MaMADS2 repression in banana fruits modifies hormone synthesis and signalling pathways prior to climacteric stage

Background: While the role of ethylene in fruit ripening has been widely studied, the contributions of additional plant hormones are less clear. Here we examined the interactions between the transcription factor MaMADS2-box which plays a major role in banana fruit ripening and hormonal regulation. Specifically, we used MaMADS2 repressed lines in transcriptome and hormonal analyses throughout ripening and assessed hormone and gene expression perturbations as compared to wild-type (WT) control fruit. Results: Our analyses revealed major differences in hormones levels and in expression of hormone synthesis and signaling genes mediated by MaMADS2 especially in preclimacteric pulp. Genes encoding ethylene biosynthesis enzymes had lower expression in the pulp of the repressed lines, consistent with reduced ethylene production. Generally, the expression of other hormone (auxin, gibberellins, abscisic acid, jasmonic acid and salicylic acid) response pathway genes were down regulated in the WT pulp prior to ripening, but remained high in MaMADS2 repressed lines. Hormone levels of abscisic acid were also higher, however, active gibberellin levels were lower and auxin levels were similar with MaMADS2 repression as compared to WT. Although abscisic level was higher in MaMADS2 repression, exogenous abscisic acid shortened the time to ethylene production and increased MaMADS2 mRNA accumulation in WT. Exogenous ethylene did not influence abscisic acid level. CRE - a cytokinin receptor, increased its expression during maturation in WT and was lower especially at prebreaker in the repressed line and zeatin level was lower at mature green of the repressed line in comparison to WT. Conclusions: In addition to previously reported effects of MaMADS2 on ethylene, this transcription factor also influences other plant hormones, particularly at the pre-climacteric stage. The cytokinin pathway may play a previously unanticipated role via MaMADS2 in banana ripening. Finally, abscisic acid enhances MaMADS2 expression to promote ripening, but the transcription factor in turn auto inhibits ABA synthesis and signaling. Together, these results demonstrate a complex interaction of plant hormones and banana fruit ripening mediated by MaMADS2

The regulation of MADS-box gene expression during ripening of banana and their regulatory interaction with ethylene

Six MaMADS-box genes have been cloned from the banana fruit cultivar Grand Nain. The similarity of these genes to tomato LeRIN is low and neither MaMADS2 nor MaMADS1 complement the tomato rin mutation. Nevertheless, the expression patterns, specifically in fruit and the induction during ripening and in response to ethylene and 1-MCP, suggest that some of these genes may participate in ripening. MaMADS1, 2, and 3, are highly expressed in fruit only, while the others are expressed in fruit as well as in other organs. Moreover, the suites of MaMADS-box genes and their temporal expression differ in peel and pulp during ripening. In the pulp, the increase in MaMADS2, 3, 4, and 5 expression preceded an increase in ethylene production, but coincides with the CO2 peak. However, MaMADS1 expression in pulp coincided with ethylene production, but a massive increase in its expression occurred late during ripening, together with a second wave in the expression of MaMADS2, 3, and 4. In the peel, on the other hand, an increase in expression of MaMADS1, 3, and to a lesser degree also of MaMADS4 and 2 coincided with an increase in ethylene production. Except MaMADS3, which was induced by ethylene in pulp and peel, only MaMADS4, and 5 in pulp and MaMADS1 in peel were induced by ethylene. 1-MCP applied at the onset of the increase in ethylene production, increased the levels of MaMADS4 and MaMADS1 in pulp, while it decreased MaMADS1, 3, 4, and 5 in peel, suggesting that MaMADS4 and MaMADS1 are negatively controlled by ethylene at the onset of ethylene production only in pulp. Only MaMADS2 is neither induced by ethylene nor by 1-MCP, and it is expressed mainly in pulp. Our results suggest that two independent ripening programs are employed in pulp and peel which involve the activation of mainly MaMADS2, 4, and 5 and later on also MaMADS1 in pulp, and mainly MaMADS1, and 3 in peel. Hence, our results are consistent with MaMADS2, a SEP3 homologue, acting in the pulp upstream of the increase in ethylene production similarly to LeMADS-RIN

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

Different Preclimacteric Events in Apple Cultivars with Modified Ripening Physiology

“Anna” is an early season apple cultivar exhibiting a fast softening and juiciness loss during storage, in comparison to two mid-late season cultivars “Galaxy” and “GD.” The poor storage capacity of “Anna” was correlated with high lipid oxidation-related autoluminescence, high respiration and ethylene production rates, associated with high expression of MdACO1, 2, 4, 7, and MdACS1. All cultivars at harvest responded to exogenous ethylene by enhancing ethylene production, typical of system-II. The contribution of pre-climacteric events to the poor storage capacity of “Anna” was examined by comparing respiration and ethylene production rates, response to exogenous ethylene, expression of genes responsible for ethylene biosynthesis and response, and developmental regulators in the three cultivars throughout fruit development. In contrast to the “Galaxy” and “GD,” “Anna” showed higher ethylene production and respiration rates during fruit development, and exhibited auto-stimulatory (system II-like) effect in response to exogenous ethylene. The higher ethylene production rate in “Anna” was correlated with higher expression of ethylene biosynthesis genes, MdACS3a MdACO2, 4, and 7 during early fruit development. The expression of negative regulators of ripening (AP2/ERF) and ethylene response pathway, (MdETR1,2 and MdCTR1) was lower in “Anna” in comparison to the other two cultivars throughout development and ripening. Similar pattern of gene expression was found for SQUAMOSA promoter binding protein (SBP)-box genes, including MdCNR and for MdFUL. Taken together, this study provides new understanding on pre-climacteric events in “Anna” that might affect its ripening behavior and physiology following storage

Microperforated Compostable Packaging Extends Shelf Life of Ethylene-Treated Banana Fruit

Plastic packaging preserves the quality of ethylene-treated bananas by generating a beneficial modified atmosphere (MA). However, petroleum-based plastics cause environmental pollution, due to their slow decomposition. Biodegradable packaging may help resolve this controversy, provided it shows adequate preservation efficacy. In this study, we tested the compostable biodegradable polyester packaging of ethylene-treated bananas in comparison with commercially available petroleum-based plastic alternatives. When compostable packaging was used in a non-perforated form, it caused hypoxic fermentation, manifested as impaired ripening, off-flavor, and excessive softening. Micro-perforation prevented fermentation and allowed MA buildup. Furthermore, no water condensation was observed in the biodegradable packages, due to their somewhat higher water vapor permeability compared to conventional plastics. The fruit weight loss in biodegradable packaging was higher than in polypropylene, but 3–4-fold lower than in open containers. The control of senescence spotting was the major advantage of microperforated biodegradable packaging, combined with the preservation of acceptable fruit firmness and flavor, and low crown rot incidence. Optimal biodegradable packages extended the shelf life of bananas by four days compared with open containers, and by two days compared with the best commercial plastic package tested. Microperforated biodegradable packages combined the advantage of improved sustainability with superior fruit preservation