Ethylene (C2H4) is a gaseous hormone that is produced by plants during growth and development and in response to environmental stress (Abeles et al., 1992). At the seedling stage, ethylene causes reduced hypocotyl elongation, increased hypocotyl thickening, and an exaggerated apical hook. Collectively, these symptoms are known as the triple response (Knight et al., 1910). Exposure to ethylene at plant maturity can lead to flower, bud, or leaf abscission; flower senescence; leaf chlorosis (yellowing); or epinasty (downward curvature of the leaf or petiole) (Abeles et al., 1992). The quality of ornamental plants may be reduced by exposure to ethylene during production, shipping, and retailing (Jones and Edelman, 2013; Jones and Ling, 2012). Ethylene also controls fruit ripening in many species, and the ripening process is accompanied by a burst of ethylene production (Alexander and Grierson, 2002; Burg and Burg, 1965). Decreasing ethylene production and inhibiting ethylene perception increase the postharvest shelf life of ethylene-sensitive fruits, cut flowers, and potted plants.
Most evaluations of ethylene sensitivity have been performed on mature plants or on detached organs (i.e., fruits or cut flowers) (Archambault et al., 2006; Dole et al., 2009; Goto et al., 1999; Serek et al., 1994, 1995; van Doorn, 2001, 2002; Woltering, 1987; Woltering and van Doorn, 1988). A few studies have used the seedling triple response to evaluate differences in ethylene sensitivity between plants (Clark et al., 2001; Edelman et al., 2014; Lanahan et al., 1994). The seedling triple response screen has been extremely successful at identifying ethylene biosynthesis and signaling mutants in tomato (Solanum lycopersicum) and arabidopsis (Arabidopsis thaliana) (Alexander and Grierson, 2002; Binder et al., 2004). In dark-grown seedlings, hypocotyl length decreases at increasing concentrations of ethylene or ACC, the immediate precursor to ethylene. This component of the triple response provides an easy screen for evaluating ethylene sensitivity. Never ripe (nr) tomato mutants were determined to be ethylene-insensitive because seedlings did not exhibit any symptoms of the triple response when grown on media containing ACC (Lanahan et al., 1994). In contrast, ACC-treated wild-type ‘Pearson’ seedlings exhibited a significant reduction in hypocotyl length. When mature plants were infiltrated with ACC, epinasty was also observed in the wild-type plants but not the nr mutants.
Solanaceae is a relatively large and very diverse family that includes many plants that are highly sensitive to ethylene. The family contains ≈90 genera consisting of 3000 to 4000 species, which include edible, ornamental, and medicinal plants (Bombarely et al., 2011). Solanum melongena (eggplant), Capsicum annum (pepper), Solanum tuberosum (potato), Solanum lycopersicum (tomato), and Physalis ixocarpa (tomatillo) are important food crops, whereas Calibrachoa ×hybrida, Petunia ×hybrida, and the genus Nicotiana include popular ornamentals. Nicotiana, petunia, and tomato are also widely used as model experimental plants for studying development and plant–pathogen interactions (Gerats and Vandenbussche, 2005; Goodin et al., 2008; Wing et al., 1994). Although studies evaluating ethylene sensitivity have been published for multiple Solanaceous plants at the seedling or mature plant stages (Chaabouni et al., 2009; Edelman et al., 2014; Lanahan et al., 1994; van Doorn, 2001, 2002), a more comprehensive screen comparing sensitivity among genera, species, and cultivars within this family has not been conducted.
We have evaluated ethylene sensitivity in 41 different plant accessions. This study included two objectives: 1) to identify ethylene sensitivity differences (levels of sensitivity and symptoms) between accessions within the Solanaceae family; and 2) to identify ethylene sensitivity differences at different developmental stages (seedling, juvenile, and mature plants). This research will determine if the seedling hypocotyl elongation assay can be used to predict mature plant sensitivity within the family Solanaceae.
Abeles, F.B., Morgan, P.W. & Saltveit, M.E. Jr 1992 Ethylene in plant biology. 2nd Ed. Academic Press, San Diego, CA
Alexander, L. & Grierson, D. 2002 Ethylene biosynthesis and action in tomato: A model for climacteric fruit ripening J. Expt. Bot. 53 2039 2055
Archambault, D.J., Xiaomei, L., Foster, K.R. & Jack, T.R. 2006 A screening test for the determination of ethylene sensitivity Environ. Monit. Assess. 115 509 530
Binder, B.M., O’Malley, R.C., Wang, W., Moore, J.M., Parks, B.M., Spalding, E. & Bleecker, A.B. 2004 Arabidopsis seedling growth response and recovery to ethylene. A kinetic analysis Plant Physiol. 136 2913 2920
Chaabouni, S., Jones, B., Delalande, C., Wang, H., Li, Z., Malia, I., Frasse, P., Latche, A., Pech, J.-C. & Bouzayen, M. 2009 SI-IAA3, a tomato AUX/IAA at the crossroads of auxin and ethylene signaling involved in differential growth J. Expt. Bot. 60 1349 1362
Clark, D., Dervinis, C., Barrett, J. & Nell, T.A. 2001 Using a seedling hypocotyl elongation assay as a genetic screen for ethylene sensitivity of seedling geranium cultivars HortTechnology 11 297 302
Dias, T.J.M., Maluf, W.R., Faria, M.V., de Freitas, J.A., Gomes, L.A.A., Resende, J.T.V. & de Asevedo, S.M. 2003 Alobaça allele and genotípica backgrounds affect yield and fruit shelf life of tomato hybrids Scientia Agricola 60 269 275
Dole, J.M., Zenaida, V., Fanelli, F.L. & Fonteno, W. 2009 Postharvest evaluation of cut dahlia, linaria, lupine, poppy, rudbeckia, trachelium, and zinnia HortTechnology 19 593 600
Edelman, N.F., Kaufman, B.A. & Jones, M.L. 2014 Comparative evaluation of seedling hypocotyl elongation and mature plant assays for determining ethylene sensitivity in bedding plants. HortScience 49:472–480
English, J.P., Lycett, G.W., Roberts, J.A. & Jackson, M.B. 1995 Increased 1-aminocyclopropane-1-carboxylic acid oxidase activity in shoots of flooded tomato plants raises ethylene production to physiologically active levels Plant Physiol. 109 1435 1440
Goodin, M.M., Zaitlin, D., Naidue, R.A. & Lommel, S.A. 2008 Nicotiana benthamiana: Its history as a model for plant–pathogen interactions Mol. Plant Microbe Interact. 21 1015 1026
Jones, M.L. & Edelman, N. 2013 How to prevent ethylene-related losses during the postproduction care and handling of crops Greenhouse Mgt. 32 38 44
Kadner, R. & Druege, U. 2004 Role of ethylene action in ethylene production and post storage leaf senescence and survival of pelargonium cuttings Plant Growth Regulat. 43 187 196
Knight, L.I., Rose, R.C. & Crocker, W. 1910 Effects of various gases and vapors upon etiolated seedlings of the sweet pea Science 311 635 636
Lanahan, M.B., Yen, H.C., Giovannoni, J.J. & Klee, H.J. 1994 The never ripe mutation blocks ethylene perception in tomato Plant Cell 6 521 530
Macnish, A.J., Leonard, R.T. & Nell, T.A. 2011 Sensitivity of potted foliage plant genotypes to ethylene and 1-methylcyclopropene HortScience 46 1127 1131
Serek, M. & Sisler, E.C. 2001 Efficacy of inhibitors of ethylene binding in improvement of the postharvest characteristics of potted flowering plants Postharvest Biol. Technol. 23 161 166
Serek, M., Sisler, E.C. & Reid, M.S. 1994 1-methylcyclopropene, a novel gaseous inhibitor of ethylene action, improves the life of fruits, cut flowers and potted plants Acta Hort. 394 337 346
Serek, M., Sisler, E.C. & Reid, M.S. 1995 Effects of 1-MCP on the vase life and ethylene response of cut flowers Plant Growth Regulat. 16 93 97
Sisler, E.C., Dupille, E. & Serek, M. 1996 Effect of 1-methylcyclopropene and methylenecyclopropene on ethylene binding and ethylene action on cut carnations Plant Growth Regulat. 18 79 86
Wing, R.A., Zhang, H.Z. & Tanksley, S.D. 1994 Map based cloning in crop plants. Tomato as a model system: I. Genetic and physical mapping of jointless Mol. Gen. Genet. 242 681 688
Woltering, E.J. & van Doorn, W.G. 1988 Role of ethylene in senescence of petals- morphological and taxonomical relationships J. Expt. Bot. 39 1605 1616
Woodson, W.R. & Lawton, K.A. 1988 Ethylene-induced gene expression in carnation petals. Relationship to autocatalytic ethylene production and senescence Plant Physiol. 87 498 503