Different postharvest conditions modulate ripening and ethylene biosynthetic and signal transduction pathways in Stony Hard peaches.

Stony hard (SH) peaches are characterized, at ripening, by the maintenance of flesh firmness and the lack of ethylene production due to a reduced expression of Pp-ACS1. In a trial comparing melting flesh (MF, cv. ‘Summer Rich’) and SH (‘IFF331’ selection) fruit at two different postharvest temperatures (10 and 20 ◦C), unexpected behaviour was observed in SH peaches that displayed an increase in ethylene production and a decrease in flesh firmness when stored at 10 ◦C, a temperature regime basically ineffective in delaying ripening in MF fruit. This appeared to be the result of an induction of Pp-ACS1 transcription, making this genotype of particular interest for studying temperature stress physiology and ethylene-related ripening processes in peaches. Comparative expression analyses of genes involved in cell wall metabolism pointed out the presence of a negative (Pp-EG4), positive (Pp-endoPG) or no (one member of the PL family) relationship with ethylene at ripening. Results clearly showed that the last stage of firmness decrease (melting) only occurs in fruit producing ethylene and is associated with Pp-endoPG transcript accumulation. The expression of genes involved in ethylene biosynthesis and signalling pathways was evaluated using QRT-PCR. Pp-ACO1 appeared to be induced in SH kept at 10 ◦C but not at 20 ◦C. Transient increases in Pp-CTR1 and Pp-EIN2like gene expression have only been detected at the early stages of ripening in samples producing ethylene, indicating that a causal relationship might exist between ethylene and elements of its transduction pathway during peach fruit ripening

Transcriptome profiling of ripening nectarine (Prunus persica L. Batsch) fruit treated with 1-MCP

A large-scale transcriptome analysis has been conducted using mPEACH1.0 microarray on nectarine (Prunus persica L. Batsch) fruit treated with 1-methylcyclopropene (1-MCP). 1-MCP maintained flesh firmness but did not block ethylene biosynthesis. Compared with samples at harvest, only nine genes appeared to be differentially expressed when fruit were sampled immediately after treatment, while a total of 90 targets were up- or down-regulated in untreated fruit. The effect of 1-MCP was confirmed by a direct comparison of transcript profiles in treated and untreated fruit after 24 h of incubation with 106 targets differentially expressed. About 30% of these targets correspond to genes involved in primary metabolism and response processes related to ethylene, auxin, and other hormones. In treated fruit, altered transcript accumulation was detected for some genes with a role in ripening-related events such as softening, colour development, and sugar metabolism. A rapid decrease in flesh firmness and an increase in ethylene production were observed in treated fruit maintained for 48 h in air at 20 ºC after the end of the incubation period. Microarray comparison of this sample with untreated fruit 24 h after harvest revealed that about 45% of the genes affected by 1-MCP at the end of the incubation period changed their expression during the following 48 h in air. Among these genes, an ethylene receptor (ETR2) and three ethylene responsive factors (ERF) were present, together with other transcription factors and ethylene-dependent genes involved in quality parameter changes

Individual Shrink Wrapping of Zucchini Fruit Improves Postharvest Chilling Tolerance Associated with a Reduction in Ethylene Production and Oxidative Stress Metabolites

We have studied the effect of individual shrink wrapping (ISW) on the postharvest performance of refrigerated fruit from two zucchini cultivars that differ in their sensitivity to cold storage: Sinatra (more sensitive) and Natura (more tolerant). The fruit was individually shrink wrapped before storing at 4°C for 0, 7 and 14 days. Quality parameters, ethylene and CO2 productions, ethylene gene expression, and oxidative stress metabolites were assessed in shrink wrapped and non-wrapped fruit after conditioning the fruit for 6 hours at 20°C. ISW decreased significantly the postharvest deterioration of chilled zucchini in both cultivars. Weight loss was reduced to less than 1%, pitting symptoms were completely absent in ISW fruit at 7 days, and were less than 25% those of control fruits at 14 days of cold storage, and firmness loss was significantly reduced in the cultivar Sinatra. These enhancements in quality of ISW fruit were associated with a significant reduction in cold-induced ethylene production, in the respiration rate, and in the level of oxidative stress metabolites such as hydrogen peroxide and malonyldialdehyde (MDA). A detailed expression analysis of ethylene biosynthesis, perception and signaling genes demonstrated a downregulation of CpACS1 and CpACO1 genes in response to ISW, two genes that are upregulated by cold storage. However, the expression patterns of six other ethylene biosynthesis genes (CpACS2 to CpACS7) and five ethylene signal transduction pathway genes (CpCTR1, CpETR1, CpERS1, CpEIN3.1 and CpEN3.2), suggest that they do not play a major role in response to cold storage and ISW packaging. In conclusion, ISW zucchini packaging resulted in improved tolerance to chilling concomitantly with a reduction in oxidative stress, respiration rate and ethylene production, as well as in the expression of ethylene biosynthesis genes, but not of those involved in ethylene perception and sensitivity.This work was supported by grants AGL2011-30568-C02/ALI from the Spanish Ministry of Science and Innovation, and AGR1423 from the Consejería de Economía, Innovación y Ciencia, Junta de Andalucía, Spain. Z.M. acknowledges FPU program scholarships from MEC, Spain. S.M. is funded by grant PTA2011-479-I from the Spanish Ministry of Science and Innovation

Pre-symptomatic transcriptome changes during cold storage of chilling sensitive and resistant peach cultivars to elucidate chilling injury mechanisms

Background: Cold storage induces chilling injury (CI) disorders in peach fruit (woolliness/mealiness, flesh browning and reddening/bleeding) manifested when ripened at shelf life. To gain insight into the mechanisms underlying CI, we analyzed the transcriptome of 'Oded' (high tolerant) and 'Hermoza' (relatively tolerant to woolliness, but sensitive to browning and bleeding) peach cultivars at pre-symptomatic stages. The expression profiles were compared and validated with two previously analyzed pools (high and low sensitive to woolliness) from the Pop-DG population. The four fruit types cover a wide range of sensitivity to CI. The four fruit types were also investigated with the ROSMETER that provides information on the specificity of the transcriptomic response to oxidative stress. Results: We identified quantitative differences in a subset of core cold responsive genes that correlated with sensitivity or tolerance to CI at harvest and during cold storage, and also subsets of genes correlating specifically with high sensitivity to woolliness and browning. Functional analysis indicated that elevated levels, at harvest and during cold storage, of genes related to antioxidant systems and the biosynthesis of metabolites with antioxidant activity correlates with tolerance. Consistent with these results, ROSMETER analysis revealed oxidative stress in 'Hermoza' and the progeny pools, but not in the cold resistant 'Oded'. By contrast, cold storage induced, in sensitivity to woolliness dependant manner, a gene expression program involving the biosynthesis of secondary cell wall and pectins. Furthermore, our results indicated that while ethylene is related to CI tolerance, differential auxin subcellular accumulation and signaling may play a role in determining chilling sensitivity/tolerance. In addition, sugar partitioning and demand during cold storage may also play a role in the tolerance/sensitive mechanism. The analysis also indicates that vesicle trafficking, membrane dynamics and cytoskeleton organization could have a role in the tolerance/sensitive mechanism. In the case of browning, our results suggest that elevated acetaldehyde related genes together with the core cold responses may increase sensitivity to browning in shelf life. Conclusions: Our data suggest that in sensitive fruit a cold response program is activated and regulated by auxin distribution and ethylene and these hormones have a role in sensitivity to CI even before fruit are cold stored.This research was funded by US-Israel Binational Agriculture Research and Development Fund (BARD) Grant no. US-4027-07. We thank the European Science Foundation for Short Term Scientific Mission grants to A. Dagar (COST Action 924, reference codes COST-STSM-924-04254 and Quality Fruit COST FA1106 for networking.Pons Puig, C.; Dagar, A.; Martí Ibáñez, MC.; Singh, V.; Crisosto, CH.; Friedman, H.; Lurie, S.... (2015). Pre-symptomatic transcriptome changes during cold storage of chilling sensitive and resistant peach cultivars to elucidate chilling injury mechanisms. BMC Genomics. 16:1-35. https://doi.org/10.1186/s12864-015-1395-6S13516Crisosto C, Mitchell F, Ju Z. Susceptibility to chilling injury of peach, nectarine, and plum cultivars grown in California. Hort Sci. 1999;34:1116–8.Lurie S, Crisosto C. Chilling injury in peach and nectarine. Postharvest Biol Technol. 2005;37:195–208.Crisosto C, Mitchell F, Johnson S. Factors in fresh market stone fruit quality. Postharvest News Inform. 1995;6(2):17–21.Dawson DM, Melton LD, Watkins CB. Cell wall changes in nectarines (Prunus persica): solubilization and depolymerization of pectic and neutral polymers during ripening and in mealy fruit. Plant Physiol. 1992;100(3):1203–10.Zhou H, Sonego L, Khalchitski A, Ben Arie R, Lers A, Lurie A. Cell wall enzymes and cell wall changes in ‘Flavortop’ nectarines: mRNA abundance, enzyme activity, and changes in pectic and neutral polymers during ripening and in woolly fruit. J Am Soc Hort Sci. 2000;125:630–7.Jarvis MC, Briggs SPH, Knox JP. Intercellular adhesion and cell separation in plants. Plant Cell Environ. 2003;26(7):977–89.Zhou H, Ben-Arie R, Lurie S. Pectin esterase, polygalacturonase and gel formation in peach pectin fractions. Phytochemistry. 2000;55(3):191–5.Brummell DA, Dal Cin V, Lurie S, Crisosto CH, Labavitch JM. Cell wall metabolism during the development of chilling injury in cold-stored peach fruit: association of mealiness with arrested disassembly of cell wall pectins. J Exp Bot. 2004;55(405):2041–52.Kader AA, Chordas A. Evaluating the browning potential of peaches. Calif Agric. 1984;38:14–5.Cevallos-Casals BA, Byrne D, Okie WR, Cisneros-Zevallos L. Selecting new peach and plum genotypes rich in phenolic compounds and enhanced functional properties. Food Chem. 2006;96(2):273–80.Rojas G, Méndez MA, Muñoz C, Lemus G, Hinrichsen P. Identification of a minimal microsatellite marker panel for the fingerprinting of peach and nectarine cultivars. Electron J Biotechnol. 2008;11:4–5.Scorza R, Sherman WB, Lightner GW. Inbreeding and co-ancestry of low chill short fruit development period freestone peaches and nectarines produced by the University of Florida breeding program. Fruit Varieties J. 1988;43:79–85.Brooks R, Olmo HP. Register of New Fruit and Nut Varieties, 2nd edition edn: Univ of California Press; 1972.Okie WR, Service USAR. Handbook of peach and nectarine varieties: performance in the southeastern United States and index of names: U.S. Dept. of Agriculture, Agricultural Research Service; 1998Martínez-García P, Peace C, Parfitt D, Ogundiwin E, Fresnedo-Ramírez J, Dandekar A, et al. Influence of year and genetic factors on chilling injury susceptibility in peach (Prunus persica (L.) Batsch). Euphytica. 2012;185(2):267–80.Ogundiwin E, Martí C, Forment J, Pons C, Granell A, Gradziel T, et al. Development of ChillPeach genomic tools and identification of cold-responsive genes in peach fruit. Plant Mol Biol. 2008;68(4–5):379–97.Pons C, Martí C, Forment J, Crisosto CH, Dandekar AM, Granell A. A Bulk Segregant Gene Expression Analysis of a Peach Population Reveals Components of the Underlying Mechanism of the Fruit Cold Response. PLoS ONE. 2014;9(3):e90706.Rosenwasser S, Fluhr R, Joshi JR, Leviatan N, Sela N, Hetzroni A, et al. ROSMETER: A Bioinformatic Tool for the Identification of Transcriptomic Imprints Related to Reactive Oxygen Species Type and Origin Provides New Insights into Stress Responses. Plant Physiol. 2013;163(2):1071–83.Kader AA, Mitchell FG. Maturity and quality. In: James H. LaRue RSJ, vol. Publication No. 3331, editor. Peaches, Plums, and Nectarines: Growing and Handling for Fresh Market. Oakland, Calif: Cooperative Extension, University of California, Division of Agriculture and Natural Resources; 1989. p. 191–6.Dagar A, Friedman H, Lurie S. Thaumatin-like proteins and their possible role in protection against chilling injury in peach fruit. Postharvest Biol Technol. 2010;57(2):77–85.Lill RE, Van Der Mespel GJ. A method for measuring the juice content of mealy nectarines. Sci Hortic. 1988;36(3–4):267–71.Tusher VG, Tibshirani R, Chu G. Significance analysis of microarrays applied to the ionizing radiation response. Proc Natl Acad Sci. 2001;98(9):5116–21.Pavlidis P, Noble WS. Matrix2png: a utility for visualizing matrix data. Bioinformatics. 2003;1-9(2):295–6.Dagar A, Pons Puig C, Marti Ibanez C, Ziliotto F, Bonghi CH, Crisosto C, et al. Comparative transcript profiling of a peach and its nectarine mutant at harvest reveals differences in gene expression related to storability. Tree Genet Genomes. 2013;9(1):223–35.Doherty CJ, Van Buskirk HA, Myers SJ, Thomashow MF. Roles for Arabidopsis CAMTA transcription factors in cold-regulated gene expression and freezing tolerance. Plant Cell. 2009;21(3):972–84.Gilmour S, Zarka D, Stockinger E, Salazar M, Houghton J, Thomashow M. Low temperature regulation of the Arabidopsis CBF family of AP2 transcriptional activators as an early step in cold-induced COR gene expression. Plant J. 1998;16(4):433–42.Dong L, Zhou H-W, Sonego L, Lers A, Lurie S. Ethylene involvement in the cold storage disorder of ‘Flavortop’ nectarine. Postharvest Biol Technol. 2001;23(2):105–15.Zhou H-W, Dong L, Ben-Arie R, Lurie S. The role of ethylene in the prevention of chilling injury in nectarines. J Plant Physiol. 2001;158(1):55–61.Kilian J, Whitehead D, Horak J, Wanke D, Weinl S, Batistic O, et al. The AtGenExpress global stress expression data set: protocols, evaluation and model data analysis of UV-B light, drought and cold stress responses. Plant J. 2007;50(2):347–63.Giraldo E, Díaz A, Corral JM, García A. Applicability of 2-DE to assess differences in the protein profile between cold storage and not cold storage in nectarine fruits. J Proteome. 2012;75(18):5774–82.Obenland D, Vensel W, Hurkman Ii W. Alterations in protein expression associated with the development of mealiness in peaches. J Hortic Sci Biotechnol. 2008;83(1):85–93.Vizoso P, Meisel L, Tittarelli A, Latorre M, Saba J, Caroca R, et al. Comparative EST transcript profiling of peach fruits under different post-harvest conditions reveals candidate genes associated with peach fruit quality. BMC Genomics. 2009;10(1):423.Hannah M, Heyer A, Hincha D. A Global Survey of Gene Regulation during Cold Acclimation in Arabidopsis thaliana. PLoS Genet. 2005;1(2):e26.Walia H, Wilson C, Condamine P, Liu X, Ismail AM, Zeng L, et al. Comparative Transcriptional Profiling of Two Contrasting Rice Genotypes under Salinity Stress during the Vegetative Growth Stage. Plant Physiol. 2005;139(2):822–35.Lurie S, Zhou H-W, Lers A, Sonego L, Alexandrov S, Shomer I. Study of pectin esterase and changes in pectin methylation during normal and abnormal peach ripening. Physiol Plant. 2003;119(2):287–94.Peace C, Crisosto C, Gradziel T. Endopolygalacturonase: A candidate gene for Freestone and Melting flesh in peach. Mol Breed. 2005;16(1):21–31.Luza JG, van Gorsel R, Polito VS, Kader AA. Chilling Injury in Peaches: A Cytochemical and Ultrastructural Cell Wall Study. J Am Soc Hortic Sci. 1992;117(1):114–8.Masia A, Zanchin A, Rascio N, Ramina A. Some Biochemical and Ultrastructural Aspects of Peach Fruit Development. J Am Soc Hortic Sci. 1992;117(5):808–15.Dean GH, Zheng H, Tewari J, Huang J, Young DS, Hwang YT, et al. The Arabidopsis MUM2 Gene Encodes a β-Galactosidase Required for the Production of Seed Coat Mucilage with Correct Hydration Properties. Plant Cell Online. 2007;19(12):4007–21.Johnson CS, Kolevski B, Smyth DR. TRANSPARENT TESTA GLABRA2, a Trichome and Seed Coat Development Gene of Arabidopsis, Encodes a WRKY Transcription Factor. Plant Cell Online. 2002;14(6):1359–75.Karssen CM, der Swan DLC B-v, Breekland AE, Koornneef M. Induction of dormancy during seed development by endogenous abscisic acid: studies on abscisic acid deficient genotypes of Arabidopsis thaliana (L.) Heynh. Planta. 1983;157(2):158–65.Bui M, Lim N, Sijacic P, Liu Z. LEUNIG_HOMOLOG and LEUNIG Regulate Seed Mucilage Extrusion in ArabidopsisF. J Integr Plant Biol. 2011;53(5):399–408.Hussey S, Mizrachi E, Spokevicius A, Bossinger G, Berger D, Myburg A. SND2, a NAC transcription factor gene, regulates genes involved in secondary cell wall development in Arabidopsis fibres and increases fibre cell area in Eucalyptus. BMC Plant Biol. 2011;11(1):173.Jin H, Cominelli E, Bailey P, Parr A, Mehrtens F, Jones J, et al. Transcriptional repression by AtMYB4 controls production of UV‐protecting sunscreens in Arabidopsis. EMBO J. 2000;19(22):6150–61.Romera-Branchat M, Ripoll JJ, Yanofsky MF, Pelaz S. The WOX13 homeobox gene promotes replum formation in the Arabidopsis thaliana fruit. Plant J. 2013;73(1):37–49.Itkin M, Seybold H, Breitel D, Rogachev I, Meir S, Aharoni A. TOMATO AGAMOUS-LIKE 1 is a component of the fruit ripening regulatory network. Plant J. 2009;60(6):1081–95.Bemer M, Karlova R, Ballester AR, Tikunov YM, Bovy AG, Wolters-Arts M, et al. The Tomato FRUITFULL Homologs TDR4/FUL1 and MBP7/FUL2 Regulate Ethylene-Independent Aspects of Fruit Ripening. Plant Cell Online. 2012;24(11):4437–51.Jaakola L, Poole M, Jones MO, Kämäräinen-Karppinen T, Koskimäki JJ, Hohtola A, et al. A SQUAMOSA MADS Box Gene Involved in the Regulation of Anthocyanin Accumulation in Bilberry Fruits. Plant Physiol. 2010;153(4):1619–29.Ogundiwin EA, Peace CP, Nicolet CM, Rashbrook VK, Gradziel TM, Bliss FA, et al. Leucoanthocyanidin dioxygenase gene (PpLDOX): a potential functional marker for cold storage browning in peach. Tree Genetics Genomes. 2008;4(3):543–54.Baxter IR, Young JC, Armstrong G, Foster N, Bogenschutz N, Cordova T, et al. A plasma membrane H + −ATPase is required for the formation of proanthocyanidins in the seed coat endothelium of Arabidopsis thaliana. Proc Natl Acad Sci U S A. 2005;102(7):2649–54.Cheng GW, Crisosto CH. Browning Potential, Phenolic Composition, and Polyphenoloxidase Activity of Buffer Extracts of Peach and Nectarine Skin Tissue. J Am Soc Hortic Sci. 1995;120(5):835–8.Wang Y-S, Tian S-P, Xu Y. Effects of high oxygen concentration on pro- and anti-oxidant enzymes in peach fruits during postharvest periods. Food Chem. 2005;91(1):99–104.Sevillano L, Sanchez-Ballesta MT, Romojaro F, Flores FB. Physiological, hormonal and molecular mechanisms regulating chilling injury in horticultural species. Postharvest technologies applied to reduce its impact. J Sci Food Agric. 2009;89(4):555–73.Provart NJ, Gil P, Chen W, Han B, Chang HS, Wang X, et al. Gene expression phenotypes of Arabidopsis associated with sensitivity to low temperatures. Plant Physiol. 2003;132(2):893–906.Prasad T, Anderson M, Stewart C. Acclimation, Hydrogen Peroxide, and Abscisic Acid Protect Mitochondria against Irreversible Chilling Injury in Maize Seedlings. Plant Physiol. 1994;105(2):619–27.Mhamdi A, Queval G, Chaouch S, Vanderauwera S, Van Breusegem F, Noctor G. Catalase function in plants: a focus on Arabidopsis mutants as stress-mimic models. J Exp Bot. 2010;61(15):4197–220.Ulmasov T, Murfett J, Hagen G, Guilfoyle TJ. Aux/IAA proteins repress expression of reporter genes containing natural and highly active synthetic auxin response elements. Plant Cell Online. 1997;9(11):1963–71.Schepetilnikov M, Dimitrova M, Mancera E, Martínez AG, Keller M, Ryabova LA. TOR and S6K1 promote translation reinitiation of uORF containing mRNAs via phosphorylation of eIF3h. EMBO J. 2013;32(8):1087–102.Xiong Y, Sheen J. The Role of Target of Rapamycin Signaling Networks in Plant Growth and Metabolism. Plant Physiol. 2014;164(2):499–512.Murray JAH, Jones A, Godin C, Traas J. Systems Analysis of Shoot Apical Meristem Growth and Development: Integrating Hormonal and Mechanical Signaling. Plant Cell Online. 2012;24(10):3907–19.Leiber R-M, John F, Verhertbruggen Y, Diet A, Knox JP, Ringli C. The TOR Pathway Modulates the Structure of Cell Walls in Arabidopsis. Plant Cell Online. 2010;22(6):1898–908.Garcia-Hernandez M, Davies E, Baskin TI, Staswick PE. Association of Plant p40 Protein with Ribosomes Is Enhanced When Polyribosomes Form during Periods of Active Tissue Growth. Plant Physiol. 1996;111(2):559–68.Cunningham JT, Rodgers JT, Arlow DH, Vazquez F, Mootha VK, Puigserver P. mTOR controls mitochondrial oxidative function through a YY1-PGC-1[agr] transcriptional complex. Nature. 2007;450(7170):736–40.Baur AH, Yang SF. Methionine metabolism in apple tissue in relation to ethylene biosynthesis. Phytochemistry. 1972;11(11):3207–14.Peiser GD, Wang T-T, Hoffman NE, Yang SF, Liu H-w, Walsh CT. Formation of cyanide from carbon 1 of 1-aminocyclopropane-1-carboxylic acid during its conversion to ethylene. Proc Natl Acad Sci. 1984;81(10):3059–63.Begheldo M, Manganaris GA, Bonghi C, Tonutti P. Different postharvest conditions modulate ripening and ethylene biosynthetic and signal transduction pathways in Stony Hard peaches. Postharvest Biol Technol. 2008;48(1):8–8.Shi Y, Tian S, Hou L, Huang X, Zhang X, Guo H, et al. Ethylene signaling negatively regulates freezing tolerance by repressing expression of CBF and type-A ARR genes in Arabidopsis. Plant Cell. 2012;24(6):2578–95.Thain SC, Vandenbussche F, Laarhoven LJJ, Dowson-Day MJ, Wang Z-Y, Tobin EM, et al. Circadian Rhythms of Ethylene Emission in Arabidopsis. Plant Physiol. 2004;136(3):3751–61.Wang KLC, Yoshida H, Lurin C, Ecker JR. Regulation of ethylene gas biosynthesis by the Arabidopsis ETO1 protein. Nature. 2004;428(6986):945–50.Zheng Z, Guo Y, Novák O, Dai X, Zhao Y, Ljung K, et al. Coordination of auxin and ethylene biosynthesis by the aminotransferase VAS1. Nat Chem Biol. 2013;9(4):244–6.Poschet G, Hannich B, Raab S, Jungkunz I, Klemens PAW, Krueger S, et al. A Novel Arabidopsis Vacuolar Glucose Exporter is involved in cellular Sugar Homeostasis and affects Composition of Seed Storage Compounds. Plant Physiol. 2011;157(4):1664–76.Wang K, Shao X, Gong Y, Zhu Y, Wang H, Zhang X, et al. The metabolism of soluble carbohydrates related to chilling injury in peach fruit exposed to cold stress. Postharvest Biol Technol. 2013;86:53–61.Liu Y-H, Offler CE, Ruan Y-L. Regulation of fruit and seed response to heat and drought by sugars as nutrients and signals. Frontiers Plant Sci. 2013;4:282.Coello P, Hey SJ, Halford NG. The sucrose non-fermenting-1-related (SnRK) family of protein kinases: potential for manipulation to improve stress tolerance and increase yield. J Exp Bot. 2011;62(3):883–93.Baena-González E, Sheen J. Convergent energy and stress signaling. Trends Plant Sci. 2008;13(9):474–82.Baena-González E. Energy Signaling in the Regulation of Gene Expression during Stress. Mol Plant. 2010;3(2):300–13.Robaglia C, Thomas M, Meyer C. Sensing nutrient and energy status by SnRK1 and TOR kinases. Curr Opin Plant Biol. 2012;15(3):301–7.Uemura M, Joseph RA, Steponkus PL. Cold Acclimation of Arabidopsis thaliana (Effect on Plasma Membrane Lipid Composition and Freeze-Induced Lesions). Plant Physiol. 1995;109(1):15–30.Zhang C, Tian S. Crucial contribution of membrane lipids’ unsaturation to acquisition of chilling-tolerance in peach fruit stored at 0°c. Food Chem. 2009;115(2):405–11.Abdrakhamanova A, Wang QY, Khokhlova L, Nick P. Is Microtubule Disassembly a Trigger for Cold Acclimation? Plant Cell Physiol. 2003;44(7):676–86.Baluška F, Hlavacka A, Šamaj J, Palme K, Robinson DG, Matoh T, et al. F-Actin-Dependent Endocytosis of Cell Wall Pectins in Meristematic Root Cells. Insights from Brefeldin A-Induced Compartments. Plant Physiology. 2002;130(1):422–31.Baluška F, Liners F, Hlavačka A, Schlicht M, Van Cutsem P, McCurdy DW, et al. Cell wall pectins and xyloglucans are internalized into dividing root cells and accumulate within cell plates during cytokinesis. Protoplasma. 2005;225(3–4):141–55.Gonzalez-Aguero M, Pavez L, Ibanez F, Pacheco I, Campos-Vargas R, Meisel L, et al. Identification of woolliness response genes in peach fruit after post-harvest treatments. J Exp Bot. 2008;59(8):1973–86.Bashline L, Lei L, Li S, Gu Y. Cell Wall, Cytoskeleton, and Cell Expansion in Higher Plants. Mol Plant. 2014;4:586–600.Dhonukshe P, Grigoriev I, Fischer R, Tominaga M, Robinson DG, Hašek J, et al. Auxin transport inhibitors impair vesicle motility and actin cytoskeleton dynamics in diverse eukaryotes. Proc Natl Acad Sci. 2008;105(11):4489–94.Fischer U, Men S, Grebe M. Lipid function in plant cell polarity. Curr Opin Plant Biol. 2004;7(6):670–6.Schrick K, Fujioka S, Takatsuto S, Stierhof Y-D, Stransky H, Yoshida S, et al. A link between sterol biosynthesis, the cell wall, and cellulose in Arabidopsis. Plant J. 2004;38(2):227–43.Cheng GW, Crisosto CH. Iron—Polyphenol Complex Formation and Skin Discoloration in Peaches and Nectarines. J Am Soc Hortic Sci. 1997;122(1):95–9.Bouché N, Fait A, Zik M, Fromm H. The root-specific glutamate decarboxylase (GAD1) is essential for sustaining GABA levels in Arabidopsis. Plant Mol Biol. 2004;55(3):315–25.Pedreschi R, Franck C, Lammertyn J, Erban A, Kopka J, Hertog M, et al. Metabolic profiling of ‘Conference’ pears under low oxygen stress. Postharvest Biol Technol. 2009;51(2):123–30

Use of genomics tools to study peach fruit postharvest physiology

Peach and nectarine fruit ripen and deteriorate quickly and even at refrigerated temperature their storage life rarely exceeds 4-5 weeks making these fruit types interesting to study in terms of ripening and postharvest physiology. In this context, biochemical and one-to-one-at-a-time gene expression studies are now paralleled by large-scale analyses and genomics approaches using high throughput tools as the first peach microarray (\ub5PEACH1.0) developed by the Italian Consortium for Genomics Studies in Prunus (ESTree Consortium). \ub5PEACH1.0 has been used to study the transition from pre-climacteric to climacteric stage and to better characterize the role of ethylene in this fruit species. New genes and basic mechanisms involved in ethylene perception, and in the definition and evolution of quality traits as colour and flesh firmness have been identified. Differently from other fruit species (e.g., apple), 1-methylcyclopropene (1-MCP) has only a limited effect in delaying peach fruit ripening: in order to elucidate the mechanisms responsible for this behaviour, transcriptome analyses have been performed and genes showing differential hybridisations have been grouped according to their expression pattern following 1-MCP treatment. The comparison of transcript profiles in peaches at the transition from immature to mature stage, and following treatment with 1-MCP or exogenous ethylene allowed to identify gene ripening- and/or ethylene-regulated in this fruit species and comparatively assess the influence of ethylene on specific metabolic pathways

Molecular and genetic aspects of ripening and qualitative traits of peach and nectarine fruits

Expressed Sequence Tags (ESTs) and cDNA-AFLP analysis have been used to study gene expression during peach fruit ripening. An EST repertoire (1007 sequences) has been constructed using transcripts in nectarine fruit cv. \u2018Fantasia\u2019 at climacteric stage. The EST repertoire was reduced to 696 unigenes: in these 579 (83%) were singletons. EST analysis confirmed that in peach ripe fruit, genes involved in ethylene biosynthesis and cell wall metabolism are highly represented. Three transcription factors (TFs) homologous to SEPALLATA3, atb2, bHLH61 belonging to MADS, bZIP and bHLH families, respectively, have been identified. The abundance of the related transcripts suggests that these TFs play a regulatory role of ripening, as reporter in other fruits species. The EST repertoire has been included in a sequence database assembled by the Italian Consortium for Prunus spp genomic study to generate the first peach fruit microarray (\ub5PEACH 1.0). EST analysis has been integrated with cDNA-AFLP to study a selection of the nectarine cv. \u2018Fantasia\u2019, named slr, characterized by a block of ripening. Data pointed out that the slr fruit phenotype might be due to disturbance in the onset of senescence