and quality. Although breeders can select varieties with different tree architecture, the biological mechanisms underlying architecture remain largely unclear. In this study, a pillar peach ('Zhaoshouhong') and a standard peach ('Okubo') were compared. 'Zhaoshouhong' was found to have significantly fewer secondary branches than 'Okubo'. Treatment with the synthetic strigolactone (SL) GR24 decreased branch number. Transcriptome analysis indicated that PpTCP18 (a homologous gene of Arabidopsis thaliana BRC1) expression was negatively correlated with strigolactone synthesis gene expression, indicating that PpTCP18 may play an important role in peach branching. Yeast one-hybrid, electrophoretic mobility shift, dual-luciferase assays and PpTCP18-knockdown in peach leaf buds indicated that PpTCP18 could increase expression of PpLBO1, PpMAX1, and PpMAX4. Furthermore, transgenic Arabidopsis plants overexpressing PpTCP18 clearly exhibited reduced primary rosette-leaf branches. Moreover, lncRNA sequencing and transient expression analysis revealed that lncRNA5 targeted PpTCP18, significantly increasing PpTCP18 expression. These results provide insights into the mRNA and lncRNA network in the peach SL signaling pathway and indicate that PpTCP18, a transcription factor downstream of SL signaling, is involved in positive feedback regulation of SL biosynthesis. This role of PpTCP18 may represent a novel mechanism in peach branching regulation. Our study improves current understanding of the mechanisms underlying peach branching and provides theoretical support for genetic improvement of peach tree architecture. [ABSTRACT FROM AUTHOR]

Background: The rapid growth of annual shoots is detrimental to peach production. While gibberellin (GA) promotes the rapid growth of peach shoots, there is limited information on the identity and expression profiles of GA-metabolism genes for this species. Results: All six GA biosynthetic gene families were identified in the peach genome, and the expression profiles of these family members were determined in peach shoots. The upstream biosynthetic gene families have only one or two members (1 CPS, 2 KSs, and 1 KO), while the downstream gene families have multiple members (7 KAOs, 6 GA20oxs, and 5 GA3oxs). Between the two KS genes, PpKS1 showed a relatively high transcript level in shoots, while PpKS2 was undetectable. Among the seven KAO genes, PpKAO2 was highly expressed in shoots, while PpKAO1 and − 6 were weakly expressed. For the six GA20ox genes, both PpGA20ox1 and − 2 were expressed in shoots, but PpGA20ox1 levels were higher than PpGA20ox2. For the five GA3ox genes, only PpGA3ox1 was highly expressed in shoots. Among these biosynthesis genes, PpGA20ox1 and PpGA3ox1 showed a gradual decrease in transcript level along shoots from top to bottom, and a similar trend was observed in bioactive GA1 and GA4 distribution. Among the GA-deactivation genes, PpGA2ox6 was highly expressed in peach shoots. PpGA2ox1 and − 5 transcripts were relatively lower and showed a similar pattern to PpGA20ox1 and PpGA3ox1 in peach shoots. Overexpression of PpGA20ox1, − 2, or PpGA2ox6 in Arabidopsis or tobacco promoted or depressed the plant growth, respectively, while PpGA3ox1 did not affect plant height. Transient expression of PpGA20ox1 in peach leaves significantly increased bioactive GA1 content. Conclusions: Our results suggest that PpGA20ox and PpGA2ox expression are closely associated with the distribution of active GA1 and GA4 in peach annual shoots. Our research lays a foundation for future studies into ways to effectively repress the rapid growth of peach shoot. [ABSTRACT FROM AUTHOR]

The heat shock protein 20 (HSP20) proteins comprise an ancient, diverse, and crucial family of proteins that exists in all organisms. As a family, the HSP20s play an obvious role in thermotolerance, but little is known about their molecular functions in addition to heat acclimation. In this study, 42 PpHSP20 genes were detected in the peach genome and were randomly distributed onto the eight chromosomes. The primary modes of gene duplication of the PpHSP20s were dispersed gene duplication (DSD) and tandem duplication (TD). PpHSP20s in the same class shared similar motifs. Based on phylogenetic analysis of HSP20s in peach, Arabidopsis thaliana, Glycine max, and Oryza sativa, the PpHSP20s were classified into 11 subclasses, except for two unclassified PpHSP20s. cis-elements related to stress and hormone responses were detected in the promoter regions of most PpHSP20s. Gene expression analysis of 42 PpHSP20 genes revealed that the expression pattern of PpHSP20-32 was highly consistent with shoot length changes in the cultivar 'Zhongyoutao 14', which is a temperature-sensitive semi-dwarf. PpHSP20-32 was selected for further functional analysis. The plant heights of three transgenic Arabidopsis lines overexpressing PpHSP20-32 were significantly higher than WT, although there was no significant difference in the number of nodes. In addition, the seeds of three over-expressing lines of PpHSP20-32 treated with high temperature showed enhanced thermotolerance. These results provide a foundation for the functional characterization of PpHSP20 genes and their potential use in the growth and development of peach. [ABSTRACT FROM AUTHOR]

Summary: Peach (Prunus persica) is one of the most important fruit crops globally, but its cultivation can be hindered by large tree size. 'Zhongyoutao 14' (CN14) is a temperature‐sensitive semi‐dwarf (TSSD) cultivar which might be useful as breeding stock. The genome of CN14 was sequenced and assembled de novo using single‐molecule real‐time sequencing and chromosome conformation capture assembly. A high‐quality genome was assembled and annotated, with 228.82 Mb mapped to eight chromosomes. Eighty‐six re‐sequenced F1 individuals and 334 previously re‐sequenced accessions were used to identify candidate genes controlling TSSD and flower type and size. An aquaporin tonoplast intrinsic protein (PpTIP2) was a strong candidate gene for control of TSSD. Sequence variations in the upstream regulatory region of PpTIP2 correlated with different transcriptional activity at different temperatures. PpB3‐1, a candidate gene for flower type (SH) and flower size, contributed to petal development and promoted petal enlargement. The locus of another 12 agronomic traits was identified through genome‐wide association study. Most of these loci exhibited consistent and precise association signals, except for flesh texture and flesh adhesion. A 6015‐bp insertion in exon 3 and a 26‐bp insertion upstream of PpMYB25 were associated with fruit hairless. Along with a 70.5‐Kb gap at the F‐M locus in CN14, another two new alleles were identified in peach accessions. Our findings will not only promote genomic research and agronomic breeding in peach but also provide a foundation for the peach pan‐genome. [ABSTRACT FROM AUTHOR]

Peach (Prunus persica L. Batsch) trees grow vigorously and are subject to intense pruning during orchard cultivation. Reducing the levels of endogenous gibberellins (GAs) represents an effective method for controlling branch growth. Gibberellin 2-oxidases (GA2oxs) deactivate bioactive GAs, but little is known about the GA2ox gene family in peach. In this study, we identified seven PpGA2ox genes in the peach genome, which were clustered into three subgroups: C19-GA2ox-I, C19-GA2ox-II, and C20-GA2ox-I. Overexpressing representative genes from the three subgroups, PpGA2ox-1 , PpGA2ox-5 , and PpGA2ox-2 , in tobacco resulted in dwarf plants with shorter stems and smaller leaves than the wild type. An analysis of the GA metabolic profiles of the transgenic plants showed that PpGA2ox-5 (a member of subgroup C19-GA2ox-II) is simultaneously active against both C19-GAs and C20-GAs,which implied that C19-GA2ox-II enzymes represent intermediates of C19-GA2oxs and C20-GA2oxs. Exogenous GA3 treatment of shoot tips activated the expression of all seven PpGA2ox genes, with different response times: the C 19- GA2ox genes were transcriptionally activated more rapidly than the C20-GA2ox genes. GA metabolic profile analysis suggested that C20-GA2ox depletes GA levels more broadly than C19-GA2ox. These results suggest that the PpGA2ox gene family is responsible for fine-tuning endogenous GA levels in peach. Our findings provide a theoretical basis for appropriately controlling the vigorous growth of peach trees. [ABSTRACT FROM AUTHOR]

Plant growth caused by ambient temperature is thought to be regulated by a complex transcriptional network. A temperature-sensitive peach (Prunus persica) was used to explore the mechanisms behind shoot internode elongation at elevated temperatures. There was a significantly positive correlation between the length of the terminal internode (TIL) and the maximum temperature three days prior to the measuring day. Four critical growth stages (initial period and initial elongation period at lower temperature, rapid growth period and stable growth period at higher temperature) were selected for comparative RNA-seq analysis. About 6.64G clean bases were obtained for each library, and 88.27% of the data were mapped to the reference genome. Differentially expressed gene (DEG) analysis among the three pairwise comparisons resulted in the detection of several genes related to the shoot elongation in temperature-sensitive peach. HSFAs were up-regulated in response to the elevated temperature, while the up-regulated expression of HSPs might influence hormone signaling pathways. Most of DEGs involved in auxin, abscisic acid and jasmonic acid were up-regulated, while some involved in cytokinin and brassinosteroid were down-regulated. Genes related to ethylene, salicylic acid and circadian rhythm were also differentially expressed. Genes related to aquaporins, expansins, pectinesterases and endoglucanase were up-regulated, which would promote cell elongation. These results lay a foundation for further dissection of the regulatory mechanisms underlying shoot elongation at elevated temperatures. [ABSTRACT FROM AUTHOR]

Summary: Plant stature is one important factor that affects the productivity of peach orchards. However, little is known about the molecular mechanism(s) underlying the dwarf phenotype of peach tree. Here, we report a dwarfing mechanism in the peach cv. FenHuaShouXingTao (FHSXT). The dwarf phenotype of 'FHSXT' was caused by shorter cell length compared to the standard cv. QiuMiHong (QMH). 'FHSXT' contained higher endogenous GA levels than did 'QMH' and did not response to exogenous GA treatment (internode elongation). These results indicated that 'FHSXT' is a GA‐insensitive dwarf mutant. A dwarf phenotype‐related single nucleotide mutation in the gibberellic acid receptor GID1 was identified in 'FHSXT' (GID1cS191F), which was also cosegregated with dwarf phenotype in 30 tested cultivars. GID1cS191F was unable to interact with the growth‐repressor DELLA1 even in the presence of GA. 'FHSXT' accumulated a higher level of DELLA1, the degradation of which is normally induced by its interaction with GID1. The DELLA1 protein level was almost undetectable in 'QMH', but not reduced in 'FHSXT' after GA3 treatment. Our results suggested that a nonsynonymous single nucleotide mutation in GID1c disrupts its interaction with DELLA1 resulting in a GA‐insensitive dwarf phenotype in peach. [ABSTRACT FROM AUTHOR]

This article discusses a study on the genome of pillar peach and its implications for certain traits in peach. The researchers used advanced sequencing techniques to analyze the genome of a specific peach variety and identified genetic variations associated with branch angle and flower type. They also discovered mutations in specific genes that are linked to these traits. The findings of this study provide valuable insights into the genetic basis of these traits in peach and can be used for further genetic improvement of the fruit. [Extracted from the article]

Background: Ubiquitin ligases (E3) are the enzymes in the ubiquitin/26S proteasome pathway responsible for targeting proteins to the degradation pathway and play major roles in multiple biological activities. However, the E3 family and their functions are yet to be identified in the fruit of peach. Results: In this study, genome-wide identification, classification and characterization of the E3 ligase genes within the genome of peach (Prunus persica) was carried out. In total, 765 E3 (PpE3) ligase genes were identified in the peach genome. The PpE3 ligase genes were divided into eight subfamilies according to the presence of known functional domains. The RBX subfamily was not detected in peach. The PpE3 ligase genes were not randomly distributed among the 8 chromosomes, with a greater concentration on the longer chromosomes. The primary mode of gene duplication of the PpE3 ligase genes was dispersed gene duplication (DSD). Four subgroups of the BTB subfamily never characterized before were newly identified in peach, namely BTBAND, BTBBL, BTBP and BTBAN. The expression patterns of the identified E3 ligase genes in two peach varieties that display different types of fruit softening (melting flesh, MF, and stony hard, SH) were analyzed at 4 different stages of ripening using Illumina technology. Among the 765 PpE3 ligase genes, 515 (67.3%) were expressed (FPKM > 1) in the fruit of either MF or SH during fruit ripening. In same-stage comparisons, 231 differentially expressed genes (DEGs) were identified between the two peach cultivars. The number of DEGs in each subfamily varied. Most DEGs were members of the BTB, F-box, U-box and RING subfamilies. PpE3 ligase genes predicted to be involved in ethylene, auxin, or ABA synthesis or signaling and DNA methylation were differentially regulated. Eight PpE3 ligase genes with possible roles in peach flesh texture and fruit ripening were discussed. Conclusions: The results of this study provide useful information for further understanding the functional roles of the ubiquitin ligase genes in peach. The findings also provide the first clues that E3 ligase genes may function in the regulation of peach ripening. [ABSTRACT FROM AUTHOR]

• The first manually annotated peach genome based on the transcriptome from 13 individual tissues. • Among the 31,546 gene models, 3981 were adjusted, accounting for 12.6%. • The tissue specific expressed genes were identified at 13 individual tissues. Peach (Prunus persica) is a fruit tree in the Rosaceae family and serves as an ideal plant for research on important agronomic characters due to its modest genome size and moderate chromosome number. The high-quality CN14 (from cultivar 'Zhongyoutao 14′) peach genome was released in 2022. To improve the predicted gene models, RNA-Seq data from 13 individual tissue samples and a tissue mixture were manually compared to the gene models. These newly adjusted gene models (released as CN14 genome, version 2.0) were including total 31546 gene models with a 99.17% BUSCO value. In this v.2.0 annotation, gene models of 3981 transcripts were adjusted, and 742 transcripts were newly added. The number of genes increased from v.1.0 (30181 genes). The newly added and adjusted gene IDs were renamed (Ppv2.XG. XXXXX), while the original names remained for genes with no structural changes. There were 2175 transcription factors/regulators and 1251 protein kinases newly identified. The gene structures of 16 of these genes were verified using RT-PCR, and all were successfully cloned. This updated annotation of the peach genome provides new genes as well as updated gene expression profiles, which will greatly improve gene identification and functional studies in peach. [ABSTRACT FROM AUTHOR]

Polyamines (PAs) are anti-senescence agents that promote maintenance of fruit quality after harvesting. Many studies have reported increases in PA synthesis and catabolism and decreases in PA levels during fruit ripening. However, few reports have addressed the modulation mechanisms of PA metabolism during fruit maturation. In this report, we found that the peach (Prunus persica L.) transcription factor PpeERF115 directly bound to the PpeADC1 and PpePAO1 promoters, activating these genes. Silencing PpeERF115 enhanced spermidine (Spd) and spermine (Spm) accumulation, reduced putrescine (Put) content, decreased ethylene production, suppressed the respiratory rate, promoted maintenance of fruit firmness, and delayed peach ripening. Conversely, fruit over-expressing PpeERF115 showed significantly reduced Spd and Spm accumulation and clear increases in Put levels. RNA-sequencing analysis indicated that PpeADC1 , PpeCuAO2 , and PpePAO1 were dramatically down-regulated in PpeERF115 -known out fruit, whereas PpeSAMDC1 was significantly up-regulated. This study is the first to show that PpeERF115 regulates peach ripening by increasing PA turnover through up-regulation of PA synthesis and catabolism. These results extend our comprehension of the coordination between ethylene and PAs during regulation of fruit maturation. • PpeERF115 up-regulates PAs turnover by activating its synthesis and catabolism. • PpeERF115 directly binds and activates the promoter of PpeADC1 and PpePAO1. • Silencing PpeERF115 increased Spd and Spm accumulation but decreased Put content. • Our work reveals coordination between ethylene and PAs to regulate fruit ripening. [ABSTRACT FROM AUTHOR]

Peach [ Prunus persica (L.) Batsch] annual shoots grow up quickly, which limits the lighting and ventilation of an orchard. Atypical bHLH proteins IBH1(INCREASED LEAF INCLINATION1 BINDING bHLH1) play substantial roles in regulating cell elongation and plant stature. In this study, three PpIBH1s (PpIBH1–1/−2/−3) were identified in peach genome and contain a conserved AS domain and a characteristic HLH domain. The transcript levels of three PpIBH1s positively correlated with internode length, which gradually increased from apex to base along the peach shoots. This positive correlation was further confirmed in apple and poplar shoots. And the PpIBH1s gene were highly expressed in the shoot tips collected from twelve dwarf peach cultivars (gid1c mutants). In tissue-specific expression analysis, PpIBH1–1 are more highly expressed in tissues at the growth-arrested stage than cell-elongating. Transgenic Arabidopsis lines showed that different plant heights depending on the dose of PpIBH1–1 transcripts. And the dwarfing PpIBH1–1 transgenic lines were caused by the shorted cell length. PpIBH1–1 interacted with two bHLH factors (PpACE2 and PpLP1). These results suggested that PpIBH1–1 probably prevents internode elongation of peach shoots in a dose-dependent manner. Our work provided a foundation for properly controlling the growth of annual peach branches. • Peach annual shoots grow up quickly, which limits the lighting and ventilation of an orchard. • PpIBH1-1 was an atypical bHLH protein. • PpIBH1-1 was highly expressed in 12 dwarfed peach cultivars. • PpIBH1-1 was reported to limit internode elongation of peach shoot in a dose-dependent manner in this study. [ABSTRACT FROM AUTHOR]

Rapid growth of branches in a peach tree restricts the light penetration and air ventilation within the orchard, which lowers fruit quality and promotes the occurrence of diseases and insects. Our previous works showed that PpDELLA1 and PpDELLA2 repress the rapid growth of annual shoots. Proteins that interact with DELLA are vital for its function. In this study, seven PpPIFs (PpPIF1 , -2 , -3 , -4 , -6 , -7 and -8) were identified in the peach genome and contain a conserved bHLH domain. Among the seven PpPIFs, PpPIF8 interacted with PpDELLA2 through an unknown motif in the C-terminal and/or the bHLH domain. Overexpression of PpPIF8 in Arabidopsis promotes plant height and branch numbers. Hypocotyl elongation was significantly enhanced by PpPIF8 under weak light intensity. PpPIF8 overexpressed in Arabidopsis and transiently expressed in peach seedlings upregulated the transcription of YUCCA and SAUR19 and downregulated SHY1 and -2. Additionally, PpPIF4 and -8 were significantly induced by weak light. Phylogentic analysis and intron patterns of the bHLH domain strongly suggested that PIFs from six species could be divided into two groups of different evolutionary origins. These results lay a foundation for the further study of the repression of shoot growth by PpDELLA2 through protein interaction with PpPIF8 in peach. • PpPIF8 interacted with PpDELLA2, which probably affects the function of PpPIF8. • Hypocotyl elongation was significantly enhanced by PpPIF8 under weak light intensity • PpPIF8 regulates peach shoot elongation possibly through auxin signaling. [ABSTRACT FROM AUTHOR]

Ethylene and polyamines (PAs) have antagonistic roles during fruit ripening. PAs affect both ethylene biosynthetic and signal transduction pathways, but the regulatory effects of ethylene on PA metabolism during fruit ripening have remained largely unknown. Here, we found that ethylene enhanced PA catabolism by regulating expression of a peach PA oxidase gene, PpePAO1. Knocking out PpePAO1 delayed peach fruit ripening, whereas PpePAO1 overexpression promoted tomato fruit ripening. Both in vitro and in vivo assays demonstrated that an ethylene response factor (ERF), PpeERF113, activated PpePAO1 by direct binding to the promoter. PA levels were significantly increased and ripening was delayed in PpeERF113 knockdown peach fruit. Correspondingly, PA levels were significantly decreased when PpeERF113 was overexpressed in peach. PpeERF113 was also found to be upregulated in PpePAO1 knockdowns, indicating that PA catabolism has a regulatory function in ethylene signal transduction. Together, our results suggest that ethylene accelerates peach fruit ripening in part by promoting PA catabolism through PpeERF113-mediated regulation of PpePAO1 expression. To our knowledge, this is the first report related to the regulatory mechanism of ethylene in PA catabolism during fruit ripening. This study contributes new understanding of the crosstalk between ethylene and PAs during fruit ripening. • Ethylene enhanced PA catabolism by regulating expression of PpePAO1. • Silencing PpePAO1 delayed peach ripening while overexpression it promoted tomato ripening. • PpeERF113 activated the expression of PpePAO1 by direct binding to its promoter. • Ethylene accelerated peach ripening by promoting PA catabolism through PpeERF113. [ABSTRACT FROM AUTHOR]

• GAI / RGA / SCR (GRAS) genes were identified from peach genome. • The 48 PpeGRAS proteins were divided into 13 subfamilies. • Gene expression in shoot tips of normal and dwarf peach cultivars was compared. • Two DEGs, PpeDELLA1 and PpeDELLA2 , showed lower expression in dwarf peach. • Expression of PpeDELLA1 and PpeDELLA2 in Arabidopsis resulted in dwarf phenotypes. The GRAS gene family contains plant-specific transcription factors that play crucial roles in plant growth. In this study, 48 PpeGRAS genes were identified throughout the whole peach genome. They appeared randomly distributed on eight chromosomes. A dispersed gene duplication (DSD, 26 of 48) event was responsible for the GRAS gene family duplication in peach. Phylogenetic analysis among peach, rice, Arabidopsis and poplar showed that the PpeGRAS family was divided into 13 subfamilies. The majority of the PpeGRAS genes did not contain any introns (41, 85.4%), while the remaining seven PpeGRAS genes had one (6, 12.5%) or two (1, 2.1%) introns. Motif analysis indicated that the putative PpeGRAS proteins clustering in the same subgroup share similar motifs. Gene expression analysis in the stem apex of the normal cultivar 'Qiumihong' (QMH) and the dwarf cultivar 'Fenhuashouxingtao' (FHSXT) revealed potential roles of different PpeGRAS genes in peach growth. Two PpeDELLA genes, PpeDELLA1 and PpeDELLA2 , were selected for further functional analysis. The dwarf phenotype was due to shorter average internode length and was also observed in transgenic Arabidopsis lines overexpressing PpeDELLA1 or PpeDELLA2. These findings provide insights into understanding the function of PpeGRAS genes and their potential use in the genetic improvement of peach. [ABSTRACT FROM AUTHOR]