Global Transcriptome Analysis of the Peach (Prunus persica) in the Interaction System of Fruit-Chitosan-Monilinia fructicola

The peach (Prunus persica L.) is one of the most important stone-fruit crops worldwide. Nevertheless, successful peach fruit production is seriously reduced by losses due to Monilinia fructicola the causal agent of brown rot. Chitosan has a broad spectrum of antimicrobial properties and may also act as an elicitor that activate defense responses in plants. As little is known about the elicitation potential of chitosan in peach fruits and its impact at their transcriptional-level profiles, the aim of this study was to uncover using RNA-seq the induced responses regulated by the action of chitosan in fruit-chitosan-M. fructicola interaction. Samples were obtained from fruits treated with chitosan or inoculated with M. fructicola, as well from fruits pre-treated with chitosan and thereafter inoculated with the fungus. Chitosan was found to delay the postharvest decay of fruits, and expression profiles showed that its defense-priming effects were mainly evident after the pathogen challenge, driven particularly by modulations of differentially expressed genes (DEGs) related to cell-wall modifications, pathogen perception, and signal transduction, preventing the spread of fungus. In contrast, as the compatible interaction of fruits with M. fructicola was challenged, a shift towards defense responses was triggered with a delay, which was insufficient to limit fungal expansion, whereas DEGs involved in particular processes have facilitated early pathogen colonization. Physiological indicators of peach fruits were also measured. Additionally, expression profiles of particular M. fructicola genes highlight the direct antimicrobial activity of chitosan against the fungus. Overall, the results clarify the possible mechanisms of chitosan-mediated tolerance to M. fructicola and set new foundations for the potential employment of chitosan in the control of brown rot in peaches.

Recent Approaches to the Formulation, Uses, and Impact of Edible Coatings on Fresh Peach Fruit

Peaches are among the most well-known fruits in the world due to their appealing taste and high nutritional value. Peach fruit, on the other hand, has a variety of postharvest quality issues like chilling injury symptoms, internal breakdown, weight loss, decay, shriveling, and over-ripeness, which makes a challenging environment for industries and researchers to develop sophisticated strategies for fruit quality preservation and extending shelf life. All over the world, consumers prefer excellent-quality, high-nutritional-value, and long-lasting fresh fruits that are free of chemicals. An eco-friendly solution to this issue is the coating and filming of fresh produce with natural edible materials. The edible coating utilization eliminates the adulteration risk, presents fruit hygienically, and improves aesthetics. Coatings are used in a way that combines food chemistry and preservation technology. This review, therefore, examines a variety of natural coatings (proteins, lipids, polysaccharides, and composite) and their effects on the quality aspects of fresh peach fruit, as well as their advantages and mode of action. From this useful information, the processors could benefit in choosing the suitable edible coating material for a variety of fresh peach fruits and their application on a commercial scale. In addition, prospects of the application of natural coatings on peach fruit and gaps observed in the literature are identified.

Virtual Cold Chain Method to Evaluate the Effect of Rising Temperature on the Quality Evolution of Peach Fruit

Poor temperature management along a cold chain leads to fruit quality deterioration and loss. In order to determine the threshold value of temperature fluctuation in a cold chain, peach fruits were stored in four different virtual cold chains applying different temperature-time scenarios. Core temperature profiling, the physicochemical qualities, and the activities of the peaches' antioxidant enzymes were monitored during cold storage and shelf life. Abusive temperature management (temperature increased to 20 and 15 °C three times) resulted in a significant increase in a peach's core temperature to the highest temperature measured: 17.6 °C. The ethylene production rate at the end of the shelf life of peaches under these temperatures was 21.03-28.16% higher than the constant-temperature group and accompanied by significantly lower levels of flesh firmness, titratable acid content, total phenol and flavonoid content, and peroxidase (POD) and catalase (CAT) activities (p < 0.05). The results of a principal component analysis (PCA) and heatmap confirmed the results. Limited temperature increases (10 °C) in a cold chain had little impact on the quality of the peaches, while temperature increases higher than 15 °C three times would negatively affect the quality of the peaches significantly. The temperature of a cold chain needs to be controlled precisely to reduce the loss of peaches.

Transcriptome Co-Expression Network Analysis of Peach Fruit with Different Sugar Concentrations Reveals Key Regulators in Sugar Metabolism Involved in Cold Tolerance

Peach fruits are known to be highly susceptible to chilling injury (CI) during low-temperature storage, which has been linked to the level of sugar concentration in the fruit. In order to better understand the relationship between sugar metabolism and CI, we conducted a study examining the concentration of sucrose, fructose, and glucose in peach fruit with different sugar concentrations and examined their relationship with CI. Through transcriptome sequencing, we screened the functional genes and transcription factors (TFs) involved in the sugar metabolism pathway that may cause CI in peach fruit. Our results identified five key functional genes (PpSS, PpINV, PpMGAM, PpFRK, and PpHXK) and eight TFs (PpMYB1/3, PpMYB-related1, PpWRKY4, PpbZIP1/2/3, and PpbHLH2) that are associated with sugar metabolism and CI development. The analysis of co-expression network mapping and binding site prediction identified the most likely associations between these TFs and functional genes. This study provides insights into the metabolic and molecular mechanisms regulating sugar changes in peach fruit with different sugar concentrations and presents potential targets for breeding high-sugar and cold-tolerant peach varieties.

A New Regulatory Network Controls Chilling Injury in Peach Fruit by γ-Aminobutyric Acid

The control of chilling injury in peach fruit by a new regulator network, that exogenous γ-aminobutyric acid (GABA) regulates the metabolisms of polyamines (PAs), the GABA shunt, and proline, is still unclear. This study found that GABA induced an increase in the expression of PpADC and PpODC and a decrease in the expression of PpPAO expression, resulting in the accumulation of PAs. There was also an increase in the expression of PpGAD, which improved GABA content, and an increase in the expression of PpP5CS and PpOAT, which improved proline content. The correlation analysis showed that an increase in PpADC/PpP5CS expression was closely associated with the accumulation of putrescine and that the synergistic increase in the expression of PpODC and PpGAD/PpP5CS/PpOAT was closely related to the accumulation of spermine, proline, and GABA induced by GABA. Importantly, arginine and PpADC played a key role in putrescine accumulation, whereas ornithine and PpODC/PpOAT played a crucial role in the synergistic accumulation of spermine, proline, and GABA induced by GABA. This study provides new information on GABA-induced cold tolerance in peach fruit.

Comparison of Inhibitory Effects of Cinnamic Acid, β-Cyclodextrin, L-Cysteine, and Ascorbic Acid on Soluble and Membrane-Bound Polyphenol Oxidase in Peach Fruit

There has been considerable interest in controlling polyphenol oxidase (PPO) activity to prevent enzymatic browning in foods. However, studies on inhibitions of different forms of PPO are very limited. Thus, this study focuses on the effects of cinnamic acid, β-cyclodextrin, L-cysteine, and ascorbic acid on soluble PPO (sPPO) and membrane-bound PPO (mPPO) in peach fruit. The activity of partially purified sPPO was 3.17 times higher than that of mPPO. However, mPPO was shown to be more stable than sPPO in the presence of inhibitors with different concentrations (i.e., 1, 3, 5 mM); activation of mPPO was found by 5 mM L-cysteine. Both sPPO and mPPO inhibitions were PPO substrate-dependent. Ascorbic acid showed the highest inhibitory effect on both sPPO and mPPO with all studied inhibitors and substrates. The inhibition of 1 mM ascorbic acid on sPPO and mPPO reached 95.42 ± 0.07% and 65.60 ± 1.16%, respectively. β-Cyclodextrin had a direct inhibitory effect only on sPPO, while the other three inhibitors had direct effects on both sPPO and mPPO. Cinnamic acid exhibited a non-competitive inhibition on sPPO and mPPO, with L-cysteine showing the same, though on sPPO. The inhibition of studied inhibitors on sPPO and mPPO is highly related to the substrate environment, type, and concentration of inhibitors. This study provides a basis for the further prevention of peach fruit browning from the perspective of different enzyme forms.

Batsch) and Ectopic Expression of PpCAMTA1 in Arabidopsis camta2,3 Mutant Restore Plant Development

Calmodulin-binding transcription activator (CAMTA) is a transcription factor family containing calmodulin (CaM) binding sites and is involved in plant development. Although CAMTAs in Arabidopsis have been extensively investigated, the functions of CAMTAs remain largely unclear in peaches. In this study, we identified five peach CAMTAs which contained conserved CG-1 box, ANK repeats, CaM binding domain (CaMBD) and IQ motifs. Overexpression in tobacco showed that PpCAMTA1/2/3 were located in the nucleus, while PpCAMTA4 and PpCAMTA5 were located in the plasma membrane. Increased expression levels were observed for PpCAMTA1 and PpCAMTA3 during peach fruit ripening. Expression of PpCAMTA1 was induced by cold treatment and was inhibited by ultraviolet B irradiation (UV-B). Driven by AtCAMTA3 promoter, PpCAMTA1/2/3 were overexpressed in Arabidopsis mutant. Here, we characterized peach PpCAMTA1, representing an ortholog of AtCAMTA3. PpCAMTA1 expression in Arabidopsis complements the developmental deficiencies of the camta2,3 mutant, and restored the plant size to the wild type level. Moreover, overexpressing PpCAMTA1 in camta2,3 mutant inhibited salicylic acid (SA) biosynthesis and expression of SA-related genes, resulting in a susceptibility phenotype to Pst DC3000. Taken together, our results provide new insights for CAMTAs in peach fruit and indicate that PpCAMTA1 is associated with response to stresses during development.

Transcriptome Analysis of Pre-Storage 1-MCP and High CO2-Treated 'Madoka' Peach Fruit Explains the Reduction in Chilling Injury and Improvement of Storage Period by Delaying Ripening

Cold storage of peach fruit at low temperatures may induce chilling injury (CI). Pre-storage 1-MCP and high CO₂ treatments were reported among the methods to ameliorate CI and reduce softening of peach fruit. However, molecular data indicating the changes associated with pre-storage 1-MCP and high CO₂ treatments during cold storage of peach fruit are insufficient. In this study, a comparative analysis of the difference in gene expression and physico-chemical properties of fruit at commercial harvest vs. stored fruit for 12 days at 0 °C (cold-stored (CS), pre-storage 1-MCP+CS, and pre-storage high CO₂+CS) were used to evaluate the variation among treatments. Several genes were differentially expressed in 1-MCP+CS- and CO₂+CS-treated fruits as compared to CS. Moreover, the physico-chemical and sensory data indicated that 1-MCP+CS and CO₂+CS suppressed CI and delayed ripening than the CS, which could lead to a longer storage period. We also identified the list of genes that were expressed commonly and exclusively in the fruit treated by 1-MCP+CS and CO₂+CS and compared them to the fruit quality parameters. An attempt was also made to identify and categorize genes related to softening, physiological changes, and other ripening-related changes. Furthermore, the transcript levels of 12 selected representative genes from the differentially expressed genes (DEGs) in the transcriptome analysis were confirmed via quantitative real-time PCR (qRT-PCR). These results add information on the molecular mechanisms of the pre-storage treatments during cold storage of peach fruit. Understanding the genetic response of susceptible cultivars such as ‘Madoka’ to CI-reducing pre-storage treatments would help breeders release CI-resistant cultivars and could help postharvest technologists to develop more CI-reducing technologies.

A Biochemical and Molecular Study

In the last decades, UV-B radiation has attracted attention due to its potential to increase nutraceutical values of fruit and vegetables, especially by inducing the accumulation of phenolics in a structure-dependent way. However, most current studies have investigated the UV-B-driven changes only in the peel or focusing on individual phenolic classes. Adopting an "-omics" approach, this work aimed to deepen the knowledge about the effects of UV-B radiation on the phenolic profile in the pulp of peach fruit. Based on these considerations, melting flesh yellow peaches (Prunus persica L., cv. Fairtime) were subjected to either a 10- or 60-min UV-B treatment (1.39 and 8.33 kJ m-2, respectively), and sampled at different time points from the exposure. A UHPLC-ESI/QTOF-MS analysis coupled with a phenolics-specific database for the annotation of compounds and a multivariate discriminant analysis revealed a marked effect of UV-B radiation on the phenolic profiles of peach pulp. Particularly, a general, transient increase was observed after 24 h from the irradiation, especially for flavanols, flavonols, and flavones. Such behavior diverges from what was observed in the peel, where an overall increase of phenolics was observed after 36 h from the irradiation. Concerning the flavonols in the pulp, UV-B exposure stimulated a specific accumulation of isorhamnetin and kaempferol derivatives, with variations imposed by the different sugar moiety bound. Anthocyanins, which were the second most abundant flavonoid group after flavonols, displayed a general decrease after 36 h that was not attributable to specific molecules. The UV-B treatments also increased the glycoside/aglycone ratio of flavonols and anthocyanins after 24 h, by increasing the glycoside concentration of both, flavonols and anthocyanins, and decreasing the aglycone concentration of anthocyanins. In support of the biochemical results, targeted gene expression analysis by RT-qPCR revealed an UV-B-induced activation of many genes involved in the flavonoid pathway, e.g., CHS, F3H, F3'H, DFR, as well as some MYB transcription factors and few genes involved in the UV-B perception. Generally, all the flavonoid-related and MYB genes showed a transient UV-B dose-dependent activation after 6 h from the irradiation, similarly to what was observed in the peel.

The Role of IP3 in NO-Enhanced Chilling Tolerance in Peach Fruit

The role of inositol 1,4,5-trisphosphate (IP3) in nitric oxide (NO)-reduced chilling injury (CI) in peach fruit was investigated. The fruit were immersed in sodium nitroprusside (SNP) (NO donor) and neomycin (IP3 inhibitor). Results showed that chilling tolerance was enhanced upon exogenous SNP in postharvest peach fruit. Further, GABA accumulation was stimulated by SNP. The increase in protein expression and activity for enzymes in GABA biosynthesis, including glutamate decarboxylase (GAD), polyamine oxidase (PAO), and amino aldehyde dehydrogenase (AMADH), upon SNP treatment was also observed. Also, the up-regulation of Δ1-pyrroline-5-carboxylate synthetase (P5CS) and ornithine d-aminotransferase (OAT) and the down-regulation of proline dehydrogenase (PDH) were induced by SNP treatment, thereby accelating proline production. Additionally, SNP treatment elevated protein expression and activity of alternative oxidase (AOX). The above effects induced upon SNP were partly weakened by neomycin. Therefore, IP3 mediated NO-activated GABA and proline accumulation as well as AOX, thus inducing chilling tolerance in postharvest peach fruit.

Inositol 1,4,5-Trisphosphate Mediates Nitric-Oxide-Induced Chilling Tolerance and Defense Response in Postharvest Peach Fruit

The function of inositol 1,4,5-trisphosphate (IP3) on nitric oxide (NO)-induced chilling tolerance and defense response in postharvest peach fruit was explored. The postharvest fruit were treated with sodium nitroprusside (SNP, exogenous NO donor), cPTIO (NO scavenger), and neomycin (IP3 inhibitor). It turned out that SNP treatment mitigated chilling injury (CI) and stimulated NO accumulation in postharvest peach fruit. Further, SNP enhanced phosphoinositide-specific phospholipase C (PI-PLC) activity and, thereby, stimulated IP3 prodution. SNP also upregulated the activity and expression of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), glutathione S-transferase (GST), and glutathione reductase (GR). In addition, SNP enhanced the expression of small ubiquitin-like modifier (SUMO) and methionine sulfoxide reductase (MSR) and weakened the activity and expression of lipoxygenase (LOX) and phospholipase D (PLD). These above impacts stimulated by SNP treatment were blocked by the addition of cPTIO and neomycin. Overall, IP3 was involved in NO-enhanced chilling tolerance and defense response in postharvest peach fruit.

Effects of hot air treatment in combination with Pichia guilliermondii on postharvest preservation of peach fruit

BACKGROUND

Antagonistic yeast and hot air treatment are two promising methods for conferring resistance to pathogenic fungi. The study assessed the effectiveness of hot-air treatment (45 °C, 4 h) and antagonistic yeast (Pichia guilliermondii at 10⁸ CFU mL^-1 ) alone or in combination on the two major postharvest diseases (Rhizopus stolonifer and Penicillium expansum), as well as the quality and antioxidant parameters in harvested peaches.

RESULTS

The combination of hot-air treatment and Pichia guilliermondii had notable inhibitory effects on infections in peach fruit wounds. In addition, the individual hot-air treatment or Pichia guilliermondii could improve quality indexes to varying degrees, but the combination of the above two treatments could achieve the highest efficacy. Furthermore, compared with other groups, the combined treatment induced the highest activities of superoxide dismutase and catalase, improved the content of total phenolics and reduced glutathione most obviously. Lastly, the most significant reductions in malondialdehyde content and relative electrical conductivity were observed in the combination-treated fruit.

CONCLUSIONS

The combined treatment could control fungal diseases, besides delay the decline of quality and antioxidant parameters, so as to achieve the purpose of fresh keeping for harvested peach fruit. © 2018 Society of Chemical Industry.

Antagonistic activities of volatiles produced by two Bacillus strains against Monilinia fructicola in peach fruit

BACKGROUND

Brown rot caused by Monilinia fructicola is one of most serious diseases of postharvest peach fruit. The objective of this study was to select effective antagonistic bacteria against Monilinia fructicola and evaluate the effects of these strains against brown rot.

RESULTS

Four bacterial strains producing inhibitory volatile gas against Monilinia fructicola were isolated from the peach rhizosphere soil. The volatiles produced by 12a (Bacillus vallismortis) and 14b (Bacillus altitudinis) showed considerable antagonistic activities. Monilinia fructicola showed 80.3% and 68.4% mycelial growth inhibition and cell damage in the presence of strains 12a and 14b, respectively. The inhibition rate of brown rot in peach fruit fumigated with the culture solution of 12a or 14b reached 77.1% and 50.0%, respectively. The volatile compounds produced by 12a and 14b were identified according to gas chromatographic-mass spectrometric analysis. Among them, 6-methyl-2-heptanone and 2-pentylfuran completely inhibited mycelial growth at 100 µL L^-1 concentration. Cedrol showed strong inhibitory activity against mycelial growth at 100 µg L^-1 and isodecyl methacrylate inhibited growth at high concentration. The inhibition rate of the 50 µL L^-1 artificial mixture of these four volatiles was 59.3% in vitro.

CONCLUSION

These results indicate that the two antagonistic bacteria and some volatiles produced by them have potential value in controlling brown rot in harvested peach fruit. © 2018 Society of Chemical Industry.

Role of Melatonin in Cell-Wall Disassembly and Chilling Tolerance in Cold-Stored Peach Fruit

Melatonin reportedly increases chilling tolerance in postharvest peach fruit during cold storage, but information on its effects on cell-wall disassembly in chilling-injured peaches is limited. In this study, we investigated the role of cell-wall depolymerization in chilling-tolerance induction in melatonin-treated peaches. Treatment with 100 μM melatonin alleviated chilling symptoms (mealiness) characterized by a decrease in fruit firmness and increase in juice extractability in treated peaches during storage. The loss of neutral sugars, such as arabinose and galactose, in both the 1,2-cyclohexylenedinitrilotetraacetic acid (CDTA)- and Na₂CO₃-soluble fractions was observed at 7 days in treated peaches, but the contents increased after 28 days of storage. Atomic-force-microscopy (AFM) analysis revealed that the polysaccharide widths in the CDTA- and Na₂CO₃-soluble fractions in the treated fruit were mainly distributed in a shorter range, as compared with those in the control fruit. In addition, the expression profiles of a series of cell-wall-related genes showed that melatonin treatment maintained the balance between transcripts of PpPME and PpPG, which accompany the up-regulation of several other genes involved in cell-wall disassembly. Taken together, our results suggested that the reduced mealiness by melatonin was probably associated with its positive regulation of numerous cell-wall-modifying enzymes and proteins; thus, the depolymerization of the cell-wall polysaccharides in the peaches treated with melatonin was maintained, and the treated fruit could soften gradually during cold storage.

Exogenous nitric oxide induces disease resistance against Monilinia fructicola through activating the phenylpropanoid pathway in peach fruit

BACKGROUND

Nitric oxide (NO) is a multifunctional signaling molecule involved in plant-induced resistance to disease. The present study aimed to investigate the relationship between disease resistance induced by NO and the phenylpropanoid pathway in peach fruit. The present study investigated the effect of NO on the main enzymes and metabolites of the phenylpropanoid pathway of harvested peach, which are probably related to disease resistance against Monilinia fructicola.

RESULTS

The results showed that treatment with 15 µmol L^-1 NO significantly (P < 0.05) enhanced the activities of phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumaroyl-CoA ligase, chalcone synthase and chalcone isomerase and the expression of their genes. Furthermore, NO treatment significantly (P < 0.05) increased the contents of total phenolics, flavonoids and lignin over the entire storage period and maintained higher total anthocyanin, phenolic acid and anthocyanin contents during the earlier storage period.

CONCLUSION

These results suggest that NO treatment could activate the phenylpropanoid pathway to enhance the activity of related enzymes and the contents of phenylpropanoid metabolites in peach to improve disease resistance and prevent pathogenic invasion. © 2016 Society of Chemical Industry.

Exogenous Melatonin Treatment Increases Chilling Tolerance and Induces Defense Response in Harvested Peach Fruit during Cold Storage

The effect of exogenous melatonin on chilling injury in peach fruit after harvest was investigated. To explore the optimum concentration of melatonin for chilling tolerance induction, peach fruit were treated with 50, 100, or 200 μM melatonin for 120 min and then stored for 28 days at 4 °C. The results showed that application of melatonin at 100 μM was most effective in reducing chilling injury of peach fruit after harvest. Peaches treated with melatonin at this concentration displayed higher levels of extractable juice rate and total soluble solids than the non-treated peaches. In addition, melatonin treatment enhanced expression of PpADC, PpODC, and PpGAD and consequently increased polyamines and γ-aminobutyric acid (GABA) contents. Meanwhile, the upregulated transcripts of PpADC and PpODC and inhibited PpPDH expression resulted in the higher proline content in melatonin-treated fruit compared to the control fruit. Our results revealed that melatonin treatment may be a useful technique to alleviate chilling injury in cold-stored peach fruit. The chilling tolerance of harvested peaches induced by melatonin treatment is associated with higher levels of polyamine, GABA, and proline. These data provided here are the first protective evidence of exogenous melatonin in harvested horticultural products in response to direct chilling stress.

Two ω-3 FADs Are Associated with Peach Fruit Volatile Formation

Aroma-related volatiles, together with sugars and acids, play an important role in determining fruit flavor quality. Characteristic volatiles of peach fruit are mainly derived from fatty acids such as linoleic acid (18:2) and linolenic acid (18:3). In the present study, six genes encoding fatty acid desaturases (FAD) were cloned, including two ω-6 FAD genes (PpFAD2, PpFAD6) and four ω-3 FAD genes (PpFAD3-1, PpFAD3-2, PpFAD7 and PpFAD8). Heterologous expression of peach FADs in tobacco plants showed that PpFAD3-1, and PpFAD3-2 significantly reduced contents of 18:2, and accumulated significant higher levels of 18:3. In the case of volatiles, transgenic plants produced lower concentrations of hexanal and higher levels of (E)-2-hexenal. Consequently, the ratio of the (E)-2-hexenal and hexanal was about 5- and 3-fold higher than that of wild type (WT) in PpFAD3-1 and PpFAD3-2 transformants, respectively. No significant changes in volatile profiles were observed in transgenic plants overexpressing the four other peach FAD genes. Real-time quantitative polymerase chain reaction (qPCR) analysis showed that ripe fruit had high PpFAD3-1 and low PpFAD3-2 transcript levels. In contrast, high PpFAD3-2 and low PpFAD3-1 transcript levels were observed in young fruit. These results indicate a temporal regulation of these two ω-3 FADs during development and ripening, influencing peach fruit volatile formation.

Differential Metabolic Rearrangements after Cold Storage Are Correlated with Chilling Injury Resistance of Peach Fruits

Reconfiguration of the metabolome is a key component involved in the acclimation to cold in plants; however, few studies have been devoted to the analysis of the overall metabolite changes after cold storage of fruits prior to consumption. Here, metabolite profiling of six peach varieties with differential susceptibility to develop mealiness, a chilling-injury (CI) symptom, was performed. According to metabolic content at harvest; after cold treatment; and after ripening, either following cold treatment or not; peach fruits clustered in distinct groups, depending on harvest-time, cold treatment, and ripening state. Both common and distinct metabolic responses among the six varieties were found; common changes including dramatic galactinol and raffinose rise; GABA, Asp, and Phe increase; and 2-oxo-glutarate and succinate decrease. Raffinose content after long cold treatment quantitatively correlated to the degree of mealiness resistance of the different peach varieties; and thus, raffinose emerges as a candidate biomarker of this CI disorder. Xylose increase after cold treatment was found only in the susceptible genotypes, indicating a particular cell wall reconfiguration of these varieties while being cold-stored. Overall, results indicate that peach fruit differential metabolic rearrangements due to cold treatment, rather than differential metabolic priming before cold, are better related with CI resistance. The plasticity of peach fruit metabolism renders it possible to induce a diverse metabolite array after cold, which is successful, in some genotypes, to avoid CI.